Re: [PATCH] blk-mq: Return invalid cookie if bio was split
flat view
From: Keith Busch <hidden>
Date: 2016-10-05 16:40:36
Subsystem:
block layer, nvm express driver, the rest · Maintainers:
Jens Axboe, Keith Busch, Christoph Hellwig, Sagi Grimberg, Linus Torvalds
On Wed, Oct 05, 2016 at 11:19:39AM +0800, Ming Lei wrote:
But .poll() need to check if the specific request is completed or not,
then blk_poll() can set 'current' as RUNNING if it is completed.
blk_poll():
...
ret = q->mq_ops->poll(hctx, blk_qc_t_to_tag(cookie));
if (ret > 0) {
hctx->poll_success++;
set_current_state(TASK_RUNNING);
return true;
}Right, but the task could be waiting on a whole lot more than just that one tag, so setting the task to running before knowing those all complete doesn't sound right.
I am glad to take a look the patch if you post it out.
Here's what I got for block + nvme. It relies on all the requests to complete to set the task back to running. ---
diff --git a/block/blk-core.c b/block/blk-core.c
index b993f88..3c1cfbf 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c@@ -3342,6 +3342,8 @@ EXPORT_SYMBOL(blk_finish_plug); bool blk_poll(struct request_queue *q, blk_qc_t cookie) { struct blk_plug *plug; + struct blk_mq_hw_ctx *hctx; + unsigned int queue_num; long state; if (!q->mq_ops || !q->mq_ops->poll || !blk_qc_t_valid(cookie) ||
@@ -3353,27 +3355,15 @@ bool blk_poll(struct request_queue *q, blk_qc_t cookie) blk_flush_plug_list(plug, false); state = current->state; + queue_num = blk_qc_t_to_queue_num(cookie); + hctx = q->queue_hw_ctx[queue_num]; while (!need_resched()) { - unsigned int queue_num = blk_qc_t_to_queue_num(cookie); - struct blk_mq_hw_ctx *hctx = q->queue_hw_ctx[queue_num]; - int ret; - - hctx->poll_invoked++; - - ret = q->mq_ops->poll(hctx, blk_qc_t_to_tag(cookie)); - if (ret > 0) { - hctx->poll_success++; - set_current_state(TASK_RUNNING); - return true; - } + q->mq_ops->poll(hctx); if (signal_pending_state(state, current)) set_current_state(TASK_RUNNING); - if (current->state == TASK_RUNNING) return true; - if (ret < 0) - break; cpu_relax(); }
diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c
index befac5b..2e359e0 100644
--- a/drivers/nvme/host/pci.c
+++ b/drivers/nvme/host/pci.c@@ -649,7 +651,7 @@ static inline bool nvme_cqe_valid(struct nvme_queue *nvmeq, u16 head, return (le16_to_cpu(nvmeq->cqes[head].status) & 1) == phase; } -static void __nvme_process_cq(struct nvme_queue *nvmeq, unsigned int *tag) +static void nvme_process_cq(struct nvme_queue *nvmeq) { u16 head, phase;
@@ -665,9 +667,6 @@ static void __nvme_process_cq(struct nvme_queue *nvmeq, unsigned int *tag) phase = !phase; } - if (tag && *tag == cqe.command_id) - *tag = -1; - if (unlikely(cqe.command_id >= nvmeq->q_depth)) { dev_warn(nvmeq->dev->ctrl.device, "invalid id %d completed on queue %d\n",
@@ -711,11 +710,6 @@ static void __nvme_process_cq(struct nvme_queue *nvmeq, unsigned int *tag) nvmeq->cqe_seen = 1; } -static void nvme_process_cq(struct nvme_queue *nvmeq) -{ - __nvme_process_cq(nvmeq, NULL); -} - static irqreturn_t nvme_irq(int irq, void *data) { irqreturn_t result;
@@ -736,20 +730,15 @@ static irqreturn_t nvme_irq_check(int irq, void *data) return IRQ_NONE; } -static int nvme_poll(struct blk_mq_hw_ctx *hctx, unsigned int tag) +static void nvme_poll(struct blk_mq_hw_ctx *hctx) { struct nvme_queue *nvmeq = hctx->driver_data; if (nvme_cqe_valid(nvmeq, nvmeq->cq_head, nvmeq->cq_phase)) { spin_lock_irq(&nvmeq->q_lock); - __nvme_process_cq(nvmeq, &tag); + nvme_process_cq(nvmeq); spin_unlock_irq(&nvmeq->q_lock); - - if (tag == -1) - return 1; } - - return 0; } static void nvme_pci_submit_async_event(struct nvme_ctrl *ctrl, int aer_idx)
diff --git a/include/linux/blk-mq.h b/include/linux/blk-mq.h
index 2498fdf..a723af9 100644
--- a/include/linux/blk-mq.h
+++ b/include/linux/blk-mq.h@@ -100,7 +100,7 @@ typedef void (exit_request_fn)(void *, struct request *, unsigned int, typedef void (busy_iter_fn)(struct blk_mq_hw_ctx *, struct request *, void *, bool); typedef void (busy_tag_iter_fn)(struct request *, void *, bool); -typedef int (poll_fn)(struct blk_mq_hw_ctx *, unsigned int); +typedef void (poll_fn)(struct blk_mq_hw_ctx *); struct blk_mq_ops { --