drm: Add drm_connector_for_each_possible_encoder()

Add a convenience macro for iterating connector->encoder_ids[].
Isolates the users from the implementation details.

Note that we don't seem to pass the file_priv down to drm_encoder_find()
because encoders apparently don't get leased. No idea why
drm_encoder_finc() even takes the file_priv actually.

Also use ARRAY_SIZE() when populating the array to avoid spreading
knowledge about the array size all over.

v2: Hide the drm_encoder_find() in the macro, and
    rename the macro appropriately (Daniel)
v3: Fix kernel docs (Daniel)

Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180628131315.14156-4-ville.syrjala@linux.intel.com
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>

3 files changed, 14 insertions, 28 deletions

diff --git a/drivers/gpu/drm/drm_connector.c b/drivers/gpu/drm/drm_connector.c
index b09b3a3e4024..7387c0377e51 100644
--- a/drivers/gpu/drm/drm_connector.c
+++ b/drivers/gpu/drm/drm_connector.c
@@ -321,7 +321,7 @@ int drm_mode_connector_attach_encoder(struct drm_connector *connector,
         if (WARN_ON(connector->encoder))
                 return -EINVAL;
 
-        for (i = 0; i < DRM_CONNECTOR_MAX_ENCODER; i++) {
+        for (i = 0; i < ARRAY_SIZE(connector->encoder_ids); i++) {
                 if (connector->encoder_ids[i] == 0) {
                         connector->encoder_ids[i] = encoder->base.id;
                         return 0;
@@ -1706,22 +1706,19 @@ int drm_mode_getconnector(struct drm_device *dev, void *data,
         if (!connector)
                 return -ENOENT;
 
-        for (i = 0; i < DRM_CONNECTOR_MAX_ENCODER; i++)
-                if (connector->encoder_ids[i] != 0)
-                        encoders_count++;
+        drm_connector_for_each_possible_encoder(connector, encoder, i)
+                encoders_count++;
 
         if ((out_resp->count_encoders >= encoders_count) && encoders_count) {
                 copied = 0;
                 encoder_ptr = (uint32_t __user *)(unsigned long)(out_resp->encoders_ptr);
-                for (i = 0; i < DRM_CONNECTOR_MAX_ENCODER; i++) {
-                        if (connector->encoder_ids[i] != 0) {
-                                if (put_user(connector->encoder_ids[i],
-                                             encoder_ptr + copied)) {
-                                        ret = -EFAULT;
-                                        goto out;
-                                }
-                                copied++;
+
+                drm_connector_for_each_possible_encoder(connector, encoder, i) {
+                        if (put_user(encoder->base.id, encoder_ptr + copied)) {
+                                ret = -EFAULT;
+                                goto out;
                         }
+                        copied++;
                 }
         }
         out_resp->count_encoders = encoders_count;
diff --git a/drivers/gpu/drm/drm_fb_helper.c b/drivers/gpu/drm/drm_fb_helper.c
index b37f06317d51..d697c1c4a067 100644
--- a/drivers/gpu/drm/drm_fb_helper.c
+++ b/drivers/gpu/drm/drm_fb_helper.c
@@ -2326,17 +2326,10 @@ retry:
 static bool connector_has_possible_crtc(struct drm_connector *connector,
                                         struct drm_crtc *crtc)
 {
+        struct drm_encoder *encoder;
         int i;
 
-        for (i = 0; i < DRM_CONNECTOR_MAX_ENCODER; i++) {
-                struct drm_encoder *encoder;
-
-                if (connector->encoder_ids[i] == 0)
-                        break;
-
-                encoder = drm_encoder_find(connector->dev, NULL,
-                                           connector->encoder_ids[i]);
-
+        drm_connector_for_each_possible_encoder(connector, encoder, i) {
                 if (encoder->possible_crtcs & drm_crtc_mask(crtc))
                         return true;
         }
diff --git a/drivers/gpu/drm/drm_probe_helper.c b/drivers/gpu/drm/drm_probe_helper.c
index 527743394150..1a901fe9e23e 100644
--- a/drivers/gpu/drm/drm_probe_helper.c
+++ b/drivers/gpu/drm/drm_probe_helper.c
@@ -88,9 +88,9 @@ drm_mode_validate_pipeline(struct drm_display_mode *mode,
                             struct drm_connector *connector)
 {
         struct drm_device *dev = connector->dev;
-        uint32_t *ids = connector->encoder_ids;
         enum drm_mode_status ret = MODE_OK;
-        unsigned int i;
+        struct drm_encoder *encoder;
+        int i;
 
         /* Step 1: Validate against connector */
         ret = drm_connector_mode_valid(connector, mode);
@@ -98,13 +98,9 @@ drm_mode_validate_pipeline(struct drm_display_mode *mode,
                 return ret;
 
         /* Step 2: Validate against encoders and crtcs */
-        for (i = 0; i < DRM_CONNECTOR_MAX_ENCODER; i++) {
-                struct drm_encoder *encoder = drm_encoder_find(dev, NULL, ids[i]);
+        drm_connector_for_each_possible_encoder(connector, encoder, i) {
                 struct drm_crtc *crtc;
 
-                if (!encoder)
-                        continue;
-
                 ret = drm_encoder_mode_valid(encoder, mode);
                 if (ret != MODE_OK) {
                         /* No point in continuing for crtc check as this encoder