netdev - [PATCH 08/12] vfio: use __anon_inode

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Date:   Fri,  8 May 2020 17:36:30 +0200
From:   Christoph Hellwig <hch@....de>
To:     Alexander Viro <viro@...iv.linux.org.uk>
Cc:     linux-integrity@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-gpio@...r.kernel.org, dri-devel@...ts.freedesktop.org,
        linux-rdma@...r.kernel.org, kvm@...r.kernel.org,
        linux-fsdevel@...r.kernel.org, io-uring@...r.kernel.org,
        netdev@...r.kernel.org, bpf@...r.kernel.org
Subject: [PATCH 08/12] vfio: use __anon_inode_getfd

Use __anon_inode_getfd instead of opencoding the logic using
get_unused_fd_flags + anon_inode_getfile.

Signed-off-by: Christoph Hellwig <hch@....de>
---
 drivers/vfio/vfio.c | 37 ++++++++-----------------------------
 1 file changed, 8 insertions(+), 29 deletions(-)

diff --git a/drivers/vfio/vfio.c b/drivers/vfio/vfio.c
index 765e0e5d83ed9..33a88103f857f 100644
--- a/drivers/vfio/vfio.c
+++ b/drivers/vfio/vfio.c
@@ -1451,42 +1451,21 @@ static int vfio_group_get_device_fd(struct vfio_group *group, char *buf)
 		return ret;
 	}
 
-	/*
-	 * We can't use anon_inode_getfd() because we need to modify
-	 * the f_mode flags directly to allow more than just ioctls
-	 */
-	ret = get_unused_fd_flags(O_CLOEXEC);
-	if (ret < 0) {
-		device->ops->release(device->device_data);
-		vfio_device_put(device);
-		return ret;
-	}
-
-	filep = anon_inode_getfile("[vfio-device]", &vfio_device_fops,
-				   device, O_RDWR);
-	if (IS_ERR(filep)) {
-		put_unused_fd(ret);
-		ret = PTR_ERR(filep);
-		device->ops->release(device->device_data);
-		vfio_device_put(device);
-		return ret;
-	}
-
-	/*
-	 * TODO: add an anon_inode interface to do this.
-	 * Appears to be missing by lack of need rather than
-	 * explicitly prevented.  Now there's need.
-	 */
+	ret = __anon_inode_getfd("[vfio-device]", &vfio_device_fops,
+				   device, O_CLOEXEC | O_RDWR, &filep);
+	if (ret < 0)
+		goto release;
 	filep->f_mode |= (FMODE_LSEEK | FMODE_PREAD | FMODE_PWRITE);
-
 	atomic_inc(&group->container_users);
-
 	fd_install(ret, filep);
 
 	if (group->noiommu)
 		dev_warn(device->dev, "vfio-noiommu device opened by user "
 			 "(%s:%d)\n", current->comm, task_pid_nr(current));
-
+	return ret;
+release:
+	device->ops->release(device->device_data);
+	vfio_device_put(device);
 	return ret;
 }
 
-- 
2.26.2