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>

drivers/gpu/drm/drm_drv.c

@@ -434,18 +434,19 @@ static int drm_version(struct drm_device *dev, void *data,
  * Looks up the ioctl function in the ::ioctls table, checking for root
  * previleges if so required, and dispatches to the respective function.
  */
-int drm_ioctl(struct inode *inode, struct file *filp,
+long drm_ioctl(struct file *filp,
 	      unsigned int cmd, unsigned long arg)
 {
 	struct drm_file *file_priv = filp->private_data;
-	struct drm_device *dev = file_priv->minor->dev;
+	struct drm_device *dev;
 	struct drm_ioctl_desc *ioctl;
 	drm_ioctl_t *func;
 	unsigned int nr = DRM_IOCTL_NR(cmd);
 	int retcode = -EINVAL;
 	char stack_kdata[128];
 	char *kdata = NULL;
 
+	dev = file_priv->minor->dev;
 	atomic_inc(&dev->ioctl_count);
 	atomic_inc(&dev->counts[_DRM_STAT_IOCTLS]);
 	++file_priv->ioctl_count;
@@ -501,7 +502,13 @@ int drm_ioctl(struct inode *inode, struct file *filp,
 				goto err_i1;
 			}
 		}
-		retcode = func(dev, kdata, file_priv);
+		if (ioctl->flags & DRM_UNLOCKED)
+			retcode = func(dev, kdata, file_priv);
+		else {
+			lock_kernel();
+			retcode = func(dev, kdata, file_priv);
+			unlock_kernel();
+		}
 
 		if (cmd & IOC_OUT) {
 			if (copy_to_user((void __user *)arg, kdata,

drivers/gpu/drm/drm_ioc32.c

@@ -104,7 +104,7 @@ static int compat_drm_version(struct file *file, unsigned int cmd,
 			  &version->desc))
 		return -EFAULT;
 
-	err = drm_ioctl(file->f_path.dentry->d_inode, file,
+	err = drm_ioctl(file,
 			DRM_IOCTL_VERSION, (unsigned long)version);
 	if (err)
 		return err;
@@ -145,8 +145,7 @@ static int compat_drm_getunique(struct file *file, unsigned int cmd,
 			  &u->unique))
 		return -EFAULT;
 
-	err = drm_ioctl(file->f_path.dentry->d_inode, file,
-			DRM_IOCTL_GET_UNIQUE, (unsigned long)u);
+	err = drm_ioctl(file, DRM_IOCTL_GET_UNIQUE, (unsigned long)u);
 	if (err)
 		return err;
 
@@ -174,8 +173,7 @@ static int compat_drm_setunique(struct file *file, unsigned int cmd,
 			  &u->unique))
 		return -EFAULT;
 
-	return drm_ioctl(file->f_path.dentry->d_inode, file,
-			 DRM_IOCTL_SET_UNIQUE, (unsigned long)u);
+	return drm_ioctl(file, DRM_IOCTL_SET_UNIQUE, (unsigned long)u);
 }
 
 typedef struct drm_map32 {
@@ -205,8 +203,7 @@ static int compat_drm_getmap(struct file *file, unsigned int cmd,
 	if (__put_user(idx, &map->offset))
 		return -EFAULT;
 
-	err = drm_ioctl(file->f_path.dentry->d_inode, file,
-			DRM_IOCTL_GET_MAP, (unsigned long)map);
+	err = drm_ioctl(file, DRM_IOCTL_GET_MAP, (unsigned long)map);
 	if (err)
 		return err;
 
@@ -246,8 +243,7 @@ static int compat_drm_addmap(struct file *file, unsigned int cmd,
 	    || __put_user(m32.flags, &map->flags))
 		return -EFAULT;
 
-	err = drm_ioctl(file->f_path.dentry->d_inode, file,
-			DRM_IOCTL_ADD_MAP, (unsigned long)map);
+	err = drm_ioctl(file, DRM_IOCTL_ADD_MAP, (unsigned long)map);
 	if (err)
 		return err;
 
@@ -284,8 +280,7 @@ static int compat_drm_rmmap(struct file *file, unsigned int cmd,
 	if (__put_user((void *)(unsigned long)handle, &map->handle))
 		return -EFAULT;
 
-	return drm_ioctl(file->f_path.dentry->d_inode, file,
-			 DRM_IOCTL_RM_MAP, (unsigned long)map);
+	return drm_ioctl(file, DRM_IOCTL_RM_MAP, (unsigned long)map);
 }
 
 typedef struct drm_client32 {
@@ -314,8 +309,7 @@ static int compat_drm_getclient(struct file *file, unsigned int cmd,
 	if (__put_user(idx, &client->idx))
 		return -EFAULT;
 
-	err = drm_ioctl(file->f_path.dentry->d_inode, file,
-			DRM_IOCTL_GET_CLIENT, (unsigned long)client);
+	err = drm_ioctl(file, DRM_IOCTL_GET_CLIENT, (unsigned long)client);
 	if (err)
 		return err;
 
@@ -351,8 +345,7 @@ static int compat_drm_getstats(struct file *file, unsigned int cmd,
 	if (!access_ok(VERIFY_WRITE, stats, sizeof(*stats)))
 		return -EFAULT;
 
-	err = drm_ioctl(file->f_path.dentry->d_inode, file,
-			DRM_IOCTL_GET_STATS, (unsigned long)stats);
+	err = drm_ioctl(file, DRM_IOCTL_GET_STATS, (unsigned long)stats);
 	if (err)
 		return err;
 
@@ -395,8 +388,7 @@ static int compat_drm_addbufs(struct file *file, unsigned int cmd,
 	    || __put_user(agp_start, &buf->agp_start))
 		return -EFAULT;
 
-	err = drm_ioctl(file->f_path.dentry->d_inode, file,
-			DRM_IOCTL_ADD_BUFS, (unsigned long)buf);
+	err = drm_ioctl(file, DRM_IOCTL_ADD_BUFS, (unsigned long)buf);
 	if (err)
 		return err;
 
@@ -427,8 +419,7 @@ static int compat_drm_markbufs(struct file *file, unsigned int cmd,
 	    || __put_user(b32.high_mark, &buf->high_mark))
 		return -EFAULT;
 
-	return drm_ioctl(file->f_path.dentry->d_inode, file,
-			 DRM_IOCTL_MARK_BUFS, (unsigned long)buf);
+	return drm_ioctl(file, DRM_IOCTL_MARK_BUFS, (unsigned long)buf);
 }
 
 typedef struct drm_buf_info32 {
@@ -469,8 +460,7 @@ static int compat_drm_infobufs(struct file *file, unsigned int cmd,
 	    || __put_user(list, &request->list))
 		return -EFAULT;
 
-	err = drm_ioctl(file->f_path.dentry->d_inode, file,
-			DRM_IOCTL_INFO_BUFS, (unsigned long)request);
+	err = drm_ioctl(file, DRM_IOCTL_INFO_BUFS, (unsigned long)request);
 	if (err)
 		return err;
 
@@ -531,8 +521,7 @@ static int compat_drm_mapbufs(struct file *file, unsigned int cmd,
 	    || __put_user(list, &request->list))
 		return -EFAULT;
 
-	err = drm_ioctl(file->f_path.dentry->d_inode, file,
-			DRM_IOCTL_MAP_BUFS, (unsigned long)request);
+	err = drm_ioctl(file, DRM_IOCTL_MAP_BUFS, (unsigned long)request);
 	if (err)
 		return err;
 
@@ -578,8 +567,7 @@ static int compat_drm_freebufs(struct file *file, unsigned int cmd,
 			  &request->list))
 		return -EFAULT;
 
-	return drm_ioctl(file->f_path.dentry->d_inode, file,
-			 DRM_IOCTL_FREE_BUFS, (unsigned long)request);
+	return drm_ioctl(file, DRM_IOCTL_FREE_BUFS, (unsigned long)request);
 }
 
 typedef struct drm_ctx_priv_map32 {
@@ -605,8 +593,7 @@ static int compat_drm_setsareactx(struct file *file, unsigned int cmd,
 			  &request->handle))
 		return -EFAULT;
 
-	return drm_ioctl(file->f_path.dentry->d_inode, file,
-			 DRM_IOCTL_SET_SAREA_CTX, (unsigned long)request);
+	return drm_ioctl(file, DRM_IOCTL_SET_SAREA_CTX, (unsigned long)request);
 }
 
 static int compat_drm_getsareactx(struct file *file, unsigned int cmd,
@@ -628,8 +615,7 @@ static int compat_drm_getsareactx(struct file *file, unsigned int cmd,
 	if (__put_user(ctx_id, &request->ctx_id))
 		return -EFAULT;
 
-	err = drm_ioctl(file->f_path.dentry->d_inode, file,
-			DRM_IOCTL_GET_SAREA_CTX, (unsigned long)request);
+	err = drm_ioctl(file, DRM_IOCTL_GET_SAREA_CTX, (unsigned long)request);
 	if (err)
 		return err;
 
@@ -664,8 +650,7 @@ static int compat_drm_resctx(struct file *file, unsigned int cmd,
 			  &res->contexts))
 		return -EFAULT;
 
-	err = drm_ioctl(file->f_path.dentry->d_inode, file,
-			DRM_IOCTL_RES_CTX, (unsigned long)res);
+	err = drm_ioctl(file, DRM_IOCTL_RES_CTX, (unsigned long)res);
 	if (err)
 		return err;
 
@@ -718,8 +703,7 @@ static int compat_drm_dma(struct file *file, unsigned int cmd,
 			  &d->request_sizes))
 		return -EFAULT;
 
-	err = drm_ioctl(file->f_path.dentry->d_inode, file,
-			DRM_IOCTL_DMA, (unsigned long)d);
+	err = drm_ioctl(file, DRM_IOCTL_DMA, (unsigned long)d);
 	if (err)
 		return err;
 
@@ -751,8 +735,7 @@ static int compat_drm_agp_enable(struct file *file, unsigned int cmd,
 	if (put_user(m32.mode, &mode->mode))
 		return -EFAULT;
 
-	return drm_ioctl(file->f_path.dentry->d_inode, file,
-			 DRM_IOCTL_AGP_ENABLE, (unsigned long)mode);
+	return drm_ioctl(file, DRM_IOCTL_AGP_ENABLE, (unsigned long)mode);
 }
 
 typedef struct drm_agp_info32 {
@@ -781,8 +764,7 @@ static int compat_drm_agp_info(struct file *file, unsigned int cmd,
 	if (!access_ok(VERIFY_WRITE, info, sizeof(*info)))
 		return -EFAULT;
 
-	err = drm_ioctl(file->f_path.dentry->d_inode, file,
-			DRM_IOCTL_AGP_INFO, (unsigned long)info);
+	err = drm_ioctl(file, DRM_IOCTL_AGP_INFO, (unsigned long)info);
 	if (err)
 		return err;
 
@@ -827,16 +809,14 @@ static int compat_drm_agp_alloc(struct file *file, unsigned int cmd,
 	    || __put_user(req32.type, &request->type))
 		return -EFAULT;
 
-	err = drm_ioctl(file->f_path.dentry->d_inode, file,
-			DRM_IOCTL_AGP_ALLOC, (unsigned long)request);
+	err = drm_ioctl(file, DRM_IOCTL_AGP_ALLOC, (unsigned long)request);
 	if (err)
 		return err;
 
 	if (__get_user(req32.handle, &request->handle)
 	    || __get_user(req32.physical, &request->physical)
 	    || copy_to_user(argp, &req32, sizeof(req32))) {
-		drm_ioctl(file->f_path.dentry->d_inode, file,
-			  DRM_IOCTL_AGP_FREE, (unsigned long)request);
+		drm_ioctl(file, DRM_IOCTL_AGP_FREE, (unsigned long)request);
 		return -EFAULT;
 	}
 
@@ -856,8 +836,7 @@ static int compat_drm_agp_free(struct file *file, unsigned int cmd,
 	    || __put_user(handle, &request->handle))
 		return -EFAULT;
 
-	return drm_ioctl(file->f_path.dentry->d_inode, file,
-			 DRM_IOCTL_AGP_FREE, (unsigned long)request);
+	return drm_ioctl(file, DRM_IOCTL_AGP_FREE, (unsigned long)request);
 }
 
 typedef struct drm_agp_binding32 {
@@ -881,8 +860,7 @@ static int compat_drm_agp_bind(struct file *file, unsigned int cmd,
 	    || __put_user(req32.offset, &request->offset))
 		return -EFAULT;
 
-	return drm_ioctl(file->f_path.dentry->d_inode, file,
-			 DRM_IOCTL_AGP_BIND, (unsigned long)request);
+	return drm_ioctl(file, DRM_IOCTL_AGP_BIND, (unsigned long)request);
 }
 
 static int compat_drm_agp_unbind(struct file *file, unsigned int cmd,
@@ -898,8 +876,7 @@ static int compat_drm_agp_unbind(struct file *file, unsigned int cmd,
 	    || __put_user(handle, &request->handle))
 		return -EFAULT;
 
-	return drm_ioctl(file->f_path.dentry->d_inode, file,
-			 DRM_IOCTL_AGP_UNBIND, (unsigned long)request);
+	return drm_ioctl(file, DRM_IOCTL_AGP_UNBIND, (unsigned long)request);
 }
 #endif				/* __OS_HAS_AGP */
 
@@ -923,8 +900,7 @@ static int compat_drm_sg_alloc(struct file *file, unsigned int cmd,
 	    || __put_user(x, &request->size))
 		return -EFAULT;
 
-	err = drm_ioctl(file->f_path.dentry->d_inode, file,
-			DRM_IOCTL_SG_ALLOC, (unsigned long)request);
+	err = drm_ioctl(file, DRM_IOCTL_SG_ALLOC, (unsigned long)request);
 	if (err)
 		return err;
 
@@ -950,8 +926,7 @@ static int compat_drm_sg_free(struct file *file, unsigned int cmd,
 	    || __put_user(x << PAGE_SHIFT, &request->handle))
 		return -EFAULT;
 
-	return drm_ioctl(file->f_path.dentry->d_inode, file,
-			 DRM_IOCTL_SG_FREE, (unsigned long)request);
+	return drm_ioctl(file, DRM_IOCTL_SG_FREE, (unsigned long)request);
 }
 
 #if defined(CONFIG_X86) || defined(CONFIG_IA64)
@@ -981,8 +956,7 @@ static int compat_drm_update_draw(struct file *file, unsigned int cmd,
 	    __put_user(update32.data, &request->data))
 		return -EFAULT;
 
-	err = drm_ioctl(file->f_path.dentry->d_inode, file,
-			DRM_IOCTL_UPDATE_DRAW, (unsigned long)request);
+	err = drm_ioctl(file, DRM_IOCTL_UPDATE_DRAW, (unsigned long)request);
 	return err;
 }
 #endif
@@ -1023,8 +997,7 @@ static int compat_drm_wait_vblank(struct file *file, unsigned int cmd,
 	    || __put_user(req32.request.signal, &request->request.signal))
 		return -EFAULT;
 
-	err = drm_ioctl(file->f_path.dentry->d_inode, file,
-			DRM_IOCTL_WAIT_VBLANK, (unsigned long)request);
+	err = drm_ioctl(file, DRM_IOCTL_WAIT_VBLANK, (unsigned long)request);
 	if (err)
 		return err;
 
@@ -1094,16 +1067,14 @@ long drm_compat_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 	 * than always failing.
 	 */
 	if (nr >= ARRAY_SIZE(drm_compat_ioctls))
-		return drm_ioctl(filp->f_dentry->d_inode, filp, cmd, arg);
+		return drm_ioctl(filp, cmd, arg);
 
 	fn = drm_compat_ioctls[nr];
 
-	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;
 }

drivers/gpu/drm/i810/i810_dma.c

@@ -115,7 +115,7 @@ static int i810_mmap_buffers(struct file *filp, struct vm_area_struct *vma)
 static const struct file_operations i810_buffer_fops = {
 	.open = drm_open,
 	.release = drm_release,
-	.ioctl = drm_ioctl,
+	.unlocked_ioctl = drm_ioctl,
 	.mmap = i810_mmap_buffers,
 	.fasync = drm_fasync,
 };

drivers/gpu/drm/i810/i810_drv.c

@@ -59,7 +59,7 @@ static struct drm_driver driver = {
 		 .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,

drivers/gpu/drm/i830/i830_dma.c

@@ -117,7 +117,7 @@ static int i830_mmap_buffers(struct file *filp, struct vm_area_struct *vma)
 static const struct file_operations i830_buffer_fops = {
 	.open = drm_open,
 	.release = drm_release,
-	.ioctl = drm_ioctl,
+	.unlocked_ioctl = drm_ioctl,
 	.mmap = i830_mmap_buffers,
 	.fasync = drm_fasync,
 };

drivers/gpu/drm/i830/i830_drv.c

@@ -70,7 +70,7 @@ static struct drm_driver driver = {
 		 .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,

drivers/gpu/drm/i915/i915_drv.c

@@ -329,7 +329,7 @@ static struct drm_driver driver = {
 		 .owner = THIS_MODULE,
 		 .open = drm_open,
 		 .release = drm_release,
-		 .ioctl = drm_ioctl,
+		 .unlocked_ioctl = drm_ioctl,
 		 .mmap = drm_gem_mmap,
 		 .poll = drm_poll,
 		 .fasync = drm_fasync,