ext4: bio_alloc with __GFP_DIRECT_RECLAIM never fails

Similar to [1] [2], bio_alloc with __GFP_DIRECT_RECLAIM flags
guarantees bio allocation under some given restrictions, as
stated in block/bio.c and fs/direct-io.c So here it's ok to
not check for NULL value from bio_alloc().

[1] https://lore.kernel.org/r/20191030035518.65477-1-gaoxiang25@huawei.com
[2] https://lore.kernel.org/r/20190830162812.GA10694@infradead.org
Cc: Theodore Ts'o <tytso@mit.edu>
Cc: Andreas Dilger <adilger.kernel@dilger.ca>
Cc: Ritesh Harjani <riteshh@linux.ibm.com>
Reviewed-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Gao Xiang <gaoxiang25@huawei.com>
Link: https://lore.kernel.org/r/20191031092315.139267-1-gaoxiang25@huawei.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
This commit is contained in:
Gao Xiang
2019-10-31 17:23:15 +08:00
committed by Theodore Ts'o
parent ebc11f7b1f
commit 5500221ea1
2 changed files with 26 additions and 37 deletions

View File

@@ -360,10 +360,12 @@ int ext4_mpage_readpages(struct address_space *mapping,
if (bio == NULL) {
struct bio_post_read_ctx *ctx;
/*
* bio_alloc will _always_ be able to allocate a bio if
* __GFP_DIRECT_RECLAIM is set, see bio_alloc_bioset().
*/
bio = bio_alloc(GFP_KERNEL,
min_t(int, nr_pages, BIO_MAX_PAGES));
if (!bio)
goto set_error_page;
ctx = get_bio_post_read_ctx(inode, bio, page->index);
if (IS_ERR(ctx)) {
bio_put(bio);