pipe-loader: move dup(fd) within pipe_loader_drm_probe_fd

Currently pipe_loader_drm_probe_fd takes ownership of the fd given.
To match that, pipe_loader_release closes it.

Yet we have many instances which do not want the change of ownership,
and thus duplicate the fd before passing it to the pipe-loader.

Move the dup() within pipe-loader, explicitly document that and document
all the cases through the codebase.

A trivial git grep -2 pipe_loader_release makes things as obvious as it
gets ;-)

Cc: Leo Liu <[email protected]>
Cc: Thomas Hellstrom <[email protected]>
Cc: Axel Davy <[email protected]>
Cc: Patrick Rudolph <[email protected]>
Signed-off-by: Emil Velikov <[email protected]>
Reviewed-by: Thomas Hellstrom <[email protected]>
Reviewed-by: Axel Davy <[email protected]> (for nine)

4 files changed, 30 insertions, 17 deletions

diff --git a/src/gallium/auxiliary/pipe-loader/pipe_loader.h b/src/gallium/auxiliary/pipe-loader/pipe_loader.h
index b50114310b4..be7e25afb02 100644
--- a/src/gallium/auxiliary/pipe-loader/pipe_loader.h
+++ b/src/gallium/auxiliary/pipe-loader/pipe_loader.h
@@ -146,6 +146,9 @@ pipe_loader_sw_probe_dri(struct pipe_loader_device **devs,
  *
  * This function is platform-specific.
  *
+ * Function does not take ownership of the fd, but duplicates it locally.
+ * The local fd is closed during pipe_loader_release.
+ *
  * \sa pipe_loader_probe
  */
 bool
diff --git a/src/gallium/auxiliary/pipe-loader/pipe_loader_drm.c b/src/gallium/auxiliary/pipe-loader/pipe_loader_drm.c
index 6d2ed6e76f8..5a88a2ac2f0 100644
--- a/src/gallium/auxiliary/pipe-loader/pipe_loader_drm.c
+++ b/src/gallium/auxiliary/pipe-loader/pipe_loader_drm.c
@@ -35,6 +35,7 @@
 #include <string.h>
 #include <xf86drm.h>
 #include <unistd.h>
+#include <fcntl.h>
 
 #include "loader.h"
 #include "target-helpers/drm_helper_public.h"
@@ -168,8 +169,8 @@ get_driver_descriptor(const char *driver_name, struct util_dl_library **plib)
    return NULL;
 }
 
-bool
-pipe_loader_drm_probe_fd(struct pipe_loader_device **dev, int fd)
+static bool
+pipe_loader_drm_probe_fd_nodup(struct pipe_loader_device **dev, int fd)
 {
    struct pipe_loader_drm_device *ddev = CALLOC_STRUCT(pipe_loader_drm_device);
    int vendor_id, chip_id;
@@ -212,6 +213,22 @@ pipe_loader_drm_probe_fd(struct pipe_loader_device **dev, int fd)
    return false;
 }
 
+bool
+pipe_loader_drm_probe_fd(struct pipe_loader_device **dev, int fd)
+{
+   bool ret;
+   int new_fd;
+
+   if (fd < 0 || (new_fd = fcntl(fd, F_DUPFD_CLOEXEC, 3)) < 0)
+     return false;
+
+   ret = pipe_loader_drm_probe_fd_nodup(dev, new_fd);
+   if (!ret)
+      close(new_fd);
+
+   return ret;
+}
+
 static int
 open_drm_render_node_minor(int minor)
 {
@@ -234,7 +251,7 @@ pipe_loader_drm_probe(struct pipe_loader_device **devs, int ndev)
       if (fd < 0)
          continue;
 
-      if (!pipe_loader_drm_probe_fd(&dev, fd)) {
+      if (!pipe_loader_drm_probe_fd_nodup(&dev, fd)) {
          close(fd);
          continue;
       }
diff --git a/src/gallium/auxiliary/vl/vl_winsys_dri.c b/src/gallium/auxiliary/vl/vl_winsys_dri.c
index cb779010a9c..137885d9475 100644
--- a/src/gallium/auxiliary/vl/vl_winsys_dri.c
+++ b/src/gallium/auxiliary/vl/vl_winsys_dri.c
@@ -29,7 +29,6 @@
 
 #include <sys/types.h>
 #include <sys/stat.h>
-#include <fcntl.h>
 
 #include <X11/Xlib-xcb.h>
 #include <X11/extensions/dri2tokens.h>
@@ -471,6 +470,8 @@ vl_dri2_screen_create(Display *display, int screen)
    vl_compositor_reset_dirty_area(&scrn->dirty_areas[0]);
    vl_compositor_reset_dirty_area(&scrn->dirty_areas[1]);
 
+   /* The pipe loader duplicates the fd */
+   close(fd);
    free(authenticate);
    free(connect);
    free(dri2_query);
@@ -479,15 +480,12 @@ vl_dri2_screen_create(Display *display, int screen)
    return &scrn->base;
 
 release_pipe:
-   if (scrn->base.dev) {
+   if (scrn->base.dev)
       pipe_loader_release(&scrn->base.dev, 1);
-      fd = -1;
-   }
 free_authenticate:
    free(authenticate);
 close_fd:
-   if (fd != -1)
-      close(fd);
+   close(fd);
 free_connect:
    free(connect);
 free_query:
@@ -515,5 +513,6 @@ vl_dri2_screen_destroy(struct vl_screen *vscreen)
    vl_dri2_destroy_drawable(scrn);
    scrn->base.pscreen->destroy(scrn->base.pscreen);
    pipe_loader_release(&scrn->base.dev, 1);
+   /* There is no user provided fd */
    FREE(scrn);
 }
diff --git a/src/gallium/auxiliary/vl/vl_winsys_drm.c b/src/gallium/auxiliary/vl/vl_winsys_drm.c
index df8809c501c..94eb6d74ee7 100644
--- a/src/gallium/auxiliary/vl/vl_winsys_drm.c
+++ b/src/gallium/auxiliary/vl/vl_winsys_drm.c
@@ -26,7 +26,6 @@
  **************************************************************************/
 
 #include <assert.h>
-#include <fcntl.h>
 
 #include "pipe/p_screen.h"
 #include "pipe-loader/pipe_loader.h"
@@ -48,10 +47,7 @@ vl_drm_screen_create(int fd)
    if (!vscreen)
       return NULL;
 
-   if (fd < 0 || (new_fd = fcntl(fd, F_DUPFD_CLOEXEC, 3)) < 0)
-      goto free_screen;
-
-   if (pipe_loader_drm_probe_fd(&vscreen->dev, new_fd))
+   if (pipe_loader_drm_probe_fd(&vscreen->dev, fd))
       vscreen->pscreen = pipe_loader_create_screen(vscreen->dev);
 
    if (!vscreen->pscreen)
@@ -68,10 +64,7 @@ vl_drm_screen_create(int fd)
 release_pipe:
    if (vscreen->dev)
       pipe_loader_release(&vscreen->dev, 1);
-   else
-      close(new_fd);
 
-free_screen:
    FREE(vscreen);
    return NULL;
 }
@@ -83,5 +76,6 @@ vl_drm_screen_destroy(struct vl_screen *vscreen)
 
    vscreen->pscreen->destroy(vscreen->pscreen);
    pipe_loader_release(&vscreen->dev, 1);
+   /* CHECK: The VAAPI loader/user preserves ownership of the original fd */
    FREE(vscreen);
 }