block: convert REQ_ATOM_COMPLETE to stealing rq->__deadline bit

We only have one atomic flag left. Instead of using an entire
unsigned long for that, steal the bottom bit of the deadline
field that we already reserved.

Remove ->atomic_flags, since it's now unused.

Reviewed-by: Bart Van Assche <bart.vanassche@wdc.com>
Reviewed-by: Omar Sandoval <osandov@fb.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/block/blk-core.c b/block/blk-core.c
index f843ae4..7ba6075 100644 (file)
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -2853,7 +2853,7 @@ void blk_start_request(struct request *req)
                wbt_issue(req->q->rq_wb, &req->issue_stat);
        }
 
-       BUG_ON(test_bit(REQ_ATOM_COMPLETE, &req->atomic_flags));
+       BUG_ON(blk_rq_is_complete(req));
        blk_add_timer(req);
 }
 EXPORT_SYMBOL(blk_start_request);

diff --git a/block/blk-mq-debugfs.c b/block/blk-mq-debugfs.c
index dd890d5..19db3f5 100644 (file)
--- a/block/blk-mq-debugfs.c
+++ b/block/blk-mq-debugfs.c
@@ -294,12 +294,6 @@ static const char *const rqf_name[] = {
 };
 #undef RQF_NAME
 
-#define RQAF_NAME(name) [REQ_ATOM_##name] = #name
-static const char *const rqaf_name[] = {
-       RQAF_NAME(COMPLETE),
-};
-#undef RQAF_NAME
-
 int __blk_mq_debugfs_rq_show(struct seq_file *m, struct request *rq)
 {
        const struct blk_mq_ops *const mq_ops = rq->q->mq_ops;
@@ -316,8 +310,7 @@ int __blk_mq_debugfs_rq_show(struct seq_file *m, struct request *rq)
        seq_puts(m, ", .rq_flags=");
        blk_flags_show(m, (__force unsigned int)rq->rq_flags, rqf_name,
                       ARRAY_SIZE(rqf_name));
-       seq_puts(m, ", .atomic_flags=");
-       blk_flags_show(m, rq->atomic_flags, rqaf_name, ARRAY_SIZE(rqaf_name));
+       seq_printf(m, ", complete=%d", blk_rq_is_complete(rq));
        seq_printf(m, ", .tag=%d, .internal_tag=%d", rq->tag,
                   rq->internal_tag);
        if (mq_ops->show_rq)

diff --git a/block/blk-mq.c b/block/blk-mq.c
index 7035c30..87e6b10 100644 (file)
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -294,7 +294,6 @@ static struct request *blk_mq_rq_ctx_init(struct blk_mq_alloc_data *data,
                rq->rq_flags |= RQF_PREEMPT;
        if (blk_queue_io_stat(data->q))
                rq->rq_flags |= RQF_IO_STAT;
-       /* do not touch atomic flags, it needs atomic ops against the timer */
        rq->cpu = -1;
        INIT_HLIST_NODE(&rq->hash);
        RB_CLEAR_NODE(&rq->rb_node);
@@ -313,6 +312,7 @@ static struct request *blk_mq_rq_ctx_init(struct blk_mq_alloc_data *data,
        rq->special = NULL;
        /* tag was already set */
        rq->extra_len = 0;
+       rq->__deadline = 0;
 
        INIT_LIST_HEAD(&rq->timeout_list);
        rq->timeout = 0;

diff --git a/block/blk.h b/block/blk.h
index bcd9cf7..c84ae0e 100644 (file)
--- a/block/blk.h
+++ b/block/blk.h
@@ -120,24 +120,23 @@ void blk_account_io_completion(struct request *req, unsigned int bytes);
 void blk_account_io_done(struct request *req);
 
 /*
- * Internal atomic flags for request handling
- */
-enum rq_atomic_flags {
-       REQ_ATOM_COMPLETE = 0,
-};
-
-/*
  * EH timer and IO completion will both attempt to 'grab' the request, make
- * sure that only one of them succeeds
+ * sure that only one of them succeeds. Steal the bottom bit of the
+ * __deadline field for this.
  */
 static inline int blk_mark_rq_complete(struct request *rq)
 {
-       return test_and_set_bit(REQ_ATOM_COMPLETE, &rq->atomic_flags);
+       return test_and_set_bit(0, &rq->__deadline);
 }
 
 static inline void blk_clear_rq_complete(struct request *rq)
 {
-       clear_bit(REQ_ATOM_COMPLETE, &rq->atomic_flags);
+       clear_bit(0, &rq->__deadline);
+}
+
+static inline bool blk_rq_is_complete(struct request *rq)
+{
+       return test_bit(0, &rq->__deadline);
 }
 
 /*

diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index aa6698c..d4b2f7b 100644 (file)
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -156,8 +156,6 @@ struct request {
 
        int internal_tag;
 
-       unsigned long atomic_flags;
-
        /* the following two fields are internal, NEVER access directly */
        unsigned int __data_len;        /* total data len */
        int tag;