[PATCH v3 4/8] vfio: Remove vfio_external_group_match_file()

[Jason Gunthorpe <jgg@xxxxxxxxxx>]

vfio_group_fops_open() ensures there is only ever one struct file open for
any struct vfio_group at any time:

	/* Do we need multiple instances of the group open?  Seems not. */
	opened = atomic_cmpxchg(&group->opened, 0, 1);
	if (opened) {
		vfio_group_put(group);
		return -EBUSY;

Therefor the struct file * can be used directly to search the list of VFIO
groups that KVM keeps instead of using the
vfio_external_group_match_file() callback to try to figure out if the
passed in FD matches the list or not.

Delete vfio_external_group_match_file().

Reviewed-by: Kevin Tian <kevin.tian@xxxxxxxxx>
Reviewed-by: Christoph Hellwig <hch@xxxxxx>
Reviewed-by: Yi Liu <yi.l.liu@xxxxxxxxx>
Signed-off-by: Jason Gunthorpe <jgg@xxxxxxxxxx>
---
 drivers/vfio/vfio.c  |  9 ---------
 include/linux/vfio.h |  2 --
 virt/kvm/vfio.c      | 19 +------------------
 3 files changed, 1 insertion(+), 29 deletions(-)

diff --git a/drivers/vfio/vfio.c b/drivers/vfio/vfio.c
index 4f031ea4cacb9d..a451800becfd86 100644
--- a/drivers/vfio/vfio.c
+++ b/drivers/vfio/vfio.c
@@ -1705,15 +1705,6 @@ void vfio_group_put_external_user(struct vfio_group *group)
 }
 EXPORT_SYMBOL_GPL(vfio_group_put_external_user);
 
-bool vfio_external_group_match_file(struct vfio_group *test_group,
-				    struct file *filep)
-{
-	struct vfio_group *group = filep->private_data;
-
-	return (filep->f_op == &vfio_group_fops) && (group == test_group);
-}
-EXPORT_SYMBOL_GPL(vfio_external_group_match_file);
-
 /**
  * vfio_file_iommu_group - Return the struct iommu_group for the vfio group file
  * @file: VFIO group file
diff --git a/include/linux/vfio.h b/include/linux/vfio.h
index 86b49fe33eaea1..4108034805fe6a 100644
--- a/include/linux/vfio.h
+++ b/include/linux/vfio.h
@@ -138,8 +138,6 @@ int vfio_mig_get_next_state(struct vfio_device *device,
  */
 extern struct vfio_group *vfio_group_get_external_user(struct file *filep);
 extern void vfio_group_put_external_user(struct vfio_group *group);
-extern bool vfio_external_group_match_file(struct vfio_group *group,
-					   struct file *filep);
 extern struct iommu_group *vfio_file_iommu_group(struct file *file);
 extern long vfio_external_check_extension(struct vfio_group *group,
 					  unsigned long arg);
diff --git a/virt/kvm/vfio.c b/virt/kvm/vfio.c
index 9b7384dde158c1..0b84916c3f71a0 100644
--- a/virt/kvm/vfio.c
+++ b/virt/kvm/vfio.c
@@ -49,22 +49,6 @@ static struct vfio_group *kvm_vfio_group_get_external_user(struct file *filep)
 	return vfio_group;
 }
 
-static bool kvm_vfio_external_group_match_file(struct vfio_group *group,
-					       struct file *filep)
-{
-	bool ret, (*fn)(struct vfio_group *, struct file *);
-
-	fn = symbol_get(vfio_external_group_match_file);
-	if (!fn)
-		return false;
-
-	ret = fn(group, filep);
-
-	symbol_put(vfio_external_group_match_file);
-
-	return ret;
-}
-
 static void kvm_vfio_group_put_external_user(struct vfio_group *vfio_group)
 {
 	void (*fn)(struct vfio_group *);
@@ -239,8 +223,7 @@ static int kvm_vfio_group_del(struct kvm_device *dev, unsigned int fd)
 	mutex_lock(&kv->lock);
 
 	list_for_each_entry(kvg, &kv->group_list, node) {
-		if (!kvm_vfio_external_group_match_file(kvg->vfio_group,
-							f.file))
+		if (kvg->file != f.file)
 			continue;
 
 		list_del(&kvg->node);
-- 
2.36.0