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>

diff --git a/drivers/block/nvme.c b/drivers/block/nvme.c
index 0ba6b7c..3278fbd 100644 (file)
--- 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);