From 762380ad9322951cea4ce9d24864265f9c66a916 Mon Sep 17 00:00:00 2001 From: Jens Axboe Date: Thu, 5 Jun 2014 13:38:39 -0600 Subject: block: add notion of a chunk size for request merging Some drivers have different limits on what size a request should optimally be, depending on the offset of the request. Similar to dividing a device into chunks. Add a setting that allows the driver to inform the block layer of such a chunk size. The block layer will then prevent merging across the chunks. This is needed to optimally support NVMe with a non-zero stripe size. Signed-off-by: Jens Axboe --- include/linux/blkdev.h | 22 +++++++++++++++++++++- 1 file changed, 21 insertions(+), 1 deletion(-) (limited to 'include/linux/blkdev.h') diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h index 3cd426e971db..dc2c703f05fd 100644 --- a/include/linux/blkdev.h +++ b/include/linux/blkdev.h @@ -280,6 +280,7 @@ struct queue_limits { unsigned long seg_boundary_mask; unsigned int max_hw_sectors; + unsigned int chunk_sectors; unsigned int max_sectors; unsigned int max_segment_size; unsigned int physical_block_size; @@ -910,6 +911,20 @@ static inline unsigned int blk_queue_get_max_sectors(struct request_queue *q, return q->limits.max_sectors; } +/* + * Return maximum size of a request at given offset. Only valid for + * file system requests. + */ +static inline unsigned int blk_max_size_offset(struct request_queue *q, + sector_t offset) +{ + if (!q->limits.chunk_sectors) + return q->limits.max_hw_sectors; + + return q->limits.chunk_sectors - + (offset & (q->limits.chunk_sectors - 1)); +} + static inline unsigned int blk_rq_get_max_sectors(struct request *rq) { struct request_queue *q = rq->q; @@ -917,7 +932,11 @@ static inline unsigned int blk_rq_get_max_sectors(struct request *rq) if (unlikely(rq->cmd_type == REQ_TYPE_BLOCK_PC)) return q->limits.max_hw_sectors; - return blk_queue_get_max_sectors(q, rq->cmd_flags); + if (!q->limits.chunk_sectors) + return blk_queue_get_max_sectors(q, rq->cmd_flags); + + return min(blk_max_size_offset(q, blk_rq_pos(rq)), + blk_queue_get_max_sectors(q, rq->cmd_flags)); } static inline unsigned int blk_rq_count_bios(struct request *rq) @@ -983,6 +1002,7 @@ extern void blk_queue_make_request(struct request_queue *, make_request_fn *); extern void blk_queue_bounce_limit(struct request_queue *, u64); extern void blk_limits_max_hw_sectors(struct queue_limits *, unsigned int); extern void blk_queue_max_hw_sectors(struct request_queue *, unsigned int); +extern void blk_queue_chunk_sectors(struct request_queue *, unsigned int); extern void blk_queue_max_segments(struct request_queue *, unsigned short); extern void blk_queue_max_segment_size(struct request_queue *, unsigned int); extern void blk_queue_max_discard_sectors(struct request_queue *q, -- cgit v1.2.3 From f27b087b81b70513b8c61ec20596c868f7b93474 Mon Sep 17 00:00:00 2001 From: Jens Axboe Date: Fri, 6 Jun 2014 07:57:37 -0600 Subject: block: add blk_rq_set_block_pc() With the optimizations around not clearing the full request at alloc time, we are leaving some of the needed init for REQ_TYPE_BLOCK_PC up to the user allocating the request. Add a blk_rq_set_block_pc() that sets the command type to REQ_TYPE_BLOCK_PC, and properly initializes the members associated with this type of request. Update callers to use this function instead of manipulating rq->cmd_type directly. Includes fixes from Christoph Hellwig for my half-assed attempt. Signed-off-by: Jens Axboe --- include/linux/blkdev.h | 1 + 1 file changed, 1 insertion(+) (limited to 'include/linux/blkdev.h') diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h index dc2c703f05fd..31e11051f1ba 100644 --- a/include/linux/blkdev.h +++ b/include/linux/blkdev.h @@ -796,6 +796,7 @@ extern void __blk_put_request(struct request_queue *, struct request *); extern struct request *blk_get_request(struct request_queue *, int, gfp_t); extern struct request *blk_make_request(struct request_queue *, struct bio *, gfp_t); +extern void blk_rq_set_block_pc(struct request *); extern void blk_requeue_request(struct request_queue *, struct request *); extern void blk_add_request_payload(struct request *rq, struct page *page, unsigned int len); -- cgit v1.2.3 From 736ed4de766d4f0e8e6142dd4f9d73ef61835ed9 Mon Sep 17 00:00:00 2001 From: Jens Axboe Date: Tue, 17 Jun 2014 22:09:29 -0700 Subject: block: blk_max_size_offset() should check ->max_sectors Commit 762380ad9322 inadvertently changed a check for max_sectors to max_hw_sectors. Revert that part, so we still compare against max_sectors. Signed-off-by: Jens Axboe --- include/linux/blkdev.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'include/linux/blkdev.h') diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h index 31e11051f1ba..713f8b62b435 100644 --- a/include/linux/blkdev.h +++ b/include/linux/blkdev.h @@ -920,7 +920,7 @@ static inline unsigned int blk_max_size_offset(struct request_queue *q, sector_t offset) { if (!q->limits.chunk_sectors) - return q->limits.max_hw_sectors; + return q->limits.max_sectors; return q->limits.chunk_sectors - (offset & (q->limits.chunk_sectors - 1)); -- cgit v1.2.3 From 66cb45aa41315d1d9972cada354fbdf7870d7714 Mon Sep 17 00:00:00 2001 From: Jens Axboe Date: Tue, 24 Jun 2014 16:22:24 -0600 Subject: block: add support for limiting gaps in SG lists Another restriction inherited for NVMe - those devices don't support SG lists that have "gaps" in them. Gaps refers to cases where the previous SG entry doesn't end on a page boundary. For NVMe, all SG entries must start at offset 0 (except the first) and end on a page boundary (except the last). Signed-off-by: Jens Axboe --- include/linux/blkdev.h | 1 + 1 file changed, 1 insertion(+) (limited to 'include/linux/blkdev.h') diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h index 713f8b62b435..8699bcf5f099 100644 --- a/include/linux/blkdev.h +++ b/include/linux/blkdev.h @@ -512,6 +512,7 @@ struct request_queue { #define QUEUE_FLAG_DEAD 19 /* queue tear-down finished */ #define QUEUE_FLAG_INIT_DONE 20 /* queue is initialized */ #define QUEUE_FLAG_NO_SG_MERGE 21 /* don't attempt to merge SG segments*/ +#define QUEUE_FLAG_SG_GAPS 22 /* queue doesn't support SG gaps */ #define QUEUE_FLAG_DEFAULT ((1 << QUEUE_FLAG_IO_STAT) | \ (1 << QUEUE_FLAG_STACKABLE) | \ -- cgit v1.2.3