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![Christoph Hellwig](/assets/img/avatar_default.png)
bmd is allocated using kmalloc in bio_alloc_map_data, so make sure
is_null_mapped is properly initialized to false for the !null_mapped
case.
Fixes: f3256075ba
("block: remove the BIO_NULL_MAPPED flag")
Reported-by: Marc Hartmayer <mhartmay@linux.ibm.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
718 lines
16 KiB
C
718 lines
16 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Functions related to mapping data to requests
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*/
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#include <linux/kernel.h>
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#include <linux/sched/task_stack.h>
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#include <linux/module.h>
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#include <linux/bio.h>
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#include <linux/blkdev.h>
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#include <linux/uio.h>
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#include "blk.h"
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struct bio_map_data {
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bool is_our_pages : 1;
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bool is_null_mapped : 1;
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struct iov_iter iter;
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struct iovec iov[];
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};
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static struct bio_map_data *bio_alloc_map_data(struct iov_iter *data,
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gfp_t gfp_mask)
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{
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struct bio_map_data *bmd;
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if (data->nr_segs > UIO_MAXIOV)
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return NULL;
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bmd = kmalloc(struct_size(bmd, iov, data->nr_segs), gfp_mask);
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if (!bmd)
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return NULL;
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memcpy(bmd->iov, data->iov, sizeof(struct iovec) * data->nr_segs);
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bmd->iter = *data;
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bmd->iter.iov = bmd->iov;
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return bmd;
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}
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/**
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* bio_copy_from_iter - copy all pages from iov_iter to bio
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* @bio: The &struct bio which describes the I/O as destination
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* @iter: iov_iter as source
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*
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* Copy all pages from iov_iter to bio.
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* Returns 0 on success, or error on failure.
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*/
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static int bio_copy_from_iter(struct bio *bio, struct iov_iter *iter)
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{
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struct bio_vec *bvec;
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struct bvec_iter_all iter_all;
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bio_for_each_segment_all(bvec, bio, iter_all) {
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ssize_t ret;
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ret = copy_page_from_iter(bvec->bv_page,
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bvec->bv_offset,
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bvec->bv_len,
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iter);
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if (!iov_iter_count(iter))
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break;
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if (ret < bvec->bv_len)
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return -EFAULT;
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}
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return 0;
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}
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/**
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* bio_copy_to_iter - copy all pages from bio to iov_iter
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* @bio: The &struct bio which describes the I/O as source
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* @iter: iov_iter as destination
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*
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* Copy all pages from bio to iov_iter.
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* Returns 0 on success, or error on failure.
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*/
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static int bio_copy_to_iter(struct bio *bio, struct iov_iter iter)
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{
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struct bio_vec *bvec;
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struct bvec_iter_all iter_all;
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bio_for_each_segment_all(bvec, bio, iter_all) {
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ssize_t ret;
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ret = copy_page_to_iter(bvec->bv_page,
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bvec->bv_offset,
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bvec->bv_len,
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&iter);
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if (!iov_iter_count(&iter))
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break;
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if (ret < bvec->bv_len)
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return -EFAULT;
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}
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return 0;
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}
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/**
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* bio_uncopy_user - finish previously mapped bio
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* @bio: bio being terminated
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*
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* Free pages allocated from bio_copy_user_iov() and write back data
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* to user space in case of a read.
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*/
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static int bio_uncopy_user(struct bio *bio)
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{
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struct bio_map_data *bmd = bio->bi_private;
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int ret = 0;
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if (!bmd->is_null_mapped) {
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/*
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* if we're in a workqueue, the request is orphaned, so
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* don't copy into a random user address space, just free
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* and return -EINTR so user space doesn't expect any data.
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*/
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if (!current->mm)
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ret = -EINTR;
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else if (bio_data_dir(bio) == READ)
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ret = bio_copy_to_iter(bio, bmd->iter);
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if (bmd->is_our_pages)
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bio_free_pages(bio);
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}
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kfree(bmd);
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bio_put(bio);
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return ret;
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}
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static int bio_copy_user_iov(struct request *rq, struct rq_map_data *map_data,
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struct iov_iter *iter, gfp_t gfp_mask)
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{
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struct bio_map_data *bmd;
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struct page *page;
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struct bio *bio, *bounce_bio;
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int i = 0, ret;
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int nr_pages;
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unsigned int len = iter->count;
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unsigned int offset = map_data ? offset_in_page(map_data->offset) : 0;
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bmd = bio_alloc_map_data(iter, gfp_mask);
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if (!bmd)
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return -ENOMEM;
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/*
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* We need to do a deep copy of the iov_iter including the iovecs.
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* The caller provided iov might point to an on-stack or otherwise
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* shortlived one.
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*/
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bmd->is_our_pages = !map_data;
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bmd->is_null_mapped = (map_data && map_data->null_mapped);
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nr_pages = DIV_ROUND_UP(offset + len, PAGE_SIZE);
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if (nr_pages > BIO_MAX_PAGES)
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nr_pages = BIO_MAX_PAGES;
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ret = -ENOMEM;
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bio = bio_kmalloc(gfp_mask, nr_pages);
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if (!bio)
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goto out_bmd;
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bio->bi_opf |= req_op(rq);
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if (map_data) {
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nr_pages = 1 << map_data->page_order;
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i = map_data->offset / PAGE_SIZE;
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}
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while (len) {
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unsigned int bytes = PAGE_SIZE;
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bytes -= offset;
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if (bytes > len)
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bytes = len;
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if (map_data) {
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if (i == map_data->nr_entries * nr_pages) {
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ret = -ENOMEM;
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goto cleanup;
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}
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page = map_data->pages[i / nr_pages];
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page += (i % nr_pages);
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i++;
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} else {
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page = alloc_page(rq->q->bounce_gfp | gfp_mask);
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if (!page) {
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ret = -ENOMEM;
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goto cleanup;
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}
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}
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if (bio_add_pc_page(rq->q, bio, page, bytes, offset) < bytes) {
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if (!map_data)
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__free_page(page);
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break;
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}
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len -= bytes;
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offset = 0;
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}
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if (map_data)
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map_data->offset += bio->bi_iter.bi_size;
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/*
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* success
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*/
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if ((iov_iter_rw(iter) == WRITE &&
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(!map_data || !map_data->null_mapped)) ||
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(map_data && map_data->from_user)) {
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ret = bio_copy_from_iter(bio, iter);
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if (ret)
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goto cleanup;
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} else {
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if (bmd->is_our_pages)
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zero_fill_bio(bio);
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iov_iter_advance(iter, bio->bi_iter.bi_size);
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}
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bio->bi_private = bmd;
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bounce_bio = bio;
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ret = blk_rq_append_bio(rq, &bounce_bio);
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if (ret)
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goto cleanup;
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/*
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* We link the bounce buffer in and could have to traverse it later, so
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* we have to get a ref to prevent it from being freed
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*/
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bio_get(bounce_bio);
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return 0;
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cleanup:
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if (!map_data)
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bio_free_pages(bio);
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bio_put(bio);
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out_bmd:
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kfree(bmd);
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return ret;
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}
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static int bio_map_user_iov(struct request *rq, struct iov_iter *iter,
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gfp_t gfp_mask)
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{
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unsigned int max_sectors = queue_max_hw_sectors(rq->q);
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struct bio *bio, *bounce_bio;
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int ret;
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int j;
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if (!iov_iter_count(iter))
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return -EINVAL;
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bio = bio_kmalloc(gfp_mask, iov_iter_npages(iter, BIO_MAX_PAGES));
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if (!bio)
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return -ENOMEM;
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bio->bi_opf |= req_op(rq);
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while (iov_iter_count(iter)) {
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struct page **pages;
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ssize_t bytes;
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size_t offs, added = 0;
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int npages;
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bytes = iov_iter_get_pages_alloc(iter, &pages, LONG_MAX, &offs);
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if (unlikely(bytes <= 0)) {
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ret = bytes ? bytes : -EFAULT;
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goto out_unmap;
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}
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npages = DIV_ROUND_UP(offs + bytes, PAGE_SIZE);
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if (unlikely(offs & queue_dma_alignment(rq->q))) {
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ret = -EINVAL;
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j = 0;
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} else {
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for (j = 0; j < npages; j++) {
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struct page *page = pages[j];
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unsigned int n = PAGE_SIZE - offs;
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bool same_page = false;
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if (n > bytes)
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n = bytes;
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if (!bio_add_hw_page(rq->q, bio, page, n, offs,
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max_sectors, &same_page)) {
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if (same_page)
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put_page(page);
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break;
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}
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added += n;
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bytes -= n;
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offs = 0;
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}
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iov_iter_advance(iter, added);
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}
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/*
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* release the pages we didn't map into the bio, if any
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*/
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while (j < npages)
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put_page(pages[j++]);
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kvfree(pages);
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/* couldn't stuff something into bio? */
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if (bytes)
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break;
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}
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/*
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* Subtle: if we end up needing to bounce a bio, it would normally
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* disappear when its bi_end_io is run. However, we need the original
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* bio for the unmap, so grab an extra reference to it
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*/
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bio_get(bio);
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bounce_bio = bio;
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ret = blk_rq_append_bio(rq, &bounce_bio);
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if (ret)
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goto out_put_orig;
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/*
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* We link the bounce buffer in and could have to traverse it
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* later, so we have to get a ref to prevent it from being freed
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*/
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bio_get(bounce_bio);
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return 0;
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out_put_orig:
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bio_put(bio);
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out_unmap:
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bio_release_pages(bio, false);
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bio_put(bio);
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return ret;
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}
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/**
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* bio_unmap_user - unmap a bio
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* @bio: the bio being unmapped
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*
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* Unmap a bio previously mapped by bio_map_user_iov(). Must be called from
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* process context.
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*
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* bio_unmap_user() may sleep.
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*/
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static void bio_unmap_user(struct bio *bio)
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{
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bio_release_pages(bio, bio_data_dir(bio) == READ);
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bio_put(bio);
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bio_put(bio);
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}
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static void bio_invalidate_vmalloc_pages(struct bio *bio)
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{
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#ifdef ARCH_HAS_FLUSH_KERNEL_DCACHE_PAGE
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if (bio->bi_private && !op_is_write(bio_op(bio))) {
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unsigned long i, len = 0;
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for (i = 0; i < bio->bi_vcnt; i++)
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len += bio->bi_io_vec[i].bv_len;
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invalidate_kernel_vmap_range(bio->bi_private, len);
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}
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#endif
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}
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static void bio_map_kern_endio(struct bio *bio)
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{
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bio_invalidate_vmalloc_pages(bio);
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bio_put(bio);
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}
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/**
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* bio_map_kern - map kernel address into bio
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* @q: the struct request_queue for the bio
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* @data: pointer to buffer to map
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* @len: length in bytes
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* @gfp_mask: allocation flags for bio allocation
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*
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* Map the kernel address into a bio suitable for io to a block
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* device. Returns an error pointer in case of error.
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*/
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static struct bio *bio_map_kern(struct request_queue *q, void *data,
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unsigned int len, gfp_t gfp_mask)
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{
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unsigned long kaddr = (unsigned long)data;
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unsigned long end = (kaddr + len + PAGE_SIZE - 1) >> PAGE_SHIFT;
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unsigned long start = kaddr >> PAGE_SHIFT;
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const int nr_pages = end - start;
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bool is_vmalloc = is_vmalloc_addr(data);
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struct page *page;
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int offset, i;
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struct bio *bio;
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bio = bio_kmalloc(gfp_mask, nr_pages);
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if (!bio)
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return ERR_PTR(-ENOMEM);
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if (is_vmalloc) {
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flush_kernel_vmap_range(data, len);
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bio->bi_private = data;
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}
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offset = offset_in_page(kaddr);
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for (i = 0; i < nr_pages; i++) {
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unsigned int bytes = PAGE_SIZE - offset;
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if (len <= 0)
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break;
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if (bytes > len)
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bytes = len;
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if (!is_vmalloc)
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page = virt_to_page(data);
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else
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page = vmalloc_to_page(data);
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if (bio_add_pc_page(q, bio, page, bytes,
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offset) < bytes) {
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/* we don't support partial mappings */
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bio_put(bio);
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return ERR_PTR(-EINVAL);
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}
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data += bytes;
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len -= bytes;
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offset = 0;
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}
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bio->bi_end_io = bio_map_kern_endio;
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return bio;
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}
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static void bio_copy_kern_endio(struct bio *bio)
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{
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bio_free_pages(bio);
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bio_put(bio);
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}
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static void bio_copy_kern_endio_read(struct bio *bio)
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{
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char *p = bio->bi_private;
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struct bio_vec *bvec;
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struct bvec_iter_all iter_all;
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bio_for_each_segment_all(bvec, bio, iter_all) {
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memcpy(p, page_address(bvec->bv_page), bvec->bv_len);
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p += bvec->bv_len;
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}
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bio_copy_kern_endio(bio);
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}
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/**
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* bio_copy_kern - copy kernel address into bio
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* @q: the struct request_queue for the bio
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* @data: pointer to buffer to copy
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* @len: length in bytes
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* @gfp_mask: allocation flags for bio and page allocation
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* @reading: data direction is READ
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*
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* copy the kernel address into a bio suitable for io to a block
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* device. Returns an error pointer in case of error.
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*/
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static struct bio *bio_copy_kern(struct request_queue *q, void *data,
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unsigned int len, gfp_t gfp_mask, int reading)
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{
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unsigned long kaddr = (unsigned long)data;
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unsigned long end = (kaddr + len + PAGE_SIZE - 1) >> PAGE_SHIFT;
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unsigned long start = kaddr >> PAGE_SHIFT;
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struct bio *bio;
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void *p = data;
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int nr_pages = 0;
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/*
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* Overflow, abort
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*/
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if (end < start)
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return ERR_PTR(-EINVAL);
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nr_pages = end - start;
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bio = bio_kmalloc(gfp_mask, nr_pages);
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if (!bio)
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return ERR_PTR(-ENOMEM);
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while (len) {
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struct page *page;
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unsigned int bytes = PAGE_SIZE;
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if (bytes > len)
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bytes = len;
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page = alloc_page(q->bounce_gfp | gfp_mask);
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if (!page)
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goto cleanup;
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if (!reading)
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memcpy(page_address(page), p, bytes);
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if (bio_add_pc_page(q, bio, page, bytes, 0) < bytes)
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break;
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len -= bytes;
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p += bytes;
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}
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if (reading) {
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bio->bi_end_io = bio_copy_kern_endio_read;
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bio->bi_private = data;
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} else {
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bio->bi_end_io = bio_copy_kern_endio;
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}
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return bio;
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cleanup:
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bio_free_pages(bio);
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bio_put(bio);
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return ERR_PTR(-ENOMEM);
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}
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/*
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* Append a bio to a passthrough request. Only works if the bio can be merged
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* into the request based on the driver constraints.
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*/
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int blk_rq_append_bio(struct request *rq, struct bio **bio)
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{
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struct bio *orig_bio = *bio;
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struct bvec_iter iter;
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struct bio_vec bv;
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unsigned int nr_segs = 0;
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blk_queue_bounce(rq->q, bio);
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bio_for_each_bvec(bv, *bio, iter)
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nr_segs++;
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if (!rq->bio) {
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blk_rq_bio_prep(rq, *bio, nr_segs);
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} else {
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if (!ll_back_merge_fn(rq, *bio, nr_segs)) {
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if (orig_bio != *bio) {
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bio_put(*bio);
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*bio = orig_bio;
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}
|
|
return -EINVAL;
|
|
}
|
|
|
|
rq->biotail->bi_next = *bio;
|
|
rq->biotail = *bio;
|
|
rq->__data_len += (*bio)->bi_iter.bi_size;
|
|
bio_crypt_free_ctx(*bio);
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
EXPORT_SYMBOL(blk_rq_append_bio);
|
|
|
|
/**
|
|
* blk_rq_map_user_iov - map user data to a request, for passthrough requests
|
|
* @q: request queue where request should be inserted
|
|
* @rq: request to map data to
|
|
* @map_data: pointer to the rq_map_data holding pages (if necessary)
|
|
* @iter: iovec iterator
|
|
* @gfp_mask: memory allocation flags
|
|
*
|
|
* Description:
|
|
* Data will be mapped directly for zero copy I/O, if possible. Otherwise
|
|
* a kernel bounce buffer is used.
|
|
*
|
|
* A matching blk_rq_unmap_user() must be issued at the end of I/O, while
|
|
* still in process context.
|
|
*
|
|
* Note: The mapped bio may need to be bounced through blk_queue_bounce()
|
|
* before being submitted to the device, as pages mapped may be out of
|
|
* reach. It's the callers responsibility to make sure this happens. The
|
|
* original bio must be passed back in to blk_rq_unmap_user() for proper
|
|
* unmapping.
|
|
*/
|
|
int blk_rq_map_user_iov(struct request_queue *q, struct request *rq,
|
|
struct rq_map_data *map_data,
|
|
const struct iov_iter *iter, gfp_t gfp_mask)
|
|
{
|
|
bool copy = false;
|
|
unsigned long align = q->dma_pad_mask | queue_dma_alignment(q);
|
|
struct bio *bio = NULL;
|
|
struct iov_iter i;
|
|
int ret = -EINVAL;
|
|
|
|
if (!iter_is_iovec(iter))
|
|
goto fail;
|
|
|
|
if (map_data)
|
|
copy = true;
|
|
else if (iov_iter_alignment(iter) & align)
|
|
copy = true;
|
|
else if (queue_virt_boundary(q))
|
|
copy = queue_virt_boundary(q) & iov_iter_gap_alignment(iter);
|
|
|
|
i = *iter;
|
|
do {
|
|
if (copy)
|
|
ret = bio_copy_user_iov(rq, map_data, &i, gfp_mask);
|
|
else
|
|
ret = bio_map_user_iov(rq, &i, gfp_mask);
|
|
if (ret)
|
|
goto unmap_rq;
|
|
if (!bio)
|
|
bio = rq->bio;
|
|
} while (iov_iter_count(&i));
|
|
|
|
return 0;
|
|
|
|
unmap_rq:
|
|
blk_rq_unmap_user(bio);
|
|
fail:
|
|
rq->bio = NULL;
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL(blk_rq_map_user_iov);
|
|
|
|
int blk_rq_map_user(struct request_queue *q, struct request *rq,
|
|
struct rq_map_data *map_data, void __user *ubuf,
|
|
unsigned long len, gfp_t gfp_mask)
|
|
{
|
|
struct iovec iov;
|
|
struct iov_iter i;
|
|
int ret = import_single_range(rq_data_dir(rq), ubuf, len, &iov, &i);
|
|
|
|
if (unlikely(ret < 0))
|
|
return ret;
|
|
|
|
return blk_rq_map_user_iov(q, rq, map_data, &i, gfp_mask);
|
|
}
|
|
EXPORT_SYMBOL(blk_rq_map_user);
|
|
|
|
/**
|
|
* blk_rq_unmap_user - unmap a request with user data
|
|
* @bio: start of bio list
|
|
*
|
|
* Description:
|
|
* Unmap a rq previously mapped by blk_rq_map_user(). The caller must
|
|
* supply the original rq->bio from the blk_rq_map_user() return, since
|
|
* the I/O completion may have changed rq->bio.
|
|
*/
|
|
int blk_rq_unmap_user(struct bio *bio)
|
|
{
|
|
struct bio *mapped_bio;
|
|
int ret = 0, ret2;
|
|
|
|
while (bio) {
|
|
mapped_bio = bio;
|
|
if (unlikely(bio_flagged(bio, BIO_BOUNCED)))
|
|
mapped_bio = bio->bi_private;
|
|
|
|
if (bio->bi_private) {
|
|
ret2 = bio_uncopy_user(mapped_bio);
|
|
if (ret2 && !ret)
|
|
ret = ret2;
|
|
} else {
|
|
bio_unmap_user(mapped_bio);
|
|
}
|
|
|
|
mapped_bio = bio;
|
|
bio = bio->bi_next;
|
|
bio_put(mapped_bio);
|
|
}
|
|
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL(blk_rq_unmap_user);
|
|
|
|
/**
|
|
* blk_rq_map_kern - map kernel data to a request, for passthrough requests
|
|
* @q: request queue where request should be inserted
|
|
* @rq: request to fill
|
|
* @kbuf: the kernel buffer
|
|
* @len: length of user data
|
|
* @gfp_mask: memory allocation flags
|
|
*
|
|
* Description:
|
|
* Data will be mapped directly if possible. Otherwise a bounce
|
|
* buffer is used. Can be called multiple times to append multiple
|
|
* buffers.
|
|
*/
|
|
int blk_rq_map_kern(struct request_queue *q, struct request *rq, void *kbuf,
|
|
unsigned int len, gfp_t gfp_mask)
|
|
{
|
|
int reading = rq_data_dir(rq) == READ;
|
|
unsigned long addr = (unsigned long) kbuf;
|
|
struct bio *bio, *orig_bio;
|
|
int ret;
|
|
|
|
if (len > (queue_max_hw_sectors(q) << 9))
|
|
return -EINVAL;
|
|
if (!len || !kbuf)
|
|
return -EINVAL;
|
|
|
|
if (!blk_rq_aligned(q, addr, len) || object_is_on_stack(kbuf))
|
|
bio = bio_copy_kern(q, kbuf, len, gfp_mask, reading);
|
|
else
|
|
bio = bio_map_kern(q, kbuf, len, gfp_mask);
|
|
|
|
if (IS_ERR(bio))
|
|
return PTR_ERR(bio);
|
|
|
|
bio->bi_opf &= ~REQ_OP_MASK;
|
|
bio->bi_opf |= req_op(rq);
|
|
|
|
orig_bio = bio;
|
|
ret = blk_rq_append_bio(rq, &bio);
|
|
if (unlikely(ret)) {
|
|
/* request is too big */
|
|
bio_put(orig_bio);
|
|
return ret;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
EXPORT_SYMBOL(blk_rq_map_kern);
|