[src/trunk]: src/sys/external/bsd/drm2/linux drm: Write comment for dma_resv_...

[riastradh <riastradh%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/9fca0ab70750
branches:  trunk
changeset: 1028900:9fca0ab70750
user:      riastradh <riastradh%NetBSD.org@localhost>
date:      Sun Dec 19 12:26:13 2021 +0000

description:
drm: Write comment for dma_resv_get_fences_rcu semantics.

diffstat:

 sys/external/bsd/drm2/linux/linux_dma_resv.c |  12 ++++++++++--
 1 files changed, 10 insertions(+), 2 deletions(-)

diffs (33 lines):

diff -r 805f75658a7c -r 9fca0ab70750 sys/external/bsd/drm2/linux/linux_dma_resv.c
--- a/sys/external/bsd/drm2/linux/linux_dma_resv.c      Sun Dec 19 12:26:04 2021 +0000
+++ b/sys/external/bsd/drm2/linux/linux_dma_resv.c      Sun Dec 19 12:26:13 2021 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: linux_dma_resv.c,v 1.12 2021/12/19 12:26:04 riastradh Exp $    */
+/*     $NetBSD: linux_dma_resv.c,v 1.13 2021/12/19 12:26:13 riastradh Exp $    */
 
 /*-
  * Copyright (c) 2018 The NetBSD Foundation, Inc.
@@ -30,7 +30,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: linux_dma_resv.c,v 1.12 2021/12/19 12:26:04 riastradh Exp $");
+__KERNEL_RCSID(0, "$NetBSD: linux_dma_resv.c,v 1.13 2021/12/19 12:26:13 riastradh Exp $");
 
 #include <sys/param.h>
 #include <sys/poll.h>
@@ -741,6 +741,14 @@
 
 /*
  * dma_resv_get_fences_rcu(robj, fencep, nsharedp, sharedp)
+ *
+ *     Get a snapshot of the exclusive and shared fences of robj.  The
+ *     shared fences are returned as a pointer *sharedp to an array,
+ *     to be freed by the caller with kfree, of *nsharedp elements.
+ *
+ *     Returns zero on success, negative (Linux-style) error code on
+ *     failure.  On failure, *fencep, *nsharedp, and *sharedp are
+ *     untouched.
  */
 int
 dma_resv_get_fences_rcu(const struct dma_resv *robj,