From fcf93f6948c3c29fd414bc00f1f713c501dfd22e Mon Sep 17 00:00:00 2001 From: Daniel Vetter Date: Wed, 12 Nov 2014 08:45:01 +0100 Subject: [PATCH] drm: More specific locking for get* ioctls Motivated by the per-plane locking I've gone through all the get* ioctls and reduced the locking to the bare minimum required. v2: Rebase and make it compile ... v3: Review from Sean: - Simplify return handling in getplane_res. - Add a comment to getplane_res that the plane list is invariant and can be walked locklessly. v4: Actually git add. Cc: Sean Paul Reviewed-by: Sean Paul Signed-off-by: Daniel Vetter Signed-off-by: Dave Airlie --- drivers/gpu/drm/drm_crtc.c | 58 +++++++++++++++----------------------- 1 file changed, 23 insertions(+), 35 deletions(-) diff --git a/drivers/gpu/drm/drm_crtc.c b/drivers/gpu/drm/drm_crtc.c index 3652ed8dda80..2beb219df1bd 100644 --- a/drivers/gpu/drm/drm_crtc.c +++ b/drivers/gpu/drm/drm_crtc.c @@ -1743,7 +1743,9 @@ int drm_mode_getresources(struct drm_device *dev, void *data, card_res->count_fbs = fb_count; mutex_unlock(&file_priv->fbs_lock); - drm_modeset_lock_all(dev); + /* mode_config.mutex protects the connector list against e.g. DP MST + * connector hot-adding. CRTC/Plane lists are invariant. */ + mutex_lock(&dev->mode_config.mutex); if (!drm_is_primary_client(file_priv)) { mode_group = NULL; @@ -1863,7 +1865,7 @@ int drm_mode_getresources(struct drm_device *dev, void *data, card_res->count_connectors, card_res->count_encoders); out: - drm_modeset_unlock_all(dev); + mutex_unlock(&dev->mode_config.mutex); return ret; } @@ -1890,14 +1892,11 @@ int drm_mode_getcrtc(struct drm_device *dev, if (!drm_core_check_feature(dev, DRIVER_MODESET)) return -EINVAL; - drm_modeset_lock_all(dev); - crtc = drm_crtc_find(dev, crtc_resp->crtc_id); - if (!crtc) { - ret = -ENOENT; - goto out; - } + if (!crtc) + return -ENOENT; + drm_modeset_lock_crtc(crtc, crtc->primary); crtc_resp->x = crtc->x; crtc_resp->y = crtc->y; crtc_resp->gamma_size = crtc->gamma_size; @@ -1914,9 +1913,8 @@ int drm_mode_getcrtc(struct drm_device *dev, } else { crtc_resp->mode_valid = 0; } + drm_modeset_unlock_crtc(crtc); -out: - drm_modeset_unlock_all(dev); return ret; } @@ -2100,24 +2098,22 @@ int drm_mode_getencoder(struct drm_device *dev, void *data, if (!drm_core_check_feature(dev, DRIVER_MODESET)) return -EINVAL; - drm_modeset_lock_all(dev); encoder = drm_encoder_find(dev, enc_resp->encoder_id); - if (!encoder) { - ret = -ENOENT; - goto out; - } + if (!encoder) + return -ENOENT; + drm_modeset_lock(&dev->mode_config.connection_mutex, NULL); if (encoder->crtc) enc_resp->crtc_id = encoder->crtc->base.id; else enc_resp->crtc_id = 0; + drm_modeset_unlock(&dev->mode_config.connection_mutex); + enc_resp->encoder_type = encoder->encoder_type; enc_resp->encoder_id = encoder->base.id; enc_resp->possible_crtcs = encoder->possible_crtcs; enc_resp->possible_clones = encoder->possible_clones; -out: - drm_modeset_unlock_all(dev); return ret; } @@ -2141,13 +2137,12 @@ int drm_mode_getplane_res(struct drm_device *dev, void *data, struct drm_mode_config *config; struct drm_plane *plane; uint32_t __user *plane_ptr; - int copied = 0, ret = 0; + int copied = 0; unsigned num_planes; if (!drm_core_check_feature(dev, DRIVER_MODESET)) return -EINVAL; - drm_modeset_lock_all(dev); config = &dev->mode_config; if (file_priv->universal_planes) @@ -2163,6 +2158,7 @@ int drm_mode_getplane_res(struct drm_device *dev, void *data, (plane_resp->count_planes >= num_planes)) { plane_ptr = (uint32_t __user *)(unsigned long)plane_resp->plane_id_ptr; + /* Plane lists are invariant, no locking needed. */ list_for_each_entry(plane, &config->plane_list, head) { /* * Unless userspace set the 'universal planes' @@ -2172,18 +2168,14 @@ int drm_mode_getplane_res(struct drm_device *dev, void *data, !file_priv->universal_planes) continue; - if (put_user(plane->base.id, plane_ptr + copied)) { - ret = -EFAULT; - goto out; - } + if (put_user(plane->base.id, plane_ptr + copied)) + return -EFAULT; copied++; } } plane_resp->count_planes = num_planes; -out: - drm_modeset_unlock_all(dev); - return ret; + return 0; } /** @@ -2210,13 +2202,11 @@ int drm_mode_getplane(struct drm_device *dev, void *data, if (!drm_core_check_feature(dev, DRIVER_MODESET)) return -EINVAL; - drm_modeset_lock_all(dev); plane = drm_plane_find(dev, plane_resp->plane_id); - if (!plane) { - ret = -ENOENT; - goto out; - } + if (!plane) + return -ENOENT; + drm_modeset_lock(&plane->mutex, NULL); if (plane->crtc) plane_resp->crtc_id = plane->crtc->base.id; else @@ -2226,6 +2216,7 @@ int drm_mode_getplane(struct drm_device *dev, void *data, plane_resp->fb_id = plane->fb->base.id; else plane_resp->fb_id = 0; + drm_modeset_unlock(&plane->mutex); plane_resp->plane_id = plane->base.id; plane_resp->possible_crtcs = plane->possible_crtcs; @@ -2241,14 +2232,11 @@ int drm_mode_getplane(struct drm_device *dev, void *data, if (copy_to_user(format_ptr, plane->format_types, sizeof(uint32_t) * plane->format_count)) { - ret = -EFAULT; - goto out; + return -EFAULT; } } plane_resp->count_format_types = plane->format_count; -out: - drm_modeset_unlock_all(dev); return ret; } -- GitLab