From 83096ebf1263b2c1ee5e653ba37d993d02e3eb7b Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Thu, 7 May 2009 22:24:39 +0900 Subject: block: convert to pos and nr_sectors accessors With recent cleanups, there is no place where low level driver directly manipulates request fields. This means that the 'hard' request fields always equal the !hard fields. Convert all rq->sectors, nr_sectors and current_nr_sectors references to accessors. While at it, drop superflous blk_rq_pos() < 0 test in swim.c. [ Impact: use pos and nr_sectors accessors ] Signed-off-by: Tejun Heo Acked-by: Geert Uytterhoeven Tested-by: Grant Likely Acked-by: Grant Likely Tested-by: Adrian McMenamin Acked-by: Adrian McMenamin Acked-by: Mike Miller Cc: James Bottomley Cc: Bartlomiej Zolnierkiewicz Cc: Borislav Petkov Cc: Sergei Shtylyov Cc: Eric Moore Cc: Alan Stern Cc: FUJITA Tomonori Cc: Pete Zaitcev Cc: Stephen Rothwell Cc: Paul Clements Cc: Tim Waugh Cc: Jeff Garzik Cc: Jeremy Fitzhardinge Cc: Alex Dubov Cc: David Woodhouse Cc: Martin Schwidefsky Cc: Dario Ballabio Cc: David S. Miller Cc: Rusty Russell Cc: unsik Kim Cc: Laurent Vivier Signed-off-by: Jens Axboe --- block/blk-merge.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) (limited to 'block/blk-merge.c') diff --git a/block/blk-merge.c b/block/blk-merge.c index 23d2a6f..bf62a87 100644 --- a/block/blk-merge.c +++ b/block/blk-merge.c @@ -259,7 +259,7 @@ int ll_back_merge_fn(struct request_queue *q, struct request *req, else max_sectors = q->max_sectors; - if (req->nr_sectors + bio_sectors(bio) > max_sectors) { + if (blk_rq_sectors(req) + bio_sectors(bio) > max_sectors) { req->cmd_flags |= REQ_NOMERGE; if (req == q->last_merge) q->last_merge = NULL; @@ -284,7 +284,7 @@ int ll_front_merge_fn(struct request_queue *q, struct request *req, max_sectors = q->max_sectors; - if (req->nr_sectors + bio_sectors(bio) > max_sectors) { + if (blk_rq_sectors(req) + bio_sectors(bio) > max_sectors) { req->cmd_flags |= REQ_NOMERGE; if (req == q->last_merge) q->last_merge = NULL; @@ -315,7 +315,7 @@ static int ll_merge_requests_fn(struct request_queue *q, struct request *req, /* * Will it become too large? */ - if ((req->nr_sectors + next->nr_sectors) > q->max_sectors) + if ((blk_rq_sectors(req) + blk_rq_sectors(next)) > q->max_sectors) return 0; total_phys_segments = req->nr_phys_segments + next->nr_phys_segments; @@ -345,7 +345,7 @@ static void blk_account_io_merge(struct request *req) int cpu; cpu = part_stat_lock(); - part = disk_map_sector_rcu(req->rq_disk, req->sector); + part = disk_map_sector_rcu(req->rq_disk, blk_rq_pos(req)); part_round_stats(cpu, part); part_dec_in_flight(part); @@ -366,7 +366,7 @@ static int attempt_merge(struct request_queue *q, struct request *req, /* * not contiguous */ - if (req->sector + req->nr_sectors != next->sector) + if (blk_rq_pos(req) + blk_rq_sectors(req) != blk_rq_pos(next)) return 0; if (rq_data_dir(req) != rq_data_dir(next) -- cgit v1.1 From 2e46e8b27aa57c6bd34b3102b40ee4d0144b4fab Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Thu, 7 May 2009 22:24:41 +0900 Subject: block: drop request->hard_* and *nr_sectors struct request has had a few different ways to represent some properties of a request. ->hard_* represent block layer's view of the request progress (completion cursor) and the ones without the prefix are supposed to represent the issue cursor and allowed to be updated as necessary by the low level drivers. The thing is that as block layer supports partial completion, the two cursors really aren't necessary and only cause confusion. In addition, manual management of request detail from low level drivers is cumbersome and error-prone at the very least. Another interesting duplicate fields are rq->[hard_]nr_sectors and rq->{hard_cur|current}_nr_sectors against rq->data_len and rq->bio->bi_size. This is more convoluted than the hard_ case. rq->[hard_]nr_sectors are initialized for requests with bio but blk_rq_bytes() uses it only for !pc requests. rq->data_len is initialized for all request but blk_rq_bytes() uses it only for pc requests. This causes good amount of confusion throughout block layer and its drivers and determining the request length has been a bit of black magic which may or may not work depending on circumstances and what the specific LLD is actually doing. rq->{hard_cur|current}_nr_sectors represent the number of sectors in the contiguous data area at the front. This is mainly used by drivers which transfers data by walking request segment-by-segment. This value always equals rq->bio->bi_size >> 9. However, data length for pc requests may not be multiple of 512 bytes and using this field becomes a bit confusing. In general, having multiple fields to represent the same property leads only to confusion and subtle bugs. With recent block low level driver cleanups, no driver is accessing or manipulating these duplicate fields directly. Drop all the duplicates. Now rq->sector means the current sector, rq->data_len the current total length and rq->bio->bi_size the current segment length. Everything else is defined in terms of these three and available only through accessors. * blk_recalc_rq_sectors() is collapsed into blk_update_request() and now handles pc and fs requests equally other than rq->sector update. This means that now pc requests can use partial completion too (no in-kernel user yet tho). * bio_cur_sectors() is replaced with bio_cur_bytes() as block layer now uses byte count as the primary data length. * blk_rq_pos() is now guranteed to be always correct. In-block users converted. * blk_rq_bytes() is now guaranteed to be always valid as is blk_rq_sectors(). In-block users converted. * blk_rq_sectors() is now guaranteed to equal blk_rq_bytes() >> 9. More convenient one is used. * blk_rq_bytes() and blk_rq_cur_bytes() are now inlined and take const pointer to request. [ Impact: API cleanup, single way to represent one property of a request ] Signed-off-by: Tejun Heo Cc: Boaz Harrosh Signed-off-by: Jens Axboe --- block/blk-merge.c | 36 ++++-------------------------------- 1 file changed, 4 insertions(+), 32 deletions(-) (limited to 'block/blk-merge.c') diff --git a/block/blk-merge.c b/block/blk-merge.c index bf62a87..b8df66a 100644 --- a/block/blk-merge.c +++ b/block/blk-merge.c @@ -9,35 +9,6 @@ #include "blk.h" -void blk_recalc_rq_sectors(struct request *rq, int nsect) -{ - if (blk_fs_request(rq) || blk_discard_rq(rq)) { - rq->hard_sector += nsect; - rq->hard_nr_sectors -= nsect; - - /* - * Move the I/O submission pointers ahead if required. - */ - if ((rq->nr_sectors >= rq->hard_nr_sectors) && - (rq->sector <= rq->hard_sector)) { - rq->sector = rq->hard_sector; - rq->nr_sectors = rq->hard_nr_sectors; - rq->hard_cur_sectors = bio_cur_sectors(rq->bio); - rq->current_nr_sectors = rq->hard_cur_sectors; - rq->buffer = bio_data(rq->bio); - } - - /* - * if total number of sectors is less than the first segment - * size, something has gone terribly wrong - */ - if (rq->nr_sectors < rq->current_nr_sectors) { - printk(KERN_ERR "blk: request botched\n"); - rq->nr_sectors = rq->current_nr_sectors; - } - } -} - static unsigned int __blk_recalc_rq_segments(struct request_queue *q, struct bio *bio) { @@ -199,8 +170,9 @@ new_segment: if (unlikely(rq->cmd_flags & REQ_COPY_USER) && - (rq->data_len & q->dma_pad_mask)) { - unsigned int pad_len = (q->dma_pad_mask & ~rq->data_len) + 1; + (blk_rq_bytes(rq) & q->dma_pad_mask)) { + unsigned int pad_len = + (q->dma_pad_mask & ~blk_rq_bytes(rq)) + 1; sg->length += pad_len; rq->extra_len += pad_len; @@ -398,7 +370,7 @@ static int attempt_merge(struct request_queue *q, struct request *req, req->biotail->bi_next = next->bio; req->biotail = next->biotail; - req->nr_sectors = req->hard_nr_sectors += next->hard_nr_sectors; + req->data_len += blk_rq_bytes(next); elv_merge_requests(q, req, next); -- cgit v1.1 From a2dec7b36364a5cc564c4d76cf16d2e7d33f5c05 Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Thu, 7 May 2009 22:24:44 +0900 Subject: block: hide request sector and data_len Block low level drivers for some reason have been pretty good at abusing block layer API. Especially struct request's fields tend to get violated in all possible ways. Make it clear that low level drivers MUST NOT access or manipulate rq->sector and rq->data_len directly by prefixing them with double underscores. This change is also necessary to break build of out-of-tree codes which assume the previous block API where internal fields can be manipulated and rq->data_len carries residual count on completion. [ Impact: hide internal fields, block API change ] Signed-off-by: Tejun Heo Signed-off-by: Jens Axboe --- block/blk-merge.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'block/blk-merge.c') diff --git a/block/blk-merge.c b/block/blk-merge.c index b8df66a..4974dd5 100644 --- a/block/blk-merge.c +++ b/block/blk-merge.c @@ -370,7 +370,7 @@ static int attempt_merge(struct request_queue *q, struct request *req, req->biotail->bi_next = next->bio; req->biotail = next->biotail; - req->data_len += blk_rq_bytes(next); + req->__data_len += blk_rq_bytes(next); elv_merge_requests(q, req, next); -- cgit v1.1 From ae03bf639a5027d27270123f5f6e3ee6a412781d Mon Sep 17 00:00:00 2001 From: "Martin K. Petersen" Date: Fri, 22 May 2009 17:17:50 -0400 Subject: block: Use accessor functions for queue limits Convert all external users of queue limits to using wrapper functions instead of poking the request queue variables directly. Signed-off-by: Martin K. Petersen Signed-off-by: Jens Axboe --- block/blk-merge.c | 27 ++++++++++++++------------- 1 file changed, 14 insertions(+), 13 deletions(-) (limited to 'block/blk-merge.c') diff --git a/block/blk-merge.c b/block/blk-merge.c index 4974dd5..39ce644 100644 --- a/block/blk-merge.c +++ b/block/blk-merge.c @@ -32,11 +32,12 @@ static unsigned int __blk_recalc_rq_segments(struct request_queue *q, * never considered part of another segment, since that * might change with the bounce page. */ - high = page_to_pfn(bv->bv_page) > q->bounce_pfn; + high = page_to_pfn(bv->bv_page) > queue_bounce_pfn(q); if (high || highprv) goto new_segment; if (cluster) { - if (seg_size + bv->bv_len > q->max_segment_size) + if (seg_size + bv->bv_len + > queue_max_segment_size(q)) goto new_segment; if (!BIOVEC_PHYS_MERGEABLE(bvprv, bv)) goto new_segment; @@ -91,7 +92,7 @@ static int blk_phys_contig_segment(struct request_queue *q, struct bio *bio, return 0; if (bio->bi_seg_back_size + nxt->bi_seg_front_size > - q->max_segment_size) + queue_max_segment_size(q)) return 0; if (!bio_has_data(bio)) @@ -134,7 +135,7 @@ int blk_rq_map_sg(struct request_queue *q, struct request *rq, int nbytes = bvec->bv_len; if (bvprv && cluster) { - if (sg->length + nbytes > q->max_segment_size) + if (sg->length + nbytes > queue_max_segment_size(q)) goto new_segment; if (!BIOVEC_PHYS_MERGEABLE(bvprv, bvec)) @@ -205,8 +206,8 @@ static inline int ll_new_hw_segment(struct request_queue *q, { int nr_phys_segs = bio_phys_segments(q, bio); - if (req->nr_phys_segments + nr_phys_segs > q->max_hw_segments - || req->nr_phys_segments + nr_phys_segs > q->max_phys_segments) { + if (req->nr_phys_segments + nr_phys_segs > queue_max_hw_segments(q) || + req->nr_phys_segments + nr_phys_segs > queue_max_phys_segments(q)) { req->cmd_flags |= REQ_NOMERGE; if (req == q->last_merge) q->last_merge = NULL; @@ -227,9 +228,9 @@ int ll_back_merge_fn(struct request_queue *q, struct request *req, unsigned short max_sectors; if (unlikely(blk_pc_request(req))) - max_sectors = q->max_hw_sectors; + max_sectors = queue_max_hw_sectors(q); else - max_sectors = q->max_sectors; + max_sectors = queue_max_sectors(q); if (blk_rq_sectors(req) + bio_sectors(bio) > max_sectors) { req->cmd_flags |= REQ_NOMERGE; @@ -251,9 +252,9 @@ int ll_front_merge_fn(struct request_queue *q, struct request *req, unsigned short max_sectors; if (unlikely(blk_pc_request(req))) - max_sectors = q->max_hw_sectors; + max_sectors = queue_max_hw_sectors(q); else - max_sectors = q->max_sectors; + max_sectors = queue_max_sectors(q); if (blk_rq_sectors(req) + bio_sectors(bio) > max_sectors) { @@ -287,7 +288,7 @@ static int ll_merge_requests_fn(struct request_queue *q, struct request *req, /* * Will it become too large? */ - if ((blk_rq_sectors(req) + blk_rq_sectors(next)) > q->max_sectors) + if ((blk_rq_sectors(req) + blk_rq_sectors(next)) > queue_max_sectors(q)) return 0; total_phys_segments = req->nr_phys_segments + next->nr_phys_segments; @@ -299,10 +300,10 @@ static int ll_merge_requests_fn(struct request_queue *q, struct request *req, total_phys_segments--; } - if (total_phys_segments > q->max_phys_segments) + if (total_phys_segments > queue_max_phys_segments(q)) return 0; - if (total_phys_segments > q->max_hw_segments) + if (total_phys_segments > queue_max_hw_segments(q)) return 0; /* Merge is OK... */ -- cgit v1.1