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 --- block/blk-core.c | 18 ++++++++++++++++++ block/bsg.c | 3 ++- block/scsi_ioctl.c | 6 +++--- drivers/block/pktcdvd.c | 2 +- drivers/cdrom/cdrom.c | 2 +- drivers/scsi/device_handler/scsi_dh_alua.c | 2 +- drivers/scsi/device_handler/scsi_dh_emc.c | 2 +- drivers/scsi/device_handler/scsi_dh_hp_sw.c | 4 ++-- drivers/scsi/device_handler/scsi_dh_rdac.c | 2 +- drivers/scsi/osd/osd_initiator.c | 4 ++-- drivers/scsi/osst.c | 2 +- drivers/scsi/scsi_error.c | 3 ++- drivers/scsi/scsi_lib.c | 2 +- drivers/scsi/sg.c | 3 +-- drivers/scsi/st.c | 2 +- drivers/target/target_core_pscsi.c | 3 ++- include/linux/blkdev.h | 1 + 17 files changed, 41 insertions(+), 20 deletions(-) (limited to 'include/linux/blkdev.h') diff --git a/block/blk-core.c b/block/blk-core.c index 40d654861c33..9aca8c71e70b 100644 --- a/block/blk-core.c +++ b/block/blk-core.c @@ -1218,6 +1218,8 @@ struct request *blk_make_request(struct request_queue *q, struct bio *bio, if (unlikely(!rq)) return ERR_PTR(-ENOMEM); + blk_rq_set_block_pc(rq); + for_each_bio(bio) { struct bio *bounce_bio = bio; int ret; @@ -1234,6 +1236,22 @@ struct request *blk_make_request(struct request_queue *q, struct bio *bio, } EXPORT_SYMBOL(blk_make_request); +/** + * blk_rq_set_block_pc - initialize a requeest to type BLOCK_PC + * @rq: request to be initialized + * + */ +void blk_rq_set_block_pc(struct request *rq) +{ + rq->cmd_type = REQ_TYPE_BLOCK_PC; + rq->__data_len = 0; + rq->__sector = (sector_t) -1; + rq->bio = rq->biotail = NULL; + memset(rq->__cmd, 0, sizeof(rq->__cmd)); + rq->cmd = rq->__cmd; +} +EXPORT_SYMBOL(blk_rq_set_block_pc); + /** * blk_requeue_request - put a request back on queue * @q: request queue where request should be inserted diff --git a/block/bsg.c b/block/bsg.c index e5214c148096..ff46addde5d8 100644 --- a/block/bsg.c +++ b/block/bsg.c @@ -196,7 +196,6 @@ static int blk_fill_sgv4_hdr_rq(struct request_queue *q, struct request *rq, * fill in request structure */ rq->cmd_len = hdr->request_len; - rq->cmd_type = REQ_TYPE_BLOCK_PC; rq->timeout = msecs_to_jiffies(hdr->timeout); if (!rq->timeout) @@ -273,6 +272,8 @@ bsg_map_hdr(struct bsg_device *bd, struct sg_io_v4 *hdr, fmode_t has_write_perm, rq = blk_get_request(q, rw, GFP_KERNEL); if (!rq) return ERR_PTR(-ENOMEM); + blk_rq_set_block_pc(rq); + ret = blk_fill_sgv4_hdr_rq(q, rq, hdr, bd, has_write_perm); if (ret) goto out; diff --git a/block/scsi_ioctl.c b/block/scsi_ioctl.c index 9c28a5b38042..14695c6221c8 100644 --- a/block/scsi_ioctl.c +++ b/block/scsi_ioctl.c @@ -229,7 +229,6 @@ static int blk_fill_sghdr_rq(struct request_queue *q, struct request *rq, * fill in request structure */ rq->cmd_len = hdr->cmd_len; - rq->cmd_type = REQ_TYPE_BLOCK_PC; rq->timeout = msecs_to_jiffies(hdr->timeout); if (!rq->timeout) @@ -311,6 +310,7 @@ static int sg_io(struct request_queue *q, struct gendisk *bd_disk, rq = blk_get_request(q, writing ? WRITE : READ, GFP_KERNEL); if (!rq) return -ENOMEM; + blk_rq_set_block_pc(rq); if (blk_fill_sghdr_rq(q, rq, hdr, mode)) { blk_put_request(rq); @@ -491,7 +491,7 @@ int sg_scsi_ioctl(struct request_queue *q, struct gendisk *disk, fmode_t mode, memset(sense, 0, sizeof(sense)); rq->sense = sense; rq->sense_len = 0; - rq->cmd_type = REQ_TYPE_BLOCK_PC; + blk_rq_set_block_pc(rq); blk_execute_rq(q, disk, rq, 0); @@ -524,7 +524,7 @@ static int __blk_send_generic(struct request_queue *q, struct gendisk *bd_disk, int err; rq = blk_get_request(q, WRITE, __GFP_WAIT); - rq->cmd_type = REQ_TYPE_BLOCK_PC; + blk_rq_set_block_pc(rq); rq->timeout = BLK_DEFAULT_SG_TIMEOUT; rq->cmd[0] = cmd; rq->cmd[4] = data; diff --git a/drivers/block/pktcdvd.c b/drivers/block/pktcdvd.c index ef166ad2dbad..758ac442c5b5 100644 --- a/drivers/block/pktcdvd.c +++ b/drivers/block/pktcdvd.c @@ -704,6 +704,7 @@ static int pkt_generic_packet(struct pktcdvd_device *pd, struct packet_command * rq = blk_get_request(q, (cgc->data_direction == CGC_DATA_WRITE) ? WRITE : READ, __GFP_WAIT); + blk_rq_set_block_pc(rq); if (cgc->buflen) { ret = blk_rq_map_kern(q, rq, cgc->buffer, cgc->buflen, @@ -716,7 +717,6 @@ static int pkt_generic_packet(struct pktcdvd_device *pd, struct packet_command * memcpy(rq->cmd, cgc->cmd, CDROM_PACKET_SIZE); rq->timeout = 60*HZ; - rq->cmd_type = REQ_TYPE_BLOCK_PC; if (cgc->quiet) rq->cmd_flags |= REQ_QUIET; diff --git a/drivers/cdrom/cdrom.c b/drivers/cdrom/cdrom.c index 49ac5662585b..0f40c95049c0 100644 --- a/drivers/cdrom/cdrom.c +++ b/drivers/cdrom/cdrom.c @@ -2184,6 +2184,7 @@ static int cdrom_read_cdda_bpc(struct cdrom_device_info *cdi, __u8 __user *ubuf, ret = -ENOMEM; break; } + blk_rq_set_block_pc(rq); ret = blk_rq_map_user(q, rq, NULL, ubuf, len, GFP_KERNEL); if (ret) { @@ -2203,7 +2204,6 @@ static int cdrom_read_cdda_bpc(struct cdrom_device_info *cdi, __u8 __user *ubuf, rq->cmd[9] = 0xf8; rq->cmd_len = 12; - rq->cmd_type = REQ_TYPE_BLOCK_PC; rq->timeout = 60 * HZ; bio = rq->bio; diff --git a/drivers/scsi/device_handler/scsi_dh_alua.c b/drivers/scsi/device_handler/scsi_dh_alua.c index 5248c888552b..7bcf67eec921 100644 --- a/drivers/scsi/device_handler/scsi_dh_alua.c +++ b/drivers/scsi/device_handler/scsi_dh_alua.c @@ -120,6 +120,7 @@ static struct request *get_alua_req(struct scsi_device *sdev, "%s: blk_get_request failed\n", __func__); return NULL; } + blk_rq_set_block_pc(rq); if (buflen && blk_rq_map_kern(q, rq, buffer, buflen, GFP_NOIO)) { blk_put_request(rq); @@ -128,7 +129,6 @@ static struct request *get_alua_req(struct scsi_device *sdev, return NULL; } - rq->cmd_type = REQ_TYPE_BLOCK_PC; rq->cmd_flags |= REQ_FAILFAST_DEV | REQ_FAILFAST_TRANSPORT | REQ_FAILFAST_DRIVER; rq->retries = ALUA_FAILOVER_RETRIES; diff --git a/drivers/scsi/device_handler/scsi_dh_emc.c b/drivers/scsi/device_handler/scsi_dh_emc.c index e1c8be06de9d..6f07f7fe3aa1 100644 --- a/drivers/scsi/device_handler/scsi_dh_emc.c +++ b/drivers/scsi/device_handler/scsi_dh_emc.c @@ -280,6 +280,7 @@ static struct request *get_req(struct scsi_device *sdev, int cmd, return NULL; } + blk_rq_set_block_pc(rq); rq->cmd_len = COMMAND_SIZE(cmd); rq->cmd[0] = cmd; @@ -304,7 +305,6 @@ static struct request *get_req(struct scsi_device *sdev, int cmd, break; } - rq->cmd_type = REQ_TYPE_BLOCK_PC; rq->cmd_flags |= REQ_FAILFAST_DEV | REQ_FAILFAST_TRANSPORT | REQ_FAILFAST_DRIVER; rq->timeout = CLARIION_TIMEOUT; diff --git a/drivers/scsi/device_handler/scsi_dh_hp_sw.c b/drivers/scsi/device_handler/scsi_dh_hp_sw.c index 084062bb8ee9..e9d9fea9e272 100644 --- a/drivers/scsi/device_handler/scsi_dh_hp_sw.c +++ b/drivers/scsi/device_handler/scsi_dh_hp_sw.c @@ -120,7 +120,7 @@ retry: if (!req) return SCSI_DH_RES_TEMP_UNAVAIL; - req->cmd_type = REQ_TYPE_BLOCK_PC; + blk_rq_set_block_pc(req); req->cmd_flags |= REQ_FAILFAST_DEV | REQ_FAILFAST_TRANSPORT | REQ_FAILFAST_DRIVER; req->cmd_len = COMMAND_SIZE(TEST_UNIT_READY); @@ -250,7 +250,7 @@ static int hp_sw_start_stop(struct hp_sw_dh_data *h) if (!req) return SCSI_DH_RES_TEMP_UNAVAIL; - req->cmd_type = REQ_TYPE_BLOCK_PC; + blk_rq_set_block_pc(req); req->cmd_flags |= REQ_FAILFAST_DEV | REQ_FAILFAST_TRANSPORT | REQ_FAILFAST_DRIVER; req->cmd_len = COMMAND_SIZE(START_STOP); diff --git a/drivers/scsi/device_handler/scsi_dh_rdac.c b/drivers/scsi/device_handler/scsi_dh_rdac.c index 4b9cf93f3fb6..826069db9848 100644 --- a/drivers/scsi/device_handler/scsi_dh_rdac.c +++ b/drivers/scsi/device_handler/scsi_dh_rdac.c @@ -279,6 +279,7 @@ static struct request *get_rdac_req(struct scsi_device *sdev, "get_rdac_req: blk_get_request failed.\n"); return NULL; } + blk_rq_set_block_pc(rq); if (buflen && blk_rq_map_kern(q, rq, buffer, buflen, GFP_NOIO)) { blk_put_request(rq); @@ -287,7 +288,6 @@ static struct request *get_rdac_req(struct scsi_device *sdev, return NULL; } - rq->cmd_type = REQ_TYPE_BLOCK_PC; rq->cmd_flags |= REQ_FAILFAST_DEV | REQ_FAILFAST_TRANSPORT | REQ_FAILFAST_DRIVER; rq->retries = RDAC_RETRIES; diff --git a/drivers/scsi/osd/osd_initiator.c b/drivers/scsi/osd/osd_initiator.c index bac04c2335aa..5f4cbf0c4759 100644 --- a/drivers/scsi/osd/osd_initiator.c +++ b/drivers/scsi/osd/osd_initiator.c @@ -1570,6 +1570,7 @@ static struct request *_make_request(struct request_queue *q, bool has_write, if (unlikely(!req)) return ERR_PTR(-ENOMEM); + blk_rq_set_block_pc(req); return req; } } @@ -1590,7 +1591,6 @@ static int _init_blk_request(struct osd_request *or, } or->request = req; - req->cmd_type = REQ_TYPE_BLOCK_PC; req->cmd_flags |= REQ_QUIET; req->timeout = or->timeout; @@ -1608,7 +1608,7 @@ static int _init_blk_request(struct osd_request *or, ret = PTR_ERR(req); goto out; } - req->cmd_type = REQ_TYPE_BLOCK_PC; + blk_rq_set_block_pc(req); or->in.req = or->request->next_rq = req; } } else if (has_in) diff --git a/drivers/scsi/osst.c b/drivers/scsi/osst.c index 21883a2d6324..0727ea7cc387 100644 --- a/drivers/scsi/osst.c +++ b/drivers/scsi/osst.c @@ -365,7 +365,7 @@ static int osst_execute(struct osst_request *SRpnt, const unsigned char *cmd, if (!req) return DRIVER_ERROR << 24; - req->cmd_type = REQ_TYPE_BLOCK_PC; + blk_rq_set_block_pc(req); req->cmd_flags |= REQ_QUIET; SRpnt->bio = NULL; diff --git a/drivers/scsi/scsi_error.c b/drivers/scsi/scsi_error.c index f17aa7aa7879..af624619d547 100644 --- a/drivers/scsi/scsi_error.c +++ b/drivers/scsi/scsi_error.c @@ -1951,6 +1951,8 @@ static void scsi_eh_lock_door(struct scsi_device *sdev) */ req = blk_get_request(sdev->request_queue, READ, GFP_KERNEL); + blk_rq_set_block_pc(req); + req->cmd[0] = ALLOW_MEDIUM_REMOVAL; req->cmd[1] = 0; req->cmd[2] = 0; @@ -1960,7 +1962,6 @@ static void scsi_eh_lock_door(struct scsi_device *sdev) req->cmd_len = COMMAND_SIZE(req->cmd[0]); - req->cmd_type = REQ_TYPE_BLOCK_PC; req->cmd_flags |= REQ_QUIET; req->timeout = 10 * HZ; req->retries = 5; diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c index a0c95cac91f0..c3c1697b143e 100644 --- a/drivers/scsi/scsi_lib.c +++ b/drivers/scsi/scsi_lib.c @@ -195,6 +195,7 @@ int scsi_execute(struct scsi_device *sdev, const unsigned char *cmd, req = blk_get_request(sdev->request_queue, write, __GFP_WAIT); if (!req) return ret; + blk_rq_set_block_pc(req); if (bufflen && blk_rq_map_kern(sdev->request_queue, req, buffer, bufflen, __GFP_WAIT)) @@ -206,7 +207,6 @@ int scsi_execute(struct scsi_device *sdev, const unsigned char *cmd, req->sense_len = 0; req->retries = retries; req->timeout = timeout; - req->cmd_type = REQ_TYPE_BLOCK_PC; req->cmd_flags |= flags | REQ_QUIET | REQ_PREEMPT; /* diff --git a/drivers/scsi/sg.c b/drivers/scsi/sg.c index df5e961484e1..53268aaba559 100644 --- a/drivers/scsi/sg.c +++ b/drivers/scsi/sg.c @@ -1653,10 +1653,9 @@ static int sg_start_req(Sg_request *srp, unsigned char *cmd) if (!rq) return -ENOMEM; + blk_rq_set_block_pc(rq); memcpy(rq->cmd, cmd, hp->cmd_len); - rq->cmd_len = hp->cmd_len; - rq->cmd_type = REQ_TYPE_BLOCK_PC; srp->rq = rq; rq->end_io_data = srp; diff --git a/drivers/scsi/st.c b/drivers/scsi/st.c index afc834e172c6..14eb4b256a03 100644 --- a/drivers/scsi/st.c +++ b/drivers/scsi/st.c @@ -484,7 +484,7 @@ static int st_scsi_execute(struct st_request *SRpnt, const unsigned char *cmd, if (!req) return DRIVER_ERROR << 24; - req->cmd_type = REQ_TYPE_BLOCK_PC; + blk_rq_set_block_pc(req); req->cmd_flags |= REQ_QUIET; mdata->null_mapped = 1; diff --git a/drivers/target/target_core_pscsi.c b/drivers/target/target_core_pscsi.c index 0f199f6a0738..94d00df28f39 100644 --- a/drivers/target/target_core_pscsi.c +++ b/drivers/target/target_core_pscsi.c @@ -1055,6 +1055,8 @@ pscsi_execute_cmd(struct se_cmd *cmd) ret = TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE; goto fail; } + + blk_rq_set_block_pc(req); } else { BUG_ON(!cmd->data_length); @@ -1071,7 +1073,6 @@ pscsi_execute_cmd(struct se_cmd *cmd) } } - req->cmd_type = REQ_TYPE_BLOCK_PC; req->end_io = pscsi_req_done; req->end_io_data = cmd; req->cmd_len = scsi_command_size(pt->pscsi_cdb); 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 --- block/bio.c | 8 ++++++++ block/blk-merge.c | 10 ++++++++++ include/linux/bio.h | 9 +++++++++ include/linux/blkdev.h | 1 + 4 files changed, 28 insertions(+) (limited to 'include/linux/blkdev.h') diff --git a/block/bio.c b/block/bio.c index 8c2e55e39a1b..0ec61c9e536c 100644 --- a/block/bio.c +++ b/block/bio.c @@ -746,6 +746,14 @@ static int __bio_add_page(struct request_queue *q, struct bio *bio, struct page goto done; } + + /* + * If the queue doesn't support SG gaps and adding this + * offset would create a gap, disallow it. + */ + if (q->queue_flags & (1 << QUEUE_FLAG_SG_GAPS) && + bvec_gap_to_prev(prev, offset)) + return 0; } if (bio->bi_vcnt >= bio->bi_max_vecs) diff --git a/block/blk-merge.c b/block/blk-merge.c index b3bf0df0f4c2..54535831f1e1 100644 --- a/block/blk-merge.c +++ b/block/blk-merge.c @@ -568,6 +568,8 @@ int blk_attempt_req_merge(struct request_queue *q, struct request *rq, bool blk_rq_merge_ok(struct request *rq, struct bio *bio) { + struct request_queue *q = rq->q; + if (!rq_mergeable(rq) || !bio_mergeable(bio)) return false; @@ -591,6 +593,14 @@ bool blk_rq_merge_ok(struct request *rq, struct bio *bio) !blk_write_same_mergeable(rq->bio, bio)) return false; + if (q->queue_flags & (1 << QUEUE_FLAG_SG_GAPS)) { + struct bio_vec *bprev; + + bprev = &rq->biotail->bi_io_vec[bio->bi_vcnt - 1]; + if (bvec_gap_to_prev(bprev, bio->bi_io_vec[0].bv_offset)) + return false; + } + return true; } diff --git a/include/linux/bio.h b/include/linux/bio.h index f91decbca96b..d2633ee099d9 100644 --- a/include/linux/bio.h +++ b/include/linux/bio.h @@ -186,6 +186,15 @@ static inline void *bio_data(struct bio *bio) #define BIOVEC_SEG_BOUNDARY(q, b1, b2) \ __BIO_SEG_BOUNDARY(bvec_to_phys((b1)), bvec_to_phys((b2)) + (b2)->bv_len, queue_segment_boundary((q))) +/* + * Check if adding a bio_vec after bprv with offset would create a gap in + * the SG list. Most drivers don't care about this, but some do. + */ +static inline bool bvec_gap_to_prev(struct bio_vec *bprv, unsigned int offset) +{ + return offset || ((bprv->bv_offset + bprv->bv_len) & (PAGE_SIZE - 1)); +} + #define bio_io_error(bio) bio_endio((bio), -EIO) /* 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