Hi Daniel,
Thank you for the patch.
On Wednesday 10 July 2013 17:25:04 Daniel Vetter wrote:
> 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 <airl...@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 <airl...@linux.ie>
> Cc: Laurent Pinchart <laurent.pinch...@ideasonboard.com>
> Cc: Rob Clark <robdcl...@gmail.com>
> Signed-off-by: Daniel Vetter <daniel.vet...@ffwll.ch>
Acked-by: Laurent Pinchart <laurent.pinch...@ideasonboard.com>
> ---
> Documentation/DocBook/drm.tmpl | 1 -
> drivers/gpu/drm/ast/ast_drv.c | 1 -
> drivers/gpu/drm/cirrus/cirrus_drv.c | 1 -
> drivers/gpu/drm/drm_fops.c | 14 --------------
> drivers/gpu/drm/gma500/psb_drv.c | 1 -
> drivers/gpu/drm/i810/i810_dma.c | 1 -
> drivers/gpu/drm/i810/i810_drv.c | 1 -
> drivers/gpu/drm/i915/i915_drv.c | 1 -
> drivers/gpu/drm/mga/mga_drv.c | 1 -
> drivers/gpu/drm/mgag200/mgag200_drv.c | 1 -
> drivers/gpu/drm/nouveau/nouveau_drm.c | 1 -
> drivers/gpu/drm/omapdrm/omap_drv.c | 1 -
> drivers/gpu/drm/qxl/qxl_drv.c | 1 -
> drivers/gpu/drm/r128/r128_drv.c | 1 -
> drivers/gpu/drm/radeon/radeon_drv.c | 2 --
> drivers/gpu/drm/rcar-du/rcar_du_drv.c | 1 -
> drivers/gpu/drm/savage/savage_drv.c | 1 -
> drivers/gpu/drm/shmobile/shmob_drm_drv.c | 1 -
> drivers/gpu/drm/sis/sis_drv.c | 1 -
> drivers/gpu/drm/tdfx/tdfx_drv.c | 1 -
> drivers/gpu/drm/tilcdc/tilcdc_drv.c | 1 -
> drivers/gpu/drm/udl/udl_drv.c | 1 -
> drivers/gpu/drm/via/via_drv.c | 1 -
> drivers/gpu/drm/vmwgfx/vmwgfx_drv.c | 1 -
> drivers/gpu/host1x/drm/drm.c | 1 -
> drivers/staging/imx-drm/imx-drm-core.c | 1 -
> include/drm/drmP.h | 3 ---
> 27 files changed, 43 deletions(-)
>
> diff --git a/Documentation/DocBook/drm.tmpl b/Documentation/DocBook/drm.tmpl
> index 4d54ac8..79dd70e 100644
> --- a/Documentation/DocBook/drm.tmpl
> +++ b/Documentation/DocBook/drm.tmpl
> @@ -2498,7 +2498,6 @@ void (*postclose) (struct drm_device *, struct
> drm_file *);</synopsis> <programlisting>
> .poll = drm_poll,
> .read = drm_read,
> - .fasync = drm_fasync,
> .llseek = no_llseek,
> </programlisting>
> </para>
> diff --git a/drivers/gpu/drm/ast/ast_drv.c b/drivers/gpu/drm/ast/ast_drv.c
> index df0d0a0..16050ed 100644
> --- a/drivers/gpu/drm/ast/ast_drv.c
> +++ b/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
> diff --git a/drivers/gpu/drm/cirrus/cirrus_drv.c
> b/drivers/gpu/drm/cirrus/cirrus_drv.c index 8ecb601..85748f6 100644
> --- a/drivers/gpu/drm/cirrus/cirrus_drv.c
> +++ b/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,
> diff --git a/drivers/gpu/drm/drm_fops.c b/drivers/gpu/drm/drm_fops.c
> index 14e0bb6..d1b4771 100644
> --- a/drivers/gpu/drm/drm_fops.c
> +++ b/drivers/gpu/drm/drm_fops.c
> @@ -75,8 +75,6 @@ static int drm_setup(struct drm_device * dev)
> dev->last_checked = 0;
> dev->if_version = 0;
>
> - dev->buf_async = NULL;
> -
> DRM_DEBUG("\n");
>
> /*
> @@ -374,18 +372,6 @@ out_put_pid:
> 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;
> diff --git a/drivers/gpu/drm/gma500/psb_drv.c
> b/drivers/gpu/drm/gma500/psb_drv.c index bddea58..c9c37ac 100644
> --- a/drivers/gpu/drm/gma500/psb_drv.c
> +++ b/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,
> };
>
> diff --git a/drivers/gpu/drm/i810/i810_dma.c
> b/drivers/gpu/drm/i810/i810_dma.c index 004ecdf..ef1c9c7 100644
> --- a/drivers/gpu/drm/i810/i810_dma.c
> +++ b/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
> diff --git a/drivers/gpu/drm/i810/i810_drv.c
> b/drivers/gpu/drm/i810/i810_drv.c index 2e91fc3..d85c05b 100644
> --- a/drivers/gpu/drm/i810/i810_drv.c
> +++ b/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
> diff --git a/drivers/gpu/drm/i915/i915_drv.c
> b/drivers/gpu/drm/i915/i915_drv.c index 062cbda..999ef21 100644
> --- a/drivers/gpu/drm/i915/i915_drv.c
> +++ b/drivers/gpu/drm/i915/i915_drv.c
> @@ -1110,7 +1110,6 @@ 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,
> diff --git a/drivers/gpu/drm/mga/mga_drv.c b/drivers/gpu/drm/mga/mga_drv.c
> index 17d0a63..fe71e1e 100644
> --- a/drivers/gpu/drm/mga/mga_drv.c
> +++ b/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
> diff --git a/drivers/gpu/drm/mgag200/mgag200_drv.c
> b/drivers/gpu/drm/mgag200/mgag200_drv.c index 122b571..31ff081 100644
> --- a/drivers/gpu/drm/mgag200/mgag200_drv.c
> +++ b/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
> diff --git a/drivers/gpu/drm/nouveau/nouveau_drm.c
> b/drivers/gpu/drm/nouveau/nouveau_drm.c index e990327..e09debe 100644
> --- a/drivers/gpu/drm/nouveau/nouveau_drm.c
> +++ b/drivers/gpu/drm/nouveau/nouveau_drm.c
> @@ -664,7 +664,6 @@ 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,
> diff --git a/drivers/gpu/drm/omapdrm/omap_drv.c
> b/drivers/gpu/drm/omapdrm/omap_drv.c index 3f7c78a..fd2cfed 100644
> --- a/drivers/gpu/drm/omapdrm/omap_drv.c
> +++ b/drivers/gpu/drm/omapdrm/omap_drv.c
> @@ -577,7 +577,6 @@ 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,
> };
> diff --git a/drivers/gpu/drm/qxl/qxl_drv.c b/drivers/gpu/drm/qxl/qxl_drv.c
> index df0b577..4be5225 100644
> --- a/drivers/gpu/drm/qxl/qxl_drv.c
> +++ b/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,
> };
>
> diff --git a/drivers/gpu/drm/r128/r128_drv.c
> b/drivers/gpu/drm/r128/r128_drv.c index 472c38f..c2338cb 100644
> --- a/drivers/gpu/drm/r128/r128_drv.c
> +++ b/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
> diff --git a/drivers/gpu/drm/radeon/radeon_drv.c
> b/drivers/gpu/drm/radeon/radeon_drv.c index 81b9baa..ae94625 100644
> --- a/drivers/gpu/drm/radeon/radeon_drv.c
> +++ b/drivers/gpu/drm/radeon/radeon_drv.c
> @@ -265,7 +265,6 @@ 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,
> @@ -374,7 +373,6 @@ 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,
> diff --git a/drivers/gpu/drm/rcar-du/rcar_du_drv.c
> b/drivers/gpu/drm/rcar-du/rcar_du_drv.c index ff82877..46e5967 100644
> --- a/drivers/gpu/drm/rcar-du/rcar_du_drv.c
> +++ b/drivers/gpu/drm/rcar-du/rcar_du_drv.c
> @@ -230,7 +230,6 @@ 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,
> };
> diff --git a/drivers/gpu/drm/savage/savage_drv.c
> b/drivers/gpu/drm/savage/savage_drv.c index 71b2081..9135c8b 100644
> --- a/drivers/gpu/drm/savage/savage_drv.c
> +++ b/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
> diff --git a/drivers/gpu/drm/shmobile/shmob_drm_drv.c
> b/drivers/gpu/drm/shmobile/shmob_drm_drv.c index edc1018..db94f2f 100644
> --- a/drivers/gpu/drm/shmobile/shmob_drm_drv.c
> +++ b/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,
> };
> diff --git a/drivers/gpu/drm/sis/sis_drv.c b/drivers/gpu/drm/sis/sis_drv.c
> index 5a5325e..b88b2d3 100644
> --- a/drivers/gpu/drm/sis/sis_drv.c
> +++ b/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
> diff --git a/drivers/gpu/drm/tdfx/tdfx_drv.c
> b/drivers/gpu/drm/tdfx/tdfx_drv.c index ddfa743..951ec13 100644
> --- a/drivers/gpu/drm/tdfx/tdfx_drv.c
> +++ b/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
> diff --git a/drivers/gpu/drm/tilcdc/tilcdc_drv.c
> b/drivers/gpu/drm/tilcdc/tilcdc_drv.c index 40b71da..ff920ff 100644
> --- a/drivers/gpu/drm/tilcdc/tilcdc_drv.c
> +++ b/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,
> };
> diff --git a/drivers/gpu/drm/udl/udl_drv.c b/drivers/gpu/drm/udl/udl_drv.c
> index c0770db..c275adb 100644
> --- a/drivers/gpu/drm/udl/udl_drv.c
> +++ b/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
> diff --git a/drivers/gpu/drm/via/via_drv.c b/drivers/gpu/drm/via/via_drv.c
> index f4ae203..4487999 100644
> --- a/drivers/gpu/drm/via/via_drv.c
> +++ b/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
> diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_drv.c
> b/drivers/gpu/drm/vmwgfx/vmwgfx_drv.c index 3e75dfa..77d503a 100644
> --- a/drivers/gpu/drm/vmwgfx/vmwgfx_drv.c
> +++ b/drivers/gpu/drm/vmwgfx/vmwgfx_drv.c
> @@ -1103,7 +1103,6 @@ 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
> diff --git a/drivers/gpu/host1x/drm/drm.c b/drivers/gpu/host1x/drm/drm.c
> index e184b00..f8b708f 100644
> --- a/drivers/gpu/host1x/drm/drm.c
> +++ b/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,
> diff --git a/drivers/staging/imx-drm/imx-drm-core.c
> b/drivers/staging/imx-drm/imx-drm-core.c index 70f9650..f1cde28 100644
> --- a/drivers/staging/imx-drm/imx-drm-core.c
> +++ b/drivers/staging/imx-drm/imx-drm-core.c
> @@ -199,7 +199,6 @@ 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,
> };
> diff --git a/include/drm/drmP.h b/include/drm/drmP.h
> index d38c358..3589736 100644
> --- a/include/drm/drmP.h
> +++ b/include/drm/drmP.h
> @@ -1169,8 +1169,6 @@ struct drm_device {
>
> /*@} */
>
> - struct fasync_struct *buf_async;/**< Processes waiting for SIGIO */
> -
> struct drm_agp_head *agp; /**< AGP data */
>
> struct device *dev; /**< Device structure */
> @@ -1277,7 +1275,6 @@ 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);
--
Regards,
Laurent Pinchart
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