drm: convert drm_ioctl to unlocked_ioctl

drm_ioctl is called with the Big Kernel Lock held,
which shows up very high in statistics on vfs_ioctl.

Moving the lock into the drm_ioctl function itself
makes sure we blame the right subsystem and it gets
us one step closer to eliminating the locked version
of fops->ioctl.

Since drm_ioctl does not require the lock itself,
we only need to hold it while calling the specific
handler. The 32 bit conversion handlers do not
interact with any other code, so they don't need
the BKL here either and can just call drm_ioctl.

As a bonus, this cleans up all the other users
of drm_ioctl which now no longer have to find
the inode or call lock_kernel.

[airlied: squashed the non-driver bits
of the second patch in here, this provides
the flag for drivers to use to select unlocked
ioctls - but doesn't modify any drivers].

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Cc: David Airlie <airlied@linux.ie>
Cc: dri-devel@lists.sourceforge.net
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Dave Airlie <airlied@redhat.com>

2 files changed, 14 insertions, 28 deletions

diff --git a/drivers/gpu/drm/radeon/radeon_drv.c b/drivers/gpu/drm/radeon/radeon_drv.c
index dbd56ef82f9c..8ba3de7994d4 100644
--- a/drivers/gpu/drm/radeon/radeon_drv.c
+++ b/drivers/gpu/drm/radeon/radeon_drv.c
@@ -196,7 +196,7 @@ static struct drm_driver driver_old = {
 		 .owner = THIS_MODULE,
 		 .open = drm_open,
 		 .release = drm_release,
-		 .ioctl = drm_ioctl,
+		 .unlocked_ioctl = drm_ioctl,
 		 .mmap = drm_mmap,
 		 .poll = drm_poll,
 		 .fasync = drm_fasync,
@@ -284,7 +284,7 @@ static struct drm_driver kms_driver = {
 		 .owner = THIS_MODULE,
 		 .open = drm_open,
 		 .release = drm_release,
-		 .ioctl = drm_ioctl,
+		 .unlocked_ioctl = drm_ioctl,
 		 .mmap = radeon_mmap,
 		 .poll = drm_poll,
 		 .fasync = drm_fasync,
diff --git a/drivers/gpu/drm/radeon/radeon_ioc32.c b/drivers/gpu/drm/radeon/radeon_ioc32.c
index a1bf11de308a..48b7cea31e08 100644
--- a/drivers/gpu/drm/radeon/radeon_ioc32.c
+++ b/drivers/gpu/drm/radeon/radeon_ioc32.c
@@ -92,8 +92,7 @@ static int compat_radeon_cp_init(struct file *file, unsigned int cmd,
 			  &init->gart_textures_offset))
 		return -EFAULT;
 
-	return drm_ioctl(file->f_path.dentry->d_inode, file,
-			 DRM_IOCTL_RADEON_CP_INIT, (unsigned long)init);
+	return drm_ioctl(file, DRM_IOCTL_RADEON_CP_INIT, (unsigned long)init);
 }
 
 typedef struct drm_radeon_clear32 {
@@ -125,8 +124,7 @@ static int compat_radeon_cp_clear(struct file *file, unsigned int cmd,
 			  &clr->depth_boxes))
 		return -EFAULT;
 
-	return drm_ioctl(file->f_path.dentry->d_inode, file,
-			 DRM_IOCTL_RADEON_CLEAR, (unsigned long)clr);
+	return drm_ioctl(file, DRM_IOCTL_RADEON_CLEAR, (unsigned long)clr);
 }
 
 typedef struct drm_radeon_stipple32 {
@@ -149,8 +147,7 @@ static int compat_radeon_cp_stipple(struct file *file, unsigned int cmd,
 			  &request->mask))
 		return -EFAULT;
 
-	return drm_ioctl(file->f_path.dentry->d_inode, file,
-			 DRM_IOCTL_RADEON_STIPPLE, (unsigned long)request);
+	return drm_ioctl(file, DRM_IOCTL_RADEON_STIPPLE, (unsigned long)request);
 }
 
 typedef struct drm_radeon_tex_image32 {
@@ -204,8 +201,7 @@ static int compat_radeon_cp_texture(struct file *file, unsigned int cmd,
 			  &image->data))
 		return -EFAULT;
 
-	return drm_ioctl(file->f_path.dentry->d_inode, file,
-			 DRM_IOCTL_RADEON_TEXTURE, (unsigned long)request);
+	return drm_ioctl(file, DRM_IOCTL_RADEON_TEXTURE, (unsigned long)request);
 }
 
 typedef struct drm_radeon_vertex2_32 {
@@ -238,8 +234,7 @@ static int compat_radeon_cp_vertex2(struct file *file, unsigned int cmd,
 			  &request->prim))
 		return -EFAULT;
 
-	return drm_ioctl(file->f_path.dentry->d_inode, file,
-			 DRM_IOCTL_RADEON_VERTEX2, (unsigned long)request);
+	return drm_ioctl(file, DRM_IOCTL_RADEON_VERTEX2, (unsigned long)request);
 }
 
 typedef struct drm_radeon_cmd_buffer32 {
@@ -268,8 +263,7 @@ static int compat_radeon_cp_cmdbuf(struct file *file, unsigned int cmd,
 			  &request->boxes))
 		return -EFAULT;
 
-	return drm_ioctl(file->f_path.dentry->d_inode, file,
-			 DRM_IOCTL_RADEON_CMDBUF, (unsigned long)request);
+	return drm_ioctl(file, DRM_IOCTL_RADEON_CMDBUF, (unsigned long)request);
 }
 
 typedef struct drm_radeon_getparam32 {
@@ -293,8 +287,7 @@ static int compat_radeon_cp_getparam(struct file *file, unsigned int cmd,
 			  &request->value))
 		return -EFAULT;
 
-	return drm_ioctl(file->f_path.dentry->d_inode, file,
-			 DRM_IOCTL_RADEON_GETPARAM, (unsigned long)request);
+	return drm_ioctl(file, DRM_IOCTL_RADEON_GETPARAM, (unsigned long)request);
 }
 
 typedef struct drm_radeon_mem_alloc32 {
@@ -322,8 +315,7 @@ static int compat_radeon_mem_alloc(struct file *file, unsigned int cmd,
 			  &request->region_offset))
 		return -EFAULT;
 
-	return drm_ioctl(file->f_path.dentry->d_inode, file,
-			 DRM_IOCTL_RADEON_ALLOC, (unsigned long)request);
+	return drm_ioctl(file, DRM_IOCTL_RADEON_ALLOC, (unsigned long)request);
 }
 
 typedef struct drm_radeon_irq_emit32 {
@@ -345,8 +337,7 @@ static int compat_radeon_irq_emit(struct file *file, unsigned int cmd,
 			  &request->irq_seq))
 		return -EFAULT;
 
-	return drm_ioctl(file->f_path.dentry->d_inode, file,
-			 DRM_IOCTL_RADEON_IRQ_EMIT, (unsigned long)request);
+	return drm_ioctl(file, DRM_IOCTL_RADEON_IRQ_EMIT, (unsigned long)request);
 }
 
 /* The two 64-bit arches where alignof(u64)==4 in 32-bit code */
@@ -372,8 +363,7 @@ static int compat_radeon_cp_setparam(struct file *file, unsigned int cmd,
 			  &request->value))
 		return -EFAULT;
 
-	return drm_ioctl(file->f_dentry->d_inode, file,
-			 DRM_IOCTL_RADEON_SETPARAM, (unsigned long) request);
+	return drm_ioctl(file, DRM_IOCTL_RADEON_SETPARAM, (unsigned long) request);
 }
 #else
 #define compat_radeon_cp_setparam NULL
@@ -413,12 +403,10 @@ long radeon_compat_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 	if (nr < DRM_COMMAND_BASE + DRM_ARRAY_SIZE(radeon_compat_ioctls))
 		fn = radeon_compat_ioctls[nr - DRM_COMMAND_BASE];
 
-	lock_kernel();		/* XXX for now */
 	if (fn != NULL)
 		ret = (*fn) (filp, cmd, arg);
 	else
-		ret = drm_ioctl(filp->f_path.dentry->d_inode, filp, cmd, arg);
-	unlock_kernel();
+		ret = drm_ioctl(filp, cmd, arg);
 
 	return ret;
 }
@@ -431,9 +419,7 @@ long radeon_kms_compat_ioctl(struct file *filp, unsigned int cmd, unsigned long
 	if (nr < DRM_COMMAND_BASE)
 		return drm_compat_ioctl(filp, cmd, arg);
 
-	lock_kernel();		/* XXX for now */
-	ret = drm_ioctl(filp->f_path.dentry->d_inode, filp, cmd, arg);
-	unlock_kernel();
+	ret = drm_ioctl(filp, cmd, arg);
 
 	return ret;
 }