Commit 57a9d89d authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge branch 'for-linus' of git://git.kernel.dk/linux-block 

Pull block layer fix from Jens Axboe:
 "Just one patch in this pull request, fixing a regression caused by a
  'mathematically correct' change to lcm()"

* 'for-linus' of git://git.kernel.dk/linux-block:
  block: fix blk_stack_limits() regression due to lcm() change
parents 567cfea9 e9637415

block/blk-settings.c

+3 −3
Original line number Diff line number Diff line
@@ -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;

	}

include/linux/lcm.h

+1 −0
Original line number Diff line number Diff line
@@ -4,5 +4,6 @@ 
#include <linux/compiler.h>



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 */

lib/lcm.c

+11 −0
Original line number Diff line number Diff line
@@ -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);