[PATCH 0/3] drm: more pre-decrement fixes

[PATCH 0/3] drm: more pre-decrement fixes

[Rasmus Villemoes]

A few more cases where one should use post-decrement when unwinding,
this time found where the unwinding is done inside the setup loop
instead of after an error label.

Rasmus Villemoes (3):
  drm/amdgpu: use post-decrement in error handling
  drm/nouveau: use post-decrement in error handling
  drm/radeon: use post-decrement in error handling

 drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c | 2 +-
 drivers/gpu/drm/nouveau/nouveau_bo.c    | 2 +-
 drivers/gpu/drm/radeon/radeon_ttm.c     | 2 +-
 3 files changed, 3 insertions(+), 3 deletions(-)

-- 
2.1.4

[PATCH 1/3] drm/amdgpu: use post-decrement in error handling

[Rasmus Villemoes]

We need to use post-decrement to get the pci_map_page undone also for
i==0, and to avoid some very unpleasant behaviour if pci_map_page
failed already at i==0.

Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
index 8a1752ff3d8e..e53558c25b6b 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
@@ -712,7 +712,7 @@ static int amdgpu_ttm_tt_populate(struct ttm_tt *ttm)
 						       0, PAGE_SIZE,
 						       PCI_DMA_BIDIRECTIONAL);
 		if (pci_dma_mapping_error(adev->pdev, gtt->ttm.dma_address[i])) {
-			while (--i) {
+			while (i--) {
 				pci_unmap_page(adev->pdev, gtt->ttm.dma_address[i],
 					       PAGE_SIZE, PCI_DMA_BIDIRECTIONAL);
 				gtt->ttm.dma_address[i] = 0;
-- 
2.1.4

[PATCH 2/3] drm/nouveau: use post-decrement in error handling

[Rasmus Villemoes]

We need to use post-decrement to get the dma_map_page undone also for
i==0, and to avoid some very unpleasant behaviour if dma_map_page
failed already at i==0.

Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
---
 drivers/gpu/drm/nouveau/nouveau_bo.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/nouveau/nouveau_bo.c b/drivers/gpu/drm/nouveau/nouveau_bo.c
index 78f520d05de9..e3acc35e3805 100644
--- a/drivers/gpu/drm/nouveau/nouveau_bo.c
+++ b/drivers/gpu/drm/nouveau/nouveau_bo.c
@@ -1520,7 +1520,7 @@ nouveau_ttm_tt_populate(struct ttm_tt *ttm)
 				    DMA_BIDIRECTIONAL);
 
 		if (dma_mapping_error(pdev, addr)) {
-			while (--i) {
+			while (i--) {
 				dma_unmap_page(pdev, ttm_dma->dma_address[i],
 					       PAGE_SIZE, DMA_BIDIRECTIONAL);
 				ttm_dma->dma_address[i] = 0;
-- 
2.1.4

[PATCH 3/3] drm/radeon: use post-decrement in error handling

[Rasmus Villemoes]

We need to use post-decrement to get the pci_map_page undone also for
i==0, and to avoid some very unpleasant behaviour if pci_map_page
failed already at i==0.

Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
---
 drivers/gpu/drm/radeon/radeon_ttm.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/radeon/radeon_ttm.c b/drivers/gpu/drm/radeon/radeon_ttm.c
index e34307459e50..e06ac546a90f 100644
--- a/drivers/gpu/drm/radeon/radeon_ttm.c
+++ b/drivers/gpu/drm/radeon/radeon_ttm.c
@@ -758,7 +758,7 @@ static int radeon_ttm_tt_populate(struct ttm_tt *ttm)
 						       0, PAGE_SIZE,
 						       PCI_DMA_BIDIRECTIONAL);
 		if (pci_dma_mapping_error(rdev->pdev, gtt->ttm.dma_address[i])) {
-			while (--i) {
+			while (i--) {
 				pci_unmap_page(rdev->pdev, gtt->ttm.dma_address[i],
 					       PAGE_SIZE, PCI_DMA_BIDIRECTIONAL);
 				gtt->ttm.dma_address[i] = 0;
-- 
2.1.4

Re: [PATCH 0/3] drm: more pre-decrement fixes

[Christian König]

Am 15.02.2016 um 19:41 schrieb Rasmus Villemoes:
> A few more cases where one should use post-decrement when unwinding,
> this time found where the unwinding is done inside the setup loop
> instead of after an error label.

Patch 1 and 3 are Reviewed-by: Christian König <christian.koenig@amd.com>.

Nice catch,
Christian.

>
> Rasmus Villemoes (3):
>    drm/amdgpu: use post-decrement in error handling
>    drm/nouveau: use post-decrement in error handling
>    drm/radeon: use post-decrement in error handling
>
>   drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c | 2 +-
>   drivers/gpu/drm/nouveau/nouveau_bo.c    | 2 +-
>   drivers/gpu/drm/radeon/radeon_ttm.c     | 2 +-
>   3 files changed, 3 insertions(+), 3 deletions(-)
>

Re: [PATCH 0/3] drm: more pre-decrement fixes

[Alex Deucher]

On Tue, Feb 16, 2016 at 3:21 AM, Christian König
<deathsimple@vodafone.de> wrote:
> Am 15.02.2016 um 19:41 schrieb Rasmus Villemoes:
>>
>> A few more cases where one should use post-decrement when unwinding,
>> this time found where the unwinding is done inside the setup loop
>> instead of after an error label.
>
>
> Patch 1 and 3 are Reviewed-by: Christian König <christian.koenig@amd.com>.

Patches 1 and 3 applied.  thanks!

Alex

>
> Nice catch,
> Christian.
>
>>
>> Rasmus Villemoes (3):
>>    drm/amdgpu: use post-decrement in error handling
>>    drm/nouveau: use post-decrement in error handling
>>    drm/radeon: use post-decrement in error handling
>>
>>   drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c | 2 +-
>>   drivers/gpu/drm/nouveau/nouveau_bo.c    | 2 +-
>>   drivers/gpu/drm/radeon/radeon_ttm.c     | 2 +-
>>   3 files changed, 3 insertions(+), 3 deletions(-)
>>
>
> _______________________________________________
> dri-devel mailing list
> dri-devel@lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/dri-devel

Re: [PATCH 2/3] drm/nouveau: use post-decrement in error handling

[Ben Skeggs]

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On 02/16/2016 04:41 AM, Rasmus Villemoes wrote:
> We need to use post-decrement to get the dma_map_page undone also for
> i==0, and to avoid some very unpleasant behaviour if dma_map_page
> failed already at i==0.
> 
> Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Reviewed-by: Ben Skeggs <bskeggs@redhat.com>

> ---
>  drivers/gpu/drm/nouveau/nouveau_bo.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/nouveau/nouveau_bo.c b/drivers/gpu/drm/nouveau/nouveau_bo.c
> index 78f520d05de9..e3acc35e3805 100644
> --- a/drivers/gpu/drm/nouveau/nouveau_bo.c
> +++ b/drivers/gpu/drm/nouveau/nouveau_bo.c
> @@ -1520,7 +1520,7 @@ nouveau_ttm_tt_populate(struct ttm_tt *ttm)
>  				    DMA_BIDIRECTIONAL);
>  
>  		if (dma_mapping_error(pdev, addr)) {
> -			while (--i) {
> +			while (i--) {
>  				dma_unmap_page(pdev, ttm_dma->dma_address[i],
>  					       PAGE_SIZE, DMA_BIDIRECTIONAL);
>  				ttm_dma->dma_address[i] = 0;
> 


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