nvme: simplify nvme_open

Now that we are protected against lookup vs free races for the namespace
by using kref_get_unless_zero we don't need the hack of NULLing out the
disk private data during removal.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>

diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
index 1d931deac83bc5eb37f3961195e9f550e47d6c03..9f8ae15c9fe8e2dc9b7cd81164b5971440d4c1b7 100644 (file)
--- a/drivers/nvme/host/core.c
+++ b/drivers/nvme/host/core.c
@@ -253,12 +253,6 @@ static void nvme_free_ns(struct kref *kref)
        if (ns->ndev)
                nvme_nvm_unregister(ns);
 
-       if (ns->disk) {
-               spin_lock(&dev_list_lock);
-               ns->disk->private_data = NULL;
-               spin_unlock(&dev_list_lock);
-       }
-
        put_disk(ns->disk);
        ida_simple_remove(&ns->ctrl->ns_ida, ns->instance);
        nvme_put_ctrl(ns->ctrl);
@@ -270,29 +264,6 @@ static void nvme_put_ns(struct nvme_ns *ns)
        kref_put(&ns->kref, nvme_free_ns);
 }
 
-static struct nvme_ns *nvme_get_ns_from_disk(struct gendisk *disk)
-{
-       struct nvme_ns *ns;
-
-       spin_lock(&dev_list_lock);
-       ns = disk->private_data;
-       if (ns) {
-               if (!kref_get_unless_zero(&ns->kref))
-                       goto fail;
-               if (!try_module_get(ns->ctrl->ops->module))
-                       goto fail_put_ns;
-       }
-       spin_unlock(&dev_list_lock);
-
-       return ns;
-
-fail_put_ns:
-       kref_put(&ns->kref, nvme_free_ns);
-fail:
-       spin_unlock(&dev_list_lock);
-       return NULL;
-}
-
 struct request *nvme_alloc_request(struct request_queue *q,
                struct nvme_command *cmd, unsigned int flags, int qid)
 {
@@ -1056,7 +1027,16 @@ static int nvme_ioctl(struct block_device *bdev, fmode_t mode,
 
 static int nvme_open(struct block_device *bdev, fmode_t mode)
 {
-       return nvme_get_ns_from_disk(bdev->bd_disk) ? 0 : -ENXIO;
+       struct nvme_ns *ns = bdev->bd_disk->private_data;
+
+       if (!kref_get_unless_zero(&ns->kref))
+               return -ENXIO;
+       if (!try_module_get(ns->ctrl->ops->module)) {
+               kref_put(&ns->kref, nvme_free_ns);
+               return -ENXIO;
+       }
+
+       return 0;
 }
 
 static void nvme_release(struct gendisk *disk, fmode_t mode)