[PATCH] drm: make drm_get_format_name atomic/irq safe again

[Rob Clark]

Fixes: 90844f00049e9f42573fd31d7c32e8fd31d3fd07

    drm: make drm_get_format_name thread-safe

    Signed-off-by: Eric Engestrom <eric at engestrom.ch>
    [danvet: Clarify that the returned pointer must be freed with
    kfree().]
    Signed-off-by: Daniel Vetter <daniel.vetter at ffwll.ch>

Note: I think we need to be a bit careful about follow-up audits of
callers of this..  now that you need to kfree the return value I think
it is fairly easy for new patches to introduce new callers which leak
the return value.  We probably should have left the function as-is and
introduce a new variant, or something like that.

Signed-off-by: Rob Clark <robdclark at gmail.com>
---
 drivers/gpu/drm/drm_fourcc.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/drm_fourcc.c b/drivers/gpu/drm/drm_fourcc.c
index cbb8b77..2be9ea8 100644
--- a/drivers/gpu/drm/drm_fourcc.c
+++ b/drivers/gpu/drm/drm_fourcc.c
@@ -87,7 +87,10 @@ EXPORT_SYMBOL(drm_mode_legacy_fb_format);
  */
 char *drm_get_format_name(uint32_t format)
 {
-	char *buf = kmalloc(32, GFP_KERNEL);
+	char *buf = kmalloc(32, GFP_ATOMIC);
+
+	if (!buf)
+		return NULL;
 
 	snprintf(buf, 32,
 		 "%c%c%c%c %s-endian (0x%08x)",
-- 
2.7.4