Re: [PATCH] block: check for max_hw_sectors underflow

[Bart Van Assche]

On 5/24/24 02:57, Hannes Reinecke wrote:

diff --git a/block/blk-settings.c b/block/blk-settings.c
index 524cf597b2e9..0cdca702e988 100644
--- a/block/blk-settings.c
+++ b/block/blk-settings.c
@@ -133,6 +133,8 @@ static int blk_validate_limits(struct queue_limits *lim)
                lim->max_hw_sectors = BLK_SAFE_MAX_SECTORS;
        if (WARN_ON_ONCE(lim->max_hw_sectors < PAGE_SECTORS))
                return -EINVAL;
+       if (WARN_ON_ONCE((lim->logical_block_size >> SECTOR_SHIFT) > 
lim->max_hw_sectors))
+               return -EINVAL;
        lim->max_hw_sectors = round_down(lim->max_hw_sectors,
                        lim->logical_block_size >> SECTOR_SHIFT);

Why is lim->max_hw_sectors checked before calling round_down() instead
of checking that round_down() returns zero?

Thanks,

Bart.