drm: remove FASYNC support

So I've stumbled over drm_fasync and wondered what it does. Digging
that up is quite a story.

First I've had to read up on what this does and ended up being rather
bewildered why peopled loved signals so much back in the days that
they've created SIGIO just for that ...

Then I wondered how this ever works, and what that strange "No-op."
comment right above it should mean. After all calling the core fasync
helper is pretty obviously not a noop. After reading through the
kernels FASYNC implementation I've noticed that signals are only sent
out to the processes attached with FASYNC by calling kill_fasync.

No merged drm driver has ever done that.

After more digging I've found out that the only driver that ever used
this is the so called GAMMA driver. I've frankly never heard of such a
gpu brand ever before. Now FASYNC seems to not have been the only bad
thing with that driver, since Dave Airlie removed it from the drm
driver with prejudice:

commit 1430163b4bbf7b00367ea1066c1c5fe85dbeefed
Author: Dave Airlie <airlied@linux.ie>
Date:   Sun Aug 29 12:04:35 2004 +0000

    Drop GAMMA DRM from a great height ...

Long story short, the drm fasync support seems to be doing absolutely
nothing. And the only user of it was never merged into the upstream
kernel. And we don't need any fops->fasync callback since the fcntl
implementation in the kernel already implements the noop case
correctly.

So stop this particular cargo-cult and rip it all out.

v2: Kill drm_fasync assignments in rcar (newly added) and imx drivers
(somehow I've missed that one in staging). Also drop the reference in
the drm DocBook. ARM compile-fail reported by Rob Clark.

v3: Move the removal of dev->buf_asnyc assignment in drm_setup to this
patch here.

v4: Actually git add ... tsk.

Cc: Dave Airlie <airlied@linux.ie>
Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Cc: Rob Clark <robdclark@gmail.com>
Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Reviewed-by: David Herrmann <dh.herrmann@gmail.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

Documentation/DocBook/drm.tmpl

@@ -2504,7 +2504,6 @@ void (*postclose) (struct drm_device *, struct drm_file *);</synopsis>
 	<programlisting>
 	.poll = drm_poll,
 	.read = drm_read,
-	.fasync = drm_fasync,
 	.llseek = no_llseek,
 	</programlisting>
       </para>

drivers/gpu/drm/ast/ast_drv.c

@@ -190,7 +190,6 @@ static const struct file_operations ast_fops = {
 	.unlocked_ioctl = drm_ioctl,
 	.mmap = ast_mmap,
 	.poll = drm_poll,
-	.fasync = drm_fasync,
 #ifdef CONFIG_COMPAT
 	.compat_ioctl = drm_compat_ioctl,
 #endif

drivers/gpu/drm/cirrus/cirrus_drv.c

@@ -85,7 +85,6 @@ static const struct file_operations cirrus_driver_fops = {
 #ifdef CONFIG_COMPAT
 	.compat_ioctl = drm_compat_ioctl,
 #endif
-	.fasync = drm_fasync,
 };
 static struct drm_driver driver = {
 	.driver_features = DRIVER_MODESET | DRIVER_GEM | DRIVER_USE_MTRR,

drivers/gpu/drm/drm_fops.c

@@ -73,8 +73,6 @@ static int drm_setup(struct drm_device * dev)
 	dev->last_context = 0;
 	dev->if_version = 0;
 
-	dev->buf_async = NULL;
-
 	DRM_DEBUG("\n");
 
 	/*
@@ -372,18 +370,6 @@ static int drm_open_helper(struct inode *inode, struct file *filp,
 	return ret;
 }
 
-/** No-op. */
-int drm_fasync(int fd, struct file *filp, int on)
-{
-	struct drm_file *priv = filp->private_data;
-	struct drm_device *dev = priv->minor->dev;
-
-	DRM_DEBUG("fd = %d, device = 0x%lx\n", fd,
-		  (long)old_encode_dev(priv->minor->device));
-	return fasync_helper(fd, filp, on, &dev->buf_async);
-}
-EXPORT_SYMBOL(drm_fasync);
-
 static void drm_master_release(struct drm_device *dev, struct file *filp)
 {
 	struct drm_file *file_priv = filp->private_data;

drivers/gpu/drm/gma500/psb_drv.c

@@ -622,7 +622,6 @@ static const struct file_operations psb_gem_fops = {
 	.unlocked_ioctl = psb_unlocked_ioctl,
 	.mmap = drm_gem_mmap,
 	.poll = drm_poll,
-	.fasync = drm_fasync,
 	.read = drm_read,
 };
 

drivers/gpu/drm/i810/i810_dma.c

@@ -113,7 +113,6 @@ static const struct file_operations i810_buffer_fops = {
 	.release = drm_release,
 	.unlocked_ioctl = drm_ioctl,
 	.mmap = i810_mmap_buffers,
-	.fasync = drm_fasync,
 #ifdef CONFIG_COMPAT
 	.compat_ioctl = drm_compat_ioctl,
 #endif

drivers/gpu/drm/i810/i810_drv.c

@@ -49,7 +49,6 @@ static const struct file_operations i810_driver_fops = {
 	.unlocked_ioctl = drm_ioctl,
 	.mmap = drm_mmap,
 	.poll = drm_poll,
-	.fasync = drm_fasync,
 #ifdef CONFIG_COMPAT
 	.compat_ioctl = drm_compat_ioctl,
 #endif

drivers/gpu/drm/i915/i915_drv.c

@@ -994,7 +994,6 @@ static const struct file_operations i915_driver_fops = {
 	.unlocked_ioctl = drm_ioctl,
 	.mmap = drm_gem_mmap,
 	.poll = drm_poll,
-	.fasync = drm_fasync,
 	.read = drm_read,
 #ifdef CONFIG_COMPAT
 	.compat_ioctl = i915_compat_ioctl,

drivers/gpu/drm/mga/mga_drv.c

@@ -50,7 +50,6 @@ static const struct file_operations mga_driver_fops = {
 	.unlocked_ioctl = drm_ioctl,
 	.mmap = drm_mmap,
 	.poll = drm_poll,
-	.fasync = drm_fasync,
 #ifdef CONFIG_COMPAT
 	.compat_ioctl = mga_compat_ioctl,
 #endif

drivers/gpu/drm/mgag200/mgag200_drv.c

@@ -81,7 +81,6 @@ static const struct file_operations mgag200_driver_fops = {
 	.unlocked_ioctl = drm_ioctl,
 	.mmap = mgag200_mmap,
 	.poll = drm_poll,
-	.fasync = drm_fasync,
 #ifdef CONFIG_COMPAT
 	.compat_ioctl = drm_compat_ioctl,
 #endif

drivers/gpu/drm/nouveau/nouveau_drm.c

@@ -673,7 +673,6 @@ nouveau_driver_fops = {
 	.unlocked_ioctl = drm_ioctl,
 	.mmap = nouveau_ttm_mmap,
 	.poll = drm_poll,
-	.fasync = drm_fasync,
 	.read = drm_read,
 #if defined(CONFIG_COMPAT)
 	.compat_ioctl = nouveau_compat_ioctl,

drivers/gpu/drm/omapdrm/omap_drv.c

@@ -592,7 +592,6 @@ static const struct file_operations omapdriver_fops = {
 		.release = drm_release,
 		.mmap = omap_gem_mmap,
 		.poll = drm_poll,
-		.fasync = drm_fasync,
 		.read = drm_read,
 		.llseek = noop_llseek,
 };

drivers/gpu/drm/qxl/qxl_drv.c

@@ -84,7 +84,6 @@ static const struct file_operations qxl_fops = {
 	.release = drm_release,
 	.unlocked_ioctl = drm_ioctl,
 	.poll = drm_poll,
-	.fasync = drm_fasync,
 	.mmap = qxl_mmap,
 };
 

drivers/gpu/drm/r128/r128_drv.c

@@ -48,7 +48,6 @@ static const struct file_operations r128_driver_fops = {
 	.unlocked_ioctl = drm_ioctl,
 	.mmap = drm_mmap,
 	.poll = drm_poll,
-	.fasync = drm_fasync,
 #ifdef CONFIG_COMPAT
 	.compat_ioctl = r128_compat_ioctl,
 #endif

drivers/gpu/drm/radeon/radeon_drv.c

@@ -266,7 +266,6 @@ static const struct file_operations radeon_driver_old_fops = {
 	.unlocked_ioctl = drm_ioctl,
 	.mmap = drm_mmap,
 	.poll = drm_poll,
-	.fasync = drm_fasync,
 	.read = drm_read,
 #ifdef CONFIG_COMPAT
 	.compat_ioctl = radeon_compat_ioctl,
@@ -375,7 +374,6 @@ static const struct file_operations radeon_driver_kms_fops = {
 	.unlocked_ioctl = drm_ioctl,
 	.mmap = radeon_mmap,
 	.poll = drm_poll,
-	.fasync = drm_fasync,
 	.read = drm_read,
 #ifdef CONFIG_COMPAT
 	.compat_ioctl = radeon_kms_compat_ioctl,

drivers/gpu/drm/rcar-du/rcar_du_drv.c

@@ -148,7 +148,6 @@ static const struct file_operations rcar_du_fops = {
 #endif
 	.poll		= drm_poll,
 	.read		= drm_read,
-	.fasync		= drm_fasync,
 	.llseek		= no_llseek,
 	.mmap		= drm_gem_cma_mmap,
 };

drivers/gpu/drm/savage/savage_drv.c

@@ -42,7 +42,6 @@ static const struct file_operations savage_driver_fops = {
 	.unlocked_ioctl = drm_ioctl,
 	.mmap = drm_mmap,
 	.poll = drm_poll,
-	.fasync = drm_fasync,
 #ifdef CONFIG_COMPAT
 	.compat_ioctl = drm_compat_ioctl,
 #endif

drivers/gpu/drm/shmobile/shmob_drm_drv.c

@@ -257,7 +257,6 @@ static const struct file_operations shmob_drm_fops = {
 #endif
 	.poll		= drm_poll,
 	.read		= drm_read,
-	.fasync		= drm_fasync,
 	.llseek		= no_llseek,
 	.mmap		= drm_gem_cma_mmap,
 };

drivers/gpu/drm/sis/sis_drv.c

@@ -72,7 +72,6 @@ static const struct file_operations sis_driver_fops = {
 	.unlocked_ioctl = drm_ioctl,
 	.mmap = drm_mmap,
 	.poll = drm_poll,
-	.fasync = drm_fasync,
 #ifdef CONFIG_COMPAT
 	.compat_ioctl = drm_compat_ioctl,
 #endif

drivers/gpu/drm/tdfx/tdfx_drv.c

@@ -48,7 +48,6 @@ static const struct file_operations tdfx_driver_fops = {
 	.unlocked_ioctl = drm_ioctl,
 	.mmap = drm_mmap,
 	.poll = drm_poll,
-	.fasync = drm_fasync,
 #ifdef CONFIG_COMPAT
 	.compat_ioctl = drm_compat_ioctl,
 #endif

drivers/gpu/drm/tilcdc/tilcdc_drv.c

@@ -497,7 +497,6 @@ static const struct file_operations fops = {
 #endif
 	.poll               = drm_poll,
 	.read               = drm_read,
-	.fasync             = drm_fasync,
 	.llseek             = no_llseek,
 	.mmap               = drm_gem_cma_mmap,
 };

drivers/gpu/drm/udl/udl_drv.c

@@ -65,7 +65,6 @@ static const struct file_operations udl_driver_fops = {
 	.read = drm_read,
 	.unlocked_ioctl	= drm_ioctl,
 	.release = drm_release,
-	.fasync = drm_fasync,
 #ifdef CONFIG_COMPAT
 	.compat_ioctl = drm_compat_ioctl,
 #endif

drivers/gpu/drm/via/via_drv.c

@@ -64,7 +64,6 @@ static const struct file_operations via_driver_fops = {
 	.unlocked_ioctl = drm_ioctl,
 	.mmap = drm_mmap,
 	.poll = drm_poll,
-	.fasync = drm_fasync,
 #ifdef CONFIG_COMPAT
 	.compat_ioctl = drm_compat_ioctl,
 #endif

drivers/gpu/drm/vmwgfx/vmwgfx_drv.c

@@ -1120,7 +1120,6 @@ static const struct file_operations vmwgfx_driver_fops = {
 	.mmap = vmw_mmap,
 	.poll = vmw_fops_poll,
 	.read = vmw_fops_read,
-	.fasync = drm_fasync,
 #if defined(CONFIG_COMPAT)
 	.compat_ioctl = drm_compat_ioctl,
 #endif

drivers/gpu/host1x/drm/drm.c

@@ -508,7 +508,6 @@ static const struct file_operations tegra_drm_fops = {
 	.unlocked_ioctl = drm_ioctl,
 	.mmap = tegra_drm_mmap,
 	.poll = drm_poll,
-	.fasync = drm_fasync,
 	.read = drm_read,
 #ifdef CONFIG_COMPAT
 	.compat_ioctl = drm_compat_ioctl,

drivers/staging/imx-drm/imx-drm-core.c

@@ -207,7 +207,6 @@ static const struct file_operations imx_drm_driver_fops = {
 	.unlocked_ioctl = drm_ioctl,
 	.mmap = drm_gem_cma_mmap,
 	.poll = drm_poll,
-	.fasync = drm_fasync,
 	.read = drm_read,
 	.llseek = noop_llseek,
 };

include/drm/drmP.h

@@ -1166,8 +1166,6 @@ struct drm_device {
 
 	/*@} */
 
-	struct fasync_struct *buf_async;/**< Processes waiting for SIGIO */
-
 	struct drm_agp_head *agp;	/**< AGP data */
 
 	struct device *dev;             /**< Device structure */
@@ -1264,7 +1262,6 @@ extern int drm_lastclose(struct drm_device *dev);
 extern struct mutex drm_global_mutex;
 extern int drm_open(struct inode *inode, struct file *filp);
 extern int drm_stub_open(struct inode *inode, struct file *filp);
-extern int drm_fasync(int fd, struct file *filp, int on);
 extern ssize_t drm_read(struct file *filp, char __user *buffer,
 			size_t count, loff_t *offset);
 extern int drm_release(struct inode *inode, struct file *filp);