PAGE_SIZE is applied in some block device queue limits, this way is very fragile and is wrong: - queue limits are read from hardware, which is often one readonly hardware property - PAGE_SIZE is one config option which can be changed during build time. In RH lab, it has been found that max segment size of some mmc card is less than 64K, then this kind of card can't work in case of 64K PAGE_SIZE. Fix this issue by using BLK_MIN_SEGMENT_SIZE in related code for dealing with queue limits and checking if bio needn't split. Define BLK_MIN_SEGMENT_SIZE as 4K(minimized PAGE_SIZE). Cc: Yi Zhang <yi.zhang@xxxxxxxxxx> Cc: Luis Chamberlain <mcgrof@xxxxxxxxxx> Cc: John Garry <john.g.garry@xxxxxxxxxx> Cc: Bart Van Assche <bvanassche@xxxxxxx> Cc: Keith Busch <kbusch@xxxxxxxxxx> Link: https://lore.kernel.org/linux-block/20250102015620.500754-1-ming.lei@xxxxxxxxxx/ Signed-off-by: Ming Lei <ming.lei@xxxxxxxxxx> --- V2: - cover bio_split_rw_at() - add BLK_MIN_SEGMENT_SIZE block/blk-merge.c | 2 +- block/blk-settings.c | 6 +++--- block/blk.h | 2 +- include/linux/blkdev.h | 1 + 4 files changed, 6 insertions(+), 5 deletions(-) diff --git a/block/blk-merge.c b/block/blk-merge.c index 15cd231d560c..b55c52a42303 100644 --- a/block/blk-merge.c +++ b/block/blk-merge.c @@ -329,7 +329,7 @@ int bio_split_rw_at(struct bio *bio, const struct queue_limits *lim, if (nsegs < lim->max_segments && bytes + bv.bv_len <= max_bytes && - bv.bv_offset + bv.bv_len <= PAGE_SIZE) { + bv.bv_offset + bv.bv_len <= BLK_MIN_SEGMENT_SIZE) { nsegs++; bytes += bv.bv_len; } else { diff --git a/block/blk-settings.c b/block/blk-settings.c index c44dadc35e1e..539a64ad7989 100644 --- a/block/blk-settings.c +++ b/block/blk-settings.c @@ -303,7 +303,7 @@ int blk_validate_limits(struct queue_limits *lim) max_hw_sectors = min_not_zero(lim->max_hw_sectors, lim->max_dev_sectors); if (lim->max_user_sectors) { - if (lim->max_user_sectors < PAGE_SIZE / SECTOR_SIZE) + if (lim->max_user_sectors < BLK_MIN_SEGMENT_SIZE / SECTOR_SIZE) return -EINVAL; lim->max_sectors = min(max_hw_sectors, lim->max_user_sectors); } else if (lim->io_opt > (BLK_DEF_MAX_SECTORS_CAP << SECTOR_SHIFT)) { @@ -341,7 +341,7 @@ int blk_validate_limits(struct queue_limits *lim) */ if (!lim->seg_boundary_mask) lim->seg_boundary_mask = BLK_SEG_BOUNDARY_MASK; - if (WARN_ON_ONCE(lim->seg_boundary_mask < PAGE_SIZE - 1)) + if (WARN_ON_ONCE(lim->seg_boundary_mask < BLK_MIN_SEGMENT_SIZE - 1)) return -EINVAL; /* @@ -362,7 +362,7 @@ int blk_validate_limits(struct queue_limits *lim) */ if (!lim->max_segment_size) lim->max_segment_size = BLK_MAX_SEGMENT_SIZE; - if (WARN_ON_ONCE(lim->max_segment_size < PAGE_SIZE)) + if (WARN_ON_ONCE(lim->max_segment_size < BLK_MIN_SEGMENT_SIZE)) return -EINVAL; } diff --git a/block/blk.h b/block/blk.h index 90fa5f28ccab..cbfa8a3d4e42 100644 --- a/block/blk.h +++ b/block/blk.h @@ -359,7 +359,7 @@ static inline bool bio_may_need_split(struct bio *bio, const struct queue_limits *lim) { return lim->chunk_sectors || bio->bi_vcnt != 1 || - bio->bi_io_vec->bv_len + bio->bi_io_vec->bv_offset > PAGE_SIZE; + bio->bi_io_vec->bv_len + bio->bi_io_vec->bv_offset > BLK_MIN_SEGMENT_SIZE; } /** diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h index 248416ecd01c..32188af4051e 100644 --- a/include/linux/blkdev.h +++ b/include/linux/blkdev.h @@ -1163,6 +1163,7 @@ static inline bool bdev_is_partition(struct block_device *bdev) enum blk_default_limits { BLK_MAX_SEGMENTS = 128, BLK_SAFE_MAX_SECTORS = 255, + BLK_MIN_SEGMENT_SIZE = 4096, /* min(PAGE_SIZE) */ BLK_MAX_SEGMENT_SIZE = 65536, BLK_SEG_BOUNDARY_MASK = 0xFFFFFFFFUL, }; -- 2.47.1
