block: rename barrier/ordered to flush

With ordering requirements dropped, barrier and ordered are misnomers.
Now all block layer does is sequencing FLUSH and FUA.  Rename them to
flush.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>

3 files changed, 60 insertions, 63 deletions

diff --git a/block/blk-core.c b/block/blk-core.c
index d316662682c8..8870ae40179d 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -136,7 +136,7 @@ static void req_bio_endio(struct request *rq, struct bio *bio,
 {
         struct request_queue *q = rq->q;
 
-        if (&q->bar_rq != rq) {
+        if (&q->flush_rq != rq) {
                 if (error)
                         clear_bit(BIO_UPTODATE, &bio->bi_flags);
                 else if (!test_bit(BIO_UPTODATE, &bio->bi_flags))
@@ -160,13 +160,12 @@ static void req_bio_endio(struct request *rq, struct bio *bio,
                 if (bio->bi_size == 0)
                         bio_endio(bio, error);
         } else {
-
                 /*
-                 * Okay, this is the barrier request in progress, just
-                 * record the error;
+                 * Okay, this is the sequenced flush request in
+                 * progress, just record the error;
                  */
-                if (error && !q->orderr)
-                        q->orderr = error;
+                if (error && !q->flush_err)
+                        q->flush_err = error;
         }
 }
 
@@ -520,7 +519,7 @@ struct request_queue *blk_alloc_queue_node(gfp_t gfp_mask, int node_id)
         init_timer(&q->unplug_timer);
         setup_timer(&q->timeout, blk_rq_timed_out_timer, (unsigned long) q);
         INIT_LIST_HEAD(&q->timeout_list);
-        INIT_LIST_HEAD(&q->pending_barriers);
+        INIT_LIST_HEAD(&q->pending_flushes);
         INIT_WORK(&q->unplug_work, blk_unplug_work);
 
         kobject_init(&q->kobj, &blk_queue_ktype);
@@ -1764,11 +1763,11 @@ static void blk_account_io_completion(struct request *req, unsigned int bytes)
 static void blk_account_io_done(struct request *req)
 {
         /*
-         * Account IO completion.  bar_rq isn't accounted as a normal
-         * IO on queueing nor completion.  Accounting the containing
-         * request is enough.
+         * Account IO completion.  flush_rq isn't accounted as a
+         * normal IO on queueing nor completion.  Accounting the
+         * containing request is enough.
          */
-        if (blk_do_io_stat(req) && req != &req->q->bar_rq) {
+        if (blk_do_io_stat(req) && req != &req->q->flush_rq) {
                 unsigned long duration = jiffies - req->start_time;
                 const int rw = rq_data_dir(req);
                 struct hd_struct *part;
diff --git a/block/blk-flush.c b/block/blk-flush.c
index e8b2e5c091b1..dd873225da97 100644
--- a/block/blk-flush.c
+++ b/block/blk-flush.c
@@ -9,41 +9,38 @@
 
 #include "blk.h"
 
-static struct request *queue_next_ordseq(struct request_queue *q);
+static struct request *queue_next_fseq(struct request_queue *q);
 
-/*
- * Cache flushing for ordered writes handling
- */
-unsigned blk_ordered_cur_seq(struct request_queue *q)
+unsigned blk_flush_cur_seq(struct request_queue *q)
 {
-        if (!q->ordseq)
+        if (!q->flush_seq)
                 return 0;
-        return 1 << ffz(q->ordseq);
+        return 1 << ffz(q->flush_seq);
 }
 
-static struct request *blk_ordered_complete_seq(struct request_queue *q,
-                                                unsigned seq, int error)
+static struct request *blk_flush_complete_seq(struct request_queue *q,
+                                              unsigned seq, int error)
 {
         struct request *next_rq = NULL;
 
-        if (error && !q->orderr)
-                q->orderr = error;
+        if (error && !q->flush_err)
+                q->flush_err = error;
 
-        BUG_ON(q->ordseq & seq);
-        q->ordseq |= seq;
+        BUG_ON(q->flush_seq & seq);
+        q->flush_seq |= seq;
 
-        if (blk_ordered_cur_seq(q) != QUEUE_ORDSEQ_DONE) {
-                /* not complete yet, queue the next ordered sequence */
-                next_rq = queue_next_ordseq(q);
+        if (blk_flush_cur_seq(q) != QUEUE_FSEQ_DONE) {
+                /* not complete yet, queue the next flush sequence */
+                next_rq = queue_next_fseq(q);
         } else {
-                /* complete this barrier request */
-                __blk_end_request_all(q->orig_bar_rq, q->orderr);
-                q->orig_bar_rq = NULL;
-                q->ordseq = 0;
-
-                /* dispatch the next barrier if there's one */
-                if (!list_empty(&q->pending_barriers)) {
-                        next_rq = list_entry_rq(q->pending_barriers.next);
+                /* complete this flush request */
+                __blk_end_request_all(q->orig_flush_rq, q->flush_err);
+                q->orig_flush_rq = NULL;
+                q->flush_seq = 0;
+
+                /* dispatch the next flush if there's one */
+                if (!list_empty(&q->pending_flushes)) {
+                        next_rq = list_entry_rq(q->pending_flushes.next);
                         list_move(&next_rq->queuelist, &q->queue_head);
                 }
         }
@@ -53,19 +50,19 @@ static struct request *blk_ordered_complete_seq(struct request_queue *q,
 static void pre_flush_end_io(struct request *rq, int error)
 {
         elv_completed_request(rq->q, rq);
-        blk_ordered_complete_seq(rq->q, QUEUE_ORDSEQ_PREFLUSH, error);
+        blk_flush_complete_seq(rq->q, QUEUE_FSEQ_PREFLUSH, error);
 }
 
-static void bar_end_io(struct request *rq, int error)
+static void flush_data_end_io(struct request *rq, int error)
 {
         elv_completed_request(rq->q, rq);
-        blk_ordered_complete_seq(rq->q, QUEUE_ORDSEQ_BAR, error);
+        blk_flush_complete_seq(rq->q, QUEUE_FSEQ_DATA, error);
 }
 
 static void post_flush_end_io(struct request *rq, int error)
 {
         elv_completed_request(rq->q, rq);
-        blk_ordered_complete_seq(rq->q, QUEUE_ORDSEQ_POSTFLUSH, error);
+        blk_flush_complete_seq(rq->q, QUEUE_FSEQ_POSTFLUSH, error);
 }
 
 static void queue_flush(struct request_queue *q, struct request *rq,
@@ -74,34 +71,34 @@ static void queue_flush(struct request_queue *q, struct request *rq,
         blk_rq_init(q, rq);
         rq->cmd_type = REQ_TYPE_FS;
         rq->cmd_flags = REQ_FLUSH;
-        rq->rq_disk = q->orig_bar_rq->rq_disk;
+        rq->rq_disk = q->orig_flush_rq->rq_disk;
         rq->end_io = end_io;
 
         elv_insert(q, rq, ELEVATOR_INSERT_FRONT);
 }
 
-static struct request *queue_next_ordseq(struct request_queue *q)
+static struct request *queue_next_fseq(struct request_queue *q)
 {
-        struct request *rq = &q->bar_rq;
+        struct request *rq = &q->flush_rq;
 
-        switch (blk_ordered_cur_seq(q)) {
-        case QUEUE_ORDSEQ_PREFLUSH:
+        switch (blk_flush_cur_seq(q)) {
+        case QUEUE_FSEQ_PREFLUSH:
                 queue_flush(q, rq, pre_flush_end_io);
                 break;
 
-        case QUEUE_ORDSEQ_BAR:
+        case QUEUE_FSEQ_DATA:
                 /* initialize proxy request and queue it */
                 blk_rq_init(q, rq);
-                init_request_from_bio(rq, q->orig_bar_rq->bio);
+                init_request_from_bio(rq, q->orig_flush_rq->bio);
                 rq->cmd_flags &= ~REQ_HARDBARRIER;
                 if (q->ordered & QUEUE_ORDERED_DO_FUA)
                         rq->cmd_flags |= REQ_FUA;
-                rq->end_io = bar_end_io;
+                rq->end_io = flush_data_end_io;
 
                 elv_insert(q, rq, ELEVATOR_INSERT_FRONT);
                 break;
 
-        case QUEUE_ORDSEQ_POSTFLUSH:
+        case QUEUE_FSEQ_POSTFLUSH:
                 queue_flush(q, rq, post_flush_end_io);
                 break;
 
@@ -111,19 +108,20 @@ static struct request *queue_next_ordseq(struct request_queue *q)
         return rq;
 }
 
-struct request *blk_do_ordered(struct request_queue *q, struct request *rq)
+struct request *blk_do_flush(struct request_queue *q, struct request *rq)
 {
         unsigned skip = 0;
 
         if (!(rq->cmd_flags & REQ_HARDBARRIER))
                 return rq;
 
-        if (q->ordseq) {
+        if (q->flush_seq) {
                 /*
-                 * Barrier is already in progress and they can't be
-                 * processed in parallel.  Queue for later processing.
+                 * Sequenced flush is already in progress and they
+                 * can't be processed in parallel.  Queue for later
+                 * processing.
                  */
-                list_move_tail(&rq->queuelist, &q->pending_barriers);
+                list_move_tail(&rq->queuelist, &q->pending_flushes);
                 return NULL;
         }
 
@@ -138,11 +136,11 @@ struct request *blk_do_ordered(struct request_queue *q, struct request *rq)
         }
 
         /*
-         * Start a new ordered sequence
+         * Start a new flush sequence
          */
-        q->orderr = 0;
+        q->flush_err = 0;
         q->ordered = q->next_ordered;
-        q->ordseq |= QUEUE_ORDSEQ_STARTED;
+        q->flush_seq |= QUEUE_FSEQ_STARTED;
 
         /*
          * For an empty barrier, there's no actual BAR request, which
@@ -154,19 +152,19 @@ struct request *blk_do_ordered(struct request_queue *q, struct request *rq)
 
         /* stash away the original request */
         blk_dequeue_request(rq);
-        q->orig_bar_rq = rq;
+        q->orig_flush_rq = rq;
 
         if (!(q->ordered & QUEUE_ORDERED_DO_PREFLUSH))
-                skip |= QUEUE_ORDSEQ_PREFLUSH;
+                skip |= QUEUE_FSEQ_PREFLUSH;
 
         if (!(q->ordered & QUEUE_ORDERED_DO_BAR))
-                skip |= QUEUE_ORDSEQ_BAR;
+                skip |= QUEUE_FSEQ_DATA;
 
         if (!(q->ordered & QUEUE_ORDERED_DO_POSTFLUSH))
-                skip |= QUEUE_ORDSEQ_POSTFLUSH;
+                skip |= QUEUE_FSEQ_POSTFLUSH;
 
         /* complete skipped sequences and return the first sequence */
-        return blk_ordered_complete_seq(q, skip, 0);
+        return blk_flush_complete_seq(q, skip, 0);
 }
 
 static void bio_end_empty_barrier(struct bio *bio, int err)
diff --git a/block/blk.h b/block/blk.h
index 08081e4b294e..24b92bd78f37 100644
--- a/block/blk.h
+++ b/block/blk.h
@@ -51,7 +51,7 @@ static inline void blk_clear_rq_complete(struct request *rq)
  */
 #define ELV_ON_HASH(rq)         (!hlist_unhashed(&(rq)->hash))
 
-struct request *blk_do_ordered(struct request_queue *q, struct request *rq);
+struct request *blk_do_flush(struct request_queue *q, struct request *rq);
 
 static inline struct request *__elv_next_request(struct request_queue *q)
 {
@@ -60,7 +60,7 @@ static inline struct request *__elv_next_request(struct request_queue *q)
         while (1) {
                 while (!list_empty(&q->queue_head)) {
                         rq = list_entry_rq(q->queue_head.next);
-                        rq = blk_do_ordered(q, rq);
+                        rq = blk_do_flush(q, rq);
                         if (rq)
                                 return rq;
                 }