[Mesa-dev] [PATCH] egl_dri2: fix EXT_image_dma_buf_import fds

[Pekka Paalanen]

From: Pekka Paalanen <pekka.paalanen at collabora.co.uk>

The EGL_EXT_image_dma_buf_import specification was revised (according to
its revision history) on Dec 5th, 2013, for EGL to not take ownership of
the file descriptors.

Do not close the file descriptors passed in to eglCreateImageKHR with
EGL_LINUX_DMA_BUF_EXT target.

It is assumed, that the drivers, which ultimately process the file
descriptors, do not close or modify them in any way either. This avoids
the need to dup(), as it seems we would only need to just close the
dup'd file descriptors right after.

Signed-off-by: Pekka Paalanen <pekka.paalanen at collabora.co.uk>
---

Hi,

the corresponding Piglit fix has already been sent to the piglit mailing
list. Both this and that need to be applied to not regress Mesa' piglit run
by one test (ext_image_dma_buf_import-ownership_transfer).

This patch fixes my test case on heavily modified Weston.

Thanks,
pq
---
 src/egl/drivers/dri2/egl_dri2.c | 37 ++++++-------------------------------
 1 file changed, 6 insertions(+), 31 deletions(-)

diff --git a/src/egl/drivers/dri2/egl_dri2.c b/src/egl/drivers/dri2/egl_dri2.c
index 5602ec3..cd85fd3 100644
--- a/src/egl/drivers/dri2/egl_dri2.c
+++ b/src/egl/drivers/dri2/egl_dri2.c
@@ -1678,36 +1678,13 @@ dri2_check_dma_buf_format(const _EGLImageAttribs *attrs)
 /**
  * The spec says:
  *
- * "If eglCreateImageKHR is successful for a EGL_LINUX_DMA_BUF_EXT target,
- *  the EGL takes ownership of the file descriptor and is responsible for
- *  closing it, which it may do at any time while the EGLDisplay is
- *  initialized."
+ * "If eglCreateImageKHR is successful for a EGL_LINUX_DMA_BUF_EXT target, the
+ *  EGL will take a reference to the dma_buf(s) which it will release at any
+ *  time while the EGLDisplay is initialized. It is the responsibility of the
+ *  application to close the dma_buf file descriptors."
+ *
+ * Therefore we must never close or otherwise modify the file descriptors.
  */
-static void
-dri2_take_dma_buf_ownership(const int *fds, unsigned num_fds)
-{
-   int already_closed[num_fds];
-   unsigned num_closed = 0;
-   unsigned i, j;
-
-   for (i = 0; i < num_fds; ++i) {
-      /**
-       * The same file descriptor can be referenced multiple times in case more
-       * than one plane is found in the same buffer, just with a different
-       * offset.
-       */
-      for (j = 0; j < num_closed; ++j) {
-         if (already_closed[j] == fds[i])
-            break;
-      }
-
-      if (j == num_closed) {
-         close(fds[i]);
-         already_closed[num_closed++] = fds[i];
-      }
-   }
-}
-
 static _EGLImage *
 dri2_create_image_dma_buf(_EGLDisplay *disp, _EGLContext *ctx,
 			  EGLClientBuffer buffer, const EGLint *attr_list)
@@ -1770,8 +1747,6 @@ dri2_create_image_dma_buf(_EGLDisplay *disp, _EGLContext *ctx,
       return EGL_NO_IMAGE_KHR;
 
    res = dri2_create_image_from_dri(disp, dri_image);
-   if (res)
-      dri2_take_dma_buf_ownership(fds, num_fds);
 
    return res;
 }
-- 
1.8.5.5