Re: [PATCH] drm: remove FASYNC support

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 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 Signed-off-by: Daniel Vetter daniel.vetter@ffwll.ch

Acked-by: Laurent Pinchart laurent.pinchart@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);