zte's code,first commit
Change-Id: I9a04da59e459a9bc0d67f101f700d9d7dc8d681b
diff --git a/ap/os/linux/linux-3.4.x/block/blk-merge.c b/ap/os/linux/linux-3.4.x/block/blk-merge.c
new file mode 100644
index 0000000..160035f
--- /dev/null
+++ b/ap/os/linux/linux-3.4.x/block/blk-merge.c
@@ -0,0 +1,510 @@
+/*
+ * Functions related to segment and merge handling
+ */
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/bio.h>
+#include <linux/blkdev.h>
+#include <linux/scatterlist.h>
+
+#include "blk.h"
+
+static unsigned int __blk_recalc_rq_segments(struct request_queue *q,
+ struct bio *bio)
+{
+ struct bio_vec *bv, *bvprv = NULL;
+ int cluster, i, high, highprv = 1;
+ unsigned int seg_size, nr_phys_segs;
+ struct bio *fbio, *bbio;
+
+ if (!bio)
+ return 0;
+
+ fbio = bio;
+ cluster = blk_queue_cluster(q);
+ seg_size = 0;
+ nr_phys_segs = 0;
+ 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;
+
+ nr_phys_segs++;
+ bvprv = bv;
+ seg_size = bv->bv_len;
+ highprv = high;
+ }
+ bbio = bio;
+ }
+
+ 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 bio *nxt = bio->bi_next;
+
+ bio->bi_next = NULL;
+ bio->bi_phys_segments = __blk_recalc_rq_segments(q, bio);
+ bio->bi_next = nxt;
+ bio->bi_flags |= (1 << BIO_SEG_VALID);
+}
+EXPORT_SYMBOL(blk_recount_segments);
+
+static int blk_phys_contig_segment(struct request_queue *q, struct bio *bio,
+ struct bio *nxt)
+{
+ if (!blk_queue_cluster(q))
+ return 0;
+
+ if (bio->bi_seg_back_size + nxt->bi_seg_front_size >
+ queue_max_segment_size(q))
+ return 0;
+
+ if (!bio_has_data(bio))
+ return 1;
+
+ if (!BIOVEC_PHYS_MERGEABLE(__BVEC_END(bio), __BVEC_START(nxt)))
+ return 0;
+
+ /*
+ * bio and nxt are contiguous in memory; check if the queue allows
+ * these two to be merged into one
+ */
+ if (BIO_SEG_BOUNDARY(q, bio, nxt))
+ return 1;
+
+ return 0;
+}
+
+/*
+ * map a request to scatterlist, return number of sg entries setup. Caller
+ * must make sure sg can hold rq->nr_phys_segments entries
+ */
+int blk_rq_map_sg(struct request_queue *q, struct request *rq,
+ struct scatterlist *sglist)
+{
+ struct bio_vec *bvec, *bvprv;
+ struct req_iterator iter;
+ struct scatterlist *sg;
+ int nsegs, cluster;
+
+ nsegs = 0;
+ cluster = blk_queue_cluster(q);
+
+ /*
+ * for each bio in rq
+ */
+ bvprv = NULL;
+ sg = NULL;
+ rq_for_each_segment(bvec, rq, iter) {
+ int nbytes = bvec->bv_len;
+
+ if (bvprv && cluster) {
+ if (sg->length + nbytes > queue_max_segment_size(q))
+ goto new_segment;
+
+ if (!BIOVEC_PHYS_MERGEABLE(bvprv, bvec))
+ goto new_segment;
+ if (!BIOVEC_SEG_BOUNDARY(q, bvprv, bvec))
+ goto new_segment;
+
+ sg->length += nbytes;
+ } else {
+new_segment:
+ if (!sg)
+ sg = sglist;
+ else {
+ /*
+ * If the driver previously mapped a shorter
+ * list, we could see a termination bit
+ * prematurely unless it fully inits the sg
+ * table on each mapping. We KNOW that there
+ * must be more entries here or the driver
+ * would be buggy, so force clear the
+ * termination bit to avoid doing a full
+ * sg_init_table() in drivers for each command.
+ */
+ sg->page_link &= ~0x02;
+ sg = sg_next(sg);
+ }
+
+ sg_set_page(sg, bvec->bv_page, nbytes, bvec->bv_offset);
+ nsegs++;
+ }
+ bvprv = bvec;
+ } /* segments in rq */
+
+
+ if (unlikely(rq->cmd_flags & REQ_COPY_USER) &&
+ (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;
+ }
+
+ if (q->dma_drain_size && q->dma_drain_needed(rq)) {
+ if (rq->cmd_flags & REQ_WRITE)
+ memset(q->dma_drain_buffer, 0, q->dma_drain_size);
+
+ sg->page_link &= ~0x02;
+ sg = sg_next(sg);
+ sg_set_page(sg, virt_to_page(q->dma_drain_buffer),
+ q->dma_drain_size,
+ ((unsigned long)q->dma_drain_buffer) &
+ (PAGE_SIZE - 1));
+ nsegs++;
+ rq->extra_len += q->dma_drain_size;
+ }
+
+ if (sg)
+ sg_mark_end(sg);
+
+ return nsegs;
+}
+EXPORT_SYMBOL(blk_rq_map_sg);
+
+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 > queue_max_segments(q))
+ goto no_merge;
+
+ if (bio_integrity(bio) && blk_integrity_merge_bio(q, req, bio))
+ goto no_merge;
+
+ /*
+ * This will form the start of a new hw segment. Bump both
+ * counters.
+ */
+ req->nr_phys_segments += nr_phys_segs;
+ return 1;
+
+no_merge:
+ req->cmd_flags |= REQ_NOMERGE;
+ if (req == q->last_merge)
+ q->last_merge = NULL;
+ return 0;
+}
+
+int ll_back_merge_fn(struct request_queue *q, struct request *req,
+ struct bio *bio)
+{
+ unsigned short max_sectors;
+
+ if (unlikely(req->cmd_type == REQ_TYPE_BLOCK_PC))
+ max_sectors = queue_max_hw_sectors(q);
+ else
+ max_sectors = queue_max_sectors(q);
+
+ if (blk_rq_sectors(req) + bio_sectors(bio) > max_sectors) {
+ req->cmd_flags |= REQ_NOMERGE;
+ if (req == q->last_merge)
+ q->last_merge = NULL;
+ return 0;
+ }
+ if (!bio_flagged(req->biotail, BIO_SEG_VALID))
+ blk_recount_segments(q, req->biotail);
+ if (!bio_flagged(bio, BIO_SEG_VALID))
+ blk_recount_segments(q, bio);
+
+ return ll_new_hw_segment(q, req, bio);
+}
+
+int ll_front_merge_fn(struct request_queue *q, struct request *req,
+ struct bio *bio)
+{
+ unsigned short max_sectors;
+
+ if (unlikely(req->cmd_type == REQ_TYPE_BLOCK_PC))
+ max_sectors = queue_max_hw_sectors(q);
+ else
+ max_sectors = queue_max_sectors(q);
+
+
+ if (blk_rq_sectors(req) + bio_sectors(bio) > max_sectors) {
+ req->cmd_flags |= REQ_NOMERGE;
+ if (req == q->last_merge)
+ q->last_merge = NULL;
+ return 0;
+ }
+ if (!bio_flagged(bio, BIO_SEG_VALID))
+ blk_recount_segments(q, bio);
+ if (!bio_flagged(req->bio, BIO_SEG_VALID))
+ blk_recount_segments(q, req->bio);
+
+ return ll_new_hw_segment(q, req, bio);
+}
+
+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
+ * requests. Can't merge them if they are.
+ */
+ if (req->special || next->special)
+ return 0;
+
+ /*
+ * Will it become too large?
+ */
+ 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 (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 > queue_max_segments(q))
+ return 0;
+
+ if (blk_integrity_rq(req) && blk_integrity_merge_rq(q, req, next))
+ return 0;
+
+ /* Merge is OK... */
+ req->nr_phys_segments = total_phys_segments;
+ 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 = req->part;
+
+ part_round_stats(cpu, part);
+ part_dec_in_flight(part, rq_data_dir(req));
+
+ hd_struct_put(part);
+ part_stat_unlock();
+ }
+}
+
+/*
+ * Has to be called with the request spinlock acquired
+ */
+static int attempt_merge(struct request_queue *q, struct request *req,
+ struct request *next)
+{
+ if (!rq_mergeable(req) || !rq_mergeable(next))
+ return 0;
+
+ /*
+ * Don't merge file system requests and discard requests
+ */
+ if ((req->cmd_flags & REQ_DISCARD) != (next->cmd_flags & REQ_DISCARD))
+ return 0;
+
+ /*
+ * Don't merge discard requests and secure discard requests
+ */
+ if ((req->cmd_flags & REQ_SECURE) != (next->cmd_flags & REQ_SECURE))
+ return 0;
+
+ /*
+ * not contiguous
+ */
+ if (blk_rq_pos(req) + blk_rq_sectors(req) != blk_rq_pos(next))
+ return 0;
+
+ if (rq_data_dir(req) != rq_data_dir(next)
+ || req->rq_disk != next->rq_disk
+ || next->special)
+ return 0;
+
+ /*
+ * If we are allowed to merge, then append bio list
+ * from next to rq and release next. merge_requests_fn
+ * will have updated segment counts, update sector
+ * counts here.
+ */
+ if (!ll_merge_requests_fn(q, req, next))
+ 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
+ * for accounting purposes.
+ */
+ if (time_after(req->start_time, next->start_time))
+ req->start_time = next->start_time;
+
+ req->biotail->bi_next = next->bio;
+ req->biotail = next->biotail;
+
+ req->__data_len += blk_rq_bytes(next);
+
+ elv_merge_requests(q, req, next);
+
+ /*
+ * '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;
+}
+
+int attempt_back_merge(struct request_queue *q, struct request *rq)
+{
+ struct request *next = elv_latter_request(q, rq);
+
+ if (next)
+ return attempt_merge(q, rq, next);
+
+ return 0;
+}
+
+int attempt_front_merge(struct request_queue *q, struct request *rq)
+{
+ struct request *prev = elv_former_request(q, rq);
+
+ if (prev)
+ return attempt_merge(q, prev, rq);
+
+ return 0;
+}
+
+int blk_attempt_req_merge(struct request_queue *q, struct request *rq,
+ struct request *next)
+{
+ return attempt_merge(q, rq, next);
+}
+
+bool blk_rq_merge_ok(struct request *rq, struct bio *bio)
+{
+ if (!rq_mergeable(rq))
+ return false;
+
+ /* don't merge file system requests and discard requests */
+ if ((bio->bi_rw & REQ_DISCARD) != (rq->bio->bi_rw & REQ_DISCARD))
+ return false;
+
+ /* don't merge discard requests and secure discard requests */
+ if ((bio->bi_rw & REQ_SECURE) != (rq->bio->bi_rw & REQ_SECURE))
+ return false;
+
+ /* different data direction or already started, don't merge */
+ if (bio_data_dir(bio) != rq_data_dir(rq))
+ return false;
+
+ /* must be same device and not a special request */
+ if (rq->rq_disk != bio->bi_bdev->bd_disk || rq->special)
+ return false;
+
+ /* only merge integrity protected bio into ditto rq */
+ if (bio_integrity(bio) != blk_integrity_rq(rq))
+ return false;
+
+ return true;
+}
+
+int blk_try_merge(struct request *rq, struct bio *bio)
+{
+ if (blk_rq_pos(rq) + blk_rq_sectors(rq) == bio->bi_sector)
+ return ELEVATOR_BACK_MERGE;
+ else if (blk_rq_pos(rq) - bio_sectors(bio) == bio->bi_sector)
+ return ELEVATOR_FRONT_MERGE;
+ return ELEVATOR_NO_MERGE;
+}