projects/linux·commit 57a9d89d

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

57a9d89d · Linus Torvalds <[email protected]> · 2015-04-03 14:49:26 -07:00

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
Commit
57a9d89dc093d86920748fa706fd55f4fcd2399a
Parents
567cfea9 · e9637415

Merge commit. Changes below are compared with the first parent: 567cfea9.

Changes

3 files changed · +15 −3

FileStatusAddDelContent
block/blk-settings.cmodified+3−3View file
include/linux/lcm.hmodified+1−0View file
lib/lcm.cmodified+11−0View file

block/blk-settings.c

View file
diff --git a/block/blk-settings.c b/block/blk-settings.c
index 6ed2cbe..12600bf 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;
}

include/linux/lcm.h

View file
diff --git a/include/linux/lcm.h b/include/linux/lcm.h
index 7bf01d7..1ce79a7 100644
--- a/include/linux/lcm.h
+++ b/include/linux/lcm.h
@@ -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

View file
diff --git a/lib/lcm.c b/lib/lcm.c
index e97dbd5..03d7fcb 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);