blk-mq: initialize struct request fields individually

This allows us to avoid a non-atomic memset over ->atomic_flags as well
as killing lots of duplicate initializations.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>

1 files changed, 45 insertions, 2 deletions

diff --git a/block/blk-mq.c b/block/blk-mq.c
index 3fdb097ebe5e..492f49f96459 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -82,9 +82,7 @@ static struct request *__blk_mq_alloc_request(struct blk_mq_hw_ctx *hctx,
         tag = blk_mq_get_tag(hctx->tags, gfp, reserved);
         if (tag != BLK_MQ_TAG_FAIL) {
                 rq = hctx->tags->rqs[tag];
-                blk_rq_init(hctx->queue, rq);
                 rq->tag = tag;
-
                 return rq;
         }
 
@@ -187,10 +185,54 @@ static void blk_mq_rq_ctx_init(struct request_queue *q, struct blk_mq_ctx *ctx,
         if (blk_queue_io_stat(q))
                 rw_flags |= REQ_IO_STAT;
 
+        INIT_LIST_HEAD(&rq->queuelist);
+        /* csd/requeue_work/fifo_time is initialized before use */
+        rq->q = q;
         rq->mq_ctx = ctx;
         rq->cmd_flags = rw_flags;
+        rq->cmd_type = 0;
+        /* do not touch atomic flags, it needs atomic ops against the timer */
+        rq->cpu = -1;
+        rq->__data_len = 0;
+        rq->__sector = (sector_t) -1;
+        rq->bio = NULL;
+        rq->biotail = NULL;
+        INIT_HLIST_NODE(&rq->hash);
+        RB_CLEAR_NODE(&rq->rb_node);
+        memset(&rq->flush, 0, max(sizeof(rq->flush), sizeof(rq->elv)));
+        rq->rq_disk = NULL;
+        rq->part = NULL;
         rq->start_time = jiffies;
+#ifdef CONFIG_BLK_CGROUP
+        rq->rl = NULL;
         set_start_time_ns(rq);
+        rq->io_start_time_ns = 0;
+#endif
+        rq->nr_phys_segments = 0;
+#if defined(CONFIG_BLK_DEV_INTEGRITY)
+        rq->nr_integrity_segments = 0;
+#endif
+        rq->ioprio = 0;
+        rq->special = NULL;
+        /* tag was already set */
+        rq->errors = 0;
+        memset(rq->__cmd, 0, sizeof(rq->__cmd));
+        rq->cmd = rq->__cmd;
+        rq->cmd_len = BLK_MAX_CDB;
+
+        rq->extra_len = 0;
+        rq->sense_len = 0;
+        rq->resid_len = 0;
+        rq->sense = NULL;
+
+        rq->deadline = 0;
+        INIT_LIST_HEAD(&rq->timeout_list);
+        rq->timeout = 0;
+        rq->retries = 0;
+        rq->end_io = NULL;
+        rq->end_io_data = NULL;
+        rq->next_rq = NULL;
+
         ctx->rq_dispatched[rw_is_sync(rw_flags)]++;
 }
 
@@ -258,6 +300,7 @@ static void __blk_mq_free_request(struct blk_mq_hw_ctx *hctx,
         const int tag = rq->tag;
         struct request_queue *q = rq->q;
 
+        clear_bit(REQ_ATOM_STARTED, &rq->atomic_flags);
         blk_mq_put_tag(hctx->tags, tag);
         blk_mq_queue_exit(q);
 }