[PATCH 02/13] nvme-pci: use atomic bitops to mark a queue enabled

[Christoph Hellwig]

This gets rid of all the messing with cq_vector and the ->polled field
by using an atomic bitop to mark the queue enabled or not.

Signed-off-by: Christoph Hellwig <h...@lst.de>
Reviewed-by: Keith Busch <keith.bu...@intel.com>
---
 drivers/nvme/host/pci.c | 43 ++++++++++++++---------------------------
 1 file changed, 15 insertions(+), 28 deletions(-)

diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c
index a1bb4bb92e7f..022395a319f4 100644
--- a/drivers/nvme/host/pci.c
+++ b/drivers/nvme/host/pci.c
@@ -201,7 +201,8 @@ struct nvme_queue {
        u16 last_cq_head;
        u16 qid;
        u8 cq_phase;
-       u8 polled;
+       unsigned long flags;
+#define NVMEQ_ENABLED          0
        u32 *dbbuf_sq_db;
        u32 *dbbuf_cq_db;
        u32 *dbbuf_sq_ei;
@@ -927,7 +928,7 @@ static blk_status_t nvme_queue_rq(struct blk_mq_hw_ctx 
*hctx,
         * We should not need to do this, but we're still using this to
         * ensure we can drain requests on a dying queue.
         */
-       if (unlikely(nvmeq->cq_vector < 0 && !nvmeq->polled))
+       if (unlikely(!test_bit(NVMEQ_ENABLED, &nvmeq->flags)))
                return BLK_STS_IOERR;
 
        ret = nvme_setup_cmd(ns, req, &cmnd);
@@ -1395,31 +1396,19 @@ static void nvme_free_queues(struct nvme_dev *dev, int 
lowest)
  */
 static int nvme_suspend_queue(struct nvme_queue *nvmeq)
 {
-       int vector;
-
-       spin_lock_irq(&nvmeq->cq_lock);
-       if (nvmeq->cq_vector == -1 && !nvmeq->polled) {
-               spin_unlock_irq(&nvmeq->cq_lock);
+       if (!test_and_clear_bit(NVMEQ_ENABLED, &nvmeq->flags))
                return 1;
-       }
-       vector = nvmeq->cq_vector;
-       nvmeq->dev->online_queues--;
-       nvmeq->cq_vector = -1;
-       nvmeq->polled = false;
-       spin_unlock_irq(&nvmeq->cq_lock);
 
-       /*
-        * Ensure that nvme_queue_rq() sees it ->cq_vector == -1 without
-        * having to grab the lock.
-        */
+       /* ensure that nvme_queue_rq() sees NVMEQ_ENABLED cleared */
        mb();
 
+       nvmeq->dev->online_queues--;
        if (!nvmeq->qid && nvmeq->dev->ctrl.admin_q)
                blk_mq_quiesce_queue(nvmeq->dev->ctrl.admin_q);
-
-       if (vector != -1)
-               pci_free_irq(to_pci_dev(nvmeq->dev->dev), vector, nvmeq);
-
+       if (nvmeq->cq_vector == -1)
+               return 0;
+       pci_free_irq(to_pci_dev(nvmeq->dev->dev), nvmeq->cq_vector, nvmeq);
+       nvmeq->cq_vector = -1;
        return 0;
 }
 
@@ -1578,13 +1567,7 @@ static int nvme_create_queue(struct nvme_queue *nvmeq, 
int qid, bool polled)
        else if (result)
                goto release_cq;
 
-       /*
-        * Set cq_vector after alloc cq/sq, otherwise nvme_suspend_queue will
-        * invoke free_irq for it and cause a 'Trying to free already-free IRQ
-        * xxx' warning if the create CQ/SQ command times out.
-        */
        nvmeq->cq_vector = vector;
-       nvmeq->polled = polled;
        nvme_init_queue(nvmeq, qid);
 
        if (vector != -1) {
@@ -1593,11 +1576,11 @@ static int nvme_create_queue(struct nvme_queue *nvmeq, 
int qid, bool polled)
                        goto release_sq;
        }
 
+       set_bit(NVMEQ_ENABLED, &nvmeq->flags);
        return result;
 
 release_sq:
        nvmeq->cq_vector = -1;
-       nvmeq->polled = false;
        dev->online_queues--;
        adapter_delete_sq(dev, qid);
 release_cq:
@@ -1751,6 +1734,7 @@ static int nvme_pci_configure_admin_queue(struct nvme_dev 
*dev)
                return result;
        }
 
+       set_bit(NVMEQ_ENABLED, &nvmeq->flags);
        return result;
 }
 
@@ -2173,6 +2157,8 @@ static int nvme_setup_io_queues(struct nvme_dev *dev)
 
        if (nr_io_queues == 0)
                return 0;
+       
+       clear_bit(NVMEQ_ENABLED, &adminq->flags);
 
        if (dev->cmb_use_sqes) {
                result = nvme_cmb_qdepth(dev, nr_io_queues,
@@ -2227,6 +2213,7 @@ static int nvme_setup_io_queues(struct nvme_dev *dev)
                adminq->cq_vector = -1;
                return result;
        }
+       set_bit(NVMEQ_ENABLED, &adminq->flags);
        return nvme_create_io_queues(dev);
 }
 
-- 
2.19.1