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io_uring: add io_pin_pages() helper

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Abstract this out from io_sqe_buffer_register() so we can use it
elsewhere too without duplicating this code.

No intended functional changes in this patch.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Jens Axboe 2022-04-28 13:02:27 -06:00
parent 3d200242a6
commit d8c2237d0a
1 changed files with 51 additions and 28 deletions
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79
fs/io_uring.c
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@ -9845,30 +9845,18 @@ static int io_buffer_account_pin(struct io_ring_ctx *ctx, struct page **pages,
return ret;
}
static int io_sqe_buffer_register(struct io_ring_ctx *ctx, struct iovec *iov,
struct io_mapped_ubuf **pimu,
struct page **last_hpage)
static struct page **io_pin_pages(unsigned long ubuf, unsigned long len,
int *npages)
{
struct io_mapped_ubuf *imu = NULL;
unsigned long start, end, nr_pages;
struct vm_area_struct **vmas = NULL;
struct page **pages = NULL;
unsigned long off, start, end, ubuf;
size_t size;
int ret, pret, nr_pages, i;
int i, pret, ret = -ENOMEM;
if (!iov->iov_base) {
*pimu = ctx->dummy_ubuf;
return 0;
}
ubuf = (unsigned long) iov->iov_base;
end = (ubuf + iov->iov_len + PAGE_SIZE - 1) >> PAGE_SHIFT;
end = (ubuf + len + PAGE_SIZE - 1) >> PAGE_SHIFT;
start = ubuf >> PAGE_SHIFT;
nr_pages = end - start;
*pimu = NULL;
ret = -ENOMEM;
pages = kvmalloc_array(nr_pages, sizeof(struct page *), GFP_KERNEL);
if (!pages)
goto done;
@ -9878,10 +9866,6 @@ static int io_sqe_buffer_register(struct io_ring_ctx *ctx, struct iovec *iov,
if (!vmas)
goto done;
imu = kvmalloc(struct_size(imu, bvec, nr_pages), GFP_KERNEL);
if (!imu)
goto done;
ret = 0;
mmap_read_lock(current->mm);
pret = pin_user_pages(ubuf, nr_pages, FOLL_WRITE | FOLL_LONGTERM,
@ -9899,6 +9883,7 @@ static int io_sqe_buffer_register(struct io_ring_ctx *ctx, struct iovec *iov,
break;
}
}
*npages = nr_pages;
} else {
ret = pret < 0 ? pret : -EFAULT;
}
@ -9912,14 +9897,53 @@ static int io_sqe_buffer_register(struct io_ring_ctx *ctx, struct iovec *iov,
unpin_user_pages(pages, pret);
goto done;
}
ret = 0;
done:
kvfree(vmas);
if (ret < 0) {
kvfree(pages);
pages = ERR_PTR(ret);
}
return pages;
}
ret = io_buffer_account_pin(ctx, pages, pret, imu, last_hpage);
if (ret) {
unpin_user_pages(pages, pret);
static int io_sqe_buffer_register(struct io_ring_ctx *ctx, struct iovec *iov,
struct io_mapped_ubuf **pimu,
struct page **last_hpage)
{
struct io_mapped_ubuf *imu = NULL;
struct page **pages = NULL;
unsigned long off;
size_t size;
int ret, nr_pages, i;
if (!iov->iov_base) {
*pimu = ctx->dummy_ubuf;
return 0;
}
*pimu = NULL;
ret = -ENOMEM;
pages = io_pin_pages((unsigned long) iov->iov_base, iov->iov_len,
&nr_pages);
if (IS_ERR(pages)) {
ret = PTR_ERR(pages);
pages = NULL;
goto done;
}
off = ubuf & ~PAGE_MASK;
imu = kvmalloc(struct_size(imu, bvec, nr_pages), GFP_KERNEL);
if (!imu)
goto done;
ret = io_buffer_account_pin(ctx, pages, nr_pages, imu, last_hpage);
if (ret) {
unpin_user_pages(pages, nr_pages);
goto done;
}
off = (unsigned long) iov->iov_base & ~PAGE_MASK;
size = iov->iov_len;
for (i = 0; i < nr_pages; i++) {
size_t vec_len;
@ -9932,8 +9956,8 @@ static int io_sqe_buffer_register(struct io_ring_ctx *ctx, struct iovec *iov,
size -= vec_len;
}
/* store original address for later verification */
imu->ubuf = ubuf;
imu->ubuf_end = ubuf + iov->iov_len;
imu->ubuf = (unsigned long) iov->iov_base;
imu->ubuf_end = imu->ubuf + iov->iov_len;
imu->nr_bvecs = nr_pages;
*pimu = imu;
ret = 0;
@ -9941,7 +9965,6 @@ static int io_sqe_buffer_register(struct io_ring_ctx *ctx, struct iovec *iov,
if (ret)
kvfree(imu);
kvfree(pages);
kvfree(vmas);
return ret;
}