blk_stack_limits() can set discard_granularity bigger than max_discard_sectors (in bytes). This makes blk_bio_discard_split() non-functional and can lead to data corruption.
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From: Florian-Ewald Mueller <[email protected]> Subject: [PATCH] blk_stack_limits() blk_stack_limits() can set discard_granularity bigger than max_discard_sectors (in bytes). This makes blk_bio_discard_split() non-functional and can lead to data corruption. Signed-off-by: Florian-Ewald Mueller <[email protected]> --- linux-4.7-rc7/block/blk-settings.c.orig 2016-07-21 19:39:44.831351396 +0200 +++ linux-4.7-rc7/block/blk-settings.c 2016-07-21 19:40:04.582968496 +0200 @@ -626,8 +626,10 @@ int blk_stack_limits(struct queue_limits b->max_hw_discard_sectors); t->discard_granularity = max(t->discard_granularity, b->discard_granularity); + if (t->discard_granularity > (t->max_discard_sectors << 9)) + t->discard_granularity = t->max_discard_sectors << 9; t->discard_alignment = lcm_not_zero(t->discard_alignment, alignment) % - t->discard_granularity; + (t->discard_granularity ? : 1); } return ret;
