[PATCH 07/12] drm: drop redundant drm_file->is_master

[David Herrmann <dh.herrmann@gmail.com>]

The drm_file->is_master field is redundant as it's equivalent to:
    drm_file->master && drm_file->master == drm_file->minor->master

1) "=>"
  Whenever we set drm_file->is_master, we also set:
      drm_file->minor->master = drm_file->master;

  Whenever we clear drm_file->is_master, we also call:
      drm_master_put(&drm_file->minor->master);
  which implicitly clears it to NULL.

2) "<="
  minor->master cannot be set if it is non-NULL. Therefore, it stays as
  is unless a file drops it.

  If minor->master is NULL, it is only set by places that also adjust
  drm_file->is_master.

Therefore, we can safely drop is_master and replace it by an inline helper
that matches:
    drm_file->master && drm_file->master == drm_file->minor->master

Signed-off-by: David Herrmann <dh.herrmann@gmail.com>
---
 drivers/gpu/drm/drm_crtc.c                 |  2 +-
 drivers/gpu/drm/drm_drv.c                  |  2 +-
 drivers/gpu/drm/drm_fops.c                 |  4 +---
 drivers/gpu/drm/drm_lock.c                 |  2 +-
 drivers/gpu/drm/drm_stub.c                 | 10 +++-------
 drivers/gpu/drm/i915/i915_gem_execbuffer.c |  4 ++--
 drivers/gpu/drm/vmwgfx/vmwgfx_drv.c        |  2 +-
 include/drm/drmP.h                         |  9 ++++++---
 8 files changed, 16 insertions(+), 19 deletions(-)

diff --git a/drivers/gpu/drm/drm_crtc.c b/drivers/gpu/drm/drm_crtc.c
index 1ccf5cb..dec0c77 100644
--- a/drivers/gpu/drm/drm_crtc.c
+++ b/drivers/gpu/drm/drm_crtc.c
@@ -3188,7 +3188,7 @@ int drm_mode_getfb(struct drm_device *dev,
 	r->bpp = fb->bits_per_pixel;
 	r->pitch = fb->pitches[0];
 	if (fb->funcs->create_handle) {
-		if (file_priv->is_master || capable(CAP_SYS_ADMIN) ||
+		if (drm_is_master(file_priv) || capable(CAP_SYS_ADMIN) ||
 		    drm_is_control_client(file_priv)) {
 			ret = fb->funcs->create_handle(fb, file_priv,
 						       &r->handle);
diff --git a/drivers/gpu/drm/drm_drv.c b/drivers/gpu/drm/drm_drv.c
index 0cc1827..7aa8121 100644
--- a/drivers/gpu/drm/drm_drv.c
+++ b/drivers/gpu/drm/drm_drv.c
@@ -307,7 +307,7 @@ static int drm_ioctl_permit(u32 flags, struct drm_file *file_priv)
 		return -EACCES;
 
 	/* MASTER is only for master or control clients */
-	if (unlikely((flags & DRM_MASTER) && !file_priv->is_master &&
+	if (unlikely((flags & DRM_MASTER) && !drm_is_master(file_priv) &&
 		     !drm_is_control_client(file_priv)))
 		return -EACCES;
 
diff --git a/drivers/gpu/drm/drm_fops.c b/drivers/gpu/drm/drm_fops.c
index afba0bf..f65087e 100644
--- a/drivers/gpu/drm/drm_fops.c
+++ b/drivers/gpu/drm/drm_fops.c
@@ -286,7 +286,6 @@ static int drm_open_helper(struct file *filp, struct drm_minor *minor)
 			goto out_close;
 		}
 
-		priv->is_master = 1;
 		/* take another reference for the copy in the local file priv */
 		priv->master = drm_master_get(priv->minor->master);
 		priv->authenticated = 1;
@@ -452,7 +451,7 @@ int drm_release(struct inode *inode, struct file *filp)
 
 	mutex_lock(&dev->master_mutex);
 
-	if (file_priv->is_master) {
+	if (drm_is_master(file_priv)) {
 		struct drm_master *master = file_priv->master;
 		struct drm_file *temp;
 
@@ -488,7 +487,6 @@ int drm_release(struct inode *inode, struct file *filp)
 	/* drop the master reference held by the file priv */
 	if (file_priv->master)
 		drm_master_put(&file_priv->master);
-	file_priv->is_master = 0;
 	mutex_unlock(&dev->master_mutex);
 
 	mutex_lock(&dev->struct_mutex);
diff --git a/drivers/gpu/drm/drm_lock.c b/drivers/gpu/drm/drm_lock.c
index f645268..786401c 100644
--- a/drivers/gpu/drm/drm_lock.c
+++ b/drivers/gpu/drm/drm_lock.c
@@ -111,7 +111,7 @@ int drm_lock(struct drm_device *dev, void *data, struct drm_file *file_priv)
 	/* don't set the block all signals on the master process for now 
 	 * really probably not the correct answer but lets us debug xkb
  	 * xserver for now */
-	if (!file_priv->is_master) {
+	if (!drm_is_master(file_priv)) {
 		sigemptyset(&dev->sigmask);
 		sigaddset(&dev->sigmask, SIGSTOP);
 		sigaddset(&dev->sigmask, SIGTSTP);
diff --git a/drivers/gpu/drm/drm_stub.c b/drivers/gpu/drm/drm_stub.c
index 233ea20..18c9b3d 100644
--- a/drivers/gpu/drm/drm_stub.c
+++ b/drivers/gpu/drm/drm_stub.c
@@ -177,7 +177,7 @@ int drm_setmaster_ioctl(struct drm_device *dev, void *data,
 	int ret = 0;
 
 	mutex_lock(&dev->master_mutex);
-	if (file_priv->is_master)
+	if (drm_is_master(file_priv))
 		goto out_unlock;
 
 	if (file_priv->minor->master) {
@@ -191,13 +191,10 @@ int drm_setmaster_ioctl(struct drm_device *dev, void *data,
 	}
 
 	file_priv->minor->master = drm_master_get(file_priv->master);
-	file_priv->is_master = 1;
 	if (dev->driver->master_set) {
 		ret = dev->driver->master_set(dev, file_priv, false);
-		if (unlikely(ret != 0)) {
-			file_priv->is_master = 0;
+		if (unlikely(ret != 0))
 			drm_master_put(&file_priv->minor->master);
-		}
 	}
 
 out_unlock:
@@ -211,7 +208,7 @@ int drm_dropmaster_ioctl(struct drm_device *dev, void *data,
 	int ret = -EINVAL;
 
 	mutex_lock(&dev->master_mutex);
-	if (!file_priv->is_master)
+	if (!drm_is_master(file_priv))
 		goto out_unlock;
 
 	if (!file_priv->minor->master)
@@ -221,7 +218,6 @@ int drm_dropmaster_ioctl(struct drm_device *dev, void *data,
 	if (dev->driver->master_drop)
 		dev->driver->master_drop(dev, file_priv, false);
 	drm_master_put(&file_priv->minor->master);
-	file_priv->is_master = 0;
 
 out_unlock:
 	mutex_unlock(&dev->master_mutex);
diff --git a/drivers/gpu/drm/i915/i915_gem_execbuffer.c b/drivers/gpu/drm/i915/i915_gem_execbuffer.c
index 60998fc..2dd19da 100644
--- a/drivers/gpu/drm/i915/i915_gem_execbuffer.c
+++ b/drivers/gpu/drm/i915/i915_gem_execbuffer.c
@@ -1260,7 +1260,7 @@ i915_gem_do_execbuffer(struct drm_device *dev, void *data,
 
 	flags = 0;
 	if (args->flags & I915_EXEC_SECURE) {
-		if (!file->is_master || !capable(CAP_SYS_ADMIN))
+		if (!drm_is_master(file) || !capable(CAP_SYS_ADMIN))
 		    return -EPERM;
 
 		flags |= I915_DISPATCH_SECURE;
@@ -1369,7 +1369,7 @@ i915_gem_do_execbuffer(struct drm_device *dev, void *data,
 		ret = i915_parse_cmds(ring,
 				      batch_obj,
 				      args->batch_start_offset,
-				      file->is_master);
+				      drm_is_master(file));
 		if (ret)
 			goto err;
 
diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_drv.c b/drivers/gpu/drm/vmwgfx/vmwgfx_drv.c
index 18b54ac..63c4d6f 100644
--- a/drivers/gpu/drm/vmwgfx/vmwgfx_drv.c
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_drv.c
@@ -990,7 +990,7 @@ static struct vmw_master *vmw_master_check(struct drm_device *dev,
 	if (unlikely(ret != 0))
 		return ERR_PTR(-ERESTARTSYS);
 
-	if (file_priv->is_master) {
+	if (drm_is_master(file_priv)) {
 		mutex_unlock(&dev->master_mutex);
 		return NULL;
 	}
diff --git a/include/drm/drmP.h b/include/drm/drmP.h
index d91e09f..e1bb585 100644
--- a/include/drm/drmP.h
+++ b/include/drm/drmP.h
@@ -387,8 +387,6 @@ struct drm_prime_file_private {
 struct drm_file {
 	unsigned always_authenticated :1;
 	unsigned authenticated :1;
-	/* Whether we're master for a minor. Protected by master_mutex */
-	unsigned is_master :1;
 	/* true when the client has asked us to expose stereo 3D mode flags */
 	unsigned stereo_allowed :1;
 	/*
@@ -1034,7 +1032,7 @@ struct drm_device {
 	/** \name Locks */
 	/*@{ */
 	struct mutex struct_mutex;	/**< For others */
-	struct mutex master_mutex;      /**< For drm_minor::master and drm_file::is_master */
+	struct mutex master_mutex;      /**< For drm_minor::master */
 	/*@} */
 
 	/** \name Usage Counters */
@@ -1172,6 +1170,11 @@ static inline bool drm_is_primary_client(const struct drm_file *file_priv)
 	return file_priv->minor->type == DRM_MINOR_LEGACY;
 }
 
+static inline bool drm_is_master(const struct drm_file *file)
+{
+	return file->master && file->master == file->minor->master;
+}
+
 /******************************************************************/
 /** \name Internal function definitions */
 /*@{*/
-- 
2.0.2