nvme: don't use PREPARE_WORK

PREPARE_[DELAYED_]WORK() are being phased out.  They have few users
and a nasty surprise in terms of reentrancy guarantee as workqueue
considers work items to be different if they don't have the same work
function.

nvme_dev->reset_work is multiplexed with multiple work functions.
Introduce nvme_reset_workfn() which invokes nvme_dev->reset_workfn and
always use it as the work function and update the users to set the
->reset_workfn field instead of overriding the work function using
PREPARE_WORK().

It would probably be best to route this with other related updates
through the workqueue tree.

Compile tested.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Matthew Wilcox <willy@linux.intel.com>
Cc: linux-nvme@lists.infradead.org

2 files changed, 13 insertions, 6 deletions

diff --git a/drivers/block/nvme-core.c b/drivers/block/nvme-core.c
index 51824d1f23ea..8459e4e7c719 100644
--- a/drivers/block/nvme-core.c
+++ b/drivers/block/nvme-core.c
@@ -993,7 +993,7 @@ static void nvme_abort_cmd(int cmdid, struct nvme_queue *nvmeq)
                 dev_warn(&dev->pci_dev->dev,
                         "I/O %d QID %d timeout, reset controller\n", cmdid,
                                                                 nvmeq->qid);
-                PREPARE_WORK(&dev->reset_work, nvme_reset_failed_dev);
+                dev->reset_workfn = nvme_reset_failed_dev;
                 queue_work(nvme_workq, &dev->reset_work);
                 return;
         }
@@ -1696,8 +1696,7 @@ static int nvme_kthread(void *data)
                                 list_del_init(&dev->node);
                                 dev_warn(&dev->pci_dev->dev,
                                         "Failed status, reset controller\n");
-                                PREPARE_WORK(&dev->reset_work,
-                                                        nvme_reset_failed_dev);
+                                dev->reset_workfn = nvme_reset_failed_dev;
                                 queue_work(nvme_workq, &dev->reset_work);
                                 continue;
                         }
@@ -2406,7 +2405,7 @@ static int nvme_dev_resume(struct nvme_dev *dev)
                 return ret;
         if (ret == -EBUSY) {
                 spin_lock(&dev_list_lock);
-                PREPARE_WORK(&dev->reset_work, nvme_remove_disks);
+                dev->reset_workfn = nvme_remove_disks;
                 queue_work(nvme_workq, &dev->reset_work);
                 spin_unlock(&dev_list_lock);
         }
@@ -2435,6 +2434,12 @@ static void nvme_reset_failed_dev(struct work_struct *ws)
         nvme_dev_reset(dev);
 }
 
+static void nvme_reset_workfn(struct work_struct *work)
+{
+        struct nvme_dev *dev = container_of(work, struct nvme_dev, reset_work);
+        dev->reset_workfn(work);
+}
+
 static int nvme_probe(struct pci_dev *pdev, const struct pci_device_id *id)
 {
         int result = -ENOMEM;
@@ -2453,7 +2458,8 @@ static int nvme_probe(struct pci_dev *pdev, const struct pci_device_id *id)
                 goto free;
 
         INIT_LIST_HEAD(&dev->namespaces);
-        INIT_WORK(&dev->reset_work, nvme_reset_failed_dev);
+        dev->reset_workfn = nvme_reset_failed_dev;
+        INIT_WORK(&dev->reset_work, nvme_reset_workfn);
         dev->pci_dev = pdev;
         pci_set_drvdata(pdev, dev);
         result = nvme_set_instance(dev);
@@ -2553,7 +2559,7 @@ static int nvme_resume(struct device *dev)
         struct nvme_dev *ndev = pci_get_drvdata(pdev);
 
         if (nvme_dev_resume(ndev) && !work_busy(&ndev->reset_work)) {
-                PREPARE_WORK(&ndev->reset_work, nvme_reset_failed_dev);
+                ndev->reset_workfn = nvme_reset_failed_dev;
                 queue_work(nvme_workq, &ndev->reset_work);
         }
         return 0;
diff --git a/include/linux/nvme.h b/include/linux/nvme.h
index 69ae03f6eb15..6b9aafed225f 100644
--- a/include/linux/nvme.h
+++ b/include/linux/nvme.h
@@ -87,6 +87,7 @@ struct nvme_dev {
         struct list_head namespaces;
         struct kref kref;
         struct miscdevice miscdev;
+        work_func_t reset_workfn;
         struct work_struct reset_work;
         char name[12];
         char serial[20];