X-Git-Url: http://ftp.safe.ca/?a=blobdiff_plain;f=block%2Fblk-merge.c;h=5e7dc9973458406c5159b8ea3b87033302bf5fcf;hb=4de85cd6d6018825e19f76f1208775f23ecc393f;hp=d81d91419ff561be9b06afd61fd419df27e2ba77;hpb=5df97b91b5d7ed426034fcc84cb6e7cf682b8838;p=safe%2Fjmp%2Flinux-2.6

diff --git a/block/blk-merge.c b/block/blk-merge.c
index d81d914..5e7dc99 100644
--- a/block/blk-merge.c
+++ b/block/blk-merge.c
@@ -9,93 +9,78 @@
 
 #include "blk.h"
 
-void blk_recalc_rq_sectors(struct request *rq, int nsect)
+static unsigned int __blk_recalc_rq_segments(struct request_queue *q,
+					     struct bio *bio)
 {
-	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;
-		}
-	}
-}
-
-void blk_recalc_rq_segments(struct request *rq)
-{
-	int nr_phys_segs;
 	unsigned int phys_size;
 	struct bio_vec *bv, *bvprv = NULL;
-	int seg_size;
-	int cluster;
-	struct req_iterator iter;
-	int high, highprv = 1;
-	struct request_queue *q = rq->q;
+	int cluster, i, high, highprv = 1;
+	unsigned int seg_size, nr_phys_segs;
+	struct bio *fbio, *bbio;
 
-	if (!rq->bio)
-		return;
+	if (!bio)
+		return 0;
 
+	fbio = bio;
 	cluster = test_bit(QUEUE_FLAG_CLUSTER, &q->queue_flags);
 	seg_size = 0;
 	phys_size = nr_phys_segs = 0;
-	rq_for_each_segment(bv, rq, iter) {
-		/*
-		 * the trick here is making sure that a high page is never
-		 * considered part of another segment, since that might
-		 * change with the bounce page.
-		 */
-		high = page_to_pfn(bv->bv_page) > q->bounce_pfn;
-		if (high || highprv)
-			goto new_segment;
-		if (cluster) {
-			if (seg_size + bv->bv_len > q->max_segment_size)
-				goto new_segment;
-			if (!BIOVEC_PHYS_MERGEABLE(bvprv, bv))
-				goto new_segment;
-			if (!BIOVEC_SEG_BOUNDARY(q, bvprv, bv))
+	for_each_bio(bio) {
+		bio_for_each_segment(bv, bio, i) {
+			/*
+			 * the trick here is making sure that a high page is
+			 * never considered part of another segment, since that
+			 * might change with the bounce page.
+			 */
+			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
+				    > queue_max_segment_size(q))
+					goto new_segment;
+				if (!BIOVEC_PHYS_MERGEABLE(bvprv, bv))
+					goto new_segment;
+				if (!BIOVEC_SEG_BOUNDARY(q, bvprv, bv))
+					goto new_segment;
+
+				seg_size += bv->bv_len;
+				bvprv = bv;
+				continue;
+			}
+new_segment:
+			if (nr_phys_segs == 1 && seg_size >
+			    fbio->bi_seg_front_size)
+				fbio->bi_seg_front_size = seg_size;
 
-			seg_size += bv->bv_len;
+			nr_phys_segs++;
 			bvprv = bv;
-			continue;
+			seg_size = bv->bv_len;
+			highprv = high;
 		}
-new_segment:
-		nr_phys_segs++;
-		bvprv = bv;
-		seg_size = bv->bv_len;
-		highprv = high;
+		bbio = bio;
 	}
 
-	rq->nr_phys_segments = nr_phys_segs;
+	if (nr_phys_segs == 1 && seg_size > fbio->bi_seg_front_size)
+		fbio->bi_seg_front_size = seg_size;
+	if (seg_size > bbio->bi_seg_back_size)
+		bbio->bi_seg_back_size = seg_size;
+
+	return nr_phys_segs;
+}
+
+void blk_recalc_rq_segments(struct request *rq)
+{
+	rq->nr_phys_segments = __blk_recalc_rq_segments(rq->q, rq->bio);
 }
 
 void blk_recount_segments(struct request_queue *q, struct bio *bio)
 {
-	struct request rq;
 	struct bio *nxt = bio->bi_next;
-	rq.q = q;
-	rq.bio = rq.biotail = bio;
+
 	bio->bi_next = NULL;
-	blk_recalc_rq_segments(&rq);
+	bio->bi_phys_segments = __blk_recalc_rq_segments(q, bio);
 	bio->bi_next = nxt;
-	bio->bi_phys_segments = rq.nr_phys_segments;
 	bio->bi_flags |= (1 << BIO_SEG_VALID);
 }
 EXPORT_SYMBOL(blk_recount_segments);
@@ -106,7 +91,8 @@ static int blk_phys_contig_segment(struct request_queue *q, struct bio *bio,
 	if (!test_bit(QUEUE_FLAG_CLUSTER, &q->queue_flags))
 		return 0;
 
-	if (bio->bi_size + nxt->bi_size > q->max_segment_size)
+	if (bio->bi_seg_back_size + nxt->bi_seg_front_size >
+	    queue_max_segment_size(q))
 		return 0;
 
 	if (!bio_has_data(bio))
@@ -149,7 +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))
@@ -185,8 +171,9 @@ 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;
@@ -213,35 +200,13 @@ new_segment:
 }
 EXPORT_SYMBOL(blk_rq_map_sg);
 
-static inline int ll_new_mergeable(struct request_queue *q,
-				   struct request *req,
-				   struct bio *bio)
-{
-	int nr_phys_segs = bio_phys_segments(q, bio);
-
-	if (req->nr_phys_segments + nr_phys_segs > q->max_phys_segments) {
-		req->cmd_flags |= REQ_NOMERGE;
-		if (req == q->last_merge)
-			q->last_merge = NULL;
-		return 0;
-	}
-
-	/*
-	 * A hw segment is just getting larger, bump just the phys
-	 * counter.
-	 */
-	req->nr_phys_segments += nr_phys_segs;
-	return 1;
-}
-
 static inline int ll_new_hw_segment(struct request_queue *q,
 				    struct request *req,
 				    struct bio *bio)
 {
 	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_segments(q)) {
 		req->cmd_flags |= REQ_NOMERGE;
 		if (req == q->last_merge)
 			q->last_merge = NULL;
@@ -262,11 +227,11 @@ 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 (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;
@@ -286,12 +251,12 @@ 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 (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;
@@ -309,6 +274,8 @@ static int ll_merge_requests_fn(struct request_queue *q, struct request *req,
 				struct request *next)
 {
 	int total_phys_segments;
+	unsigned int seg_size =
+		req->biotail->bi_seg_back_size + next->bio->bi_seg_front_size;
 
 	/*
 	 * First check if the either of the requests are re-queued
@@ -320,17 +287,19 @@ 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)) > queue_max_sectors(q))
 		return 0;
 
 	total_phys_segments = req->nr_phys_segments + next->nr_phys_segments;
-	if (blk_phys_contig_segment(q, req->biotail, next->bio))
+	if (blk_phys_contig_segment(q, req->biotail, next->bio)) {
+		if (req->nr_phys_segments == 1)
+			req->bio->bi_seg_front_size = seg_size;
+		if (next->nr_phys_segments == 1)
+			next->biotail->bi_seg_back_size = seg_size;
 		total_phys_segments--;
+	}
 
-	if (total_phys_segments > q->max_phys_segments)
-		return 0;
-
-	if (total_phys_segments > q->max_hw_segments)
+	if (total_phys_segments > queue_max_segments(q))
 		return 0;
 
 	/* Merge is OK... */
@@ -338,6 +307,52 @@ static int ll_merge_requests_fn(struct request_queue *q, struct request *req,
 	return 1;
 }
 
+/**
+ * blk_rq_set_mixed_merge - mark a request as mixed merge
+ * @rq: request to mark as mixed merge
+ *
+ * Description:
+ *     @rq is about to be mixed merged.  Make sure the attributes
+ *     which can be mixed are set in each bio and mark @rq as mixed
+ *     merged.
+ */
+void blk_rq_set_mixed_merge(struct request *rq)
+{
+	unsigned int ff = rq->cmd_flags & REQ_FAILFAST_MASK;
+	struct bio *bio;
+
+	if (rq->cmd_flags & REQ_MIXED_MERGE)
+		return;
+
+	/*
+	 * @rq will no longer represent mixable attributes for all the
+	 * contained bios.  It will just track those of the first one.
+	 * Distributes the attributs to each bio.
+	 */
+	for (bio = rq->bio; bio; bio = bio->bi_next) {
+		WARN_ON_ONCE((bio->bi_rw & REQ_FAILFAST_MASK) &&
+			     (bio->bi_rw & REQ_FAILFAST_MASK) != ff);
+		bio->bi_rw |= ff;
+	}
+	rq->cmd_flags |= REQ_MIXED_MERGE;
+}
+
+static void blk_account_io_merge(struct request *req)
+{
+	if (blk_do_io_stat(req)) {
+		struct hd_struct *part;
+		int cpu;
+
+		cpu = part_stat_lock();
+		part = disk_map_sector_rcu(req->rq_disk, blk_rq_pos(req));
+
+		part_round_stats(cpu, part);
+		part_dec_in_flight(part, rq_data_dir(req));
+
+		part_stat_unlock();
+	}
+}
+
 /*
  * Has to be called with the request spinlock acquired
  */
@@ -350,7 +365,7 @@ 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)
@@ -371,6 +386,19 @@ static int attempt_merge(struct request_queue *q, struct request *req,
 		return 0;
 
 	/*
+	 * If failfast settings disagree or any of the two is already
+	 * a mixed merge, mark both as mixed before proceeding.  This
+	 * makes sure that all involved bios have mixable attributes
+	 * set properly.
+	 */
+	if ((req->cmd_flags | next->cmd_flags) & REQ_MIXED_MERGE ||
+	    (req->cmd_flags & REQ_FAILFAST_MASK) !=
+	    (next->cmd_flags & REQ_FAILFAST_MASK)) {
+		blk_rq_set_mixed_merge(req);
+		blk_rq_set_mixed_merge(next);
+	}
+
+	/*
 	 * At this point we have either done a back merge
 	 * or front merge. We need the smaller start_time of
 	 * the merged requests to be the current request
@@ -382,23 +410,21 @@ 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);
 
-	if (req->rq_disk) {
-		struct hd_struct *part
-			= get_part(req->rq_disk, req->sector);
-		disk_round_stats(req->rq_disk);
-		req->rq_disk->in_flight--;
-		if (part) {
-			part_round_stats(part);
-			part->in_flight--;
-		}
-	}
+	/*
+	 * 'next' is going away, so update stats accordingly
+	 */
+	blk_account_io_merge(next);
 
 	req->ioprio = ioprio_best(req->ioprio, next->ioprio);
+	if (blk_rq_cpu_valid(next))
+		req->cpu = next->cpu;
 
+	/* owner-ship of bio passed from next to req */
+	next->bio = NULL;
 	__blk_put_request(q, next);
 	return 1;
 }