diff --git a/block/blk-settings.c b/block/blk-settings.c index 6ed2cbe5e8c9..12600bfffca9 100644 --- a/block/blk-settings.c +++ b/block/blk-settings.c @@ -585,7 +585,7 @@ int blk_stack_limits(struct queue_limits *t, struct queue_limits *b, b->physical_block_size); t->io_min = max(t->io_min, b->io_min); - t->io_opt = lcm(t->io_opt, b->io_opt); + t->io_opt = lcm_not_zero(t->io_opt, b->io_opt); t->cluster &= b->cluster; t->discard_zeroes_data &= b->discard_zeroes_data; @@ -616,7 +616,7 @@ int blk_stack_limits(struct queue_limits *t, struct queue_limits *b, b->raid_partial_stripes_expensive); /* Find lowest common alignment_offset */ - t->alignment_offset = lcm(t->alignment_offset, alignment) + t->alignment_offset = lcm_not_zero(t->alignment_offset, alignment) % max(t->physical_block_size, t->io_min); /* Verify that new alignment_offset is on a logical block boundary */ @@ -643,7 +643,7 @@ 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_alignment = lcm_not_zero(t->discard_alignment, alignment) % t->discard_granularity; } diff --git a/include/linux/lcm.h b/include/linux/lcm.h index 7bf01d779b45..1ce79a7f1daa 100644 --- a/include/linux/lcm.h +++ b/include/linux/lcm.h @@ -4,5 +4,6 @@ #include unsigned long lcm(unsigned long a, unsigned long b) __attribute_const__; +unsigned long lcm_not_zero(unsigned long a, unsigned long b) __attribute_const__; #endif /* _LCM_H */ diff --git a/lib/lcm.c b/lib/lcm.c index e97dbd51e756..03d7fcb420b5 100644 --- a/lib/lcm.c +++ b/lib/lcm.c @@ -12,3 +12,14 @@ unsigned long lcm(unsigned long a, unsigned long b) return 0; } EXPORT_SYMBOL_GPL(lcm); + +unsigned long lcm_not_zero(unsigned long a, unsigned long b) +{ + unsigned long l = lcm(a, b); + + if (l) + return l; + + return (b ? : a); +} +EXPORT_SYMBOL_GPL(lcm_not_zero);