nvme-pci: use attribute group for cmb sysfs

Appending sysfs files to the controller kobject is a bit clunky and
becomes a maintenance problem as more attributes are added. The
attribute group infrastructure handles this better, so use that.

Signed-off-by: Keith Busch <kbusch@kernel.org>
Signed-off-by: Christoph Hellwig <hch@lst.de>

diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c
index 0471c2c..6658f58 100644 (file)
--- a/drivers/nvme/host/pci.c
+++ b/drivers/nvme/host/pci.c
@@ -155,6 +155,8 @@ struct nvme_dev {
        unsigned int nr_allocated_queues;
        unsigned int nr_write_queues;
        unsigned int nr_poll_queues;
+
+       bool attrs_added;
 };
 
 static int io_queue_depth_set(const char *val, const struct kernel_param *kp)
@@ -1804,17 +1806,6 @@ static int nvme_create_io_queues(struct nvme_dev *dev)
        return ret >= 0 ? 0 : ret;
 }
 
-static ssize_t nvme_cmb_show(struct device *dev,
-                            struct device_attribute *attr,
-                            char *buf)
-{
-       struct nvme_dev *ndev = to_nvme_dev(dev_get_drvdata(dev));
-
-       return scnprintf(buf, PAGE_SIZE, "cmbloc : x%08x\ncmbsz  : x%08x\n",
-                      ndev->cmbloc, ndev->cmbsz);
-}
-static DEVICE_ATTR(cmb, S_IRUGO, nvme_cmb_show, NULL);
-
 static u64 nvme_cmb_size_unit(struct nvme_dev *dev)
 {
        u8 szu = (dev->cmbsz >> NVME_CMBSZ_SZU_SHIFT) & NVME_CMBSZ_SZU_MASK;
@@ -1883,20 +1874,6 @@ static void nvme_map_cmb(struct nvme_dev *dev)
        if ((dev->cmbsz & (NVME_CMBSZ_WDS | NVME_CMBSZ_RDS)) ==
                        (NVME_CMBSZ_WDS | NVME_CMBSZ_RDS))
                pci_p2pmem_publish(pdev, true);
-
-       if (sysfs_add_file_to_group(&dev->ctrl.device->kobj,
-                                   &dev_attr_cmb.attr, NULL))
-               dev_warn(dev->ctrl.device,
-                        "failed to add sysfs attribute for CMB\n");
-}
-
-static inline void nvme_release_cmb(struct nvme_dev *dev)
-{
-       if (dev->cmb_size) {
-               sysfs_remove_file_from_group(&dev->ctrl.device->kobj,
-                                            &dev_attr_cmb.attr, NULL);
-               dev->cmb_size = 0;
-       }
 }
 
 static int nvme_set_host_mem(struct nvme_dev *dev, u32 bits)
@@ -2076,6 +2053,38 @@ static int nvme_setup_host_mem(struct nvme_dev *dev)
        return ret;
 }
 
+static ssize_t cmb_show(struct device *dev, struct device_attribute *attr,
+               char *buf)
+{
+       struct nvme_dev *ndev = to_nvme_dev(dev_get_drvdata(dev));
+
+       return sysfs_emit(buf, "cmbloc : x%08x\ncmbsz  : x%08x\n",
+                      ndev->cmbloc, ndev->cmbsz);
+}
+static DEVICE_ATTR_RO(cmb);
+
+static umode_t nvme_pci_attrs_are_visible(struct kobject *kobj,
+               struct attribute *a, int n)
+{
+       struct nvme_ctrl *ctrl =
+               dev_get_drvdata(container_of(kobj, struct device, kobj));
+       struct nvme_dev *dev = to_nvme_dev(ctrl);
+
+       if (a == &dev_attr_cmb.attr && !dev->cmbsz)
+               return 0;
+       return a->mode;
+}
+
+static struct attribute *nvme_pci_attrs[] = {
+       &dev_attr_cmb.attr,
+       NULL,
+};
+
+static const struct attribute_group nvme_pci_attr_group = {
+       .attrs          = nvme_pci_attrs,
+       .is_visible     = nvme_pci_attrs_are_visible,
+};
+
 /*
  * nirqs is the number of interrupts available for write and read
  * queues. The core already reserved an interrupt for the admin queue.
@@ -2747,6 +2756,10 @@ static void nvme_reset_work(struct work_struct *work)
                goto out;
        }
 
+       if (!dev->attrs_added && !sysfs_create_group(&dev->ctrl.device->kobj,
+                       &nvme_pci_attr_group))
+               dev->attrs_added = true;
+
        nvme_start_ctrl(&dev->ctrl);
        return;
 
@@ -2995,6 +3008,13 @@ static void nvme_shutdown(struct pci_dev *pdev)
        nvme_disable_prepare_reset(dev, true);
 }
 
+static void nvme_remove_attrs(struct nvme_dev *dev)
+{
+       if (dev->attrs_added)
+               sysfs_remove_group(&dev->ctrl.device->kobj,
+                                  &nvme_pci_attr_group);
+}
+
 /*
  * The driver's remove may be called on a device in a partially initialized
  * state. This function must not have any dependencies on the device state in
@@ -3016,7 +3036,7 @@ static void nvme_remove(struct pci_dev *pdev)
        nvme_stop_ctrl(&dev->ctrl);
        nvme_remove_namespaces(&dev->ctrl);
        nvme_dev_disable(dev, true);
-       nvme_release_cmb(dev);
+       nvme_remove_attrs(dev);
        nvme_free_host_mem(dev);
        nvme_dev_remove_admin(dev);
        nvme_free_queues(dev, 0);