From 8dd2cb7e880d2f77fba53b523c99133ad5054cfd Mon Sep 17 00:00:00 2001 From: Shaohua Li Date: Fri, 14 Dec 2012 11:15:36 +0800 Subject: block: discard granularity might not be power of 2 In MD raid case, discard granularity might not be power of 2, for example, a 4-disk raid5 has 3*chunk_size discard granularity. Correct the calculation for such cases. Reported-by: Neil Brown Signed-off-by: Shaohua Li Signed-off-by: Jens Axboe --- block/blk-settings.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) (limited to 'block/blk-settings.c') diff --git a/block/blk-settings.c b/block/blk-settings.c index 779bb7646bc..c50ecf0ea3b 100644 --- a/block/blk-settings.c +++ b/block/blk-settings.c @@ -611,7 +611,7 @@ int blk_stack_limits(struct queue_limits *t, struct queue_limits *b, bottom = b->discard_granularity + alignment; /* Verify that top and bottom intervals line up */ - if (max(top, bottom) & (min(top, bottom) - 1)) + if ((max(top, bottom) % min(top, bottom)) != 0) t->discard_misaligned = 1; } @@ -619,8 +619,8 @@ int blk_stack_limits(struct queue_limits *t, struct queue_limits *b, b->max_discard_sectors); t->discard_granularity = max(t->discard_granularity, b->discard_granularity); - t->discard_alignment = lcm(t->discard_alignment, alignment) & - (t->discard_granularity - 1); + t->discard_alignment = lcm(t->discard_alignment, alignment) % + t->discard_granularity; } return ret; -- cgit v1.2.3