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![Petar Penkov](/assets/img/avatar_default.png)
Issue is that if the data crosses a page boundary inside a compound
page, this check will incorrectly trigger a WARN_ON.
To fix this, compute the order using the head of the compound page and
adjust the offset to be relative to that head.
Fixes: 72e809ed81
("iov_iter: sanity checks for copy to/from page
primitives")
Signed-off-by: Petar Penkov <ppenkov@google.com>
CC: Al Viro <viro@zeniv.linux.org.uk>
CC: Eric Dumazet <edumazet@google.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
1448 lines
34 KiB
C
1448 lines
34 KiB
C
#include <linux/export.h>
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#include <linux/bvec.h>
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#include <linux/uio.h>
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#include <linux/pagemap.h>
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#include <linux/slab.h>
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#include <linux/vmalloc.h>
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#include <linux/splice.h>
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#include <net/checksum.h>
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#define PIPE_PARANOIA /* for now */
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#define iterate_iovec(i, n, __v, __p, skip, STEP) { \
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size_t left; \
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size_t wanted = n; \
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__p = i->iov; \
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__v.iov_len = min(n, __p->iov_len - skip); \
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if (likely(__v.iov_len)) { \
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__v.iov_base = __p->iov_base + skip; \
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left = (STEP); \
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__v.iov_len -= left; \
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skip += __v.iov_len; \
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n -= __v.iov_len; \
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} else { \
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left = 0; \
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} \
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while (unlikely(!left && n)) { \
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__p++; \
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__v.iov_len = min(n, __p->iov_len); \
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if (unlikely(!__v.iov_len)) \
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continue; \
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__v.iov_base = __p->iov_base; \
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left = (STEP); \
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__v.iov_len -= left; \
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skip = __v.iov_len; \
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n -= __v.iov_len; \
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} \
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n = wanted - n; \
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}
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#define iterate_kvec(i, n, __v, __p, skip, STEP) { \
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size_t wanted = n; \
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__p = i->kvec; \
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__v.iov_len = min(n, __p->iov_len - skip); \
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if (likely(__v.iov_len)) { \
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__v.iov_base = __p->iov_base + skip; \
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(void)(STEP); \
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skip += __v.iov_len; \
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n -= __v.iov_len; \
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} \
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while (unlikely(n)) { \
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__p++; \
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__v.iov_len = min(n, __p->iov_len); \
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if (unlikely(!__v.iov_len)) \
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continue; \
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__v.iov_base = __p->iov_base; \
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(void)(STEP); \
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skip = __v.iov_len; \
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n -= __v.iov_len; \
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} \
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n = wanted; \
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}
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#define iterate_bvec(i, n, __v, __bi, skip, STEP) { \
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struct bvec_iter __start; \
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__start.bi_size = n; \
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__start.bi_bvec_done = skip; \
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__start.bi_idx = 0; \
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for_each_bvec(__v, i->bvec, __bi, __start) { \
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if (!__v.bv_len) \
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continue; \
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(void)(STEP); \
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} \
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}
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#define iterate_all_kinds(i, n, v, I, B, K) { \
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if (likely(n)) { \
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size_t skip = i->iov_offset; \
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if (unlikely(i->type & ITER_BVEC)) { \
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struct bio_vec v; \
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struct bvec_iter __bi; \
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iterate_bvec(i, n, v, __bi, skip, (B)) \
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} else if (unlikely(i->type & ITER_KVEC)) { \
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const struct kvec *kvec; \
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struct kvec v; \
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iterate_kvec(i, n, v, kvec, skip, (K)) \
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} else { \
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const struct iovec *iov; \
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struct iovec v; \
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iterate_iovec(i, n, v, iov, skip, (I)) \
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} \
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} \
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}
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#define iterate_and_advance(i, n, v, I, B, K) { \
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if (unlikely(i->count < n)) \
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n = i->count; \
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if (i->count) { \
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size_t skip = i->iov_offset; \
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if (unlikely(i->type & ITER_BVEC)) { \
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const struct bio_vec *bvec = i->bvec; \
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struct bio_vec v; \
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struct bvec_iter __bi; \
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iterate_bvec(i, n, v, __bi, skip, (B)) \
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i->bvec = __bvec_iter_bvec(i->bvec, __bi); \
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i->nr_segs -= i->bvec - bvec; \
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skip = __bi.bi_bvec_done; \
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} else if (unlikely(i->type & ITER_KVEC)) { \
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const struct kvec *kvec; \
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struct kvec v; \
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iterate_kvec(i, n, v, kvec, skip, (K)) \
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if (skip == kvec->iov_len) { \
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kvec++; \
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skip = 0; \
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} \
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i->nr_segs -= kvec - i->kvec; \
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i->kvec = kvec; \
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} else { \
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const struct iovec *iov; \
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struct iovec v; \
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iterate_iovec(i, n, v, iov, skip, (I)) \
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if (skip == iov->iov_len) { \
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iov++; \
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skip = 0; \
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} \
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i->nr_segs -= iov - i->iov; \
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i->iov = iov; \
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} \
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i->count -= n; \
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i->iov_offset = skip; \
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} \
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}
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static int copyout(void __user *to, const void *from, size_t n)
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{
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if (access_ok(VERIFY_WRITE, to, n)) {
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kasan_check_read(from, n);
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n = raw_copy_to_user(to, from, n);
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}
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return n;
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}
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static int copyin(void *to, const void __user *from, size_t n)
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{
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if (access_ok(VERIFY_READ, from, n)) {
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kasan_check_write(to, n);
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n = raw_copy_from_user(to, from, n);
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}
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return n;
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}
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static size_t copy_page_to_iter_iovec(struct page *page, size_t offset, size_t bytes,
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struct iov_iter *i)
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{
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size_t skip, copy, left, wanted;
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const struct iovec *iov;
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char __user *buf;
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void *kaddr, *from;
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if (unlikely(bytes > i->count))
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bytes = i->count;
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if (unlikely(!bytes))
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return 0;
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might_fault();
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wanted = bytes;
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iov = i->iov;
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skip = i->iov_offset;
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buf = iov->iov_base + skip;
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copy = min(bytes, iov->iov_len - skip);
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if (IS_ENABLED(CONFIG_HIGHMEM) && !fault_in_pages_writeable(buf, copy)) {
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kaddr = kmap_atomic(page);
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from = kaddr + offset;
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/* first chunk, usually the only one */
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left = copyout(buf, from, copy);
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copy -= left;
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skip += copy;
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from += copy;
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bytes -= copy;
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while (unlikely(!left && bytes)) {
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iov++;
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buf = iov->iov_base;
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copy = min(bytes, iov->iov_len);
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left = copyout(buf, from, copy);
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copy -= left;
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skip = copy;
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from += copy;
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bytes -= copy;
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}
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if (likely(!bytes)) {
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kunmap_atomic(kaddr);
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goto done;
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}
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offset = from - kaddr;
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buf += copy;
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kunmap_atomic(kaddr);
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copy = min(bytes, iov->iov_len - skip);
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}
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/* Too bad - revert to non-atomic kmap */
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kaddr = kmap(page);
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from = kaddr + offset;
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left = copyout(buf, from, copy);
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copy -= left;
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skip += copy;
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from += copy;
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bytes -= copy;
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while (unlikely(!left && bytes)) {
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iov++;
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buf = iov->iov_base;
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copy = min(bytes, iov->iov_len);
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left = copyout(buf, from, copy);
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copy -= left;
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skip = copy;
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from += copy;
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bytes -= copy;
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}
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kunmap(page);
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done:
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if (skip == iov->iov_len) {
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iov++;
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skip = 0;
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}
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i->count -= wanted - bytes;
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i->nr_segs -= iov - i->iov;
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i->iov = iov;
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i->iov_offset = skip;
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return wanted - bytes;
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}
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static size_t copy_page_from_iter_iovec(struct page *page, size_t offset, size_t bytes,
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struct iov_iter *i)
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{
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size_t skip, copy, left, wanted;
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const struct iovec *iov;
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char __user *buf;
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void *kaddr, *to;
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if (unlikely(bytes > i->count))
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bytes = i->count;
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if (unlikely(!bytes))
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return 0;
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might_fault();
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wanted = bytes;
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iov = i->iov;
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skip = i->iov_offset;
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buf = iov->iov_base + skip;
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copy = min(bytes, iov->iov_len - skip);
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if (IS_ENABLED(CONFIG_HIGHMEM) && !fault_in_pages_readable(buf, copy)) {
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kaddr = kmap_atomic(page);
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to = kaddr + offset;
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/* first chunk, usually the only one */
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left = copyin(to, buf, copy);
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copy -= left;
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skip += copy;
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to += copy;
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bytes -= copy;
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while (unlikely(!left && bytes)) {
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iov++;
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buf = iov->iov_base;
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copy = min(bytes, iov->iov_len);
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left = copyin(to, buf, copy);
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copy -= left;
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skip = copy;
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to += copy;
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bytes -= copy;
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}
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if (likely(!bytes)) {
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kunmap_atomic(kaddr);
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goto done;
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}
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offset = to - kaddr;
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buf += copy;
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kunmap_atomic(kaddr);
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copy = min(bytes, iov->iov_len - skip);
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}
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/* Too bad - revert to non-atomic kmap */
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kaddr = kmap(page);
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to = kaddr + offset;
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left = copyin(to, buf, copy);
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copy -= left;
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skip += copy;
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to += copy;
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bytes -= copy;
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while (unlikely(!left && bytes)) {
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iov++;
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buf = iov->iov_base;
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copy = min(bytes, iov->iov_len);
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left = copyin(to, buf, copy);
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copy -= left;
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skip = copy;
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to += copy;
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bytes -= copy;
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}
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kunmap(page);
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done:
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if (skip == iov->iov_len) {
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iov++;
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skip = 0;
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}
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i->count -= wanted - bytes;
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i->nr_segs -= iov - i->iov;
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i->iov = iov;
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i->iov_offset = skip;
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return wanted - bytes;
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}
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#ifdef PIPE_PARANOIA
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static bool sanity(const struct iov_iter *i)
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{
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struct pipe_inode_info *pipe = i->pipe;
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int idx = i->idx;
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int next = pipe->curbuf + pipe->nrbufs;
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if (i->iov_offset) {
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struct pipe_buffer *p;
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if (unlikely(!pipe->nrbufs))
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goto Bad; // pipe must be non-empty
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if (unlikely(idx != ((next - 1) & (pipe->buffers - 1))))
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goto Bad; // must be at the last buffer...
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p = &pipe->bufs[idx];
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if (unlikely(p->offset + p->len != i->iov_offset))
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goto Bad; // ... at the end of segment
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} else {
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if (idx != (next & (pipe->buffers - 1)))
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goto Bad; // must be right after the last buffer
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}
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return true;
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Bad:
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printk(KERN_ERR "idx = %d, offset = %zd\n", i->idx, i->iov_offset);
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printk(KERN_ERR "curbuf = %d, nrbufs = %d, buffers = %d\n",
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pipe->curbuf, pipe->nrbufs, pipe->buffers);
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for (idx = 0; idx < pipe->buffers; idx++)
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printk(KERN_ERR "[%p %p %d %d]\n",
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pipe->bufs[idx].ops,
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pipe->bufs[idx].page,
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pipe->bufs[idx].offset,
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pipe->bufs[idx].len);
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WARN_ON(1);
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return false;
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}
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#else
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#define sanity(i) true
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#endif
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static inline int next_idx(int idx, struct pipe_inode_info *pipe)
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{
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return (idx + 1) & (pipe->buffers - 1);
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}
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static size_t copy_page_to_iter_pipe(struct page *page, size_t offset, size_t bytes,
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struct iov_iter *i)
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{
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struct pipe_inode_info *pipe = i->pipe;
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struct pipe_buffer *buf;
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size_t off;
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int idx;
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if (unlikely(bytes > i->count))
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bytes = i->count;
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if (unlikely(!bytes))
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return 0;
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if (!sanity(i))
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return 0;
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off = i->iov_offset;
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idx = i->idx;
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buf = &pipe->bufs[idx];
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if (off) {
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if (offset == off && buf->page == page) {
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/* merge with the last one */
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buf->len += bytes;
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i->iov_offset += bytes;
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goto out;
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}
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idx = next_idx(idx, pipe);
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buf = &pipe->bufs[idx];
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}
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if (idx == pipe->curbuf && pipe->nrbufs)
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return 0;
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pipe->nrbufs++;
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buf->ops = &page_cache_pipe_buf_ops;
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get_page(buf->page = page);
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buf->offset = offset;
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buf->len = bytes;
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i->iov_offset = offset + bytes;
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i->idx = idx;
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out:
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i->count -= bytes;
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return bytes;
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}
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/*
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* Fault in one or more iovecs of the given iov_iter, to a maximum length of
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* bytes. For each iovec, fault in each page that constitutes the iovec.
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*
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* Return 0 on success, or non-zero if the memory could not be accessed (i.e.
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* because it is an invalid address).
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*/
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int iov_iter_fault_in_readable(struct iov_iter *i, size_t bytes)
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{
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size_t skip = i->iov_offset;
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const struct iovec *iov;
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int err;
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struct iovec v;
|
|
|
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if (!(i->type & (ITER_BVEC|ITER_KVEC))) {
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iterate_iovec(i, bytes, v, iov, skip, ({
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err = fault_in_pages_readable(v.iov_base, v.iov_len);
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|
if (unlikely(err))
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return err;
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0;}))
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}
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return 0;
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}
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EXPORT_SYMBOL(iov_iter_fault_in_readable);
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|
|
|
void iov_iter_init(struct iov_iter *i, int direction,
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const struct iovec *iov, unsigned long nr_segs,
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size_t count)
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{
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/* It will get better. Eventually... */
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if (uaccess_kernel()) {
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direction |= ITER_KVEC;
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i->type = direction;
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i->kvec = (struct kvec *)iov;
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} else {
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i->type = direction;
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i->iov = iov;
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}
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i->nr_segs = nr_segs;
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i->iov_offset = 0;
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i->count = count;
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}
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EXPORT_SYMBOL(iov_iter_init);
|
|
|
|
static void memcpy_from_page(char *to, struct page *page, size_t offset, size_t len)
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|
{
|
|
char *from = kmap_atomic(page);
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memcpy(to, from + offset, len);
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kunmap_atomic(from);
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|
}
|
|
|
|
static void memcpy_to_page(struct page *page, size_t offset, const char *from, size_t len)
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{
|
|
char *to = kmap_atomic(page);
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memcpy(to + offset, from, len);
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kunmap_atomic(to);
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|
}
|
|
|
|
static void memzero_page(struct page *page, size_t offset, size_t len)
|
|
{
|
|
char *addr = kmap_atomic(page);
|
|
memset(addr + offset, 0, len);
|
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kunmap_atomic(addr);
|
|
}
|
|
|
|
static inline bool allocated(struct pipe_buffer *buf)
|
|
{
|
|
return buf->ops == &default_pipe_buf_ops;
|
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}
|
|
|
|
static inline void data_start(const struct iov_iter *i, int *idxp, size_t *offp)
|
|
{
|
|
size_t off = i->iov_offset;
|
|
int idx = i->idx;
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if (off && (!allocated(&i->pipe->bufs[idx]) || off == PAGE_SIZE)) {
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idx = next_idx(idx, i->pipe);
|
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off = 0;
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}
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*idxp = idx;
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*offp = off;
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}
|
|
|
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static size_t push_pipe(struct iov_iter *i, size_t size,
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int *idxp, size_t *offp)
|
|
{
|
|
struct pipe_inode_info *pipe = i->pipe;
|
|
size_t off;
|
|
int idx;
|
|
ssize_t left;
|
|
|
|
if (unlikely(size > i->count))
|
|
size = i->count;
|
|
if (unlikely(!size))
|
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return 0;
|
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|
|
left = size;
|
|
data_start(i, &idx, &off);
|
|
*idxp = idx;
|
|
*offp = off;
|
|
if (off) {
|
|
left -= PAGE_SIZE - off;
|
|
if (left <= 0) {
|
|
pipe->bufs[idx].len += size;
|
|
return size;
|
|
}
|
|
pipe->bufs[idx].len = PAGE_SIZE;
|
|
idx = next_idx(idx, pipe);
|
|
}
|
|
while (idx != pipe->curbuf || !pipe->nrbufs) {
|
|
struct page *page = alloc_page(GFP_USER);
|
|
if (!page)
|
|
break;
|
|
pipe->nrbufs++;
|
|
pipe->bufs[idx].ops = &default_pipe_buf_ops;
|
|
pipe->bufs[idx].page = page;
|
|
pipe->bufs[idx].offset = 0;
|
|
if (left <= PAGE_SIZE) {
|
|
pipe->bufs[idx].len = left;
|
|
return size;
|
|
}
|
|
pipe->bufs[idx].len = PAGE_SIZE;
|
|
left -= PAGE_SIZE;
|
|
idx = next_idx(idx, pipe);
|
|
}
|
|
return size - left;
|
|
}
|
|
|
|
static size_t copy_pipe_to_iter(const void *addr, size_t bytes,
|
|
struct iov_iter *i)
|
|
{
|
|
struct pipe_inode_info *pipe = i->pipe;
|
|
size_t n, off;
|
|
int idx;
|
|
|
|
if (!sanity(i))
|
|
return 0;
|
|
|
|
bytes = n = push_pipe(i, bytes, &idx, &off);
|
|
if (unlikely(!n))
|
|
return 0;
|
|
for ( ; n; idx = next_idx(idx, pipe), off = 0) {
|
|
size_t chunk = min_t(size_t, n, PAGE_SIZE - off);
|
|
memcpy_to_page(pipe->bufs[idx].page, off, addr, chunk);
|
|
i->idx = idx;
|
|
i->iov_offset = off + chunk;
|
|
n -= chunk;
|
|
addr += chunk;
|
|
}
|
|
i->count -= bytes;
|
|
return bytes;
|
|
}
|
|
|
|
size_t _copy_to_iter(const void *addr, size_t bytes, struct iov_iter *i)
|
|
{
|
|
const char *from = addr;
|
|
if (unlikely(i->type & ITER_PIPE))
|
|
return copy_pipe_to_iter(addr, bytes, i);
|
|
if (iter_is_iovec(i))
|
|
might_fault();
|
|
iterate_and_advance(i, bytes, v,
|
|
copyout(v.iov_base, (from += v.iov_len) - v.iov_len, v.iov_len),
|
|
memcpy_to_page(v.bv_page, v.bv_offset,
|
|
(from += v.bv_len) - v.bv_len, v.bv_len),
|
|
memcpy(v.iov_base, (from += v.iov_len) - v.iov_len, v.iov_len)
|
|
)
|
|
|
|
return bytes;
|
|
}
|
|
EXPORT_SYMBOL(_copy_to_iter);
|
|
|
|
size_t _copy_from_iter(void *addr, size_t bytes, struct iov_iter *i)
|
|
{
|
|
char *to = addr;
|
|
if (unlikely(i->type & ITER_PIPE)) {
|
|
WARN_ON(1);
|
|
return 0;
|
|
}
|
|
if (iter_is_iovec(i))
|
|
might_fault();
|
|
iterate_and_advance(i, bytes, v,
|
|
copyin((to += v.iov_len) - v.iov_len, v.iov_base, v.iov_len),
|
|
memcpy_from_page((to += v.bv_len) - v.bv_len, v.bv_page,
|
|
v.bv_offset, v.bv_len),
|
|
memcpy((to += v.iov_len) - v.iov_len, v.iov_base, v.iov_len)
|
|
)
|
|
|
|
return bytes;
|
|
}
|
|
EXPORT_SYMBOL(_copy_from_iter);
|
|
|
|
bool _copy_from_iter_full(void *addr, size_t bytes, struct iov_iter *i)
|
|
{
|
|
char *to = addr;
|
|
if (unlikely(i->type & ITER_PIPE)) {
|
|
WARN_ON(1);
|
|
return false;
|
|
}
|
|
if (unlikely(i->count < bytes))
|
|
return false;
|
|
|
|
if (iter_is_iovec(i))
|
|
might_fault();
|
|
iterate_all_kinds(i, bytes, v, ({
|
|
if (copyin((to += v.iov_len) - v.iov_len,
|
|
v.iov_base, v.iov_len))
|
|
return false;
|
|
0;}),
|
|
memcpy_from_page((to += v.bv_len) - v.bv_len, v.bv_page,
|
|
v.bv_offset, v.bv_len),
|
|
memcpy((to += v.iov_len) - v.iov_len, v.iov_base, v.iov_len)
|
|
)
|
|
|
|
iov_iter_advance(i, bytes);
|
|
return true;
|
|
}
|
|
EXPORT_SYMBOL(_copy_from_iter_full);
|
|
|
|
size_t _copy_from_iter_nocache(void *addr, size_t bytes, struct iov_iter *i)
|
|
{
|
|
char *to = addr;
|
|
if (unlikely(i->type & ITER_PIPE)) {
|
|
WARN_ON(1);
|
|
return 0;
|
|
}
|
|
iterate_and_advance(i, bytes, v,
|
|
__copy_from_user_inatomic_nocache((to += v.iov_len) - v.iov_len,
|
|
v.iov_base, v.iov_len),
|
|
memcpy_from_page((to += v.bv_len) - v.bv_len, v.bv_page,
|
|
v.bv_offset, v.bv_len),
|
|
memcpy((to += v.iov_len) - v.iov_len, v.iov_base, v.iov_len)
|
|
)
|
|
|
|
return bytes;
|
|
}
|
|
EXPORT_SYMBOL(_copy_from_iter_nocache);
|
|
|
|
#ifdef CONFIG_ARCH_HAS_UACCESS_FLUSHCACHE
|
|
size_t _copy_from_iter_flushcache(void *addr, size_t bytes, struct iov_iter *i)
|
|
{
|
|
char *to = addr;
|
|
if (unlikely(i->type & ITER_PIPE)) {
|
|
WARN_ON(1);
|
|
return 0;
|
|
}
|
|
iterate_and_advance(i, bytes, v,
|
|
__copy_from_user_flushcache((to += v.iov_len) - v.iov_len,
|
|
v.iov_base, v.iov_len),
|
|
memcpy_page_flushcache((to += v.bv_len) - v.bv_len, v.bv_page,
|
|
v.bv_offset, v.bv_len),
|
|
memcpy_flushcache((to += v.iov_len) - v.iov_len, v.iov_base,
|
|
v.iov_len)
|
|
)
|
|
|
|
return bytes;
|
|
}
|
|
EXPORT_SYMBOL_GPL(_copy_from_iter_flushcache);
|
|
#endif
|
|
|
|
bool _copy_from_iter_full_nocache(void *addr, size_t bytes, struct iov_iter *i)
|
|
{
|
|
char *to = addr;
|
|
if (unlikely(i->type & ITER_PIPE)) {
|
|
WARN_ON(1);
|
|
return false;
|
|
}
|
|
if (unlikely(i->count < bytes))
|
|
return false;
|
|
iterate_all_kinds(i, bytes, v, ({
|
|
if (__copy_from_user_inatomic_nocache((to += v.iov_len) - v.iov_len,
|
|
v.iov_base, v.iov_len))
|
|
return false;
|
|
0;}),
|
|
memcpy_from_page((to += v.bv_len) - v.bv_len, v.bv_page,
|
|
v.bv_offset, v.bv_len),
|
|
memcpy((to += v.iov_len) - v.iov_len, v.iov_base, v.iov_len)
|
|
)
|
|
|
|
iov_iter_advance(i, bytes);
|
|
return true;
|
|
}
|
|
EXPORT_SYMBOL(_copy_from_iter_full_nocache);
|
|
|
|
static inline bool page_copy_sane(struct page *page, size_t offset, size_t n)
|
|
{
|
|
struct page *head = compound_head(page);
|
|
size_t v = n + offset + page_address(page) - page_address(head);
|
|
|
|
if (likely(n <= v && v <= (PAGE_SIZE << compound_order(head))))
|
|
return true;
|
|
WARN_ON(1);
|
|
return false;
|
|
}
|
|
|
|
size_t copy_page_to_iter(struct page *page, size_t offset, size_t bytes,
|
|
struct iov_iter *i)
|
|
{
|
|
if (unlikely(!page_copy_sane(page, offset, bytes)))
|
|
return 0;
|
|
if (i->type & (ITER_BVEC|ITER_KVEC)) {
|
|
void *kaddr = kmap_atomic(page);
|
|
size_t wanted = copy_to_iter(kaddr + offset, bytes, i);
|
|
kunmap_atomic(kaddr);
|
|
return wanted;
|
|
} else if (likely(!(i->type & ITER_PIPE)))
|
|
return copy_page_to_iter_iovec(page, offset, bytes, i);
|
|
else
|
|
return copy_page_to_iter_pipe(page, offset, bytes, i);
|
|
}
|
|
EXPORT_SYMBOL(copy_page_to_iter);
|
|
|
|
size_t copy_page_from_iter(struct page *page, size_t offset, size_t bytes,
|
|
struct iov_iter *i)
|
|
{
|
|
if (unlikely(!page_copy_sane(page, offset, bytes)))
|
|
return 0;
|
|
if (unlikely(i->type & ITER_PIPE)) {
|
|
WARN_ON(1);
|
|
return 0;
|
|
}
|
|
if (i->type & (ITER_BVEC|ITER_KVEC)) {
|
|
void *kaddr = kmap_atomic(page);
|
|
size_t wanted = _copy_from_iter(kaddr + offset, bytes, i);
|
|
kunmap_atomic(kaddr);
|
|
return wanted;
|
|
} else
|
|
return copy_page_from_iter_iovec(page, offset, bytes, i);
|
|
}
|
|
EXPORT_SYMBOL(copy_page_from_iter);
|
|
|
|
static size_t pipe_zero(size_t bytes, struct iov_iter *i)
|
|
{
|
|
struct pipe_inode_info *pipe = i->pipe;
|
|
size_t n, off;
|
|
int idx;
|
|
|
|
if (!sanity(i))
|
|
return 0;
|
|
|
|
bytes = n = push_pipe(i, bytes, &idx, &off);
|
|
if (unlikely(!n))
|
|
return 0;
|
|
|
|
for ( ; n; idx = next_idx(idx, pipe), off = 0) {
|
|
size_t chunk = min_t(size_t, n, PAGE_SIZE - off);
|
|
memzero_page(pipe->bufs[idx].page, off, chunk);
|
|
i->idx = idx;
|
|
i->iov_offset = off + chunk;
|
|
n -= chunk;
|
|
}
|
|
i->count -= bytes;
|
|
return bytes;
|
|
}
|
|
|
|
size_t iov_iter_zero(size_t bytes, struct iov_iter *i)
|
|
{
|
|
if (unlikely(i->type & ITER_PIPE))
|
|
return pipe_zero(bytes, i);
|
|
iterate_and_advance(i, bytes, v,
|
|
clear_user(v.iov_base, v.iov_len),
|
|
memzero_page(v.bv_page, v.bv_offset, v.bv_len),
|
|
memset(v.iov_base, 0, v.iov_len)
|
|
)
|
|
|
|
return bytes;
|
|
}
|
|
EXPORT_SYMBOL(iov_iter_zero);
|
|
|
|
size_t iov_iter_copy_from_user_atomic(struct page *page,
|
|
struct iov_iter *i, unsigned long offset, size_t bytes)
|
|
{
|
|
char *kaddr = kmap_atomic(page), *p = kaddr + offset;
|
|
if (unlikely(!page_copy_sane(page, offset, bytes))) {
|
|
kunmap_atomic(kaddr);
|
|
return 0;
|
|
}
|
|
if (unlikely(i->type & ITER_PIPE)) {
|
|
kunmap_atomic(kaddr);
|
|
WARN_ON(1);
|
|
return 0;
|
|
}
|
|
iterate_all_kinds(i, bytes, v,
|
|
copyin((p += v.iov_len) - v.iov_len, v.iov_base, v.iov_len),
|
|
memcpy_from_page((p += v.bv_len) - v.bv_len, v.bv_page,
|
|
v.bv_offset, v.bv_len),
|
|
memcpy((p += v.iov_len) - v.iov_len, v.iov_base, v.iov_len)
|
|
)
|
|
kunmap_atomic(kaddr);
|
|
return bytes;
|
|
}
|
|
EXPORT_SYMBOL(iov_iter_copy_from_user_atomic);
|
|
|
|
static inline void pipe_truncate(struct iov_iter *i)
|
|
{
|
|
struct pipe_inode_info *pipe = i->pipe;
|
|
if (pipe->nrbufs) {
|
|
size_t off = i->iov_offset;
|
|
int idx = i->idx;
|
|
int nrbufs = (idx - pipe->curbuf) & (pipe->buffers - 1);
|
|
if (off) {
|
|
pipe->bufs[idx].len = off - pipe->bufs[idx].offset;
|
|
idx = next_idx(idx, pipe);
|
|
nrbufs++;
|
|
}
|
|
while (pipe->nrbufs > nrbufs) {
|
|
pipe_buf_release(pipe, &pipe->bufs[idx]);
|
|
idx = next_idx(idx, pipe);
|
|
pipe->nrbufs--;
|
|
}
|
|
}
|
|
}
|
|
|
|
static void pipe_advance(struct iov_iter *i, size_t size)
|
|
{
|
|
struct pipe_inode_info *pipe = i->pipe;
|
|
if (unlikely(i->count < size))
|
|
size = i->count;
|
|
if (size) {
|
|
struct pipe_buffer *buf;
|
|
size_t off = i->iov_offset, left = size;
|
|
int idx = i->idx;
|
|
if (off) /* make it relative to the beginning of buffer */
|
|
left += off - pipe->bufs[idx].offset;
|
|
while (1) {
|
|
buf = &pipe->bufs[idx];
|
|
if (left <= buf->len)
|
|
break;
|
|
left -= buf->len;
|
|
idx = next_idx(idx, pipe);
|
|
}
|
|
i->idx = idx;
|
|
i->iov_offset = buf->offset + left;
|
|
}
|
|
i->count -= size;
|
|
/* ... and discard everything past that point */
|
|
pipe_truncate(i);
|
|
}
|
|
|
|
void iov_iter_advance(struct iov_iter *i, size_t size)
|
|
{
|
|
if (unlikely(i->type & ITER_PIPE)) {
|
|
pipe_advance(i, size);
|
|
return;
|
|
}
|
|
iterate_and_advance(i, size, v, 0, 0, 0)
|
|
}
|
|
EXPORT_SYMBOL(iov_iter_advance);
|
|
|
|
void iov_iter_revert(struct iov_iter *i, size_t unroll)
|
|
{
|
|
if (!unroll)
|
|
return;
|
|
if (WARN_ON(unroll > MAX_RW_COUNT))
|
|
return;
|
|
i->count += unroll;
|
|
if (unlikely(i->type & ITER_PIPE)) {
|
|
struct pipe_inode_info *pipe = i->pipe;
|
|
int idx = i->idx;
|
|
size_t off = i->iov_offset;
|
|
while (1) {
|
|
size_t n = off - pipe->bufs[idx].offset;
|
|
if (unroll < n) {
|
|
off -= unroll;
|
|
break;
|
|
}
|
|
unroll -= n;
|
|
if (!unroll && idx == i->start_idx) {
|
|
off = 0;
|
|
break;
|
|
}
|
|
if (!idx--)
|
|
idx = pipe->buffers - 1;
|
|
off = pipe->bufs[idx].offset + pipe->bufs[idx].len;
|
|
}
|
|
i->iov_offset = off;
|
|
i->idx = idx;
|
|
pipe_truncate(i);
|
|
return;
|
|
}
|
|
if (unroll <= i->iov_offset) {
|
|
i->iov_offset -= unroll;
|
|
return;
|
|
}
|
|
unroll -= i->iov_offset;
|
|
if (i->type & ITER_BVEC) {
|
|
const struct bio_vec *bvec = i->bvec;
|
|
while (1) {
|
|
size_t n = (--bvec)->bv_len;
|
|
i->nr_segs++;
|
|
if (unroll <= n) {
|
|
i->bvec = bvec;
|
|
i->iov_offset = n - unroll;
|
|
return;
|
|
}
|
|
unroll -= n;
|
|
}
|
|
} else { /* same logics for iovec and kvec */
|
|
const struct iovec *iov = i->iov;
|
|
while (1) {
|
|
size_t n = (--iov)->iov_len;
|
|
i->nr_segs++;
|
|
if (unroll <= n) {
|
|
i->iov = iov;
|
|
i->iov_offset = n - unroll;
|
|
return;
|
|
}
|
|
unroll -= n;
|
|
}
|
|
}
|
|
}
|
|
EXPORT_SYMBOL(iov_iter_revert);
|
|
|
|
/*
|
|
* Return the count of just the current iov_iter segment.
|
|
*/
|
|
size_t iov_iter_single_seg_count(const struct iov_iter *i)
|
|
{
|
|
if (unlikely(i->type & ITER_PIPE))
|
|
return i->count; // it is a silly place, anyway
|
|
if (i->nr_segs == 1)
|
|
return i->count;
|
|
else if (i->type & ITER_BVEC)
|
|
return min(i->count, i->bvec->bv_len - i->iov_offset);
|
|
else
|
|
return min(i->count, i->iov->iov_len - i->iov_offset);
|
|
}
|
|
EXPORT_SYMBOL(iov_iter_single_seg_count);
|
|
|
|
void iov_iter_kvec(struct iov_iter *i, int direction,
|
|
const struct kvec *kvec, unsigned long nr_segs,
|
|
size_t count)
|
|
{
|
|
BUG_ON(!(direction & ITER_KVEC));
|
|
i->type = direction;
|
|
i->kvec = kvec;
|
|
i->nr_segs = nr_segs;
|
|
i->iov_offset = 0;
|
|
i->count = count;
|
|
}
|
|
EXPORT_SYMBOL(iov_iter_kvec);
|
|
|
|
void iov_iter_bvec(struct iov_iter *i, int direction,
|
|
const struct bio_vec *bvec, unsigned long nr_segs,
|
|
size_t count)
|
|
{
|
|
BUG_ON(!(direction & ITER_BVEC));
|
|
i->type = direction;
|
|
i->bvec = bvec;
|
|
i->nr_segs = nr_segs;
|
|
i->iov_offset = 0;
|
|
i->count = count;
|
|
}
|
|
EXPORT_SYMBOL(iov_iter_bvec);
|
|
|
|
void iov_iter_pipe(struct iov_iter *i, int direction,
|
|
struct pipe_inode_info *pipe,
|
|
size_t count)
|
|
{
|
|
BUG_ON(direction != ITER_PIPE);
|
|
WARN_ON(pipe->nrbufs == pipe->buffers);
|
|
i->type = direction;
|
|
i->pipe = pipe;
|
|
i->idx = (pipe->curbuf + pipe->nrbufs) & (pipe->buffers - 1);
|
|
i->iov_offset = 0;
|
|
i->count = count;
|
|
i->start_idx = i->idx;
|
|
}
|
|
EXPORT_SYMBOL(iov_iter_pipe);
|
|
|
|
unsigned long iov_iter_alignment(const struct iov_iter *i)
|
|
{
|
|
unsigned long res = 0;
|
|
size_t size = i->count;
|
|
|
|
if (unlikely(i->type & ITER_PIPE)) {
|
|
if (size && i->iov_offset && allocated(&i->pipe->bufs[i->idx]))
|
|
return size | i->iov_offset;
|
|
return size;
|
|
}
|
|
iterate_all_kinds(i, size, v,
|
|
(res |= (unsigned long)v.iov_base | v.iov_len, 0),
|
|
res |= v.bv_offset | v.bv_len,
|
|
res |= (unsigned long)v.iov_base | v.iov_len
|
|
)
|
|
return res;
|
|
}
|
|
EXPORT_SYMBOL(iov_iter_alignment);
|
|
|
|
unsigned long iov_iter_gap_alignment(const struct iov_iter *i)
|
|
{
|
|
unsigned long res = 0;
|
|
size_t size = i->count;
|
|
|
|
if (unlikely(i->type & ITER_PIPE)) {
|
|
WARN_ON(1);
|
|
return ~0U;
|
|
}
|
|
|
|
iterate_all_kinds(i, size, v,
|
|
(res |= (!res ? 0 : (unsigned long)v.iov_base) |
|
|
(size != v.iov_len ? size : 0), 0),
|
|
(res |= (!res ? 0 : (unsigned long)v.bv_offset) |
|
|
(size != v.bv_len ? size : 0)),
|
|
(res |= (!res ? 0 : (unsigned long)v.iov_base) |
|
|
(size != v.iov_len ? size : 0))
|
|
);
|
|
return res;
|
|
}
|
|
EXPORT_SYMBOL(iov_iter_gap_alignment);
|
|
|
|
static inline size_t __pipe_get_pages(struct iov_iter *i,
|
|
size_t maxsize,
|
|
struct page **pages,
|
|
int idx,
|
|
size_t *start)
|
|
{
|
|
struct pipe_inode_info *pipe = i->pipe;
|
|
ssize_t n = push_pipe(i, maxsize, &idx, start);
|
|
if (!n)
|
|
return -EFAULT;
|
|
|
|
maxsize = n;
|
|
n += *start;
|
|
while (n > 0) {
|
|
get_page(*pages++ = pipe->bufs[idx].page);
|
|
idx = next_idx(idx, pipe);
|
|
n -= PAGE_SIZE;
|
|
}
|
|
|
|
return maxsize;
|
|
}
|
|
|
|
static ssize_t pipe_get_pages(struct iov_iter *i,
|
|
struct page **pages, size_t maxsize, unsigned maxpages,
|
|
size_t *start)
|
|
{
|
|
unsigned npages;
|
|
size_t capacity;
|
|
int idx;
|
|
|
|
if (!maxsize)
|
|
return 0;
|
|
|
|
if (!sanity(i))
|
|
return -EFAULT;
|
|
|
|
data_start(i, &idx, start);
|
|
/* some of this one + all after this one */
|
|
npages = ((i->pipe->curbuf - idx - 1) & (i->pipe->buffers - 1)) + 1;
|
|
capacity = min(npages,maxpages) * PAGE_SIZE - *start;
|
|
|
|
return __pipe_get_pages(i, min(maxsize, capacity), pages, idx, start);
|
|
}
|
|
|
|
ssize_t iov_iter_get_pages(struct iov_iter *i,
|
|
struct page **pages, size_t maxsize, unsigned maxpages,
|
|
size_t *start)
|
|
{
|
|
if (maxsize > i->count)
|
|
maxsize = i->count;
|
|
|
|
if (unlikely(i->type & ITER_PIPE))
|
|
return pipe_get_pages(i, pages, maxsize, maxpages, start);
|
|
iterate_all_kinds(i, maxsize, v, ({
|
|
unsigned long addr = (unsigned long)v.iov_base;
|
|
size_t len = v.iov_len + (*start = addr & (PAGE_SIZE - 1));
|
|
int n;
|
|
int res;
|
|
|
|
if (len > maxpages * PAGE_SIZE)
|
|
len = maxpages * PAGE_SIZE;
|
|
addr &= ~(PAGE_SIZE - 1);
|
|
n = DIV_ROUND_UP(len, PAGE_SIZE);
|
|
res = get_user_pages_fast(addr, n, (i->type & WRITE) != WRITE, pages);
|
|
if (unlikely(res < 0))
|
|
return res;
|
|
return (res == n ? len : res * PAGE_SIZE) - *start;
|
|
0;}),({
|
|
/* can't be more than PAGE_SIZE */
|
|
*start = v.bv_offset;
|
|
get_page(*pages = v.bv_page);
|
|
return v.bv_len;
|
|
}),({
|
|
return -EFAULT;
|
|
})
|
|
)
|
|
return 0;
|
|
}
|
|
EXPORT_SYMBOL(iov_iter_get_pages);
|
|
|
|
static struct page **get_pages_array(size_t n)
|
|
{
|
|
return kvmalloc_array(n, sizeof(struct page *), GFP_KERNEL);
|
|
}
|
|
|
|
static ssize_t pipe_get_pages_alloc(struct iov_iter *i,
|
|
struct page ***pages, size_t maxsize,
|
|
size_t *start)
|
|
{
|
|
struct page **p;
|
|
size_t n;
|
|
int idx;
|
|
int npages;
|
|
|
|
if (!maxsize)
|
|
return 0;
|
|
|
|
if (!sanity(i))
|
|
return -EFAULT;
|
|
|
|
data_start(i, &idx, start);
|
|
/* some of this one + all after this one */
|
|
npages = ((i->pipe->curbuf - idx - 1) & (i->pipe->buffers - 1)) + 1;
|
|
n = npages * PAGE_SIZE - *start;
|
|
if (maxsize > n)
|
|
maxsize = n;
|
|
else
|
|
npages = DIV_ROUND_UP(maxsize + *start, PAGE_SIZE);
|
|
p = get_pages_array(npages);
|
|
if (!p)
|
|
return -ENOMEM;
|
|
n = __pipe_get_pages(i, maxsize, p, idx, start);
|
|
if (n > 0)
|
|
*pages = p;
|
|
else
|
|
kvfree(p);
|
|
return n;
|
|
}
|
|
|
|
ssize_t iov_iter_get_pages_alloc(struct iov_iter *i,
|
|
struct page ***pages, size_t maxsize,
|
|
size_t *start)
|
|
{
|
|
struct page **p;
|
|
|
|
if (maxsize > i->count)
|
|
maxsize = i->count;
|
|
|
|
if (unlikely(i->type & ITER_PIPE))
|
|
return pipe_get_pages_alloc(i, pages, maxsize, start);
|
|
iterate_all_kinds(i, maxsize, v, ({
|
|
unsigned long addr = (unsigned long)v.iov_base;
|
|
size_t len = v.iov_len + (*start = addr & (PAGE_SIZE - 1));
|
|
int n;
|
|
int res;
|
|
|
|
addr &= ~(PAGE_SIZE - 1);
|
|
n = DIV_ROUND_UP(len, PAGE_SIZE);
|
|
p = get_pages_array(n);
|
|
if (!p)
|
|
return -ENOMEM;
|
|
res = get_user_pages_fast(addr, n, (i->type & WRITE) != WRITE, p);
|
|
if (unlikely(res < 0)) {
|
|
kvfree(p);
|
|
return res;
|
|
}
|
|
*pages = p;
|
|
return (res == n ? len : res * PAGE_SIZE) - *start;
|
|
0;}),({
|
|
/* can't be more than PAGE_SIZE */
|
|
*start = v.bv_offset;
|
|
*pages = p = get_pages_array(1);
|
|
if (!p)
|
|
return -ENOMEM;
|
|
get_page(*p = v.bv_page);
|
|
return v.bv_len;
|
|
}),({
|
|
return -EFAULT;
|
|
})
|
|
)
|
|
return 0;
|
|
}
|
|
EXPORT_SYMBOL(iov_iter_get_pages_alloc);
|
|
|
|
size_t csum_and_copy_from_iter(void *addr, size_t bytes, __wsum *csum,
|
|
struct iov_iter *i)
|
|
{
|
|
char *to = addr;
|
|
__wsum sum, next;
|
|
size_t off = 0;
|
|
sum = *csum;
|
|
if (unlikely(i->type & ITER_PIPE)) {
|
|
WARN_ON(1);
|
|
return 0;
|
|
}
|
|
iterate_and_advance(i, bytes, v, ({
|
|
int err = 0;
|
|
next = csum_and_copy_from_user(v.iov_base,
|
|
(to += v.iov_len) - v.iov_len,
|
|
v.iov_len, 0, &err);
|
|
if (!err) {
|
|
sum = csum_block_add(sum, next, off);
|
|
off += v.iov_len;
|
|
}
|
|
err ? v.iov_len : 0;
|
|
}), ({
|
|
char *p = kmap_atomic(v.bv_page);
|
|
next = csum_partial_copy_nocheck(p + v.bv_offset,
|
|
(to += v.bv_len) - v.bv_len,
|
|
v.bv_len, 0);
|
|
kunmap_atomic(p);
|
|
sum = csum_block_add(sum, next, off);
|
|
off += v.bv_len;
|
|
}),({
|
|
next = csum_partial_copy_nocheck(v.iov_base,
|
|
(to += v.iov_len) - v.iov_len,
|
|
v.iov_len, 0);
|
|
sum = csum_block_add(sum, next, off);
|
|
off += v.iov_len;
|
|
})
|
|
)
|
|
*csum = sum;
|
|
return bytes;
|
|
}
|
|
EXPORT_SYMBOL(csum_and_copy_from_iter);
|
|
|
|
bool csum_and_copy_from_iter_full(void *addr, size_t bytes, __wsum *csum,
|
|
struct iov_iter *i)
|
|
{
|
|
char *to = addr;
|
|
__wsum sum, next;
|
|
size_t off = 0;
|
|
sum = *csum;
|
|
if (unlikely(i->type & ITER_PIPE)) {
|
|
WARN_ON(1);
|
|
return false;
|
|
}
|
|
if (unlikely(i->count < bytes))
|
|
return false;
|
|
iterate_all_kinds(i, bytes, v, ({
|
|
int err = 0;
|
|
next = csum_and_copy_from_user(v.iov_base,
|
|
(to += v.iov_len) - v.iov_len,
|
|
v.iov_len, 0, &err);
|
|
if (err)
|
|
return false;
|
|
sum = csum_block_add(sum, next, off);
|
|
off += v.iov_len;
|
|
0;
|
|
}), ({
|
|
char *p = kmap_atomic(v.bv_page);
|
|
next = csum_partial_copy_nocheck(p + v.bv_offset,
|
|
(to += v.bv_len) - v.bv_len,
|
|
v.bv_len, 0);
|
|
kunmap_atomic(p);
|
|
sum = csum_block_add(sum, next, off);
|
|
off += v.bv_len;
|
|
}),({
|
|
next = csum_partial_copy_nocheck(v.iov_base,
|
|
(to += v.iov_len) - v.iov_len,
|
|
v.iov_len, 0);
|
|
sum = csum_block_add(sum, next, off);
|
|
off += v.iov_len;
|
|
})
|
|
)
|
|
*csum = sum;
|
|
iov_iter_advance(i, bytes);
|
|
return true;
|
|
}
|
|
EXPORT_SYMBOL(csum_and_copy_from_iter_full);
|
|
|
|
size_t csum_and_copy_to_iter(const void *addr, size_t bytes, __wsum *csum,
|
|
struct iov_iter *i)
|
|
{
|
|
const char *from = addr;
|
|
__wsum sum, next;
|
|
size_t off = 0;
|
|
sum = *csum;
|
|
if (unlikely(i->type & ITER_PIPE)) {
|
|
WARN_ON(1); /* for now */
|
|
return 0;
|
|
}
|
|
iterate_and_advance(i, bytes, v, ({
|
|
int err = 0;
|
|
next = csum_and_copy_to_user((from += v.iov_len) - v.iov_len,
|
|
v.iov_base,
|
|
v.iov_len, 0, &err);
|
|
if (!err) {
|
|
sum = csum_block_add(sum, next, off);
|
|
off += v.iov_len;
|
|
}
|
|
err ? v.iov_len : 0;
|
|
}), ({
|
|
char *p = kmap_atomic(v.bv_page);
|
|
next = csum_partial_copy_nocheck((from += v.bv_len) - v.bv_len,
|
|
p + v.bv_offset,
|
|
v.bv_len, 0);
|
|
kunmap_atomic(p);
|
|
sum = csum_block_add(sum, next, off);
|
|
off += v.bv_len;
|
|
}),({
|
|
next = csum_partial_copy_nocheck((from += v.iov_len) - v.iov_len,
|
|
v.iov_base,
|
|
v.iov_len, 0);
|
|
sum = csum_block_add(sum, next, off);
|
|
off += v.iov_len;
|
|
})
|
|
)
|
|
*csum = sum;
|
|
return bytes;
|
|
}
|
|
EXPORT_SYMBOL(csum_and_copy_to_iter);
|
|
|
|
int iov_iter_npages(const struct iov_iter *i, int maxpages)
|
|
{
|
|
size_t size = i->count;
|
|
int npages = 0;
|
|
|
|
if (!size)
|
|
return 0;
|
|
|
|
if (unlikely(i->type & ITER_PIPE)) {
|
|
struct pipe_inode_info *pipe = i->pipe;
|
|
size_t off;
|
|
int idx;
|
|
|
|
if (!sanity(i))
|
|
return 0;
|
|
|
|
data_start(i, &idx, &off);
|
|
/* some of this one + all after this one */
|
|
npages = ((pipe->curbuf - idx - 1) & (pipe->buffers - 1)) + 1;
|
|
if (npages >= maxpages)
|
|
return maxpages;
|
|
} else iterate_all_kinds(i, size, v, ({
|
|
unsigned long p = (unsigned long)v.iov_base;
|
|
npages += DIV_ROUND_UP(p + v.iov_len, PAGE_SIZE)
|
|
- p / PAGE_SIZE;
|
|
if (npages >= maxpages)
|
|
return maxpages;
|
|
0;}),({
|
|
npages++;
|
|
if (npages >= maxpages)
|
|
return maxpages;
|
|
}),({
|
|
unsigned long p = (unsigned long)v.iov_base;
|
|
npages += DIV_ROUND_UP(p + v.iov_len, PAGE_SIZE)
|
|
- p / PAGE_SIZE;
|
|
if (npages >= maxpages)
|
|
return maxpages;
|
|
})
|
|
)
|
|
return npages;
|
|
}
|
|
EXPORT_SYMBOL(iov_iter_npages);
|
|
|
|
const void *dup_iter(struct iov_iter *new, struct iov_iter *old, gfp_t flags)
|
|
{
|
|
*new = *old;
|
|
if (unlikely(new->type & ITER_PIPE)) {
|
|
WARN_ON(1);
|
|
return NULL;
|
|
}
|
|
if (new->type & ITER_BVEC)
|
|
return new->bvec = kmemdup(new->bvec,
|
|
new->nr_segs * sizeof(struct bio_vec),
|
|
flags);
|
|
else
|
|
/* iovec and kvec have identical layout */
|
|
return new->iov = kmemdup(new->iov,
|
|
new->nr_segs * sizeof(struct iovec),
|
|
flags);
|
|
}
|
|
EXPORT_SYMBOL(dup_iter);
|
|
|
|
/**
|
|
* import_iovec() - Copy an array of &struct iovec from userspace
|
|
* into the kernel, check that it is valid, and initialize a new
|
|
* &struct iov_iter iterator to access it.
|
|
*
|
|
* @type: One of %READ or %WRITE.
|
|
* @uvector: Pointer to the userspace array.
|
|
* @nr_segs: Number of elements in userspace array.
|
|
* @fast_segs: Number of elements in @iov.
|
|
* @iov: (input and output parameter) Pointer to pointer to (usually small
|
|
* on-stack) kernel array.
|
|
* @i: Pointer to iterator that will be initialized on success.
|
|
*
|
|
* If the array pointed to by *@iov is large enough to hold all @nr_segs,
|
|
* then this function places %NULL in *@iov on return. Otherwise, a new
|
|
* array will be allocated and the result placed in *@iov. This means that
|
|
* the caller may call kfree() on *@iov regardless of whether the small
|
|
* on-stack array was used or not (and regardless of whether this function
|
|
* returns an error or not).
|
|
*
|
|
* Return: 0 on success or negative error code on error.
|
|
*/
|
|
int import_iovec(int type, const struct iovec __user * uvector,
|
|
unsigned nr_segs, unsigned fast_segs,
|
|
struct iovec **iov, struct iov_iter *i)
|
|
{
|
|
ssize_t n;
|
|
struct iovec *p;
|
|
n = rw_copy_check_uvector(type, uvector, nr_segs, fast_segs,
|
|
*iov, &p);
|
|
if (n < 0) {
|
|
if (p != *iov)
|
|
kfree(p);
|
|
*iov = NULL;
|
|
return n;
|
|
}
|
|
iov_iter_init(i, type, p, nr_segs, n);
|
|
*iov = p == *iov ? NULL : p;
|
|
return 0;
|
|
}
|
|
EXPORT_SYMBOL(import_iovec);
|
|
|
|
#ifdef CONFIG_COMPAT
|
|
#include <linux/compat.h>
|
|
|
|
int compat_import_iovec(int type, const struct compat_iovec __user * uvector,
|
|
unsigned nr_segs, unsigned fast_segs,
|
|
struct iovec **iov, struct iov_iter *i)
|
|
{
|
|
ssize_t n;
|
|
struct iovec *p;
|
|
n = compat_rw_copy_check_uvector(type, uvector, nr_segs, fast_segs,
|
|
*iov, &p);
|
|
if (n < 0) {
|
|
if (p != *iov)
|
|
kfree(p);
|
|
*iov = NULL;
|
|
return n;
|
|
}
|
|
iov_iter_init(i, type, p, nr_segs, n);
|
|
*iov = p == *iov ? NULL : p;
|
|
return 0;
|
|
}
|
|
#endif
|
|
|
|
int import_single_range(int rw, void __user *buf, size_t len,
|
|
struct iovec *iov, struct iov_iter *i)
|
|
{
|
|
if (len > MAX_RW_COUNT)
|
|
len = MAX_RW_COUNT;
|
|
if (unlikely(!access_ok(!rw, buf, len)))
|
|
return -EFAULT;
|
|
|
|
iov->iov_base = buf;
|
|
iov->iov_len = len;
|
|
iov_iter_init(i, rw, iov, 1, len);
|
|
return 0;
|
|
}
|
|
EXPORT_SYMBOL(import_single_range);
|