xwayland: use drmDevice to compare DRM devices

The linux_dmabuf_v1 protocol doesn't guarantee any DRM node type:
the compositor may send a primary node or a render node. Use
drmDevice so that device comparisons are node-type-insensitive.

Signed-off-by: Simon Ser <contact@emersion.fr>
Closes: https://gitlab.freedesktop.org/xorg/xserver/-/issues/1447

5 files changed, 37 insertions, 21 deletions

diff --git a/hw/xwayland/xwayland-glamor-gbm.c b/hw/xwayland/xwayland-glamor-gbm.c
index dcad1df04..8e46f30f7 100644
--- a/hw/xwayland/xwayland-glamor-gbm.c
+++ b/hw/xwayland/xwayland-glamor-gbm.c
@@ -53,7 +53,7 @@
 #include "linux-dmabuf-unstable-v1-client-protocol.h"
 
 struct xwl_gbm_private {
-    dev_t device;
+    drmDevice *device;
     char *device_name;
     struct gbm_device *gbm;
     struct wl_drm *drm;
@@ -460,6 +460,7 @@ xwl_glamor_gbm_cleanup(struct xwl_screen *xwl_screen)
 
     if (xwl_gbm->device_name)
         free(xwl_gbm->device_name);
+    drmFreeDevice(&xwl_gbm->device);
     if (xwl_gbm->drm_fd)
         close(xwl_gbm->drm_fd);
     if (xwl_gbm->drm)
@@ -784,7 +785,6 @@ xwl_drm_handle_device(void *data, struct wl_drm *drm, const char *device)
    struct xwl_gbm_private *xwl_gbm = xwl_gbm_get(xwl_screen);
    drm_magic_t magic;
    char *render_node_path = NULL;
-   struct stat stat;
 
    if (!is_device_path_render_node(device))
        render_node_path = get_render_node_path(device);
@@ -807,12 +807,11 @@ xwl_drm_handle_device(void *data, struct wl_drm *drm, const char *device)
        return;
    }
 
-   if (fstat(xwl_gbm->drm_fd, &stat)) {
-       ErrorF("wayland-egl: Could not stat file %s (%s)\n",
-              xwl_gbm->device_name, strerror(errno));
+   if (drmGetDevice2(xwl_gbm->drm_fd, 0, &xwl_gbm->device) != 0) {
+       ErrorF("wayland-egl: Could not fetch DRM device %s\n",
+              xwl_gbm->device_name);
        return;
    }
-   xwl_gbm->device = stat.st_rdev;
 
    if (drmGetNodeTypeFromFd(xwl_gbm->drm_fd) == DRM_NODE_RENDER) {
        xwl_gbm->fd_render_node = 1;
@@ -1111,7 +1110,7 @@ error:
     return FALSE;
 }
 
-static dev_t xwl_gbm_get_main_device(struct xwl_screen *xwl_screen)
+static drmDevice *xwl_gbm_get_main_device(struct xwl_screen *xwl_screen)
 {
     struct xwl_gbm_private *xwl_gbm = xwl_gbm_get(xwl_screen);
 
diff --git a/hw/xwayland/xwayland-glamor.c b/hw/xwayland/xwayland-glamor.c
index e7cc7eaf0..edb028978 100644
--- a/hw/xwayland/xwayland-glamor.c
+++ b/hw/xwayland/xwayland-glamor.c
@@ -187,7 +187,7 @@ wl_drm_format_for_depth(int depth)
     }
 }
 
-static dev_t
+static drmDevice *
 xwl_screen_get_main_dev(struct xwl_screen *xwl_screen)
 {
     /*
@@ -222,7 +222,7 @@ xwl_get_formats(struct xwl_format *format_array, int format_array_len,
 }
 
 static Bool
-xwl_get_formats_for_device(struct xwl_dmabuf_feedback *xwl_feedback, dev_t device,
+xwl_get_formats_for_device(struct xwl_dmabuf_feedback *xwl_feedback, drmDevice *device,
                            uint32_t *num_formats, uint32_t **formats)
 {
     uint32_t *ret = NULL;
@@ -230,7 +230,7 @@ xwl_get_formats_for_device(struct xwl_dmabuf_feedback *xwl_feedback, dev_t devic
 
     /* go through all matching sets of tranches for the window's device */
     for (int i = 0; i < xwl_feedback->dev_formats_len; i++) {
-        if (xwl_feedback->dev_formats[i].drm_dev == device) {
+        if (drmDevicesEqual(xwl_feedback->dev_formats[i].drm_dev, device)) {
             struct xwl_device_formats *dev_formats = &xwl_feedback->dev_formats[i];
 
             /* Append the formats from this tranche to the list */
@@ -273,7 +273,7 @@ xwl_glamor_get_formats(ScreenPtr screen,
         return FALSE;
 
     if (xwl_screen->dmabuf_protocol_version >= 4) {
-        dev_t main_dev = xwl_screen_get_main_dev(xwl_screen);
+        drmDevice *main_dev = xwl_screen_get_main_dev(xwl_screen);
 
         return xwl_get_formats_for_device(&xwl_screen->default_feedback, main_dev,
                                           num_formats, formats);
@@ -320,7 +320,7 @@ xwl_get_modifiers_for_format(struct xwl_format *format_array, int num_formats,
 }
 
 static Bool
-xwl_get_modifiers_for_device(struct xwl_dmabuf_feedback *feedback, dev_t device,
+xwl_get_modifiers_for_device(struct xwl_dmabuf_feedback *feedback, drmDevice *device,
                              uint32_t format, uint32_t *num_modifiers,
                              uint64_t **modifiers)
 {
@@ -328,7 +328,7 @@ xwl_get_modifiers_for_device(struct xwl_dmabuf_feedback *feedback, dev_t device,
     for (int i = 0; i < feedback->dev_formats_len; i++) {
         struct xwl_device_formats *dev_formats = &feedback->dev_formats[i];
 
-        if (dev_formats->drm_dev == device &&
+        if (drmDevicesEqual(dev_formats->drm_dev, device) &&
             xwl_get_modifiers_for_format(dev_formats->formats, dev_formats->num_formats,
                                          format, num_modifiers, modifiers))
             return TRUE;
@@ -342,7 +342,7 @@ xwl_glamor_get_modifiers(ScreenPtr screen, uint32_t format,
                          uint32_t *num_modifiers, uint64_t **modifiers)
 {
     struct xwl_screen *xwl_screen = xwl_screen_get(screen);
-    dev_t main_dev;
+    drmDevice *main_dev;
 
     /* Explicitly zero the count as the caller may ignore the return value */
     *num_modifiers = 0;
@@ -368,7 +368,7 @@ xwl_glamor_get_drawable_modifiers(DrawablePtr drawable, uint32_t format,
 {
     struct xwl_screen *xwl_screen = xwl_screen_get(drawable->pScreen);
     struct xwl_window *xwl_window;
-    dev_t main_dev;
+    drmDevice *main_dev;
 
     *num_modifiers = 0;
     *modifiers = NULL;
@@ -475,11 +475,15 @@ xwl_dmabuf_feedback_main_device(void *data,
                                 struct wl_array *dev)
 {
     struct xwl_dmabuf_feedback *xwl_feedback = data;
+    dev_t devid;
 
     xwl_check_reset_tranche_info(xwl_feedback);
 
     assert(dev->size == sizeof(dev_t));
-    memcpy(&xwl_feedback->main_dev, dev->data, sizeof(dev_t));
+    memcpy(&devid, dev->data, sizeof(dev_t));
+
+    if (drmGetDeviceFromDevId(devid, 0, &xwl_feedback->main_dev) != 0)
+        ErrorF("linux_dmabuf_feedback.main_device: Failed to fetch DRM device\n");
 }
 
 static void
@@ -488,11 +492,15 @@ xwl_dmabuf_feedback_tranche_target_device(void *data,
                                           struct wl_array *dev)
 {
     struct xwl_dmabuf_feedback *xwl_feedback = data;
+    dev_t devid;
 
     xwl_check_reset_tranche_info(xwl_feedback);
 
     assert(dev->size == sizeof(dev_t));
-    memcpy(&xwl_feedback->tmp_tranche.drm_dev, dev->data, sizeof(dev_t));
+    memcpy(&devid, dev->data, sizeof(dev_t));
+
+    if (drmGetDeviceFromDevId(devid, 0, &xwl_feedback->tmp_tranche.drm_dev) != 0)
+        ErrorF("linux_dmabuf_feedback.tranche_target_device: Failed to fetch DRM device\n");
 }
 
 static void
@@ -564,6 +572,11 @@ xwl_dmabuf_feedback_tranche_done(void *data,
      * triggered first
      */
 
+    if (xwl_feedback->tmp_tranche.drm_dev == NULL) {
+        xwl_device_formats_destroy(&xwl_feedback->tmp_tranche);
+        goto out;
+    }
+
     /*
      * First check if there is an existing tranche for this device+flags combo. We
      * will combine it with this tranche, since we can only send one modifier list
@@ -598,6 +611,7 @@ xwl_dmabuf_feedback_tranche_done(void *data,
                sizeof(struct xwl_device_formats));
     }
 
+out:
     /* reset the tranche */
     memset(&xwl_feedback->tmp_tranche, 0, sizeof(struct xwl_device_formats));
 }
diff --git a/hw/xwayland/xwayland-glamor.h b/hw/xwayland/xwayland-glamor.h
index aed65b50f..0ecd25b38 100644
--- a/hw/xwayland/xwayland-glamor.h
+++ b/hw/xwayland/xwayland-glamor.h
@@ -31,6 +31,7 @@
 #include <sys/types.h>
 
 #include <wayland-client.h>
+#include <xf86drm.h>
 
 #include "xwayland-types.h"
 
@@ -99,10 +100,10 @@ struct xwl_egl_backend {
      */
     Bool (*check_flip)(PixmapPtr pixmap);
 
-    /* Called to get the dev_t of the primary GPU that this backend
+    /* Called to get the DRM device of the primary GPU that this backend
      * is set up on.
      */
-    dev_t (*get_main_device)(struct xwl_screen *xwl_screen);
+    drmDevice *(*get_main_device)(struct xwl_screen *xwl_screen);
 };
 
 #ifdef XWL_HAS_GLAMOR
diff --git a/hw/xwayland/xwayland-window.c b/hw/xwayland/xwayland-window.c
index eba81b8cb..e159743a0 100644
--- a/hw/xwayland/xwayland-window.c
+++ b/hw/xwayland/xwayland-window.c
@@ -1014,6 +1014,7 @@ xwl_device_formats_destroy(struct xwl_device_formats *dev_formats)
     for (int j = 0; j < dev_formats->num_formats; j++)
         free(dev_formats->formats[j].modifiers);
     free(dev_formats->formats);
+    drmFreeDevice(&dev_formats->drm_dev);
 }
 
 void
diff --git a/hw/xwayland/xwayland-window.h b/hw/xwayland/xwayland-window.h
index c5c42f097..65dfb69ff 100644
--- a/hw/xwayland/xwayland-window.h
+++ b/hw/xwayland/xwayland-window.h
@@ -38,6 +38,7 @@
 #include <propertyst.h>
 #include <validate.h>
 #include <wayland-util.h>
+#include <xf86drm.h>
 
 #include "xwayland-types.h"
 
@@ -54,7 +55,7 @@ struct xwl_format_table_entry {
 };
 
 struct xwl_device_formats {
-    dev_t drm_dev;
+    drmDevice *drm_dev;
     int supports_scanout;
     uint32_t num_formats;
     struct xwl_format *formats;
@@ -74,7 +75,7 @@ struct xwl_format_table {
 struct xwl_dmabuf_feedback {
     struct zwp_linux_dmabuf_feedback_v1 *dmabuf_feedback;
     struct xwl_format_table format_table;
-    dev_t main_dev;
+    drmDevice *main_dev;
     /*
      * This will be filled in during wl events and copied to
      * dev_formats on dmabuf_feedback.tranche_done