1d6d48196SJens Axboe /* 2d6d48196SJens Axboe * Functions related to segment and merge handling 3d6d48196SJens Axboe */ 4d6d48196SJens Axboe #include <linux/kernel.h> 5d6d48196SJens Axboe #include <linux/module.h> 6d6d48196SJens Axboe #include <linux/bio.h> 7d6d48196SJens Axboe #include <linux/blkdev.h> 8d6d48196SJens Axboe #include <linux/scatterlist.h> 9d6d48196SJens Axboe 10d6d48196SJens Axboe #include "blk.h" 11d6d48196SJens Axboe 1254efd50bSKent Overstreet static struct bio *blk_bio_discard_split(struct request_queue *q, 1354efd50bSKent Overstreet struct bio *bio, 1454efd50bSKent Overstreet struct bio_set *bs) 1554efd50bSKent Overstreet { 1654efd50bSKent Overstreet unsigned int max_discard_sectors, granularity; 1754efd50bSKent Overstreet int alignment; 1854efd50bSKent Overstreet sector_t tmp; 1954efd50bSKent Overstreet unsigned split_sectors; 2054efd50bSKent Overstreet 2154efd50bSKent Overstreet /* Zero-sector (unknown) and one-sector granularities are the same. */ 2254efd50bSKent Overstreet granularity = max(q->limits.discard_granularity >> 9, 1U); 2354efd50bSKent Overstreet 2454efd50bSKent Overstreet max_discard_sectors = min(q->limits.max_discard_sectors, UINT_MAX >> 9); 2554efd50bSKent Overstreet max_discard_sectors -= max_discard_sectors % granularity; 2654efd50bSKent Overstreet 2754efd50bSKent Overstreet if (unlikely(!max_discard_sectors)) { 2854efd50bSKent Overstreet /* XXX: warn */ 2954efd50bSKent Overstreet return NULL; 3054efd50bSKent Overstreet } 3154efd50bSKent Overstreet 3254efd50bSKent Overstreet if (bio_sectors(bio) <= max_discard_sectors) 3354efd50bSKent Overstreet return NULL; 3454efd50bSKent Overstreet 3554efd50bSKent Overstreet split_sectors = max_discard_sectors; 3654efd50bSKent Overstreet 3754efd50bSKent Overstreet /* 3854efd50bSKent Overstreet * If the next starting sector would be misaligned, stop the discard at 3954efd50bSKent Overstreet * the previous aligned sector. 4054efd50bSKent Overstreet */ 4154efd50bSKent Overstreet alignment = (q->limits.discard_alignment >> 9) % granularity; 4254efd50bSKent Overstreet 4354efd50bSKent Overstreet tmp = bio->bi_iter.bi_sector + split_sectors - alignment; 4454efd50bSKent Overstreet tmp = sector_div(tmp, granularity); 4554efd50bSKent Overstreet 4654efd50bSKent Overstreet if (split_sectors > tmp) 4754efd50bSKent Overstreet split_sectors -= tmp; 4854efd50bSKent Overstreet 4954efd50bSKent Overstreet return bio_split(bio, split_sectors, GFP_NOIO, bs); 5054efd50bSKent Overstreet } 5154efd50bSKent Overstreet 5254efd50bSKent Overstreet static struct bio *blk_bio_write_same_split(struct request_queue *q, 5354efd50bSKent Overstreet struct bio *bio, 5454efd50bSKent Overstreet struct bio_set *bs) 5554efd50bSKent Overstreet { 5654efd50bSKent Overstreet if (!q->limits.max_write_same_sectors) 5754efd50bSKent Overstreet return NULL; 5854efd50bSKent Overstreet 5954efd50bSKent Overstreet if (bio_sectors(bio) <= q->limits.max_write_same_sectors) 6054efd50bSKent Overstreet return NULL; 6154efd50bSKent Overstreet 6254efd50bSKent Overstreet return bio_split(bio, q->limits.max_write_same_sectors, GFP_NOIO, bs); 6354efd50bSKent Overstreet } 6454efd50bSKent Overstreet 6554efd50bSKent Overstreet static struct bio *blk_bio_segment_split(struct request_queue *q, 6654efd50bSKent Overstreet struct bio *bio, 6754efd50bSKent Overstreet struct bio_set *bs) 6854efd50bSKent Overstreet { 6954efd50bSKent Overstreet struct bio *split; 7054efd50bSKent Overstreet struct bio_vec bv, bvprv; 7154efd50bSKent Overstreet struct bvec_iter iter; 7254efd50bSKent Overstreet unsigned seg_size = 0, nsegs = 0; 7354efd50bSKent Overstreet int prev = 0; 7454efd50bSKent Overstreet 7554efd50bSKent Overstreet struct bvec_merge_data bvm = { 7654efd50bSKent Overstreet .bi_bdev = bio->bi_bdev, 7754efd50bSKent Overstreet .bi_sector = bio->bi_iter.bi_sector, 7854efd50bSKent Overstreet .bi_size = 0, 7954efd50bSKent Overstreet .bi_rw = bio->bi_rw, 8054efd50bSKent Overstreet }; 8154efd50bSKent Overstreet 8254efd50bSKent Overstreet bio_for_each_segment(bv, bio, iter) { 8354efd50bSKent Overstreet if (q->merge_bvec_fn && 8454efd50bSKent Overstreet q->merge_bvec_fn(q, &bvm, &bv) < (int) bv.bv_len) 8554efd50bSKent Overstreet goto split; 8654efd50bSKent Overstreet 8754efd50bSKent Overstreet bvm.bi_size += bv.bv_len; 8854efd50bSKent Overstreet 8954efd50bSKent Overstreet if (bvm.bi_size >> 9 > queue_max_sectors(q)) 9054efd50bSKent Overstreet goto split; 9154efd50bSKent Overstreet 9254efd50bSKent Overstreet /* 9354efd50bSKent Overstreet * If the queue doesn't support SG gaps and adding this 9454efd50bSKent Overstreet * offset would create a gap, disallow it. 9554efd50bSKent Overstreet */ 9654efd50bSKent Overstreet if (q->queue_flags & (1 << QUEUE_FLAG_SG_GAPS) && 9754efd50bSKent Overstreet prev && bvec_gap_to_prev(&bvprv, bv.bv_offset)) 9854efd50bSKent Overstreet goto split; 9954efd50bSKent Overstreet 10054efd50bSKent Overstreet if (prev && blk_queue_cluster(q)) { 10154efd50bSKent Overstreet if (seg_size + bv.bv_len > queue_max_segment_size(q)) 10254efd50bSKent Overstreet goto new_segment; 10354efd50bSKent Overstreet if (!BIOVEC_PHYS_MERGEABLE(&bvprv, &bv)) 10454efd50bSKent Overstreet goto new_segment; 10554efd50bSKent Overstreet if (!BIOVEC_SEG_BOUNDARY(q, &bvprv, &bv)) 10654efd50bSKent Overstreet goto new_segment; 10754efd50bSKent Overstreet 10854efd50bSKent Overstreet seg_size += bv.bv_len; 10954efd50bSKent Overstreet bvprv = bv; 11054efd50bSKent Overstreet prev = 1; 11154efd50bSKent Overstreet continue; 11254efd50bSKent Overstreet } 11354efd50bSKent Overstreet new_segment: 11454efd50bSKent Overstreet if (nsegs == queue_max_segments(q)) 11554efd50bSKent Overstreet goto split; 11654efd50bSKent Overstreet 11754efd50bSKent Overstreet nsegs++; 11854efd50bSKent Overstreet bvprv = bv; 11954efd50bSKent Overstreet prev = 1; 12054efd50bSKent Overstreet seg_size = bv.bv_len; 12154efd50bSKent Overstreet } 12254efd50bSKent Overstreet 12354efd50bSKent Overstreet return NULL; 12454efd50bSKent Overstreet split: 12554efd50bSKent Overstreet split = bio_clone_bioset(bio, GFP_NOIO, bs); 12654efd50bSKent Overstreet 12754efd50bSKent Overstreet split->bi_iter.bi_size -= iter.bi_size; 12854efd50bSKent Overstreet bio->bi_iter = iter; 12954efd50bSKent Overstreet 13054efd50bSKent Overstreet if (bio_integrity(bio)) { 13154efd50bSKent Overstreet bio_integrity_advance(bio, split->bi_iter.bi_size); 13254efd50bSKent Overstreet bio_integrity_trim(split, 0, bio_sectors(split)); 13354efd50bSKent Overstreet } 13454efd50bSKent Overstreet 13554efd50bSKent Overstreet return split; 13654efd50bSKent Overstreet } 13754efd50bSKent Overstreet 13854efd50bSKent Overstreet void blk_queue_split(struct request_queue *q, struct bio **bio, 13954efd50bSKent Overstreet struct bio_set *bs) 14054efd50bSKent Overstreet { 14154efd50bSKent Overstreet struct bio *split; 14254efd50bSKent Overstreet 14354efd50bSKent Overstreet if ((*bio)->bi_rw & REQ_DISCARD) 14454efd50bSKent Overstreet split = blk_bio_discard_split(q, *bio, bs); 14554efd50bSKent Overstreet else if ((*bio)->bi_rw & REQ_WRITE_SAME) 14654efd50bSKent Overstreet split = blk_bio_write_same_split(q, *bio, bs); 14754efd50bSKent Overstreet else 14854efd50bSKent Overstreet split = blk_bio_segment_split(q, *bio, q->bio_split); 14954efd50bSKent Overstreet 15054efd50bSKent Overstreet if (split) { 15154efd50bSKent Overstreet bio_chain(split, *bio); 15254efd50bSKent Overstreet generic_make_request(*bio); 15354efd50bSKent Overstreet *bio = split; 15454efd50bSKent Overstreet } 15554efd50bSKent Overstreet } 15654efd50bSKent Overstreet EXPORT_SYMBOL(blk_queue_split); 15754efd50bSKent Overstreet 1581e428079SJens Axboe static unsigned int __blk_recalc_rq_segments(struct request_queue *q, 15907388549SMing Lei struct bio *bio, 16007388549SMing Lei bool no_sg_merge) 161d6d48196SJens Axboe { 1627988613bSKent Overstreet struct bio_vec bv, bvprv = { NULL }; 16354efd50bSKent Overstreet int cluster, prev = 0; 1641e428079SJens Axboe unsigned int seg_size, nr_phys_segs; 16559247eaeSJens Axboe struct bio *fbio, *bbio; 1667988613bSKent Overstreet struct bvec_iter iter; 167d6d48196SJens Axboe 1681e428079SJens Axboe if (!bio) 1691e428079SJens Axboe return 0; 170d6d48196SJens Axboe 1715cb8850cSKent Overstreet /* 1725cb8850cSKent Overstreet * This should probably be returning 0, but blk_add_request_payload() 1735cb8850cSKent Overstreet * (Christoph!!!!) 1745cb8850cSKent Overstreet */ 1755cb8850cSKent Overstreet if (bio->bi_rw & REQ_DISCARD) 1765cb8850cSKent Overstreet return 1; 1775cb8850cSKent Overstreet 1785cb8850cSKent Overstreet if (bio->bi_rw & REQ_WRITE_SAME) 1795cb8850cSKent Overstreet return 1; 1805cb8850cSKent Overstreet 1811e428079SJens Axboe fbio = bio; 182e692cb66SMartin K. Petersen cluster = blk_queue_cluster(q); 1835df97b91SMikulas Patocka seg_size = 0; 1842c8919deSAndi Kleen nr_phys_segs = 0; 1851e428079SJens Axboe for_each_bio(bio) { 1867988613bSKent Overstreet bio_for_each_segment(bv, bio, iter) { 187d6d48196SJens Axboe /* 18805f1dd53SJens Axboe * If SG merging is disabled, each bio vector is 18905f1dd53SJens Axboe * a segment 19005f1dd53SJens Axboe */ 19105f1dd53SJens Axboe if (no_sg_merge) 19205f1dd53SJens Axboe goto new_segment; 19305f1dd53SJens Axboe 19454efd50bSKent Overstreet if (prev && cluster) { 1957988613bSKent Overstreet if (seg_size + bv.bv_len 196ae03bf63SMartin K. Petersen > queue_max_segment_size(q)) 197d6d48196SJens Axboe goto new_segment; 1987988613bSKent Overstreet if (!BIOVEC_PHYS_MERGEABLE(&bvprv, &bv)) 199d6d48196SJens Axboe goto new_segment; 2007988613bSKent Overstreet if (!BIOVEC_SEG_BOUNDARY(q, &bvprv, &bv)) 201d6d48196SJens Axboe goto new_segment; 202d6d48196SJens Axboe 2037988613bSKent Overstreet seg_size += bv.bv_len; 204d6d48196SJens Axboe bvprv = bv; 205d6d48196SJens Axboe continue; 206d6d48196SJens Axboe } 207d6d48196SJens Axboe new_segment: 2081e428079SJens Axboe if (nr_phys_segs == 1 && seg_size > 2091e428079SJens Axboe fbio->bi_seg_front_size) 2101e428079SJens Axboe fbio->bi_seg_front_size = seg_size; 21186771427SFUJITA Tomonori 212d6d48196SJens Axboe nr_phys_segs++; 213d6d48196SJens Axboe bvprv = bv; 21454efd50bSKent Overstreet prev = 1; 2157988613bSKent Overstreet seg_size = bv.bv_len; 216d6d48196SJens Axboe } 21759247eaeSJens Axboe bbio = bio; 2181e428079SJens Axboe } 219d6d48196SJens Axboe 22059247eaeSJens Axboe if (nr_phys_segs == 1 && seg_size > fbio->bi_seg_front_size) 22159247eaeSJens Axboe fbio->bi_seg_front_size = seg_size; 22259247eaeSJens Axboe if (seg_size > bbio->bi_seg_back_size) 22359247eaeSJens Axboe bbio->bi_seg_back_size = seg_size; 2241e428079SJens Axboe 2251e428079SJens Axboe return nr_phys_segs; 2261e428079SJens Axboe } 2271e428079SJens Axboe 2281e428079SJens Axboe void blk_recalc_rq_segments(struct request *rq) 2291e428079SJens Axboe { 23007388549SMing Lei bool no_sg_merge = !!test_bit(QUEUE_FLAG_NO_SG_MERGE, 23107388549SMing Lei &rq->q->queue_flags); 23207388549SMing Lei 23307388549SMing Lei rq->nr_phys_segments = __blk_recalc_rq_segments(rq->q, rq->bio, 23407388549SMing Lei no_sg_merge); 235d6d48196SJens Axboe } 236d6d48196SJens Axboe 237d6d48196SJens Axboe void blk_recount_segments(struct request_queue *q, struct bio *bio) 238d6d48196SJens Axboe { 2397f60dcaaSMing Lei unsigned short seg_cnt; 240764f612cSMing Lei 2417f60dcaaSMing Lei /* estimate segment number by bi_vcnt for non-cloned bio */ 2427f60dcaaSMing Lei if (bio_flagged(bio, BIO_CLONED)) 2437f60dcaaSMing Lei seg_cnt = bio_segments(bio); 2447f60dcaaSMing Lei else 2457f60dcaaSMing Lei seg_cnt = bio->bi_vcnt; 2467f60dcaaSMing Lei 2477f60dcaaSMing Lei if (test_bit(QUEUE_FLAG_NO_SG_MERGE, &q->queue_flags) && 2487f60dcaaSMing Lei (seg_cnt < queue_max_segments(q))) 2497f60dcaaSMing Lei bio->bi_phys_segments = seg_cnt; 25005f1dd53SJens Axboe else { 251d6d48196SJens Axboe struct bio *nxt = bio->bi_next; 2521e428079SJens Axboe 253d6d48196SJens Axboe bio->bi_next = NULL; 2547f60dcaaSMing Lei bio->bi_phys_segments = __blk_recalc_rq_segments(q, bio, false); 255d6d48196SJens Axboe bio->bi_next = nxt; 25605f1dd53SJens Axboe } 25705f1dd53SJens Axboe 258b7c44ed9SJens Axboe bio_set_flag(bio, BIO_SEG_VALID); 259d6d48196SJens Axboe } 260d6d48196SJens Axboe EXPORT_SYMBOL(blk_recount_segments); 261d6d48196SJens Axboe 262d6d48196SJens Axboe static int blk_phys_contig_segment(struct request_queue *q, struct bio *bio, 263d6d48196SJens Axboe struct bio *nxt) 264d6d48196SJens Axboe { 2652b8221e1SKent Overstreet struct bio_vec end_bv = { NULL }, nxt_bv; 266f619d254SKent Overstreet struct bvec_iter iter; 267f619d254SKent Overstreet 268e692cb66SMartin K. Petersen if (!blk_queue_cluster(q)) 269d6d48196SJens Axboe return 0; 270d6d48196SJens Axboe 27186771427SFUJITA Tomonori if (bio->bi_seg_back_size + nxt->bi_seg_front_size > 272ae03bf63SMartin K. Petersen queue_max_segment_size(q)) 273d6d48196SJens Axboe return 0; 274d6d48196SJens Axboe 275e17fc0a1SDavid Woodhouse if (!bio_has_data(bio)) 276e17fc0a1SDavid Woodhouse return 1; 277e17fc0a1SDavid Woodhouse 278f619d254SKent Overstreet bio_for_each_segment(end_bv, bio, iter) 279f619d254SKent Overstreet if (end_bv.bv_len == iter.bi_size) 280f619d254SKent Overstreet break; 281f619d254SKent Overstreet 282f619d254SKent Overstreet nxt_bv = bio_iovec(nxt); 283f619d254SKent Overstreet 284f619d254SKent Overstreet if (!BIOVEC_PHYS_MERGEABLE(&end_bv, &nxt_bv)) 285e17fc0a1SDavid Woodhouse return 0; 286e17fc0a1SDavid Woodhouse 287d6d48196SJens Axboe /* 288e17fc0a1SDavid Woodhouse * bio and nxt are contiguous in memory; check if the queue allows 289d6d48196SJens Axboe * these two to be merged into one 290d6d48196SJens Axboe */ 291f619d254SKent Overstreet if (BIOVEC_SEG_BOUNDARY(q, &end_bv, &nxt_bv)) 292d6d48196SJens Axboe return 1; 293d6d48196SJens Axboe 294d6d48196SJens Axboe return 0; 295d6d48196SJens Axboe } 296d6d48196SJens Axboe 2977988613bSKent Overstreet static inline void 298963ab9e5SAsias He __blk_segment_map_sg(struct request_queue *q, struct bio_vec *bvec, 2997988613bSKent Overstreet struct scatterlist *sglist, struct bio_vec *bvprv, 300963ab9e5SAsias He struct scatterlist **sg, int *nsegs, int *cluster) 301963ab9e5SAsias He { 302963ab9e5SAsias He 303963ab9e5SAsias He int nbytes = bvec->bv_len; 304963ab9e5SAsias He 3057988613bSKent Overstreet if (*sg && *cluster) { 306963ab9e5SAsias He if ((*sg)->length + nbytes > queue_max_segment_size(q)) 307963ab9e5SAsias He goto new_segment; 308963ab9e5SAsias He 3097988613bSKent Overstreet if (!BIOVEC_PHYS_MERGEABLE(bvprv, bvec)) 310963ab9e5SAsias He goto new_segment; 3117988613bSKent Overstreet if (!BIOVEC_SEG_BOUNDARY(q, bvprv, bvec)) 312963ab9e5SAsias He goto new_segment; 313963ab9e5SAsias He 314963ab9e5SAsias He (*sg)->length += nbytes; 315963ab9e5SAsias He } else { 316963ab9e5SAsias He new_segment: 317963ab9e5SAsias He if (!*sg) 318963ab9e5SAsias He *sg = sglist; 319963ab9e5SAsias He else { 320963ab9e5SAsias He /* 321963ab9e5SAsias He * If the driver previously mapped a shorter 322963ab9e5SAsias He * list, we could see a termination bit 323963ab9e5SAsias He * prematurely unless it fully inits the sg 324963ab9e5SAsias He * table on each mapping. We KNOW that there 325963ab9e5SAsias He * must be more entries here or the driver 326963ab9e5SAsias He * would be buggy, so force clear the 327963ab9e5SAsias He * termination bit to avoid doing a full 328963ab9e5SAsias He * sg_init_table() in drivers for each command. 329963ab9e5SAsias He */ 330c8164d89SPaolo Bonzini sg_unmark_end(*sg); 331963ab9e5SAsias He *sg = sg_next(*sg); 332963ab9e5SAsias He } 333963ab9e5SAsias He 334963ab9e5SAsias He sg_set_page(*sg, bvec->bv_page, nbytes, bvec->bv_offset); 335963ab9e5SAsias He (*nsegs)++; 336963ab9e5SAsias He } 3377988613bSKent Overstreet *bvprv = *bvec; 338963ab9e5SAsias He } 339963ab9e5SAsias He 3405cb8850cSKent Overstreet static int __blk_bios_map_sg(struct request_queue *q, struct bio *bio, 3415cb8850cSKent Overstreet struct scatterlist *sglist, 3425cb8850cSKent Overstreet struct scatterlist **sg) 3435cb8850cSKent Overstreet { 3445cb8850cSKent Overstreet struct bio_vec bvec, bvprv = { NULL }; 3455cb8850cSKent Overstreet struct bvec_iter iter; 3465cb8850cSKent Overstreet int nsegs, cluster; 3475cb8850cSKent Overstreet 3485cb8850cSKent Overstreet nsegs = 0; 3495cb8850cSKent Overstreet cluster = blk_queue_cluster(q); 3505cb8850cSKent Overstreet 3515cb8850cSKent Overstreet if (bio->bi_rw & REQ_DISCARD) { 3525cb8850cSKent Overstreet /* 3535cb8850cSKent Overstreet * This is a hack - drivers should be neither modifying the 3545cb8850cSKent Overstreet * biovec, nor relying on bi_vcnt - but because of 3555cb8850cSKent Overstreet * blk_add_request_payload(), a discard bio may or may not have 3565cb8850cSKent Overstreet * a payload we need to set up here (thank you Christoph) and 3575cb8850cSKent Overstreet * bi_vcnt is really the only way of telling if we need to. 3585cb8850cSKent Overstreet */ 3595cb8850cSKent Overstreet 3605cb8850cSKent Overstreet if (bio->bi_vcnt) 3615cb8850cSKent Overstreet goto single_segment; 3625cb8850cSKent Overstreet 3635cb8850cSKent Overstreet return 0; 3645cb8850cSKent Overstreet } 3655cb8850cSKent Overstreet 3665cb8850cSKent Overstreet if (bio->bi_rw & REQ_WRITE_SAME) { 3675cb8850cSKent Overstreet single_segment: 3685cb8850cSKent Overstreet *sg = sglist; 3695cb8850cSKent Overstreet bvec = bio_iovec(bio); 3705cb8850cSKent Overstreet sg_set_page(*sg, bvec.bv_page, bvec.bv_len, bvec.bv_offset); 3715cb8850cSKent Overstreet return 1; 3725cb8850cSKent Overstreet } 3735cb8850cSKent Overstreet 3745cb8850cSKent Overstreet for_each_bio(bio) 3755cb8850cSKent Overstreet bio_for_each_segment(bvec, bio, iter) 3765cb8850cSKent Overstreet __blk_segment_map_sg(q, &bvec, sglist, &bvprv, sg, 3775cb8850cSKent Overstreet &nsegs, &cluster); 3785cb8850cSKent Overstreet 3795cb8850cSKent Overstreet return nsegs; 3805cb8850cSKent Overstreet } 3815cb8850cSKent Overstreet 382d6d48196SJens Axboe /* 383d6d48196SJens Axboe * map a request to scatterlist, return number of sg entries setup. Caller 384d6d48196SJens Axboe * must make sure sg can hold rq->nr_phys_segments entries 385d6d48196SJens Axboe */ 386d6d48196SJens Axboe int blk_rq_map_sg(struct request_queue *q, struct request *rq, 387d6d48196SJens Axboe struct scatterlist *sglist) 388d6d48196SJens Axboe { 3895cb8850cSKent Overstreet struct scatterlist *sg = NULL; 3905cb8850cSKent Overstreet int nsegs = 0; 391d6d48196SJens Axboe 3925cb8850cSKent Overstreet if (rq->bio) 3935cb8850cSKent Overstreet nsegs = __blk_bios_map_sg(q, rq->bio, sglist, &sg); 394f18573abSFUJITA Tomonori 395f18573abSFUJITA Tomonori if (unlikely(rq->cmd_flags & REQ_COPY_USER) && 3962e46e8b2STejun Heo (blk_rq_bytes(rq) & q->dma_pad_mask)) { 3972e46e8b2STejun Heo unsigned int pad_len = 3982e46e8b2STejun Heo (q->dma_pad_mask & ~blk_rq_bytes(rq)) + 1; 399f18573abSFUJITA Tomonori 400f18573abSFUJITA Tomonori sg->length += pad_len; 401f18573abSFUJITA Tomonori rq->extra_len += pad_len; 402f18573abSFUJITA Tomonori } 403f18573abSFUJITA Tomonori 4042fb98e84STejun Heo if (q->dma_drain_size && q->dma_drain_needed(rq)) { 4057b6d91daSChristoph Hellwig if (rq->cmd_flags & REQ_WRITE) 406db0a2e00STejun Heo memset(q->dma_drain_buffer, 0, q->dma_drain_size); 407db0a2e00STejun Heo 408d6d48196SJens Axboe sg->page_link &= ~0x02; 409d6d48196SJens Axboe sg = sg_next(sg); 410d6d48196SJens Axboe sg_set_page(sg, virt_to_page(q->dma_drain_buffer), 411d6d48196SJens Axboe q->dma_drain_size, 412d6d48196SJens Axboe ((unsigned long)q->dma_drain_buffer) & 413d6d48196SJens Axboe (PAGE_SIZE - 1)); 414d6d48196SJens Axboe nsegs++; 4157a85f889SFUJITA Tomonori rq->extra_len += q->dma_drain_size; 416d6d48196SJens Axboe } 417d6d48196SJens Axboe 418d6d48196SJens Axboe if (sg) 419d6d48196SJens Axboe sg_mark_end(sg); 420d6d48196SJens Axboe 421d6d48196SJens Axboe return nsegs; 422d6d48196SJens Axboe } 423d6d48196SJens Axboe EXPORT_SYMBOL(blk_rq_map_sg); 424d6d48196SJens Axboe 425d6d48196SJens Axboe static inline int ll_new_hw_segment(struct request_queue *q, 426d6d48196SJens Axboe struct request *req, 427d6d48196SJens Axboe struct bio *bio) 428d6d48196SJens Axboe { 429d6d48196SJens Axboe int nr_phys_segs = bio_phys_segments(q, bio); 430d6d48196SJens Axboe 43113f05c8dSMartin K. Petersen if (req->nr_phys_segments + nr_phys_segs > queue_max_segments(q)) 43213f05c8dSMartin K. Petersen goto no_merge; 43313f05c8dSMartin K. Petersen 4344eaf99beSMartin K. Petersen if (blk_integrity_merge_bio(q, req, bio) == false) 43513f05c8dSMartin K. Petersen goto no_merge; 436d6d48196SJens Axboe 437d6d48196SJens Axboe /* 438d6d48196SJens Axboe * This will form the start of a new hw segment. Bump both 439d6d48196SJens Axboe * counters. 440d6d48196SJens Axboe */ 441d6d48196SJens Axboe req->nr_phys_segments += nr_phys_segs; 442d6d48196SJens Axboe return 1; 44313f05c8dSMartin K. Petersen 44413f05c8dSMartin K. Petersen no_merge: 44513f05c8dSMartin K. Petersen req->cmd_flags |= REQ_NOMERGE; 44613f05c8dSMartin K. Petersen if (req == q->last_merge) 44713f05c8dSMartin K. Petersen q->last_merge = NULL; 44813f05c8dSMartin K. Petersen return 0; 449d6d48196SJens Axboe } 450d6d48196SJens Axboe 451d6d48196SJens Axboe int ll_back_merge_fn(struct request_queue *q, struct request *req, 452d6d48196SJens Axboe struct bio *bio) 453d6d48196SJens Axboe { 454f31dc1cdSMartin K. Petersen if (blk_rq_sectors(req) + bio_sectors(bio) > 455f31dc1cdSMartin K. Petersen blk_rq_get_max_sectors(req)) { 456d6d48196SJens Axboe req->cmd_flags |= REQ_NOMERGE; 457d6d48196SJens Axboe if (req == q->last_merge) 458d6d48196SJens Axboe q->last_merge = NULL; 459d6d48196SJens Axboe return 0; 460d6d48196SJens Axboe } 4612cdf79caSJens Axboe if (!bio_flagged(req->biotail, BIO_SEG_VALID)) 462d6d48196SJens Axboe blk_recount_segments(q, req->biotail); 4632cdf79caSJens Axboe if (!bio_flagged(bio, BIO_SEG_VALID)) 464d6d48196SJens Axboe blk_recount_segments(q, bio); 465d6d48196SJens Axboe 466d6d48196SJens Axboe return ll_new_hw_segment(q, req, bio); 467d6d48196SJens Axboe } 468d6d48196SJens Axboe 469d6d48196SJens Axboe int ll_front_merge_fn(struct request_queue *q, struct request *req, 470d6d48196SJens Axboe struct bio *bio) 471d6d48196SJens Axboe { 472f31dc1cdSMartin K. Petersen if (blk_rq_sectors(req) + bio_sectors(bio) > 473f31dc1cdSMartin K. Petersen blk_rq_get_max_sectors(req)) { 474d6d48196SJens Axboe req->cmd_flags |= REQ_NOMERGE; 475d6d48196SJens Axboe if (req == q->last_merge) 476d6d48196SJens Axboe q->last_merge = NULL; 477d6d48196SJens Axboe return 0; 478d6d48196SJens Axboe } 4792cdf79caSJens Axboe if (!bio_flagged(bio, BIO_SEG_VALID)) 480d6d48196SJens Axboe blk_recount_segments(q, bio); 4812cdf79caSJens Axboe if (!bio_flagged(req->bio, BIO_SEG_VALID)) 482d6d48196SJens Axboe blk_recount_segments(q, req->bio); 483d6d48196SJens Axboe 484d6d48196SJens Axboe return ll_new_hw_segment(q, req, bio); 485d6d48196SJens Axboe } 486d6d48196SJens Axboe 487e7e24500SJens Axboe /* 488e7e24500SJens Axboe * blk-mq uses req->special to carry normal driver per-request payload, it 489e7e24500SJens Axboe * does not indicate a prepared command that we cannot merge with. 490e7e24500SJens Axboe */ 491e7e24500SJens Axboe static bool req_no_special_merge(struct request *req) 492e7e24500SJens Axboe { 493e7e24500SJens Axboe struct request_queue *q = req->q; 494e7e24500SJens Axboe 495e7e24500SJens Axboe return !q->mq_ops && req->special; 496e7e24500SJens Axboe } 497e7e24500SJens Axboe 498854fbb9cSKeith Busch static int req_gap_to_prev(struct request *req, struct request *next) 499854fbb9cSKeith Busch { 500854fbb9cSKeith Busch struct bio *prev = req->biotail; 501854fbb9cSKeith Busch 502854fbb9cSKeith Busch return bvec_gap_to_prev(&prev->bi_io_vec[prev->bi_vcnt - 1], 503854fbb9cSKeith Busch next->bio->bi_io_vec[0].bv_offset); 504854fbb9cSKeith Busch } 505854fbb9cSKeith Busch 506d6d48196SJens Axboe static int ll_merge_requests_fn(struct request_queue *q, struct request *req, 507d6d48196SJens Axboe struct request *next) 508d6d48196SJens Axboe { 509d6d48196SJens Axboe int total_phys_segments; 51086771427SFUJITA Tomonori unsigned int seg_size = 51186771427SFUJITA Tomonori req->biotail->bi_seg_back_size + next->bio->bi_seg_front_size; 512d6d48196SJens Axboe 513d6d48196SJens Axboe /* 514d6d48196SJens Axboe * First check if the either of the requests are re-queued 515d6d48196SJens Axboe * requests. Can't merge them if they are. 516d6d48196SJens Axboe */ 517e7e24500SJens Axboe if (req_no_special_merge(req) || req_no_special_merge(next)) 518d6d48196SJens Axboe return 0; 519d6d48196SJens Axboe 520854fbb9cSKeith Busch if (test_bit(QUEUE_FLAG_SG_GAPS, &q->queue_flags) && 521854fbb9cSKeith Busch req_gap_to_prev(req, next)) 522854fbb9cSKeith Busch return 0; 523854fbb9cSKeith Busch 524d6d48196SJens Axboe /* 525d6d48196SJens Axboe * Will it become too large? 526d6d48196SJens Axboe */ 527f31dc1cdSMartin K. Petersen if ((blk_rq_sectors(req) + blk_rq_sectors(next)) > 528f31dc1cdSMartin K. Petersen blk_rq_get_max_sectors(req)) 529d6d48196SJens Axboe return 0; 530d6d48196SJens Axboe 531d6d48196SJens Axboe total_phys_segments = req->nr_phys_segments + next->nr_phys_segments; 53286771427SFUJITA Tomonori if (blk_phys_contig_segment(q, req->biotail, next->bio)) { 53386771427SFUJITA Tomonori if (req->nr_phys_segments == 1) 53486771427SFUJITA Tomonori req->bio->bi_seg_front_size = seg_size; 53586771427SFUJITA Tomonori if (next->nr_phys_segments == 1) 53686771427SFUJITA Tomonori next->biotail->bi_seg_back_size = seg_size; 537d6d48196SJens Axboe total_phys_segments--; 53886771427SFUJITA Tomonori } 539d6d48196SJens Axboe 5408a78362cSMartin K. Petersen if (total_phys_segments > queue_max_segments(q)) 541d6d48196SJens Axboe return 0; 542d6d48196SJens Axboe 5434eaf99beSMartin K. Petersen if (blk_integrity_merge_rq(q, req, next) == false) 54413f05c8dSMartin K. Petersen return 0; 54513f05c8dSMartin K. Petersen 546d6d48196SJens Axboe /* Merge is OK... */ 547d6d48196SJens Axboe req->nr_phys_segments = total_phys_segments; 548d6d48196SJens Axboe return 1; 549d6d48196SJens Axboe } 550d6d48196SJens Axboe 55180a761fdSTejun Heo /** 55280a761fdSTejun Heo * blk_rq_set_mixed_merge - mark a request as mixed merge 55380a761fdSTejun Heo * @rq: request to mark as mixed merge 55480a761fdSTejun Heo * 55580a761fdSTejun Heo * Description: 55680a761fdSTejun Heo * @rq is about to be mixed merged. Make sure the attributes 55780a761fdSTejun Heo * which can be mixed are set in each bio and mark @rq as mixed 55880a761fdSTejun Heo * merged. 55980a761fdSTejun Heo */ 56080a761fdSTejun Heo void blk_rq_set_mixed_merge(struct request *rq) 56180a761fdSTejun Heo { 56280a761fdSTejun Heo unsigned int ff = rq->cmd_flags & REQ_FAILFAST_MASK; 56380a761fdSTejun Heo struct bio *bio; 56480a761fdSTejun Heo 56580a761fdSTejun Heo if (rq->cmd_flags & REQ_MIXED_MERGE) 56680a761fdSTejun Heo return; 56780a761fdSTejun Heo 56880a761fdSTejun Heo /* 56980a761fdSTejun Heo * @rq will no longer represent mixable attributes for all the 57080a761fdSTejun Heo * contained bios. It will just track those of the first one. 57180a761fdSTejun Heo * Distributes the attributs to each bio. 57280a761fdSTejun Heo */ 57380a761fdSTejun Heo for (bio = rq->bio; bio; bio = bio->bi_next) { 57480a761fdSTejun Heo WARN_ON_ONCE((bio->bi_rw & REQ_FAILFAST_MASK) && 57580a761fdSTejun Heo (bio->bi_rw & REQ_FAILFAST_MASK) != ff); 57680a761fdSTejun Heo bio->bi_rw |= ff; 57780a761fdSTejun Heo } 57880a761fdSTejun Heo rq->cmd_flags |= REQ_MIXED_MERGE; 57980a761fdSTejun Heo } 58080a761fdSTejun Heo 58126308eabSJerome Marchand static void blk_account_io_merge(struct request *req) 58226308eabSJerome Marchand { 58326308eabSJerome Marchand if (blk_do_io_stat(req)) { 58426308eabSJerome Marchand struct hd_struct *part; 58526308eabSJerome Marchand int cpu; 58626308eabSJerome Marchand 58726308eabSJerome Marchand cpu = part_stat_lock(); 58809e099d4SJerome Marchand part = req->part; 58926308eabSJerome Marchand 59026308eabSJerome Marchand part_round_stats(cpu, part); 591316d315bSNikanth Karthikesan part_dec_in_flight(part, rq_data_dir(req)); 59226308eabSJerome Marchand 5936c23a968SJens Axboe hd_struct_put(part); 59426308eabSJerome Marchand part_stat_unlock(); 59526308eabSJerome Marchand } 59626308eabSJerome Marchand } 59726308eabSJerome Marchand 598d6d48196SJens Axboe /* 599d6d48196SJens Axboe * Has to be called with the request spinlock acquired 600d6d48196SJens Axboe */ 601d6d48196SJens Axboe static int attempt_merge(struct request_queue *q, struct request *req, 602d6d48196SJens Axboe struct request *next) 603d6d48196SJens Axboe { 604d6d48196SJens Axboe if (!rq_mergeable(req) || !rq_mergeable(next)) 605d6d48196SJens Axboe return 0; 606d6d48196SJens Axboe 607f31dc1cdSMartin K. Petersen if (!blk_check_merge_flags(req->cmd_flags, next->cmd_flags)) 608f31dc1cdSMartin K. Petersen return 0; 609f31dc1cdSMartin K. Petersen 610d6d48196SJens Axboe /* 611d6d48196SJens Axboe * not contiguous 612d6d48196SJens Axboe */ 61383096ebfSTejun Heo if (blk_rq_pos(req) + blk_rq_sectors(req) != blk_rq_pos(next)) 614d6d48196SJens Axboe return 0; 615d6d48196SJens Axboe 616d6d48196SJens Axboe if (rq_data_dir(req) != rq_data_dir(next) 617d6d48196SJens Axboe || req->rq_disk != next->rq_disk 618e7e24500SJens Axboe || req_no_special_merge(next)) 619d6d48196SJens Axboe return 0; 620d6d48196SJens Axboe 6214363ac7cSMartin K. Petersen if (req->cmd_flags & REQ_WRITE_SAME && 6224363ac7cSMartin K. Petersen !blk_write_same_mergeable(req->bio, next->bio)) 6234363ac7cSMartin K. Petersen return 0; 6244363ac7cSMartin K. Petersen 625d6d48196SJens Axboe /* 626d6d48196SJens Axboe * If we are allowed to merge, then append bio list 627d6d48196SJens Axboe * from next to rq and release next. merge_requests_fn 628d6d48196SJens Axboe * will have updated segment counts, update sector 629d6d48196SJens Axboe * counts here. 630d6d48196SJens Axboe */ 631d6d48196SJens Axboe if (!ll_merge_requests_fn(q, req, next)) 632d6d48196SJens Axboe return 0; 633d6d48196SJens Axboe 634d6d48196SJens Axboe /* 63580a761fdSTejun Heo * If failfast settings disagree or any of the two is already 63680a761fdSTejun Heo * a mixed merge, mark both as mixed before proceeding. This 63780a761fdSTejun Heo * makes sure that all involved bios have mixable attributes 63880a761fdSTejun Heo * set properly. 63980a761fdSTejun Heo */ 64080a761fdSTejun Heo if ((req->cmd_flags | next->cmd_flags) & REQ_MIXED_MERGE || 64180a761fdSTejun Heo (req->cmd_flags & REQ_FAILFAST_MASK) != 64280a761fdSTejun Heo (next->cmd_flags & REQ_FAILFAST_MASK)) { 64380a761fdSTejun Heo blk_rq_set_mixed_merge(req); 64480a761fdSTejun Heo blk_rq_set_mixed_merge(next); 64580a761fdSTejun Heo } 64680a761fdSTejun Heo 64780a761fdSTejun Heo /* 648d6d48196SJens Axboe * At this point we have either done a back merge 649d6d48196SJens Axboe * or front merge. We need the smaller start_time of 650d6d48196SJens Axboe * the merged requests to be the current request 651d6d48196SJens Axboe * for accounting purposes. 652d6d48196SJens Axboe */ 653d6d48196SJens Axboe if (time_after(req->start_time, next->start_time)) 654d6d48196SJens Axboe req->start_time = next->start_time; 655d6d48196SJens Axboe 656d6d48196SJens Axboe req->biotail->bi_next = next->bio; 657d6d48196SJens Axboe req->biotail = next->biotail; 658d6d48196SJens Axboe 659a2dec7b3STejun Heo req->__data_len += blk_rq_bytes(next); 660d6d48196SJens Axboe 661d6d48196SJens Axboe elv_merge_requests(q, req, next); 662d6d48196SJens Axboe 66342dad764SJerome Marchand /* 66442dad764SJerome Marchand * 'next' is going away, so update stats accordingly 66542dad764SJerome Marchand */ 66642dad764SJerome Marchand blk_account_io_merge(next); 667d6d48196SJens Axboe 668d6d48196SJens Axboe req->ioprio = ioprio_best(req->ioprio, next->ioprio); 669ab780f1eSJens Axboe if (blk_rq_cpu_valid(next)) 670ab780f1eSJens Axboe req->cpu = next->cpu; 671d6d48196SJens Axboe 6721cd96c24SBoaz Harrosh /* owner-ship of bio passed from next to req */ 6731cd96c24SBoaz Harrosh next->bio = NULL; 674d6d48196SJens Axboe __blk_put_request(q, next); 675d6d48196SJens Axboe return 1; 676d6d48196SJens Axboe } 677d6d48196SJens Axboe 678d6d48196SJens Axboe int attempt_back_merge(struct request_queue *q, struct request *rq) 679d6d48196SJens Axboe { 680d6d48196SJens Axboe struct request *next = elv_latter_request(q, rq); 681d6d48196SJens Axboe 682d6d48196SJens Axboe if (next) 683d6d48196SJens Axboe return attempt_merge(q, rq, next); 684d6d48196SJens Axboe 685d6d48196SJens Axboe return 0; 686d6d48196SJens Axboe } 687d6d48196SJens Axboe 688d6d48196SJens Axboe int attempt_front_merge(struct request_queue *q, struct request *rq) 689d6d48196SJens Axboe { 690d6d48196SJens Axboe struct request *prev = elv_former_request(q, rq); 691d6d48196SJens Axboe 692d6d48196SJens Axboe if (prev) 693d6d48196SJens Axboe return attempt_merge(q, prev, rq); 694d6d48196SJens Axboe 695d6d48196SJens Axboe return 0; 696d6d48196SJens Axboe } 6975e84ea3aSJens Axboe 6985e84ea3aSJens Axboe int blk_attempt_req_merge(struct request_queue *q, struct request *rq, 6995e84ea3aSJens Axboe struct request *next) 7005e84ea3aSJens Axboe { 7015e84ea3aSJens Axboe return attempt_merge(q, rq, next); 7025e84ea3aSJens Axboe } 703050c8ea8STejun Heo 704050c8ea8STejun Heo bool blk_rq_merge_ok(struct request *rq, struct bio *bio) 705050c8ea8STejun Heo { 70666cb45aaSJens Axboe struct request_queue *q = rq->q; 70766cb45aaSJens Axboe 708e2a60da7SMartin K. Petersen if (!rq_mergeable(rq) || !bio_mergeable(bio)) 709050c8ea8STejun Heo return false; 710050c8ea8STejun Heo 711f31dc1cdSMartin K. Petersen if (!blk_check_merge_flags(rq->cmd_flags, bio->bi_rw)) 712f31dc1cdSMartin K. Petersen return false; 713f31dc1cdSMartin K. Petersen 714050c8ea8STejun Heo /* different data direction or already started, don't merge */ 715050c8ea8STejun Heo if (bio_data_dir(bio) != rq_data_dir(rq)) 716050c8ea8STejun Heo return false; 717050c8ea8STejun Heo 718050c8ea8STejun Heo /* must be same device and not a special request */ 719e7e24500SJens Axboe if (rq->rq_disk != bio->bi_bdev->bd_disk || req_no_special_merge(rq)) 720050c8ea8STejun Heo return false; 721050c8ea8STejun Heo 722050c8ea8STejun Heo /* only merge integrity protected bio into ditto rq */ 7234eaf99beSMartin K. Petersen if (blk_integrity_merge_bio(rq->q, rq, bio) == false) 724050c8ea8STejun Heo return false; 725050c8ea8STejun Heo 7264363ac7cSMartin K. Petersen /* must be using the same buffer */ 7274363ac7cSMartin K. Petersen if (rq->cmd_flags & REQ_WRITE_SAME && 7284363ac7cSMartin K. Petersen !blk_write_same_mergeable(rq->bio, bio)) 7294363ac7cSMartin K. Petersen return false; 7304363ac7cSMartin K. Petersen 731beefa6baSJens Axboe /* Only check gaps if the bio carries data */ 732beefa6baSJens Axboe if (q->queue_flags & (1 << QUEUE_FLAG_SG_GAPS) && bio_has_data(bio)) { 73366cb45aaSJens Axboe struct bio_vec *bprev; 73466cb45aaSJens Axboe 7357ee8e4f3SWenbo Wang bprev = &rq->biotail->bi_io_vec[rq->biotail->bi_vcnt - 1]; 73666cb45aaSJens Axboe if (bvec_gap_to_prev(bprev, bio->bi_io_vec[0].bv_offset)) 73766cb45aaSJens Axboe return false; 73866cb45aaSJens Axboe } 73966cb45aaSJens Axboe 740050c8ea8STejun Heo return true; 741050c8ea8STejun Heo } 742050c8ea8STejun Heo 743050c8ea8STejun Heo int blk_try_merge(struct request *rq, struct bio *bio) 744050c8ea8STejun Heo { 7454f024f37SKent Overstreet if (blk_rq_pos(rq) + blk_rq_sectors(rq) == bio->bi_iter.bi_sector) 746050c8ea8STejun Heo return ELEVATOR_BACK_MERGE; 7474f024f37SKent Overstreet else if (blk_rq_pos(rq) - bio_sectors(bio) == bio->bi_iter.bi_sector) 748050c8ea8STejun Heo return ELEVATOR_FRONT_MERGE; 749050c8ea8STejun Heo return ELEVATOR_NO_MERGE; 750050c8ea8STejun Heo } 751