block: add accessors for setting/querying request deadline

We reduce the resolution of request expiry, but since we're already
using jiffies for this where resolution depends on the kernel
configuration and since the timeout resolution is coarse anyway,
that should be fine.

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-mq.c b/block/blk-mq.c
index 3239ca9e199f52a0fc01e1be6af133782b406401..7035c305be45e6da151a5117f7558a7a077c5dd7 100644 (file)
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -858,7 +858,7 @@ static void blk_mq_check_expired(struct blk_mq_hw_ctx *hctx,
        while (true) {
                start = read_seqcount_begin(&rq->gstate_seq);
                gstate = READ_ONCE(rq->gstate);
-               deadline = rq->deadline;
+               deadline = blk_rq_deadline(rq);
                if (!read_seqcount_retry(&rq->gstate_seq, start))
                        break;
                cond_resched();

diff --git a/block/blk-timeout.c b/block/blk-timeout.c
index ebe99963386c0a08d76877b83b7a87901ad99378..a05e3676d24a262992729201036c7e8d4eb1d9e6 100644 (file)
--- a/block/blk-timeout.c
+++ b/block/blk-timeout.c
@@ -112,7 +112,9 @@ static void blk_rq_timed_out(struct request *req)
 static void blk_rq_check_expired(struct request *rq, unsigned long *next_timeout,
                          unsigned int *next_set)
 {
-       if (time_after_eq(jiffies, rq->deadline)) {
+       const unsigned long deadline = blk_rq_deadline(rq);
+
+       if (time_after_eq(jiffies, deadline)) {
                list_del_init(&rq->timeout_list);
 
                /*
@@ -120,8 +122,8 @@ static void blk_rq_check_expired(struct request *rq, unsigned long *next_timeout
                 */
                if (!blk_mark_rq_complete(rq))
                        blk_rq_timed_out(rq);
-       } else if (!*next_set || time_after(*next_timeout, rq->deadline)) {
-               *next_timeout = rq->deadline;
+       } else if (!*next_set || time_after(*next_timeout, deadline)) {
+               *next_timeout = deadline;
                *next_set = 1;
        }
 }
@@ -162,7 +164,7 @@ void blk_abort_request(struct request *req)
                 * immediately and that scan sees the new timeout value.
                 * No need for fancy synchronizations.
                 */
-               req->deadline = jiffies;
+               blk_rq_set_deadline(req, jiffies);
                mod_timer(&req->q->timeout, 0);
        } else {
                if (blk_mark_rq_complete(req))
@@ -213,7 +215,7 @@ void blk_add_timer(struct request *req)
        if (!req->timeout)
                req->timeout = q->rq_timeout;
 
-       req->deadline = jiffies + req->timeout;
+       blk_rq_set_deadline(req, jiffies + req->timeout);
        req->rq_flags &= ~RQF_MQ_TIMEOUT_EXPIRED;
 
        /*
@@ -228,7 +230,7 @@ void blk_add_timer(struct request *req)
         * than an existing one, modify the timer. Round up to next nearest
         * second.
         */
-       expiry = blk_rq_timeout(round_jiffies_up(req->deadline));
+       expiry = blk_rq_timeout(round_jiffies_up(blk_rq_deadline(req)));
 
        if (!timer_pending(&q->timeout) ||
            time_before(expiry, q->timeout.expires)) {

diff --git a/block/blk.h b/block/blk.h
index eb306c52121ed70b8a3c84f394a8970e9ba834e5..bcd9cf7db0d4fc47fbe2e338d7859a3ca0243922 100644 (file)
--- a/block/blk.h
+++ b/block/blk.h
@@ -236,6 +236,21 @@ static inline void req_set_nomerge(struct request_queue *q, struct request *req)
                q->last_merge = NULL;
 }
 
+/*
+ * Steal a bit from this field for legacy IO path atomic IO marking. Note that
+ * setting the deadline clears the bottom bit, potentially clearing the
+ * completed bit. The user has to be OK with this (current ones are fine).
+ */
+static inline void blk_rq_set_deadline(struct request *rq, unsigned long time)
+{
+       rq->__deadline = time & ~0x1UL;
+}
+
+static inline unsigned long blk_rq_deadline(struct request *rq)
+{
+       return rq->__deadline & ~0x1UL;
+}
+
 /*
  * Internal io_context interface
  */

diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index ba31674d8581de32d5bb1e7f7c298822de529b8a..aa6698cf483c35a9d6ebdffa5df1c29654347c48 100644 (file)
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -257,7 +257,9 @@ struct request {
        struct u64_stats_sync aborted_gstate_sync;
        u64 aborted_gstate;
 
-       unsigned long deadline;
+       /* access through blk_rq_set_deadline, blk_rq_deadline */
+       unsigned long __deadline;
+
        struct list_head timeout_list;
 
        /*