From: Kent Overstreet <kent.overstreet@linux.dev>
To: linux-kernel@vger.kernel.org, axboe@kernel.dk
Cc: Kent Overstreet <kent.overstreet@linux.dev>,
linux-block@vger.kernel.org, linux-fsdevel@vger.kernel.org
Subject: [PATCH 2/7] block: Allow bio_iov_iter_get_pages() with bio->bi_bdev unset
Date: Thu, 25 May 2023 17:48:17 -0400 [thread overview]
Message-ID: <20230525214822.2725616-3-kent.overstreet@linux.dev> (raw)
In-Reply-To: <20230525214822.2725616-1-kent.overstreet@linux.dev>
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 <kent.overstreet@linux.dev>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: linux-block@vger.kernel.org
---
block/bio.c | 10 ++++++----
1 file changed, 6 insertions(+), 4 deletions(-)
diff --git a/block/bio.c b/block/bio.c
index 1e75840d17..e74a04ea14 100644
--- a/block/bio.c
+++ b/block/bio.c
@@ -1245,7 +1245,7 @@ static int __bio_iov_iter_get_pages(struct bio *bio, struct iov_iter *iter)
struct page **pages = (struct page **)bv;
ssize_t size, left;
unsigned len, i = 0;
- size_t offset, trim;
+ size_t offset;
int ret = 0;
/*
@@ -1274,10 +1274,12 @@ static int __bio_iov_iter_get_pages(struct bio *bio, struct iov_iter *iter)
nr_pages = DIV_ROUND_UP(offset + size, PAGE_SIZE);
- trim = size & (bdev_logical_block_size(bio->bi_bdev) - 1);
- iov_iter_revert(iter, trim);
+ if (bio->bi_bdev) {
+ size_t trim = size & (bdev_logical_block_size(bio->bi_bdev) - 1);
+ iov_iter_revert(iter, trim);
+ size -= trim;
+ }
- size -= trim;
if (unlikely(!size)) {
ret = -EFAULT;
goto out;
--
2.40.1
next prev parent reply other threads:[~2023-05-25 21:49 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-05-25 21:48 [PATCH 0/7] block layer patches for bcachefs Kent Overstreet
2023-05-25 21:48 ` [PATCH 1/7] block: Add some exports " Kent Overstreet
2023-05-25 21:48 ` Kent Overstreet [this message]
2023-05-25 21:48 ` [PATCH 3/7] block: Bring back zero_fill_bio_iter Kent Overstreet
2023-05-25 21:48 ` [PATCH 4/7] block: Rework bio_for_each_segment_all() Kent Overstreet
2023-05-25 21:48 ` [PATCH 5/7] block: Rework bio_for_each_folio_all() Kent Overstreet
2023-05-26 0:36 ` Dave Chinner
2023-05-26 0:50 ` Kent Overstreet
2023-05-25 21:48 ` [PATCH 6/7] block: Add documentation for bio iterator macros Kent Overstreet
2023-05-25 21:48 ` [PATCH 7/7] block: Don't block on s_umount from __invalidate_super() Kent Overstreet
2023-05-26 14:35 ` [PATCH 0/7] block layer patches for bcachefs Jens Axboe
2023-05-26 20:44 ` Kent Overstreet
2023-05-30 14:22 ` Jens Axboe
2023-05-30 16:06 ` Kent Overstreet
2023-05-30 16:50 ` Jens Axboe
2023-05-30 23:30 ` Kent Overstreet
2023-06-04 23:38 ` Kent Overstreet
2023-06-05 16:49 ` Jens Axboe
2023-06-05 21:26 ` Kent Overstreet
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