NVMe: Use ida for nvme device instance

Signed-off-by: Quoc-Son Anh <quoc-sonx.anh@intel.com>
Signed-off-by: Matthew Wilcox <matthew.r.wilcox@intel.com>

1 files changed, 26 insertions, 5 deletions

diff --git a/drivers/block/nvme.c b/drivers/block/nvme.c
index 0ba6b7cb344b..3278fbdb8dc0 100644
--- a/drivers/block/nvme.c
+++ b/drivers/block/nvme.c
@@ -1576,15 +1576,33 @@ static void nvme_release_prp_pools(struct nvme_dev *dev)
         dma_pool_destroy(dev->prp_small_pool);
 }
 
-/* XXX: Use an ida or something to let remove / add work correctly */
-static void nvme_set_instance(struct nvme_dev *dev)
+static DEFINE_IDA(nvme_instance_ida);
+
+static int nvme_set_instance(struct nvme_dev *dev)
 {
-        static int instance;
-        dev->instance = instance++;
+        int instance, error;
+
+        do {
+                if (!ida_pre_get(&nvme_instance_ida, GFP_KERNEL))
+                        return -ENODEV;
+
+                spin_lock(&dev_list_lock);
+                error = ida_get_new(&nvme_instance_ida, &instance);
+                spin_unlock(&dev_list_lock);
+        } while (error == -EAGAIN);
+
+        if (error)
+                return -ENODEV;
+
+        dev->instance = instance;
+        return 0;
 }
 
 static void nvme_release_instance(struct nvme_dev *dev)
 {
+        spin_lock(&dev_list_lock);
+        ida_remove(&nvme_instance_ida, dev->instance);
+        spin_unlock(&dev_list_lock);
 }
 
 static int __devinit nvme_probe(struct pci_dev *pdev,
@@ -1617,7 +1635,10 @@ static int __devinit nvme_probe(struct pci_dev *pdev,
         pci_set_drvdata(pdev, dev);
         dma_set_mask(&pdev->dev, DMA_BIT_MASK(64));
         dma_set_coherent_mask(&pdev->dev, DMA_BIT_MASK(64));
-        nvme_set_instance(dev);
+        result = nvme_set_instance(dev);
+        if (result)
+                goto disable;
+
         dev->entry[0].vector = pdev->irq;
 
         result = nvme_setup_prp_pools(dev);