[PATCH -next] drm/i915: fix error return code in init_pipe_control()

[PATCH -next] drm/i915: fix error return code in init_pipe_control()

[Wei Yongjun]

From: Wei Yongjun <yongjun_wei@trendmicro.com.cn>

Fix to return -ENOMEM in the kmap() error handling case
instead of 0, as done elsewhere in this function.

Signed-off-by: Wei Yongjun <yongjun_wei@trendmicro.com.cn>
---
 drivers/gpu/drm/i915/intel_ringbuffer.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.c b/drivers/gpu/drm/i915/intel_ringbuffer.c
index 5698fae..9b97cf6 100644
--- a/drivers/gpu/drm/i915/intel_ringbuffer.c
+++ b/drivers/gpu/drm/i915/intel_ringbuffer.c
@@ -464,9 +464,11 @@ init_pipe_control(struct intel_ring_buffer *ring)
 		goto err_unref;
 
 	pc->gtt_offset = obj->gtt_offset;
-	pc->cpu_page =  kmap(sg_page(obj->pages->sgl));
-	if (pc->cpu_page == NULL)
+	pc->cpu_page = kmap(sg_page(obj->pages->sgl));
+	if (pc->cpu_page == NULL) {
+		ret = -ENOMEM;
 		goto err_unpin;
+	}
 
 	DRM_DEBUG_DRIVER("%s pipe control offset: 0x%08x\n",
 			 ring->name, pc->gtt_offset);

Re: [PATCH -next] drm/i915: fix error return code in init_pipe_control()

[Daniel Vetter]

On Tue, May 28, 2013 at 05:51:44PM +0800, Wei Yongjun wrote:
> From: Wei Yongjun <yongjun_wei@trendmicro.com.cn>
> 
> Fix to return -ENOMEM in the kmap() error handling case
> instead of 0, as done elsewhere in this function.
> 
> Signed-off-by: Wei Yongjun <yongjun_wei@trendmicro.com.cn>
Queued for -next, thanks for the patch.
-Daniel
-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch

Re: [PATCH -next] drm/i915: fix error return code in init_pipe_control()

[Chris Wilson]

On Tue, May 28, 2013 at 05:51:44PM +0800, Wei Yongjun wrote:
> From: Wei Yongjun <yongjun_wei@trendmicro.com.cn>
> 
> Fix to return -ENOMEM in the kmap() error handling case
> instead of 0, as done elsewhere in this function.

kmap() can fail?

It is either translated to page_address() or kmap_high() (on x86),
neither of which may return NULL. However, only kmap_atomic() is
documented as being guaranteed to return a valid value. If we could
have a similar definitive statement for kmap(), we can then cleanup
quite a bit of redundant error handling.
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre