@@ -317,7 +317,7 @@ static void bt_tags_for_each(struct blk_mq_tags *tags, struct sbitmap_queue *bt,
* true to continue iterating tags, false to stop.
* @priv: Will be passed as second argument to @fn.
*/
-static void blk_mq_all_tag_busy_iter(struct blk_mq_tags *tags,
+void blk_mq_all_tag_busy_iter(struct blk_mq_tags *tags,
busy_tag_iter_fn *fn, void *priv)
{
if (tags->nr_reserved_tags)
@@ -34,6 +34,8 @@ extern int blk_mq_tag_update_depth(struct blk_mq_hw_ctx *hctx,
extern void blk_mq_tag_wakeup_all(struct blk_mq_tags *tags, bool);
void blk_mq_queue_tag_busy_iter(struct request_queue *q, busy_iter_fn *fn,
void *priv);
+void blk_mq_all_tag_busy_iter(struct blk_mq_tags *tags,
+ busy_tag_iter_fn *fn, void *priv);
static inline struct sbq_wait_state *bt_wait_ptr(struct sbitmap_queue *bt,
struct blk_mq_hw_ctx *hctx)
@@ -1054,6 +1054,11 @@ bool blk_mq_get_driver_tag(struct request *rq)
data.hctx->tags->rqs[rq->tag] = rq;
}
+ if (unlikely(test_bit(BLK_MQ_S_INACTIVE, &data.hctx->state))) {
+ blk_mq_put_driver_tag(rq);
+ return false;
+ }
+
return rq->tag != -1;
}
@@ -2249,8 +2254,68 @@ int blk_mq_alloc_rqs(struct blk_mq_tag_set *set, struct blk_mq_tags *tags,
return -ENOMEM;
}
+struct count_inflight_data {
+ unsigned count;
+ struct blk_mq_hw_ctx *hctx;
+};
+
+static bool blk_mq_count_inflight_rq(struct request *rq, void *data,
+ bool reserved)
+{
+ struct count_inflight_data *count_data = data;
+
+ /*
+ * Can't check rq's state because it is updated to MQ_RQ_IN_FLIGHT
+ * in blk_mq_start_request(), at that time we can't prevent this rq
+ * from being issued.
+ *
+ * So check if driver tag is assigned, if yes, count this rq as
+ * inflight.
+ */
+ if (rq->tag >= 0 && rq->mq_hctx == count_data->hctx)
+ count_data->count++;
+
+ return true;
+}
+
+static unsigned blk_mq_tags_inflight_rqs(struct blk_mq_hw_ctx *hctx)
+{
+ struct count_inflight_data count_data = {
+ .count = 0,
+ .hctx = hctx,
+ };
+
+ blk_mq_all_tag_busy_iter(hctx->tags, blk_mq_count_inflight_rq,
+ &count_data);
+
+ return count_data.count;
+}
+
+static void blk_mq_hctx_drain_inflight_rqs(struct blk_mq_hw_ctx *hctx)
+{
+ while (1) {
+ if (!blk_mq_tags_inflight_rqs(hctx))
+ break;
+ msleep(5);
+ }
+}
+
static int blk_mq_hctx_notify_online(unsigned int cpu, struct hlist_node *node)
{
+ struct blk_mq_hw_ctx *hctx = hlist_entry_safe(node,
+ struct blk_mq_hw_ctx, cpuhp_online);
+
+ if ((cpumask_next_and(-1, hctx->cpumask, cpu_online_mask) == cpu) &&
+ (cpumask_next_and(cpu, hctx->cpumask, cpu_online_mask)
+ >= nr_cpu_ids)) {
+ /*
+ * The current CPU is the last one in this hctx, S_INACTIVE
+ * can be observed in dispatch path without any barrier needed,
+ * cause both are run on one same CPU.
+ */
+ set_bit(BLK_MQ_S_INACTIVE, &hctx->state);
+ blk_mq_hctx_drain_inflight_rqs(hctx);
+ }
return 0;
}
@@ -2277,6 +2342,8 @@ static int blk_mq_hctx_notify_dead(unsigned int cpu, struct hlist_node *node)
}
spin_unlock(&ctx->lock);
+ clear_bit(BLK_MQ_S_INACTIVE, &hctx->state);
+
if (list_empty(&tmp))
return 0;
Before one CPU becomes offline, check if it is the last online CPU of hctx. If yes, mark this hctx as inactive, meantime wait for completion of all in-flight IOs originated from this hctx. This way guarantees that there isn't any inflight IO before shutdowning the managed IRQ line. Cc: John Garry <john.garry@huawei.com> Cc: Bart Van Assche <bvanassche@acm.org> Cc: Hannes Reinecke <hare@suse.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Ming Lei <ming.lei@redhat.com> --- block/blk-mq-tag.c | 2 +- block/blk-mq-tag.h | 2 ++ block/blk-mq.c | 67 ++++++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 70 insertions(+), 1 deletion(-)