kernel/linux.git/block/bio.c, branch v6.7.3

block: Remove special-casing of compound pages

2024-01-25T23:45:14+00:00

commit 1b151e2435fc3a9b10c8946c6aebe9f3e1938c55 upstream. The special casing was originally added in pre-git history; reproducing the commit log here: > commit a318a92567d77 > Author: Andrew Morton > Date: Sun Sep 21 01:42:22 2003 -0700 > > [PATCH] Speed up direct-io hugetlbpage handling > > This patch short-circuits all the direct-io page dirtying logic for > higher-order pages. Without this, we pointlessly bounce BIOs up to > keventd all the time. In the last twenty years, compound pages have become used for more than just hugetlb. Rewrite these functions to operate on folios instead of pages and remove the special case for hugetlbfs; I don't think it's needed any more (and if it is, we can put it back in as a call to folio_test_hugetlb()). This was found by inspection; as far as I can tell, this bug can lead to pages used as the destination of a direct I/O read not being marked as dirty. If those pages are then reclaimed by the MM without being dirtied for some other reason, they won't be written out. Then when they're faulted back in, they will not contain the data they should. It'll take a pretty unusual setup to produce this problem with several races all going the wrong way. This problem predates the folio work; it could for example have been triggered by mmaping a THP in tmpfs and using that as the target of an O_DIRECT read. Fixes: 800d8c63b2e98 ("shmem: add huge pages support") Cc: Signed-off-by: Matthew Wilcox (Oracle) Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman

block: Bring back zero_fill_bio_iter

2023-08-14T21:40:42+00:00

This reverts 6f822e1b5d9dda3d20e87365de138046e3baa03a - this helper is used by bcachefs. Signed-off-by: Kent Overstreet Cc: Jens Axboe Cc: linux-block@vger.kernel.org Link: https://lore.kernel.org/r/20230813182636.2966159-4-kent.overstreet@linux.dev Signed-off-by: Jens Axboe

block: Allow bio_iov_iter_get_pages() with bio->bi_bdev unset

2023-08-14T21:40:42+00:00

bio_iov_iter_get_pages() trims the IO based on the block size of the block device the IO will be issued to. However, bcachefs is a multi device filesystem; when we're creating the bio we don't yet know which block device the bio will be submitted to - we have to handle the alignment checks elsewhere. Thus this is needed to avoid a null ptr deref. Signed-off-by: Kent Overstreet Cc: Jens Axboe Cc: linux-block@vger.kernel.org Link: https://lore.kernel.org/r/20230813182636.2966159-3-kent.overstreet@linux.dev Signed-off-by: Jens Axboe

block: Add some exports for bcachefs

2023-08-14T21:40:42+00:00

- bio_set_pages_dirty(), bio_check_pages_dirty() - dio path - blk_status_to_str() - error messages - bio_add_folio() - this should definitely be exported for everyone, it's the modern version of bio_add_page() Signed-off-by: Kent Overstreet Cc: linux-block@vger.kernel.org Cc: Jens Axboe Signed-off-by: Kent Overstreet Link: https://lore.kernel.org/r/20230813182636.2966159-2-kent.overstreet@linux.dev Signed-off-by: Jens Axboe

block: make bvec_try_merge_hw_page() non-static

2023-08-09T22:05:35+00:00

This will be used for multi-page configuration for integrity payload. Cc: Christoph Hellwig Cc: Martin K. Petersen Reviewed-by: Christoph Hellwig Signed-off-by: Jinyoung Choi Tested-by: "Martin K. Petersen" Reviewed-by: "Martin K. Petersen" Link: https://lore.kernel.org/r/20230803024827epcms2p838d9e9131492c86a159fff25d195658f@epcms2p8 Signed-off-by: Jens Axboe

block: don't pass a bio to bio_try_merge_hw_seg

2023-07-25T01:55:16+00:00

There is no good reason to pass the bio to bio_try_merge_hw_seg. Just pass the current bvec and rename the function to bvec_try_merge_hw_page. This will allow reusing this function for supporting multi-page integrity payload bvecs. Signed-off-by: Christoph Hellwig Reviewed-by: Jinyoung Choi Link: https://lore.kernel.org/r/20230724165433.117645-9-hch@lst.de Signed-off-by: Jens Axboe

block: move the bi_size update out of __bio_try_merge_page

2023-07-25T01:55:16+00:00

The update of bi_size is the only thing in __bio_try_merge_page that needs a bio. Move it to the callers, and merge __bio_try_merge_page and page_is_mergeable into a single bvec_try_merge_page that only takes the current bvec instead of a full bio. This will allow reusing this function for supporting multi-page integrity payload bvecs. Signed-off-by: Christoph Hellwig Reviewed-by: Jinyoung Choi Link: https://lore.kernel.org/r/20230724165433.117645-8-hch@lst.de Signed-off-by: Jens Axboe

block: downgrade a bio_full call in bio_add_page

2023-07-25T01:55:16+00:00

bio_add_page already checks that there is space in bi_size a little earlier. So after we failed to add to an existing segment, just check that there is another one available instead of duplicating the bi_size check. Signed-off-by: Christoph Hellwig Reviewed-by: Jinyoung Choi Link: https://lore.kernel.org/r/20230724165433.117645-7-hch@lst.de Signed-off-by: Jens Axboe

block: move the bi_size overflow check in __bio_try_merge_page

2023-07-25T01:55:16+00:00

Checking for availability in bi_size in a function that attempts to merge into an existing segment is a bit odd, as the limit also applies when adding a new segment. This code works fine as we always call __bio_try_merge_page, but contributes to sub-optimal calling conventions and doesn't lead to clear code. Move it to two of the callers instead, the third one already has a more strict check that includes max_hw_segments anyway. Signed-off-by: Christoph Hellwig Reviewed-by: Jinyoung Choi Reviewed-by: Johannes Thumshirn Link: https://lore.kernel.org/r/20230724165433.117645-6-hch@lst.de Signed-off-by: Jens Axboe

block: move the bi_vcnt check out of __bio_try_merge_page

2023-07-25T01:55:16+00:00

Move the bi_vcnt out of __bio_try_merge_page and into the two callers that don't already have it in preparation for additional changes to __bio_try_merge_page. Signed-off-by: Christoph Hellwig Reviewed-by: Jinyoung Choi Reviewed-by: Johannes Thumshirn Link: https://lore.kernel.org/r/20230724165433.117645-5-hch@lst.de Signed-off-by: Jens Axboe