This is a note to let you know that I've just added the patch titled
block: properly handle REQ_OP_ZONE_APPEND in __bio_split_to_limits
to the 6.11-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
block-properly-handle-req_op_zone_append-in-__bio_sp.patch
and it can be found in the queue-6.11 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit becf8078393cd8e497c0ad8f0be8effa2376e464
Author: Christoph Hellwig <hch@xxxxxx>
Date: Mon Aug 26 19:37:56 2024 +0200
block: properly handle REQ_OP_ZONE_APPEND in __bio_split_to_limits
[ Upstream commit 1e8a7f6af926e266cc1d7ac49b56bd064057d625 ]
Currently REQ_OP_ZONE_APPEND is handled by the bio_split_rw case in
__bio_split_to_limits. This is harmful because REQ_OP_ZONE_APPEND
bios do not adhere to the soft max_limits value but instead use their
own capped version of max_hw_sectors, leading to incorrect splits that
later blow up in bio_split.
We still need the bio_split_rw logic to count nr_segs for blk-mq code,
so add a new wrapper that passes in the right limit, and turns any bio
that would need a split into an error as an additional debugging aid.
Signed-off-by: Christoph Hellwig <hch@xxxxxx>
Reviewed-by: Damien Le Moal <dlemoal@xxxxxxxxxx>
Tested-by: Hans Holmberg <hans.holmberg@xxxxxxx>
Reviewed-by: Hans Holmberg <hans.holmberg@xxxxxxx>
Link: https://lore.kernel.org/r/20240826173820.1690925-4-hch@xxxxxx
Signed-off-by: Jens Axboe <axboe@xxxxxxxxx>
Stable-dep-of: 60dc5ea6bcfd ("block: take chunk_sectors into account in bio_split_write_zeroes")
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/block/blk-merge.c b/block/blk-merge.c
index c7222c4685e06..56769c4bcd799 100644
--- a/block/blk-merge.c
+++ b/block/blk-merge.c
@@ -378,6 +378,26 @@ struct bio *bio_split_rw(struct bio *bio, const struct queue_limits *lim,
get_max_io_size(bio, lim) << SECTOR_SHIFT));
}
+/*
+ * REQ_OP_ZONE_APPEND bios must never be split by the block layer.
+ *
+ * But we want the nr_segs calculation provided by bio_split_rw_at, and having
+ * a good sanity check that the submitter built the bio correctly is nice to
+ * have as well.
+ */
+struct bio *bio_split_zone_append(struct bio *bio,
+ const struct queue_limits *lim, unsigned *nr_segs)
+{
+ unsigned int max_sectors = queue_limits_max_zone_append_sectors(lim);
+ int split_sectors;
+
+ split_sectors = bio_split_rw_at(bio, lim, nr_segs,
+ max_sectors << SECTOR_SHIFT);
+ if (WARN_ON_ONCE(split_sectors > 0))
+ split_sectors = -EINVAL;
+ return bio_submit_split(bio, split_sectors);
+}
+
/**
* bio_split_to_limits - split a bio to fit the queue limits
* @bio: bio to be split
diff --git a/block/blk.h b/block/blk.h
index 0d8cd64c12606..61c2afa67daab 100644
--- a/block/blk.h
+++ b/block/blk.h
@@ -337,6 +337,8 @@ struct bio *bio_split_write_zeroes(struct bio *bio,
const struct queue_limits *lim, unsigned *nsegs);
struct bio *bio_split_rw(struct bio *bio, const struct queue_limits *lim,
unsigned *nr_segs);
+struct bio *bio_split_zone_append(struct bio *bio,
+ const struct queue_limits *lim, unsigned *nr_segs);
/*
* All drivers must accept single-segments bios that are smaller than PAGE_SIZE.
@@ -375,6 +377,8 @@ static inline struct bio *__bio_split_to_limits(struct bio *bio,
return bio_split_rw(bio, lim, nr_segs);
*nr_segs = 1;
return bio;
+ case REQ_OP_ZONE_APPEND:
+ return bio_split_zone_append(bio, lim, nr_segs);
case REQ_OP_DISCARD:
case REQ_OP_SECURE_ERASE:
return bio_split_discard(bio, lim, nr_segs);
