drm: Simplify GETRESOURCES ioctl

Looping twice when we can do it once is silly. Also use a consistent
style. Note that there's a good race with the connector list walking,
since that is no longer protected by mode_config.mutex. But that's for
a later patch to fix.

v2: Actually try to not blow up, somehow I lost the hunk that checks
we don't copy too much. Noticed by Chris.

v3:
- squash all drm_mode_getresources cleanups into one
- use consistent style for walking objects (Chris)

v4:
- Use u64_to_user_ptr (Chris)
- Don't forget to copy the last connector (Chris)

v5: Chris was right ...

Cc: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20161211192019.29603-1-daniel.vetter@ffwll.ch

diff --git a/drivers/gpu/drm/drm_mode_config.c b/drivers/gpu/drm/drm_mode_config.c
index 2735a5847ffadc1bcbbcda8c14b1d18d4e7100f5..b1e8bbceaf3916795590bcbccced69281e2768a2 100644 (file)
--- a/drivers/gpu/drm/drm_mode_config.c
+++ b/drivers/gpu/drm/drm_mode_config.c
@@ -84,17 +84,11 @@ int drm_mode_getresources(struct drm_device *dev, void *data,
                          struct drm_file *file_priv)
 {
        struct drm_mode_card_res *card_res = data;
-       struct list_head *lh;
        struct drm_framebuffer *fb;
        struct drm_connector *connector;
        struct drm_crtc *crtc;
        struct drm_encoder *encoder;
-       int ret = 0;
-       int connector_count = 0;
-       int crtc_count = 0;
-       int fb_count = 0;
-       int encoder_count = 0;
-       int copied = 0;
+       int count, ret = 0;
        uint32_t __user *fb_id;
        uint32_t __user *crtc_id;
        uint32_t __user *connector_id;
@@ -105,89 +99,62 @@ int drm_mode_getresources(struct drm_device *dev, void *data,
 
 
        mutex_lock(&file_priv->fbs_lock);
-       /*
-        * For the non-control nodes we need to limit the list of resources
-        * by IDs in the group list for this node
-        */
-       list_for_each(lh, &file_priv->fbs)
-               fb_count++;
-
-       /* handle this in 4 parts */
-       /* FBs */
-       if (card_res->count_fbs >= fb_count) {
-               copied = 0;
-               fb_id = (uint32_t __user *)(unsigned long)card_res->fb_id_ptr;
-               list_for_each_entry(fb, &file_priv->fbs, filp_head) {
-                       if (put_user(fb->base.id, fb_id + copied)) {
-                               mutex_unlock(&file_priv->fbs_lock);
-                               return -EFAULT;
-                       }
-                       copied++;
+       count = 0;
+       fb_id = u64_to_user_ptr(card_res->fb_id_ptr);
+       list_for_each_entry(fb, &file_priv->fbs, filp_head) {
+               if (count < card_res->count_fbs &&
+                   put_user(fb->base.id, fb_id + count)) {
+                       mutex_unlock(&file_priv->fbs_lock);
+                       return -EFAULT;
                }
+               count++;
        }
-       card_res->count_fbs = fb_count;
+       card_res->count_fbs = count;
        mutex_unlock(&file_priv->fbs_lock);
 
        /* 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);
-       drm_for_each_crtc(crtc, dev)
-               crtc_count++;
-
-       drm_for_each_connector(connector, dev)
-               connector_count++;
-
-       drm_for_each_encoder(encoder, dev)
-               encoder_count++;
-
        card_res->max_height = dev->mode_config.max_height;
        card_res->min_height = dev->mode_config.min_height;
        card_res->max_width = dev->mode_config.max_width;
        card_res->min_width = dev->mode_config.min_width;
 
-       /* CRTCs */
-       if (card_res->count_crtcs >= crtc_count) {
-               copied = 0;
-               crtc_id = (uint32_t __user *)(unsigned long)card_res->crtc_id_ptr;
-               drm_for_each_crtc(crtc, dev) {
-                       if (put_user(crtc->base.id, crtc_id + copied)) {
-                               ret = -EFAULT;
-                               goto out;
-                       }
-                       copied++;
+       count = 0;
+       crtc_id = u64_to_user_ptr(card_res->crtc_id_ptr);
+       drm_for_each_crtc(crtc, dev) {
+               if (count < card_res->count_crtcs &&
+                   put_user(crtc->base.id, crtc_id + count)) {
+                       ret = -EFAULT;
+                       goto out;
                }
+               count++;
        }
-       card_res->count_crtcs = crtc_count;
-
-       /* Encoders */
-       if (card_res->count_encoders >= encoder_count) {
-               copied = 0;
-               encoder_id = (uint32_t __user *)(unsigned long)card_res->encoder_id_ptr;
-               drm_for_each_encoder(encoder, dev) {
-                       if (put_user(encoder->base.id, encoder_id +
-                                    copied)) {
-                               ret = -EFAULT;
-                               goto out;
-                       }
-                       copied++;
+       card_res->count_crtcs = count;
+
+       count = 0;
+       encoder_id = u64_to_user_ptr(card_res->encoder_id_ptr);
+       drm_for_each_encoder(encoder, dev) {
+               if (count < card_res->count_encoders &&
+                   put_user(encoder->base.id, encoder_id + count)) {
+                       ret = -EFAULT;
+                       goto out;
                }
+               count++;
        }
-       card_res->count_encoders = encoder_count;
-
-       /* Connectors */
-       if (card_res->count_connectors >= connector_count) {
-               copied = 0;
-               connector_id = (uint32_t __user *)(unsigned long)card_res->connector_id_ptr;
-               drm_for_each_connector(connector, dev) {
-                       if (put_user(connector->base.id,
-                                    connector_id + copied)) {
-                               ret = -EFAULT;
-                               goto out;
-                       }
-                       copied++;
+       card_res->count_encoders = count;
+
+       count = 0;
+       connector_id = u64_to_user_ptr(card_res->connector_id_ptr);
+       drm_for_each_connector(connector, dev) {
+               if (count < card_res->count_connectors &&
+                   put_user(connector->base.id, connector_id + count)) {
+                       ret = -EFAULT;
+                       goto out;
                }
+               count++;
        }
-       card_res->count_connectors = connector_count;
+       card_res->count_connectors = count;
 
 out:
        mutex_unlock(&dev->mode_config.mutex);