block: Stop using byte offsets
All callers of the stacking functions use 512-byte sector units rather than byte offsets. Simplify the code so the stacking functions take sectors when specifying data offsets. Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
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ce289321b7
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e03a72e136
3 changed files with 18 additions and 32 deletions
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@ -507,7 +507,7 @@ static unsigned int lcm(unsigned int a, unsigned int b)
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* blk_stack_limits - adjust queue_limits for stacked devices
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* @t: the stacking driver limits (top device)
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* @b: the underlying queue limits (bottom, component device)
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* @offset: offset to beginning of data within component device
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* @start: first data sector within component device
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*
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* Description:
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* This function is used by stacking drivers like MD and DM to ensure
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@ -525,10 +525,9 @@ static unsigned int lcm(unsigned int a, unsigned int b)
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* the alignment_offset is undefined.
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*/
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int blk_stack_limits(struct queue_limits *t, struct queue_limits *b,
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sector_t offset)
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sector_t start)
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{
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sector_t alignment;
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unsigned int top, bottom, ret = 0;
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unsigned int top, bottom, alignment, ret = 0;
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t->max_sectors = min_not_zero(t->max_sectors, b->max_sectors);
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t->max_hw_sectors = min_not_zero(t->max_hw_sectors, b->max_hw_sectors);
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@ -548,7 +547,7 @@ int blk_stack_limits(struct queue_limits *t, struct queue_limits *b,
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t->misaligned |= b->misaligned;
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alignment = queue_limit_alignment_offset(b, offset);
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alignment = queue_limit_alignment_offset(b, start);
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/* Bottom device has different alignment. Check that it is
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* compatible with the current top alignment.
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@ -611,11 +610,7 @@ int blk_stack_limits(struct queue_limits *t, struct queue_limits *b,
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/* Discard alignment and granularity */
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if (b->discard_granularity) {
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unsigned int granularity = b->discard_granularity;
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offset &= granularity - 1;
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alignment = (granularity + b->discard_alignment - offset)
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& (granularity - 1);
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alignment = queue_limit_discard_alignment(b, start);
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if (t->discard_granularity != 0 &&
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t->discard_alignment != alignment) {
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@ -657,7 +652,7 @@ int bdev_stack_limits(struct queue_limits *t, struct block_device *bdev,
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start += get_start_sect(bdev);
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return blk_stack_limits(t, &bq->limits, start << 9);
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return blk_stack_limits(t, &bq->limits, start);
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}
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EXPORT_SYMBOL(bdev_stack_limits);
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@ -668,9 +663,8 @@ EXPORT_SYMBOL(bdev_stack_limits);
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* @offset: offset to beginning of data within component device
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*
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* Description:
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* Merges the limits for two queues. Returns 0 if alignment
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* didn't change. Returns -1 if adding the bottom device caused
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* misalignment.
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* Merges the limits for a top level gendisk and a bottom level
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* block_device.
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*/
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void disk_stack_limits(struct gendisk *disk, struct block_device *bdev,
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sector_t offset)
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@ -678,9 +672,7 @@ void disk_stack_limits(struct gendisk *disk, struct block_device *bdev,
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struct request_queue *t = disk->queue;
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struct request_queue *b = bdev_get_queue(bdev);
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offset += get_start_sect(bdev) << 9;
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if (blk_stack_limits(&t->limits, &b->limits, offset) < 0) {
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if (bdev_stack_limits(&t->limits, bdev, offset >> 9) < 0) {
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char top[BDEVNAME_SIZE], bottom[BDEVNAME_SIZE];
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disk_name(disk, 0, top);
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@ -412,9 +412,10 @@ struct hd_struct *add_partition(struct gendisk *disk, int partno,
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pdev = part_to_dev(p);
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p->start_sect = start;
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p->alignment_offset = queue_sector_alignment_offset(disk->queue, start);
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p->discard_alignment = queue_sector_discard_alignment(disk->queue,
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start);
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p->alignment_offset =
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queue_limit_alignment_offset(&disk->queue->limits, start);
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p->discard_alignment =
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queue_limit_discard_alignment(&disk->queue->limits, start);
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p->nr_sects = len;
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p->partno = partno;
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p->policy = get_disk_ro(disk);
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@ -1112,18 +1112,13 @@ static inline int queue_alignment_offset(struct request_queue *q)
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return q->limits.alignment_offset;
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}
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static inline int queue_limit_alignment_offset(struct queue_limits *lim, sector_t offset)
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static inline int queue_limit_alignment_offset(struct queue_limits *lim, sector_t sector)
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{
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unsigned int granularity = max(lim->physical_block_size, lim->io_min);
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unsigned int alignment = (sector << 9) & (granularity - 1);
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offset &= granularity - 1;
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return (granularity + lim->alignment_offset - offset) & (granularity - 1);
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}
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static inline int queue_sector_alignment_offset(struct request_queue *q,
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sector_t sector)
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{
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return queue_limit_alignment_offset(&q->limits, sector << 9);
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return (granularity + lim->alignment_offset - alignment)
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& (granularity - 1);
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}
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static inline int bdev_alignment_offset(struct block_device *bdev)
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@ -1147,10 +1142,8 @@ static inline int queue_discard_alignment(struct request_queue *q)
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return q->limits.discard_alignment;
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}
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static inline int queue_sector_discard_alignment(struct request_queue *q,
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sector_t sector)
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static inline int queue_limit_discard_alignment(struct queue_limits *lim, sector_t sector)
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{
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struct queue_limits *lim = &q->limits;
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unsigned int alignment = (sector << 9) & (lim->discard_granularity - 1);
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return (lim->discard_granularity + lim->discard_alignment - alignment)
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