From 0226ba393eb1a90d63955cc407340c5d506ecacf Mon Sep 17 00:00:00 2001 From: Simon Ser Date: Fri, 20 Oct 2023 10:19:38 +0000 Subject: drm: extract closefb logic in separate function MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit drm_mode_rmfb performs two operations: drop the FB from the file_priv->fbs list, and make sure the FB is no longer used on a plane. In the next commit an IOCTL which only does so former will be introduced, so let's split it into a separate function. No functional change, only refactoring. v2: no change Signed-off-by: Simon Ser Cc: Hans de Goede Cc: Dennis Filder Cc: Daniel Vetter Cc: Pekka Paalanen Cc: Rob Clark Cc: Sean Paul Reviewed-by: Daniel Stone Reviewed-by: Ville Syrjälä Link: https://patchwork.freedesktop.org/patch/msgid/20231020101926.145327-1-contact@emersion.fr --- drivers/gpu/drm/drm_framebuffer.c | 53 +++++++++++++++++++++++---------------- 1 file changed, 31 insertions(+), 22 deletions(-) (limited to 'drivers/gpu/drm/drm_framebuffer.c') diff --git a/drivers/gpu/drm/drm_framebuffer.c b/drivers/gpu/drm/drm_framebuffer.c index d3ba0698b84b..ef3f1e4bc334 100644 --- a/drivers/gpu/drm/drm_framebuffer.c +++ b/drivers/gpu/drm/drm_framebuffer.c @@ -394,6 +394,31 @@ static void drm_mode_rmfb_work_fn(struct work_struct *w) } } +static int drm_mode_closefb(struct drm_framebuffer *fb, + struct drm_file *file_priv) +{ + struct drm_framebuffer *fbl; + bool found = false; + + mutex_lock(&file_priv->fbs_lock); + list_for_each_entry(fbl, &file_priv->fbs, filp_head) + if (fb == fbl) + found = true; + + if (!found) { + mutex_unlock(&file_priv->fbs_lock); + return -ENOENT; + } + + list_del_init(&fb->filp_head); + mutex_unlock(&file_priv->fbs_lock); + + /* Drop the reference that was stored in the fbs list */ + drm_framebuffer_put(fb); + + return 0; +} + /** * drm_mode_rmfb - remove an FB from the configuration * @dev: drm device @@ -410,9 +435,8 @@ static void drm_mode_rmfb_work_fn(struct work_struct *w) int drm_mode_rmfb(struct drm_device *dev, u32 fb_id, struct drm_file *file_priv) { - struct drm_framebuffer *fb = NULL; - struct drm_framebuffer *fbl = NULL; - int found = 0; + struct drm_framebuffer *fb; + int ret; if (!drm_core_check_feature(dev, DRIVER_MODESET)) return -EOPNOTSUPP; @@ -421,24 +445,13 @@ int drm_mode_rmfb(struct drm_device *dev, u32 fb_id, if (!fb) return -ENOENT; - mutex_lock(&file_priv->fbs_lock); - list_for_each_entry(fbl, &file_priv->fbs, filp_head) - if (fb == fbl) - found = 1; - if (!found) { - mutex_unlock(&file_priv->fbs_lock); - goto fail_unref; + ret = drm_mode_closefb(fb, file_priv); + if (ret != 0) { + drm_framebuffer_put(fb); + return ret; } - list_del_init(&fb->filp_head); - mutex_unlock(&file_priv->fbs_lock); - - /* drop the reference we picked up in framebuffer lookup */ - drm_framebuffer_put(fb); - /* - * we now own the reference that was stored in the fbs list - * * drm_framebuffer_remove may fail with -EINTR on pending signals, * so run this in a separate stack as there's no way to correctly * handle this after the fb is already removed from the lookup table. @@ -457,10 +470,6 @@ int drm_mode_rmfb(struct drm_device *dev, u32 fb_id, drm_framebuffer_put(fb); return 0; - -fail_unref: - drm_framebuffer_put(fb); - return -ENOENT; } int drm_mode_rmfb_ioctl(struct drm_device *dev, -- cgit From d208d875667e2a29beeec5d475f4b6b164b632fa Mon Sep 17 00:00:00 2001 From: Simon Ser Date: Fri, 20 Oct 2023 10:19:45 +0000 Subject: drm: introduce CLOSEFB IOCTL This new IOCTL allows callers to close a framebuffer without disabling planes or CRTCs. This takes inspiration from Rob Clark's unref_fb IOCTL [1] and DRM_MODE_FB_PERSIST [2]. User-space patch for wlroots available at [3]. IGT test available at [4]. v2: add an extra pad field just in case we want to extend this IOCTL in the future (Pekka, Sima). [1]: https://lore.kernel.org/dri-devel/20170509153654.23464-1-robdclark@gmail.com/ [2]: https://lore.kernel.org/dri-devel/20211006151921.312714-1-contact@emersion.fr/ [3]: https://gitlab.freedesktop.org/wlroots/wlroots/-/merge_requests/4394 [4]: https://lists.freedesktop.org/archives/igt-dev/2023-October/063294.html Signed-off-by: Simon Ser Reviewed-by: Daniel Stone Acked-by: Pekka Paalanen Cc: Hans de Goede Cc: Dennis Filder Cc: Daniel Vetter Cc: Rob Clark Cc: Sean Paul Link: https://patchwork.freedesktop.org/patch/msgid/20231020101926.145327-2-contact@emersion.fr --- drivers/gpu/drm/drm_crtc_internal.h | 2 ++ drivers/gpu/drm/drm_framebuffer.c | 22 ++++++++++++++++++++++ drivers/gpu/drm/drm_ioctl.c | 1 + include/uapi/drm/drm.h | 20 ++++++++++++++++++++ include/uapi/drm/drm_mode.h | 10 ++++++++++ 5 files changed, 55 insertions(+) (limited to 'drivers/gpu/drm/drm_framebuffer.c') diff --git a/drivers/gpu/drm/drm_crtc_internal.h b/drivers/gpu/drm/drm_crtc_internal.h index 8556c3b3ff88..6b646e0783be 100644 --- a/drivers/gpu/drm/drm_crtc_internal.h +++ b/drivers/gpu/drm/drm_crtc_internal.h @@ -222,6 +222,8 @@ int drm_mode_addfb2_ioctl(struct drm_device *dev, void *data, struct drm_file *file_priv); int drm_mode_rmfb_ioctl(struct drm_device *dev, void *data, struct drm_file *file_priv); +int drm_mode_closefb_ioctl(struct drm_device *dev, + void *data, struct drm_file *file_priv); int drm_mode_getfb(struct drm_device *dev, void *data, struct drm_file *file_priv); int drm_mode_getfb2_ioctl(struct drm_device *dev, diff --git a/drivers/gpu/drm/drm_framebuffer.c b/drivers/gpu/drm/drm_framebuffer.c index ef3f1e4bc334..09e289fca5c3 100644 --- a/drivers/gpu/drm/drm_framebuffer.c +++ b/drivers/gpu/drm/drm_framebuffer.c @@ -480,6 +480,28 @@ int drm_mode_rmfb_ioctl(struct drm_device *dev, return drm_mode_rmfb(dev, *fb_id, file_priv); } +int drm_mode_closefb_ioctl(struct drm_device *dev, + void *data, struct drm_file *file_priv) +{ + struct drm_mode_closefb *r = data; + struct drm_framebuffer *fb; + int ret; + + if (!drm_core_check_feature(dev, DRIVER_MODESET)) + return -EOPNOTSUPP; + + if (r->pad) + return -EINVAL; + + fb = drm_framebuffer_lookup(dev, file_priv, r->fb_id); + if (!fb) + return -ENOENT; + + ret = drm_mode_closefb(fb, file_priv); + drm_framebuffer_put(fb); + return ret; +} + /** * drm_mode_getfb - get FB info * @dev: drm device for the ioctl diff --git a/drivers/gpu/drm/drm_ioctl.c b/drivers/gpu/drm/drm_ioctl.c index 77590b0f38fa..44fda68c28ae 100644 --- a/drivers/gpu/drm/drm_ioctl.c +++ b/drivers/gpu/drm/drm_ioctl.c @@ -675,6 +675,7 @@ static const struct drm_ioctl_desc drm_ioctls[] = { DRM_IOCTL_DEF(DRM_IOCTL_MODE_ADDFB, drm_mode_addfb_ioctl, 0), DRM_IOCTL_DEF(DRM_IOCTL_MODE_ADDFB2, drm_mode_addfb2_ioctl, 0), DRM_IOCTL_DEF(DRM_IOCTL_MODE_RMFB, drm_mode_rmfb_ioctl, 0), + DRM_IOCTL_DEF(DRM_IOCTL_MODE_CLOSEFB, drm_mode_closefb_ioctl, 0), DRM_IOCTL_DEF(DRM_IOCTL_MODE_PAGE_FLIP, drm_mode_page_flip_ioctl, DRM_MASTER), DRM_IOCTL_DEF(DRM_IOCTL_MODE_DIRTYFB, drm_mode_dirtyfb_ioctl, DRM_MASTER), DRM_IOCTL_DEF(DRM_IOCTL_MODE_CREATE_DUMB, drm_mode_create_dumb_ioctl, 0), diff --git a/include/uapi/drm/drm.h b/include/uapi/drm/drm.h index de723566c5ae..8662b5aeea0c 100644 --- a/include/uapi/drm/drm.h +++ b/include/uapi/drm/drm.h @@ -1218,6 +1218,26 @@ extern "C" { #define DRM_IOCTL_SYNCOBJ_EVENTFD DRM_IOWR(0xCF, struct drm_syncobj_eventfd) +/** + * DRM_IOCTL_MODE_CLOSEFB - Close a framebuffer. + * + * This closes a framebuffer previously added via ADDFB/ADDFB2. The IOCTL + * argument is a framebuffer object ID. + * + * This IOCTL is similar to &DRM_IOCTL_MODE_RMFB, except it doesn't disable + * planes and CRTCs. As long as the framebuffer is used by a plane, it's kept + * alive. When the plane no longer uses the framebuffer (because the + * framebuffer is replaced with another one, or the plane is disabled), the + * framebuffer is cleaned up. + * + * This is useful to implement flicker-free transitions between two processes. + * + * Depending on the threat model, user-space may want to ensure that the + * framebuffer doesn't expose any sensitive user information: closed + * framebuffers attached to a plane can be read back by the next DRM master. + */ +#define DRM_IOCTL_MODE_CLOSEFB DRM_IOWR(0xD0, struct drm_mode_closefb) + /* * Device specific ioctls should only be in their respective headers * The device specific ioctl range is from 0x40 to 0x9f. diff --git a/include/uapi/drm/drm_mode.h b/include/uapi/drm/drm_mode.h index 128d09138ceb..09e7a471ee30 100644 --- a/include/uapi/drm/drm_mode.h +++ b/include/uapi/drm/drm_mode.h @@ -1323,6 +1323,16 @@ struct drm_mode_rect { __s32 y2; }; +/** + * struct drm_mode_closefb + * @fb_id: Framebuffer ID. + * @pad: Must be zero. + */ +struct drm_mode_closefb { + __u32 fb_id; + __u32 pad; +}; + #if defined(__cplusplus) } #endif -- cgit