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Message-Id: <20230908193201.3462957-26-sashal@kernel.org>
Date: Fri, 8 Sep 2023 15:31:55 -0400
From: Sasha Levin <sashal@...nel.org>
To: linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc: Kent Overstreet <kent.overstreet@...ux.dev>,
Jens Axboe <axboe@...nel.dk>, linux-block@...r.kernel.org,
Sasha Levin <sashal@...nel.org>
Subject: [PATCH AUTOSEL 6.4 26/31] block: Allow bio_iov_iter_get_pages() with bio->bi_bdev unset
From: Kent Overstreet <kent.overstreet@...ux.dev>
[ Upstream commit 168145f617d57bf4e474901b7ffa869337a802e6 ]
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@...ux.dev>
Cc: Jens Axboe <axboe@...nel.dk>
Cc: linux-block@...r.kernel.org
Link: https://lore.kernel.org/r/20230813182636.2966159-3-kent.overstreet@linux.dev
Signed-off-by: Jens Axboe <axboe@...nel.dk>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
block/bio.c | 10 ++++++----
1 file changed, 6 insertions(+), 4 deletions(-)
diff --git a/block/bio.c b/block/bio.c
index 043944fd46ebb..e54f2a9cbf9ba 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
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