diff options
| author | Bart Van Assche <bvanassche@acm.org> | 2020-05-18 21:07:36 -0700 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2020-05-19 09:40:29 -0600 |
| commit | 854b5f01dc6a7b59f0dddd646a80b1fcd767a8db (patch) | |
| tree | b2a5537dcf591125d869e6c3d7d97e9f59aab81a | |
| parent | c1527c0e12d461ff4c603996f77983f37b85c286 (diff) | |
block: Document the bio_vec properties
Since it is nontrivial that nth_page() does not have to be used for a
bio_vec, document this.
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
CC: Christoph Hellwig <hch@infradead.org>
Cc: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
| -rw-r--r-- | include/linux/bvec.h | 13 |
1 files changed, 11 insertions, 2 deletions
diff --git a/include/linux/bvec.h b/include/linux/bvec.h index a81c13ac1972..ac0c7299d5b8 100644 --- a/include/linux/bvec.h +++ b/include/linux/bvec.h @@ -12,8 +12,17 @@ #include <linux/errno.h> #include <linux/mm.h> -/* - * was unsigned short, but we might as well be ready for > 64kB I/O pages +/** + * struct bio_vec - a contiguous range of physical memory addresses + * @bv_page: First page associated with the address range. + * @bv_len: Number of bytes in the address range. + * @bv_offset: Start of the address range relative to the start of @bv_page. + * + * The following holds for a bvec if n * PAGE_SIZE < bv_offset + bv_len: + * + * nth_page(@bv_page, n) == @bv_page + n + * + * This holds because page_is_mergeable() checks the above property. */ struct bio_vec { struct page *bv_page; |