block: sanitize chunk_sectors for atomic write limits

Currently we just ensure that a non-zero value in chunk_sectors aligns
with any atomic write boundary, as the blk boundary functionality uses
both these values.

However it is also improper to have atomic write unit max > chunk_sectors
(for non-zero chunk_sectors), as this would lead to splitting of atomic
write bios (which is disallowed).

Sanitize atomic write unit max against chunk_sectors to avoid any
potential problems.

Fixes: d00eea91deaf3 ("block: Add extra checks in blk_validate_atomic_write_limits()")
Reviewed-by: Nilay Shroff <nilay@linux.ibm.com>
Signed-off-by: John Garry <john.g.garry@oracle.com>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Link: https://lore.kernel.org/r/20250711105258.3135198-3-john.g.garry@oracle.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/block/blk-settings.c b/block/blk-settings.c
index a000daafbfb489fa6a23c794af0f9bbe3513e1bb..3425ae1b1f014654e59bab357cb54bb87cb98f7e 100644 (file)
--- a/block/blk-settings.c
+++ b/block/blk-settings.c
@@ -181,6 +181,8 @@ static void blk_atomic_writes_update_limits(struct queue_limits *lim)
 static void blk_validate_atomic_write_limits(struct queue_limits *lim)
 {
        unsigned int boundary_sectors;
+       unsigned int atomic_write_hw_max_sectors =
+                       lim->atomic_write_hw_max >> SECTOR_SHIFT;
 
        if (!(lim->features & BLK_FEAT_ATOMIC_WRITES))
                goto unsupported;
@@ -202,6 +204,10 @@ static void blk_validate_atomic_write_limits(struct queue_limits *lim)
                         lim->atomic_write_hw_max))
                goto unsupported;
 
+       if (WARN_ON_ONCE(lim->chunk_sectors &&
+                       atomic_write_hw_max_sectors > lim->chunk_sectors))
+               goto unsupported;
+
        boundary_sectors = lim->atomic_write_hw_boundary >> SECTOR_SHIFT;
 
        if (boundary_sectors) {