block: Fix discard topology stacking and reporting

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.

Martin K. Petersen committed 15 years ago

Commit a934a001 parent bbdd3043 files · +9 −4Browse files

Unified · Split

3 files

block/blk-settings.c +2 −1
block/blk-sysfs.c +2 −1
include/linux/blkdev.h +5 −2

block/blk-settings.c+2−1

@@ -120,7 +120,7 @@ void blk_set_default_limits(struct queue_limits *lim) · 119 unmodified lines
120	120	lim->discard_granularity = 0;
121	121	lim->discard_alignment = 0;
122	122	lim->discard_misaligned = 0;
123		− lim->discard_zeroes_data = -1;
	123	+ lim->discard_zeroes_data = 1;
124	124	lim->logical_block_size = lim->physical_block_size = lim->io_min = 512;
125	125	lim->bounce_pfn = (unsigned long)(BLK_BOUNCE_ANY >> PAGE_SHIFT);
126	126	lim->alignment_offset = 0;
@@ -166,6 +166,7 @@ void blk_queue_make_request(struct request_queue q, make_request_fn mfn) · 39 unmodified lines
166	166
167	167	blk_set_default_limits(&q->limits);
168	168	blk_queue_max_hw_sectors(q, BLK_SAFE_MAX_SECTORS);
	169	+ q->limits.discard_zeroes_data = 0;
169	170
170	171	/*
171	172	* by default assume old behaviour and bounce for any highmem page

block/blk-sysfs.c+2−1

@@ -152,7 +152,8 @@ static ssize_t queue_discard_granularity_show(struct request_queue q, char pag · 151 unmodified lines
152	152
153	153	static ssize_t queue_discard_max_show(struct request_queue q, char page)
154	154	{
155		− return queue_var_show(q->limits.max_discard_sectors << 9, page);
	155	+ return sprintf(page, "%llu\n",
	156	+ (unsigned long long)q->limits.max_discard_sectors << 9);
156	157	}
157	158
158	159	static ssize_t queue_discard_zeroes_data_show(struct request_queue q, char page)

include/linux/blkdev.h+5−2

@@ -257,7 +257,7 @@ struct queue_limits { · 256 unmodified lines
257	257	unsigned char misaligned;
258	258	unsigned char discard_misaligned;
259	259	unsigned char cluster;
260		− signed char discard_zeroes_data;
	260	+ unsigned char discard_zeroes_data;
261	261	};
262	262
263	263	struct request_queue
@@ -1069,13 +1069,16 @@ static inline int queue_limit_discard_alignment(struct queue_limits *lim, sector · 805 unmodified lines
1069	1069	{
1070	1070	unsigned int alignment = (sector << 9) & (lim->discard_granularity - 1);
1071	1071
	1072	+ if (!lim->max_discard_sectors)
	1073	+ return 0;
	1074	+
1072	1075	return (lim->discard_granularity + lim->discard_alignment - alignment)
1073	1076	& (lim->discard_granularity - 1);
1074	1077	}
1075	1078
1076	1079	static inline unsigned int queue_discard_zeroes_data(struct request_queue *q)
1077	1080	{
1078		− if (q->limits.discard_zeroes_data == 1)
	1081	+ if (q->limits.max_discard_sectors && q->limits.discard_zeroes_data == 1)
1079	1082	return 1;
1080	1083
1081	1084	return 0;