diff options
Diffstat (limited to 'block/bio.c')
| -rw-r--r-- | block/bio.c | 111 |
1 files changed, 87 insertions, 24 deletions
diff --git a/block/bio.c b/block/bio.c index 4db1008309ed..71a78d9fb8b7 100644 --- a/block/bio.c +++ b/block/bio.c @@ -753,6 +753,8 @@ EXPORT_SYMBOL(bio_add_pc_page); * @page: page to add * @len: length of the data to add * @off: offset of the data in @page + * @same_page: if %true only merge if the new data is in the same physical + * page as the last segment of the bio. * * Try to add the data at @page + @off to the last bvec of @bio. This is a * a useful optimisation for file systems with a block size smaller than the @@ -761,19 +763,25 @@ EXPORT_SYMBOL(bio_add_pc_page); * Return %true on success or %false on failure. */ bool __bio_try_merge_page(struct bio *bio, struct page *page, - unsigned int len, unsigned int off) + unsigned int len, unsigned int off, bool same_page) { if (WARN_ON_ONCE(bio_flagged(bio, BIO_CLONED))) return false; if (bio->bi_vcnt > 0) { struct bio_vec *bv = &bio->bi_io_vec[bio->bi_vcnt - 1]; + phys_addr_t vec_end_addr = page_to_phys(bv->bv_page) + + bv->bv_offset + bv->bv_len - 1; + phys_addr_t page_addr = page_to_phys(page); - if (page == bv->bv_page && off == bv->bv_offset + bv->bv_len) { - bv->bv_len += len; - bio->bi_iter.bi_size += len; - return true; - } + if (vec_end_addr + 1 != page_addr + off) + return false; + if (same_page && (vec_end_addr & PAGE_MASK) != page_addr) + return false; + + bv->bv_len += len; + bio->bi_iter.bi_size += len; + return true; } return false; } @@ -819,7 +827,7 @@ EXPORT_SYMBOL_GPL(__bio_add_page); int bio_add_page(struct bio *bio, struct page *page, unsigned int len, unsigned int offset) { - if (!__bio_try_merge_page(bio, page, len, offset)) { + if (!__bio_try_merge_page(bio, page, len, offset, false)) { if (bio_full(bio)) return 0; __bio_add_page(bio, page, len, offset); @@ -828,6 +836,40 @@ int bio_add_page(struct bio *bio, struct page *page, } EXPORT_SYMBOL(bio_add_page); +static int __bio_iov_bvec_add_pages(struct bio *bio, struct iov_iter *iter) +{ + const struct bio_vec *bv = iter->bvec; + unsigned int len; + size_t size; + + if (WARN_ON_ONCE(iter->iov_offset > bv->bv_len)) + return -EINVAL; + + len = min_t(size_t, bv->bv_len - iter->iov_offset, iter->count); + size = bio_add_page(bio, bv->bv_page, len, + bv->bv_offset + iter->iov_offset); + if (size == len) { + struct page *page; + int i; + + /* + * For the normal O_DIRECT case, we could skip grabbing this + * reference and then not have to put them again when IO + * completes. But this breaks some in-kernel users, like + * splicing to/from a loop device, where we release the pipe + * pages unconditionally. If we can fix that case, we can + * get rid of the get here and the need to call + * bio_release_pages() at IO completion time. + */ + mp_bvec_for_each_page(page, bv, i) + get_page(page); + iov_iter_advance(iter, size); + return 0; + } + + return -EINVAL; +} + #define PAGE_PTRS_PER_BVEC (sizeof(struct bio_vec) / sizeof(struct page *)) /** @@ -876,23 +918,35 @@ static int __bio_iov_iter_get_pages(struct bio *bio, struct iov_iter *iter) } /** - * bio_iov_iter_get_pages - pin user or kernel pages and add them to a bio + * bio_iov_iter_get_pages - add user or kernel pages to a bio * @bio: bio to add pages to - * @iter: iov iterator describing the region to be mapped + * @iter: iov iterator describing the region to be added + * + * This takes either an iterator pointing to user memory, or one pointing to + * kernel pages (BVEC iterator). If we're adding user pages, we pin them and + * map them into the kernel. On IO completion, the caller should put those + * pages. For now, when adding kernel pages, we still grab a reference to the + * page. This isn't strictly needed for the common case, but some call paths + * end up releasing pages from eg a pipe and we can't easily control these. + * See comment in __bio_iov_bvec_add_pages(). * - * Pins pages from *iter and appends them to @bio's bvec array. The - * pages will have to be released using put_page() when done. * The function tries, but does not guarantee, to pin as many pages as - * fit into the bio, or are requested in *iter, whatever is smaller. - * If MM encounters an error pinning the requested pages, it stops. - * Error is returned only if 0 pages could be pinned. + * fit into the bio, or are requested in *iter, whatever is smaller. If + * MM encounters an error pinning the requested pages, it stops. Error + * is returned only if 0 pages could be pinned. */ int bio_iov_iter_get_pages(struct bio *bio, struct iov_iter *iter) { + const bool is_bvec = iov_iter_is_bvec(iter); unsigned short orig_vcnt = bio->bi_vcnt; do { - int ret = __bio_iov_iter_get_pages(bio, iter); + int ret; + + if (is_bvec) + ret = __bio_iov_bvec_add_pages(bio, iter); + else + ret = __bio_iov_iter_get_pages(bio, iter); if (unlikely(ret)) return bio->bi_vcnt > orig_vcnt ? 0 : ret; @@ -1072,8 +1126,9 @@ static int bio_copy_from_iter(struct bio *bio, struct iov_iter *iter) { int i; struct bio_vec *bvec; + struct bvec_iter_all iter_all; - bio_for_each_segment_all(bvec, bio, i) { + bio_for_each_segment_all(bvec, bio, i, iter_all) { ssize_t ret; ret = copy_page_from_iter(bvec->bv_page, @@ -1103,8 +1158,9 @@ static int bio_copy_to_iter(struct bio *bio, struct iov_iter iter) { int i; struct bio_vec *bvec; + struct bvec_iter_all iter_all; - bio_for_each_segment_all(bvec, bio, i) { + bio_for_each_segment_all(bvec, bio, i, iter_all) { ssize_t ret; ret = copy_page_to_iter(bvec->bv_page, @@ -1126,8 +1182,9 @@ void bio_free_pages(struct bio *bio) { struct bio_vec *bvec; int i; + struct bvec_iter_all iter_all; - bio_for_each_segment_all(bvec, bio, i) + bio_for_each_segment_all(bvec, bio, i, iter_all) __free_page(bvec->bv_page); } EXPORT_SYMBOL(bio_free_pages); @@ -1295,6 +1352,7 @@ struct bio *bio_map_user_iov(struct request_queue *q, struct bio *bio; int ret; struct bio_vec *bvec; + struct bvec_iter_all iter_all; if (!iov_iter_count(iter)) return ERR_PTR(-EINVAL); @@ -1368,7 +1426,7 @@ struct bio *bio_map_user_iov(struct request_queue *q, return bio; out_unmap: - bio_for_each_segment_all(bvec, bio, j) { + bio_for_each_segment_all(bvec, bio, j, iter_all) { put_page(bvec->bv_page); } bio_put(bio); @@ -1379,11 +1437,12 @@ static void __bio_unmap_user(struct bio *bio) { struct bio_vec *bvec; int i; + struct bvec_iter_all iter_all; /* * make sure we dirty pages we wrote to */ - bio_for_each_segment_all(bvec, bio, i) { + bio_for_each_segment_all(bvec, bio, i, iter_all) { if (bio_data_dir(bio) == READ) set_page_dirty_lock(bvec->bv_page); @@ -1475,8 +1534,9 @@ static void bio_copy_kern_endio_read(struct bio *bio) char *p = bio->bi_private; struct bio_vec *bvec; int i; + struct bvec_iter_all iter_all; - bio_for_each_segment_all(bvec, bio, i) { + bio_for_each_segment_all(bvec, bio, i, iter_all) { memcpy(p, page_address(bvec->bv_page), bvec->bv_len); p += bvec->bv_len; } @@ -1585,8 +1645,9 @@ void bio_set_pages_dirty(struct bio *bio) { struct bio_vec *bvec; int i; + struct bvec_iter_all iter_all; - bio_for_each_segment_all(bvec, bio, i) { + bio_for_each_segment_all(bvec, bio, i, iter_all) { if (!PageCompound(bvec->bv_page)) set_page_dirty_lock(bvec->bv_page); } @@ -1596,8 +1657,9 @@ static void bio_release_pages(struct bio *bio) { struct bio_vec *bvec; int i; + struct bvec_iter_all iter_all; - bio_for_each_segment_all(bvec, bio, i) + bio_for_each_segment_all(bvec, bio, i, iter_all) put_page(bvec->bv_page); } @@ -1644,8 +1706,9 @@ void bio_check_pages_dirty(struct bio *bio) struct bio_vec *bvec; unsigned long flags; int i; + struct bvec_iter_all iter_all; - bio_for_each_segment_all(bvec, bio, i) { + bio_for_each_segment_all(bvec, bio, i, iter_all) { if (!PageDirty(bvec->bv_page) && !PageCompound(bvec->bv_page)) goto defer; } |