Merge branch 'for-4.2/writeback' of git://git.kernel.dk/linux-block
[deliverable/linux.git] / block / blk-core.c
index 03b5f8d77f37b4cbad3a12f3a98f9c3ea63a50e7..688ae9482cb8eab438d3bbcaf6d61602a366cfc8 100644 (file)
 #include <linux/delay.h>
 #include <linux/ratelimit.h>
 #include <linux/pm_runtime.h>
+#include <linux/blk-cgroup.h>
 
 #define CREATE_TRACE_POINTS
 #include <trace/events/block.h>
 
 #include "blk.h"
-#include "blk-cgroup.h"
 #include "blk-mq.h"
 
 EXPORT_TRACEPOINT_SYMBOL_GPL(block_bio_remap);
@@ -63,6 +63,31 @@ struct kmem_cache *blk_requestq_cachep;
  */
 static struct workqueue_struct *kblockd_workqueue;
 
+static void blk_clear_congested(struct request_list *rl, int sync)
+{
+#ifdef CONFIG_CGROUP_WRITEBACK
+       clear_wb_congested(rl->blkg->wb_congested, sync);
+#else
+       /*
+        * If !CGROUP_WRITEBACK, all blkg's map to bdi->wb and we shouldn't
+        * flip its congestion state for events on other blkcgs.
+        */
+       if (rl == &rl->q->root_rl)
+               clear_wb_congested(rl->q->backing_dev_info.wb.congested, sync);
+#endif
+}
+
+static void blk_set_congested(struct request_list *rl, int sync)
+{
+#ifdef CONFIG_CGROUP_WRITEBACK
+       set_wb_congested(rl->blkg->wb_congested, sync);
+#else
+       /* see blk_clear_congested() */
+       if (rl == &rl->q->root_rl)
+               set_wb_congested(rl->q->backing_dev_info.wb.congested, sync);
+#endif
+}
+
 void blk_queue_congestion_threshold(struct request_queue *q)
 {
        int nr;
@@ -117,7 +142,7 @@ EXPORT_SYMBOL(blk_rq_init);
 static void req_bio_endio(struct request *rq, struct bio *bio,
                          unsigned int nbytes, int error)
 {
-       if (error)
+       if (error && !(rq->cmd_flags & REQ_CLONE))
                clear_bit(BIO_UPTODATE, &bio->bi_flags);
        else if (!test_bit(BIO_UPTODATE, &bio->bi_flags))
                error = -EIO;
@@ -128,7 +153,8 @@ static void req_bio_endio(struct request *rq, struct bio *bio,
        bio_advance(bio, nbytes);
 
        /* don't actually finish bio if it's part of flush sequence */
-       if (bio->bi_iter.bi_size == 0 && !(rq->cmd_flags & REQ_FLUSH_SEQ))
+       if (bio->bi_iter.bi_size == 0 &&
+           !(rq->cmd_flags & (REQ_FLUSH_SEQ|REQ_CLONE)))
                bio_endio(bio, error);
 }
 
@@ -285,6 +311,7 @@ inline void __blk_run_queue_uncond(struct request_queue *q)
        q->request_fn(q);
        q->request_fn_active--;
 }
+EXPORT_SYMBOL_GPL(__blk_run_queue_uncond);
 
 /**
  * __blk_run_queue - run a single device queue
@@ -621,8 +648,7 @@ struct request_queue *blk_alloc_queue_node(gfp_t gfp_mask, int node_id)
 
        q->backing_dev_info.ra_pages =
                        (VM_MAX_READAHEAD * 1024) / PAGE_CACHE_SIZE;
-       q->backing_dev_info.state = 0;
-       q->backing_dev_info.capabilities = 0;
+       q->backing_dev_info.capabilities = BDI_CAP_CGROUP_WRITEBACK;
        q->backing_dev_info.name = "block";
        q->node = node_id;
 
@@ -845,13 +871,8 @@ static void __freed_request(struct request_list *rl, int sync)
 {
        struct request_queue *q = rl->q;
 
-       /*
-        * bdi isn't aware of blkcg yet.  As all async IOs end up root
-        * blkcg anyway, just use root blkcg state.
-        */
-       if (rl == &q->root_rl &&
-           rl->count[sync] < queue_congestion_off_threshold(q))
-               blk_clear_queue_congested(q, sync);
+       if (rl->count[sync] < queue_congestion_off_threshold(q))
+               blk_clear_congested(rl, sync);
 
        if (rl->count[sync] + 1 <= q->nr_requests) {
                if (waitqueue_active(&rl->wait[sync]))
@@ -884,25 +905,25 @@ static void freed_request(struct request_list *rl, unsigned int flags)
 int blk_update_nr_requests(struct request_queue *q, unsigned int nr)
 {
        struct request_list *rl;
+       int on_thresh, off_thresh;
 
        spin_lock_irq(q->queue_lock);
        q->nr_requests = nr;
        blk_queue_congestion_threshold(q);
+       on_thresh = queue_congestion_on_threshold(q);
+       off_thresh = queue_congestion_off_threshold(q);
 
-       /* congestion isn't cgroup aware and follows root blkcg for now */
-       rl = &q->root_rl;
-
-       if (rl->count[BLK_RW_SYNC] >= queue_congestion_on_threshold(q))
-               blk_set_queue_congested(q, BLK_RW_SYNC);
-       else if (rl->count[BLK_RW_SYNC] < queue_congestion_off_threshold(q))
-               blk_clear_queue_congested(q, BLK_RW_SYNC);
+       blk_queue_for_each_rl(rl, q) {
+               if (rl->count[BLK_RW_SYNC] >= on_thresh)
+                       blk_set_congested(rl, BLK_RW_SYNC);
+               else if (rl->count[BLK_RW_SYNC] < off_thresh)
+                       blk_clear_congested(rl, BLK_RW_SYNC);
 
-       if (rl->count[BLK_RW_ASYNC] >= queue_congestion_on_threshold(q))
-               blk_set_queue_congested(q, BLK_RW_ASYNC);
-       else if (rl->count[BLK_RW_ASYNC] < queue_congestion_off_threshold(q))
-               blk_clear_queue_congested(q, BLK_RW_ASYNC);
+               if (rl->count[BLK_RW_ASYNC] >= on_thresh)
+                       blk_set_congested(rl, BLK_RW_ASYNC);
+               else if (rl->count[BLK_RW_ASYNC] < off_thresh)
+                       blk_clear_congested(rl, BLK_RW_ASYNC);
 
-       blk_queue_for_each_rl(rl, q) {
                if (rl->count[BLK_RW_SYNC] >= q->nr_requests) {
                        blk_set_rl_full(rl, BLK_RW_SYNC);
                } else {
@@ -1012,12 +1033,7 @@ static struct request *__get_request(struct request_list *rl, int rw_flags,
                                }
                        }
                }
-               /*
-                * bdi isn't aware of blkcg yet.  As all async IOs end up
-                * root blkcg anyway, just use root blkcg state.
-                */
-               if (rl == &q->root_rl)
-                       blk_set_queue_congested(q, is_sync);
+               blk_set_congested(rl, is_sync);
        }
 
        /*
@@ -1525,7 +1541,8 @@ bool bio_attempt_front_merge(struct request_queue *q, struct request *req,
  * Caller must ensure !blk_queue_nomerges(q) beforehand.
  */
 bool blk_attempt_plug_merge(struct request_queue *q, struct bio *bio,
-                           unsigned int *request_count)
+                           unsigned int *request_count,
+                           struct request **same_queue_rq)
 {
        struct blk_plug *plug;
        struct request *rq;
@@ -1545,8 +1562,16 @@ bool blk_attempt_plug_merge(struct request_queue *q, struct bio *bio,
        list_for_each_entry_reverse(rq, plug_list, queuelist) {
                int el_ret;
 
-               if (rq->q == q)
+               if (rq->q == q) {
                        (*request_count)++;
+                       /*
+                        * Only blk-mq multiple hardware queues case checks the
+                        * rq in the same queue, there should be only one such
+                        * rq in a queue
+                        **/
+                       if (same_queue_rq)
+                               *same_queue_rq = rq;
+               }
 
                if (rq->q != q || !blk_rq_merge_ok(rq, bio))
                        continue;
@@ -1611,7 +1636,7 @@ static void blk_queue_bio(struct request_queue *q, struct bio *bio)
         * any locks.
         */
        if (!blk_queue_nomerges(q) &&
-           blk_attempt_plug_merge(q, bio, &request_count))
+           blk_attempt_plug_merge(q, bio, &request_count, NULL))
                return;
 
        spin_lock_irq(q->queue_lock);
@@ -1718,8 +1743,6 @@ static void handle_bad_sector(struct bio *bio)
                        bio->bi_rw,
                        (unsigned long long)bio_end_sector(bio),
                        (long long)(i_size_read(bio->bi_bdev->bd_inode) >> 9));
-
-       set_bit(BIO_EOF, &bio->bi_flags);
 }
 
 #ifdef CONFIG_FAIL_MAKE_REQUEST
@@ -2904,95 +2927,22 @@ int blk_lld_busy(struct request_queue *q)
 }
 EXPORT_SYMBOL_GPL(blk_lld_busy);
 
-/**
- * blk_rq_unprep_clone - Helper function to free all bios in a cloned request
- * @rq: the clone request to be cleaned up
- *
- * Description:
- *     Free all bios in @rq for a cloned request.
- */
-void blk_rq_unprep_clone(struct request *rq)
-{
-       struct bio *bio;
-
-       while ((bio = rq->bio) != NULL) {
-               rq->bio = bio->bi_next;
-
-               bio_put(bio);
-       }
-}
-EXPORT_SYMBOL_GPL(blk_rq_unprep_clone);
-
-/*
- * Copy attributes of the original request to the clone request.
- * The actual data parts (e.g. ->cmd, ->sense) are not copied.
- */
-static void __blk_rq_prep_clone(struct request *dst, struct request *src)
+void blk_rq_prep_clone(struct request *dst, struct request *src)
 {
        dst->cpu = src->cpu;
-       dst->cmd_flags |= (src->cmd_flags & REQ_CLONE_MASK) | REQ_NOMERGE;
+       dst->cmd_flags |= (src->cmd_flags & REQ_CLONE_MASK);
+       dst->cmd_flags |= REQ_NOMERGE | REQ_CLONE;
        dst->cmd_type = src->cmd_type;
        dst->__sector = blk_rq_pos(src);
        dst->__data_len = blk_rq_bytes(src);
        dst->nr_phys_segments = src->nr_phys_segments;
        dst->ioprio = src->ioprio;
        dst->extra_len = src->extra_len;
-}
-
-/**
- * blk_rq_prep_clone - Helper function to setup clone request
- * @rq: the request to be setup
- * @rq_src: original request to be cloned
- * @bs: bio_set that bios for clone are allocated from
- * @gfp_mask: memory allocation mask for bio
- * @bio_ctr: setup function to be called for each clone bio.
- *           Returns %0 for success, non %0 for failure.
- * @data: private data to be passed to @bio_ctr
- *
- * Description:
- *     Clones bios in @rq_src to @rq, and copies attributes of @rq_src to @rq.
- *     The actual data parts of @rq_src (e.g. ->cmd, ->sense)
- *     are not copied, and copying such parts is the caller's responsibility.
- *     Also, pages which the original bios are pointing to are not copied
- *     and the cloned bios just point same pages.
- *     So cloned bios must be completed before original bios, which means
- *     the caller must complete @rq before @rq_src.
- */
-int blk_rq_prep_clone(struct request *rq, struct request *rq_src,
-                     struct bio_set *bs, gfp_t gfp_mask,
-                     int (*bio_ctr)(struct bio *, struct bio *, void *),
-                     void *data)
-{
-       struct bio *bio, *bio_src;
-
-       if (!bs)
-               bs = fs_bio_set;
-
-       __rq_for_each_bio(bio_src, rq_src) {
-               bio = bio_clone_fast(bio_src, gfp_mask, bs);
-               if (!bio)
-                       goto free_and_out;
-
-               if (bio_ctr && bio_ctr(bio, bio_src, data))
-                       goto free_and_out;
-
-               if (rq->bio) {
-                       rq->biotail->bi_next = bio;
-                       rq->biotail = bio;
-               } else
-                       rq->bio = rq->biotail = bio;
-       }
-
-       __blk_rq_prep_clone(rq, rq_src);
-
-       return 0;
-
-free_and_out:
-       if (bio)
-               bio_put(bio);
-       blk_rq_unprep_clone(rq);
-
-       return -ENOMEM;
+       dst->bio = src->bio;
+       dst->biotail = src->biotail;
+       dst->cmd = src->cmd;
+       dst->cmd_len = src->cmd_len;
+       dst->sense = src->sense;
 }
 EXPORT_SYMBOL_GPL(blk_rq_prep_clone);
 
@@ -3034,21 +2984,20 @@ void blk_start_plug(struct blk_plug *plug)
 {
        struct task_struct *tsk = current;
 
+       /*
+        * If this is a nested plug, don't actually assign it.
+        */
+       if (tsk->plug)
+               return;
+
        INIT_LIST_HEAD(&plug->list);
        INIT_LIST_HEAD(&plug->mq_list);
        INIT_LIST_HEAD(&plug->cb_list);
-
        /*
-        * If this is a nested plug, don't actually assign it. It will be
-        * flushed on its own.
+        * Store ordering should not be needed here, since a potential
+        * preempt will imply a full memory barrier
         */
-       if (!tsk->plug) {
-               /*
-                * Store ordering should not be needed here, since a potential
-                * preempt will imply a full memory barrier
-                */
-               tsk->plug = plug;
-       }
+       tsk->plug = plug;
 }
 EXPORT_SYMBOL(blk_start_plug);
 
@@ -3195,10 +3144,11 @@ void blk_flush_plug_list(struct blk_plug *plug, bool from_schedule)
 
 void blk_finish_plug(struct blk_plug *plug)
 {
+       if (plug != current->plug)
+               return;
        blk_flush_plug_list(plug, false);
 
-       if (plug == current->plug)
-               current->plug = NULL;
+       current->plug = NULL;
 }
 EXPORT_SYMBOL(blk_finish_plug);
 
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