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authorMartin K. Petersen <martin.petersen@oracle.com>2011-05-18 10:37:35 +0200
committerGreg Kroah-Hartman <gregkh@suse.de>2011-06-03 10:33:44 +0900
commit5d8ddba27676c7f753b01ac75f90ea90be0ffcea (patch)
tree6d9470748405d37ea71ceef1c94e95e71b9b641a
parentc63356c3ed12f1242ec7fb4b14a6a28b0e0c72a2 (diff)
block: Fix discard topology stacking and reporting
commit a934a00a69e940b126b9bdbf83e630ef5fe43523 upstream. In some cases we would end up stacking discard_zeroes_data incorrectly. Fix this by enabling the feature by default for stacking drivers and clearing it for low-level drivers. Incorporating a device that does not support dzd will then cause the feature to be disabled in the stacking driver. Also ensure that the maximum discard value does not overflow when exported in sysfs and return 0 in the alignment and dzd fields for devices that don't support discard. Reported-by: Lukas Czerner <lczerner@redhat.com> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com> Acked-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Jens Axboe <jaxboe@fusionio.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
-rw-r--r--block/blk-settings.c3
-rw-r--r--block/blk-sysfs.c3
-rw-r--r--include/linux/blkdev.h7
3 files changed, 9 insertions, 4 deletions
diff --git a/block/blk-settings.c b/block/blk-settings.c
index 36c8c1f2af1..0aef26e6dc2 100644
--- a/block/blk-settings.c
+++ b/block/blk-settings.c
@@ -120,7 +120,7 @@ void blk_set_default_limits(struct queue_limits *lim)
lim->discard_granularity = 0;
lim->discard_alignment = 0;
lim->discard_misaligned = 0;
- lim->discard_zeroes_data = -1;
+ lim->discard_zeroes_data = 1;
lim->logical_block_size = lim->physical_block_size = lim->io_min = 512;
lim->bounce_pfn = (unsigned long)(BLK_BOUNCE_ANY >> PAGE_SHIFT);
lim->alignment_offset = 0;
@@ -174,6 +174,7 @@ void blk_queue_make_request(struct request_queue *q, make_request_fn *mfn)
blk_set_default_limits(&q->limits);
blk_queue_max_hw_sectors(q, BLK_SAFE_MAX_SECTORS);
+ q->limits.discard_zeroes_data = 0;
/*
* If the caller didn't supply a lock, fall back to our embedded
diff --git a/block/blk-sysfs.c b/block/blk-sysfs.c
index 3655e193e60..629070309f0 100644
--- a/block/blk-sysfs.c
+++ b/block/blk-sysfs.c
@@ -152,7 +152,8 @@ static ssize_t queue_discard_granularity_show(struct request_queue *q, char *pag
static ssize_t queue_discard_max_show(struct request_queue *q, char *page)
{
- return queue_var_show(q->limits.max_discard_sectors << 9, page);
+ return sprintf(page, "%llu\n",
+ (unsigned long long)q->limits.max_discard_sectors << 9);
}
static ssize_t queue_discard_zeroes_data_show(struct request_queue *q, char *page)
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index d5063e1b555..65661479a23 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -252,7 +252,7 @@ struct queue_limits {
unsigned char misaligned;
unsigned char discard_misaligned;
unsigned char cluster;
- signed char discard_zeroes_data;
+ unsigned char discard_zeroes_data;
};
struct request_queue
@@ -1032,13 +1032,16 @@ static inline int queue_limit_discard_alignment(struct queue_limits *lim, sector
{
unsigned int alignment = (sector << 9) & (lim->discard_granularity - 1);
+ if (!lim->max_discard_sectors)
+ return 0;
+
return (lim->discard_granularity + lim->discard_alignment - alignment)
& (lim->discard_granularity - 1);
}
static inline unsigned int queue_discard_zeroes_data(struct request_queue *q)
{
- if (q->limits.discard_zeroes_data == 1)
+ if (q->limits.max_discard_sectors && q->limits.discard_zeroes_data == 1)
return 1;
return 0;