Mesa (master): util: add some defensive coding in u_upload_alloc()

[Brian Paul]

Module: Mesa
Branch: master
Commit: 68a097596efdf314ec60487a1761cac789ae2367
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=68a097596efdf314ec60487a1761cac789ae2367

Author: Brian Paul <brianp at vmware.com>
Date:   Thu Jan 24 14:44:09 2013 -0700

util: add some defensive coding in u_upload_alloc()

Some callers of this function were checking the 'ptr' result to see if
the function failed.  But the correct way is to check the regular
return value for PIPE_ERROR_x.  Now we initialize all the returned
values at the top of the function in case we do hit an error (like OOM).

Callers are more likely to detect OOM conditions now.  But there
are some callers which don't do any error checking...

Note: This is a candidate for the 9.0 branch.

Reviewed-by: Jose Fonseca <jfonseca at vmware.com>

---

 src/gallium/auxiliary/util/u_upload_mgr.c |    8 +++++++-
 1 files changed, 7 insertions(+), 1 deletions(-)

diff --git a/src/gallium/auxiliary/util/u_upload_mgr.c b/src/gallium/auxiliary/util/u_upload_mgr.c
index ee1c688..47d39af 100644
--- a/src/gallium/auxiliary/util/u_upload_mgr.c
+++ b/src/gallium/auxiliary/util/u_upload_mgr.c
@@ -163,6 +163,13 @@ enum pipe_error u_upload_alloc( struct u_upload_mgr *upload,
    unsigned alloc_offset = align(min_out_offset, upload->alignment);
    unsigned offset;
 
+   /* Init these return values here in case we fail below to make
+    * sure the caller doesn't get garbage values.
+    */
+   *out_offset = ~0;
+   *outbuf = NULL;
+   *ptr = NULL;
+
    /* Make sure we have enough space in the upload buffer
     * for the sub-allocation. */
    if (MAX2(upload->offset, alloc_offset) + alloc_size > upload->size) {
@@ -183,7 +190,6 @@ enum pipe_error u_upload_alloc( struct u_upload_mgr *upload,
 					  &upload->transfer);
       if (!upload->map) {
          pipe_resource_reference(outbuf, NULL);
-         *ptr = NULL;
          upload->transfer = NULL;
          return PIPE_ERROR_OUT_OF_MEMORY;
       }