Re: [Intel-gfx] [PATCH v5 07/10] vfio: Add helper to search vfio_device in a dev_set

[Cédric Le Goater]

On 5/13/23 15:21, Yi Liu wrote:

There are drivers that need to search vfio_device within a given dev_set.
e.g. vfio-pci. So add a helper.

Signed-off-by: Yi Liu <yi.l....@intel.com>
---
  drivers/vfio/pci/vfio_pci_core.c |  8 +++-----
  drivers/vfio/vfio_main.c         | 15 +++++++++++++++
  include/linux/vfio.h             |  3 +++
  3 files changed, 21 insertions(+), 5 deletions(-)

diff --git a/drivers/vfio/pci/vfio_pci_core.c b/drivers/vfio/pci/vfio_pci_core.c
index 39e7823088e7..4df2def35bdd 100644
--- a/drivers/vfio/pci/vfio_pci_core.c
+++ b/drivers/vfio/pci/vfio_pci_core.c
@@ -2335,12 +2335,10 @@ static bool vfio_dev_in_groups(struct 
vfio_pci_core_device *vdev,
  static int vfio_pci_is_device_in_set(struct pci_dev *pdev, void *data)
  {
        struct vfio_device_set *dev_set = data;
-       struct vfio_device *cur;

- list_for_each_entry(cur, &dev_set->device_list, dev_set_list)

-               if (cur->dev == &pdev->dev)
-                       return 0;
-       return -EBUSY;
+       lockdep_assert_held(&dev_set->lock);

May be drop the lockdep_assert_held() above since there is one in
vfio_find_device_in_devset().

Thanks,

C.

+
+       return vfio_find_device_in_devset(dev_set, &pdev->dev) ? 0 : -EBUSY;
  }

/*

diff --git a/drivers/vfio/vfio_main.c b/drivers/vfio/vfio_main.c
index f0ca33b2e1df..ab4f3a794f78 100644
--- a/drivers/vfio/vfio_main.c
+++ b/drivers/vfio/vfio_main.c
@@ -141,6 +141,21 @@ unsigned int vfio_device_set_open_count(struct 
vfio_device_set *dev_set)
  }
  EXPORT_SYMBOL_GPL(vfio_device_set_open_count);

+struct vfio_device *

+vfio_find_device_in_devset(struct vfio_device_set *dev_set,
+                          struct device *dev)
+{
+       struct vfio_device *cur;
+
+       lockdep_assert_held(&dev_set->lock);
+
+       list_for_each_entry(cur, &dev_set->device_list, dev_set_list)
+               if (cur->dev == dev)
+                       return cur;
+       return NULL;
+}
+EXPORT_SYMBOL_GPL(vfio_find_device_in_devset);
+
  /*
   * Device objects - create, release, get, put, search
   */
diff --git a/include/linux/vfio.h b/include/linux/vfio.h
index fcbe084b18c8..4c17395ed4d2 100644
--- a/include/linux/vfio.h
+++ b/include/linux/vfio.h
@@ -259,6 +259,9 @@ void vfio_unregister_group_dev(struct vfio_device *device);

int vfio_assign_device_set(struct vfio_device *device, void *set_id);

  unsigned int vfio_device_set_open_count(struct vfio_device_set *dev_set);
+struct vfio_device *
+vfio_find_device_in_devset(struct vfio_device_set *dev_set,
+                          struct device *dev);

int vfio_mig_get_next_state(struct vfio_device *device,

                            enum vfio_device_mig_state cur_fsm,