summaryrefslogtreecommitdiff
path: root/include/linux
diff options
context:
space:
mode:
Diffstat (limited to 'include/linux')
-rw-r--r--include/linux/blkdev.h42
-rw-r--r--include/linux/device-mapper.h2
-rw-r--r--include/linux/ide.h1
3 files changed, 31 insertions, 14 deletions
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index bd2cac892325..a7b535c265e1 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -836,6 +836,19 @@ static inline struct request_queue *bdev_get_queue(struct block_device *bdev)
}
/*
+ * The basic unit of block I/O is a sector. It is used in a number of contexts
+ * in Linux (blk, bio, genhd). The size of one sector is 512 = 2**9
+ * bytes. Variables of type sector_t represent an offset or size that is a
+ * multiple of 512 bytes. Hence these two constants.
+ */
+#ifndef SECTOR_SHIFT
+#define SECTOR_SHIFT 9
+#endif
+#ifndef SECTOR_SIZE
+#define SECTOR_SIZE (1 << SECTOR_SHIFT)
+#endif
+
+/*
* blk_rq_pos() : the current sector
* blk_rq_bytes() : bytes left in the entire request
* blk_rq_cur_bytes() : bytes left in the current segment
@@ -862,19 +875,20 @@ extern unsigned int blk_rq_err_bytes(const struct request *rq);
static inline unsigned int blk_rq_sectors(const struct request *rq)
{
- return blk_rq_bytes(rq) >> 9;
+ return blk_rq_bytes(rq) >> SECTOR_SHIFT;
}
static inline unsigned int blk_rq_cur_sectors(const struct request *rq)
{
- return blk_rq_cur_bytes(rq) >> 9;
+ return blk_rq_cur_bytes(rq) >> SECTOR_SHIFT;
}
static inline unsigned int blk_queue_get_max_sectors(struct request_queue *q,
unsigned int cmd_flags)
{
if (unlikely(cmd_flags & REQ_DISCARD))
- return min(q->limits.max_discard_sectors, UINT_MAX >> 9);
+ return min(q->limits.max_discard_sectors,
+ UINT_MAX >> SECTOR_SHIFT);
if (unlikely(cmd_flags & REQ_WRITE_SAME))
return q->limits.max_write_same_sectors;
@@ -1137,16 +1151,21 @@ extern int blkdev_issue_zeroout(struct block_device *bdev, sector_t sector,
static inline int sb_issue_discard(struct super_block *sb, sector_t block,
sector_t nr_blocks, gfp_t gfp_mask, unsigned long flags)
{
- return blkdev_issue_discard(sb->s_bdev, block << (sb->s_blocksize_bits - 9),
- nr_blocks << (sb->s_blocksize_bits - 9),
+ return blkdev_issue_discard(sb->s_bdev,
+ block << (sb->s_blocksize_bits -
+ SECTOR_SHIFT),
+ nr_blocks << (sb->s_blocksize_bits -
+ SECTOR_SHIFT),
gfp_mask, flags);
}
static inline int sb_issue_zeroout(struct super_block *sb, sector_t block,
sector_t nr_blocks, gfp_t gfp_mask)
{
return blkdev_issue_zeroout(sb->s_bdev,
- block << (sb->s_blocksize_bits - 9),
- nr_blocks << (sb->s_blocksize_bits - 9),
+ block << (sb->s_blocksize_bits -
+ SECTOR_SHIFT),
+ nr_blocks << (sb->s_blocksize_bits -
+ SECTOR_SHIFT),
gfp_mask, true);
}
@@ -1253,7 +1272,8 @@ static inline int queue_alignment_offset(struct request_queue *q)
static inline int queue_limit_alignment_offset(struct queue_limits *lim, sector_t sector)
{
unsigned int granularity = max(lim->physical_block_size, lim->io_min);
- unsigned int alignment = sector_div(sector, granularity >> 9) << 9;
+ unsigned int alignment = sector_div(sector, granularity >> SECTOR_SHIFT)
+ << SECTOR_SHIFT;
return (granularity + lim->alignment_offset - alignment) % granularity;
}
@@ -1287,8 +1307,8 @@ static inline int queue_limit_discard_alignment(struct queue_limits *lim, sector
return 0;
/* Why are these in bytes, not sectors? */
- alignment = lim->discard_alignment >> 9;
- granularity = lim->discard_granularity >> 9;
+ alignment = lim->discard_alignment >> SECTOR_SHIFT;
+ granularity = lim->discard_granularity >> SECTOR_SHIFT;
if (!granularity)
return 0;
@@ -1299,7 +1319,7 @@ static inline int queue_limit_discard_alignment(struct queue_limits *lim, sector
offset = (granularity + alignment - offset) % granularity;
/* Turn it back into bytes, gaah */
- return offset << 9;
+ return offset << SECTOR_SHIFT;
}
static inline int bdev_discard_alignment(struct block_device *bdev)
diff --git a/include/linux/device-mapper.h b/include/linux/device-mapper.h
index 4a08fef28acc..37d40dec74b4 100644
--- a/include/linux/device-mapper.h
+++ b/include/linux/device-mapper.h
@@ -556,8 +556,6 @@ extern struct ratelimit_state dm_ratelimit_state;
#define DMEMIT(x...) sz += ((sz >= maxlen) ? \
0 : scnprintf(result + sz, maxlen - sz, x))
-#define SECTOR_SHIFT 9
-
/*
* Definitions of return values from target end_io function.
*/
diff --git a/include/linux/ide.h b/include/linux/ide.h
index a633898f36ac..eb2ac48c99db 100644
--- a/include/linux/ide.h
+++ b/include/linux/ide.h
@@ -128,7 +128,6 @@ struct ide_io_ports {
*/
#define PARTN_BITS 6 /* number of minor dev bits for partitions */
#define MAX_DRIVES 2 /* per interface; 2 assumed by lots of code */
-#define SECTOR_SIZE 512
/*
* Timeouts for various operations: