6.12-stable review patch. If anyone has any objections, please let me know.
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From: Christoph Hellwig hch@lst.de
[ Upstream commit 60dc5ea6bcfd078b71419640d49afa649acf9450 ]
For zoned devices, write zeroes must be split at the zone boundary which is represented as chunk_sectors. For other uses like the internally RAIDed NVMe devices it is probably at least useful.
Enhance get_max_io_size to know about write zeroes and use it in bio_split_write_zeroes. Also add a comment about the seemingly nonsensical zero max_write_zeroes limit.
Fixes: 885fa13f6559 ("block: implement splitting of REQ_OP_WRITE_ZEROES bios") Signed-off-by: Christoph Hellwig hch@lst.de Reviewed-by: Damien Le Moal dlemoal@kernel.org Link: https://lore.kernel.org/r/20241104062647.91160-2-hch@lst.de Signed-off-by: Jens Axboe axboe@kernel.dk Signed-off-by: Sasha Levin sashal@kernel.org --- block/blk-merge.c | 35 +++++++++++++++++++++++------------ 1 file changed, 23 insertions(+), 12 deletions(-)
diff --git a/block/blk-merge.c b/block/blk-merge.c index ad763ec313b6a..75d2461b69e40 100644 --- a/block/blk-merge.c +++ b/block/blk-merge.c @@ -166,17 +166,6 @@ struct bio *bio_split_discard(struct bio *bio, const struct queue_limits *lim, return bio_submit_split(bio, split_sectors); }
-struct bio *bio_split_write_zeroes(struct bio *bio, - const struct queue_limits *lim, unsigned *nsegs) -{ - *nsegs = 0; - if (!lim->max_write_zeroes_sectors) - return bio; - if (bio_sectors(bio) <= lim->max_write_zeroes_sectors) - return bio; - return bio_submit_split(bio, lim->max_write_zeroes_sectors); -} - static inline unsigned int blk_boundary_sectors(const struct queue_limits *lim, bool is_atomic) { @@ -211,7 +200,9 @@ static inline unsigned get_max_io_size(struct bio *bio, * We ignore lim->max_sectors for atomic writes because it may less * than the actual bio size, which we cannot tolerate. */ - if (is_atomic) + if (bio_op(bio) == REQ_OP_WRITE_ZEROES) + max_sectors = lim->max_write_zeroes_sectors; + else if (is_atomic) max_sectors = lim->atomic_write_max_sectors; else max_sectors = lim->max_sectors; @@ -398,6 +389,26 @@ struct bio *bio_split_zone_append(struct bio *bio, return bio_submit_split(bio, split_sectors); }
+struct bio *bio_split_write_zeroes(struct bio *bio, + const struct queue_limits *lim, unsigned *nsegs) +{ + unsigned int max_sectors = get_max_io_size(bio, lim); + + *nsegs = 0; + + /* + * An unset limit should normally not happen, as bio submission is keyed + * off having a non-zero limit. But SCSI can clear the limit in the + * I/O completion handler, and we can race and see this. Splitting to a + * zero limit obviously doesn't make sense, so band-aid it here. + */ + if (!max_sectors) + return bio; + if (bio_sectors(bio) <= max_sectors) + return bio; + return bio_submit_split(bio, max_sectors); +} + /** * bio_split_to_limits - split a bio to fit the queue limits * @bio: bio to be split