* [PATCH 1/2] drm/tegra: Return an error code if fails
@ 2023-06-26 14:33 Sui Jingfeng
2023-06-26 14:33 ` [PATCH 2/2] drm/tegra: Remove surplus else after return Sui Jingfeng
` (2 more replies)
0 siblings, 3 replies; 7+ messages in thread
From: Sui Jingfeng @ 2023-06-26 14:33 UTC (permalink / raw)
To: Thierry Reding, Mikko Perttunen, David Airlie, Daniel Vetter,
Jonathan Hunter
Cc: linux-tegra, linux-kernel, dri-devel
Return -ENOMEM if tegra_bo_mmap() fails.
Signed-off-by: Sui Jingfeng <suijingfeng@loongson.cn>
---
drivers/gpu/drm/tegra/gem.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/drivers/gpu/drm/tegra/gem.c b/drivers/gpu/drm/tegra/gem.c
index dea38892d6e6..0ce22935fbd3 100644
--- a/drivers/gpu/drm/tegra/gem.c
+++ b/drivers/gpu/drm/tegra/gem.c
@@ -710,6 +710,8 @@ static int tegra_gem_prime_vmap(struct dma_buf *buf, struct iosys_map *map)
void *vaddr;
vaddr = tegra_bo_mmap(&bo->base);
+ if (!vaddr)
+ return -ENOMEM;
if (IS_ERR(vaddr))
return PTR_ERR(vaddr);
--
2.25.1
^ permalink raw reply related [flat|nested] 7+ messages in thread
* [PATCH 2/2] drm/tegra: Remove surplus else after return
2023-06-26 14:33 [PATCH 1/2] drm/tegra: Return an error code if fails Sui Jingfeng
@ 2023-06-26 14:33 ` Sui Jingfeng
2023-10-10 15:28 ` Thierry Reding
2023-07-27 10:02 ` [1/2] drm/tegra: Return an error code if fails suijingfeng
2023-10-10 13:22 ` [PATCH 1/2] " Thierry Reding
2 siblings, 1 reply; 7+ messages in thread
From: Sui Jingfeng @ 2023-06-26 14:33 UTC (permalink / raw)
To: Thierry Reding, Mikko Perttunen, David Airlie, Daniel Vetter,
Jonathan Hunter
Cc: linux-tegra, linux-kernel, dri-devel
else is not generally useful after return
Signed-off-by: Sui Jingfeng <suijingfeng@loongson.cn>
---
drivers/gpu/drm/tegra/gem.c | 19 ++++++++++---------
1 file changed, 10 insertions(+), 9 deletions(-)
diff --git a/drivers/gpu/drm/tegra/gem.c b/drivers/gpu/drm/tegra/gem.c
index 0ce22935fbd3..26d64f4545bd 100644
--- a/drivers/gpu/drm/tegra/gem.c
+++ b/drivers/gpu/drm/tegra/gem.c
@@ -180,15 +180,15 @@ static void *tegra_bo_mmap(struct host1x_bo *bo)
struct iosys_map map;
int ret;
- if (obj->vaddr) {
+ if (obj->vaddr)
return obj->vaddr;
- } else if (obj->gem.import_attach) {
+
+ if (obj->gem.import_attach) {
ret = dma_buf_vmap_unlocked(obj->gem.import_attach->dmabuf, &map);
return ret ? NULL : map.vaddr;
- } else {
- return vmap(obj->pages, obj->num_pages, VM_MAP,
- pgprot_writecombine(PAGE_KERNEL));
}
+
+ return vmap(obj->pages, obj->num_pages, VM_MAP, pgprot_writecombine(PAGE_KERNEL));
}
static void tegra_bo_munmap(struct host1x_bo *bo, void *addr)
@@ -198,10 +198,11 @@ static void tegra_bo_munmap(struct host1x_bo *bo, void *addr)
if (obj->vaddr)
return;
- else if (obj->gem.import_attach)
- dma_buf_vunmap_unlocked(obj->gem.import_attach->dmabuf, &map);
- else
- vunmap(addr);
+
+ if (obj->gem.import_attach)
+ return dma_buf_vunmap_unlocked(obj->gem.import_attach->dmabuf, &map);
+
+ vunmap(addr);
}
static struct host1x_bo *tegra_bo_get(struct host1x_bo *bo)
--
2.25.1
^ permalink raw reply related [flat|nested] 7+ messages in thread
* Re: [1/2] drm/tegra: Return an error code if fails
2023-06-26 14:33 [PATCH 1/2] drm/tegra: Return an error code if fails Sui Jingfeng
2023-06-26 14:33 ` [PATCH 2/2] drm/tegra: Remove surplus else after return Sui Jingfeng
@ 2023-07-27 10:02 ` suijingfeng
2023-10-10 13:22 ` [PATCH 1/2] " Thierry Reding
2 siblings, 0 replies; 7+ messages in thread
From: suijingfeng @ 2023-07-27 10:02 UTC (permalink / raw)
To: Thierry Reding, Mikko Perttunen, David Airlie, Daniel Vetter,
Jonathan Hunter
Cc: linux-tegra, linux-kernel, dri-devel
Hi,
Gentle ping for this series.
On 2023/6/26 22:33, Sui Jingfeng wrote:
> Return -ENOMEM if tegra_bo_mmap() fails.
>
> Signed-off-by: Sui Jingfeng <suijingfeng@loongson.cn>
> ---
> drivers/gpu/drm/tegra/gem.c | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/drivers/gpu/drm/tegra/gem.c b/drivers/gpu/drm/tegra/gem.c
> index dea38892d6e6..0ce22935fbd3 100644
> --- a/drivers/gpu/drm/tegra/gem.c
> +++ b/drivers/gpu/drm/tegra/gem.c
> @@ -710,6 +710,8 @@ static int tegra_gem_prime_vmap(struct dma_buf *buf, struct iosys_map *map)
> void *vaddr;
>
> vaddr = tegra_bo_mmap(&bo->base);
> + if (!vaddr)
> + return -ENOMEM;
> if (IS_ERR(vaddr))
> return PTR_ERR(vaddr);
>
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH 1/2] drm/tegra: Return an error code if fails
2023-06-26 14:33 [PATCH 1/2] drm/tegra: Return an error code if fails Sui Jingfeng
2023-06-26 14:33 ` [PATCH 2/2] drm/tegra: Remove surplus else after return Sui Jingfeng
2023-07-27 10:02 ` [1/2] drm/tegra: Return an error code if fails suijingfeng
@ 2023-10-10 13:22 ` Thierry Reding
2023-10-10 15:31 ` Thierry Reding
2 siblings, 1 reply; 7+ messages in thread
From: Thierry Reding @ 2023-10-10 13:22 UTC (permalink / raw)
To: Sui Jingfeng
Cc: linux-kernel, dri-devel, Jonathan Hunter, linux-tegra, Mikko Perttunen
[-- Attachment #1: Type: text/plain, Size: 1592 bytes --]
On Mon, Jun 26, 2023 at 10:33:30PM +0800, Sui Jingfeng wrote:
> Return -ENOMEM if tegra_bo_mmap() fails.
>
> Signed-off-by: Sui Jingfeng <suijingfeng@loongson.cn>
> ---
> drivers/gpu/drm/tegra/gem.c | 2 ++
> 1 file changed, 2 insertions(+)
Sorry, this fell through the cracks. I think it'd be better if
tegra_bo_mmap() were to be improved to always return either an ERR_PTR()
encoded error code or a valid pointer. Throwing NULL into the mix isn't
useful because it typically means something like -ENOMEM anyway. Error
codes are more explicit, so since we're already using them for some
cases, might as well return them for all.
Actually, looks like tegra_bo_mmap() never actually returns an ERR_PTR()
encoded error code. It's either obj->vaddr, the return value of vmap()
(which is either NULL or the address of the mapping), or the address
obtained from dma_buf_vmap_unlocked() (i.e. map.vaddr) or NULL on
failure. So I think it would equally make sense to keep your patch and
to remove the IS_ERR() check below it.
I would slightly prefer the first option, but either is fine.
Thierry
> diff --git a/drivers/gpu/drm/tegra/gem.c b/drivers/gpu/drm/tegra/gem.c
> index dea38892d6e6..0ce22935fbd3 100644
> --- a/drivers/gpu/drm/tegra/gem.c
> +++ b/drivers/gpu/drm/tegra/gem.c
> @@ -710,6 +710,8 @@ static int tegra_gem_prime_vmap(struct dma_buf *buf, struct iosys_map *map)
> void *vaddr;
>
> vaddr = tegra_bo_mmap(&bo->base);
> + if (!vaddr)
> + return -ENOMEM;
> if (IS_ERR(vaddr))
> return PTR_ERR(vaddr);
>
> --
> 2.25.1
>
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^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH 2/2] drm/tegra: Remove surplus else after return
2023-06-26 14:33 ` [PATCH 2/2] drm/tegra: Remove surplus else after return Sui Jingfeng
@ 2023-10-10 15:28 ` Thierry Reding
0 siblings, 0 replies; 7+ messages in thread
From: Thierry Reding @ 2023-10-10 15:28 UTC (permalink / raw)
To: Sui Jingfeng
Cc: linux-kernel, dri-devel, Jonathan Hunter, linux-tegra, Mikko Perttunen
[-- Attachment #1: Type: text/plain, Size: 317 bytes --]
On Mon, Jun 26, 2023 at 10:33:31PM +0800, Sui Jingfeng wrote:
> else is not generally useful after return
>
> Signed-off-by: Sui Jingfeng <suijingfeng@loongson.cn>
> ---
> drivers/gpu/drm/tegra/gem.c | 19 ++++++++++---------
> 1 file changed, 10 insertions(+), 9 deletions(-)
Applied, thanks.
Thierry
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^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH 1/2] drm/tegra: Return an error code if fails
2023-10-10 13:22 ` [PATCH 1/2] " Thierry Reding
@ 2023-10-10 15:31 ` Thierry Reding
2023-10-11 3:06 ` Sui Jingfeng
0 siblings, 1 reply; 7+ messages in thread
From: Thierry Reding @ 2023-10-10 15:31 UTC (permalink / raw)
To: Sui Jingfeng
Cc: linux-kernel, dri-devel, Jonathan Hunter, linux-tegra, Mikko Perttunen
[-- Attachment #1.1: Type: text/plain, Size: 1264 bytes --]
On Tue, Oct 10, 2023 at 03:22:56PM +0200, Thierry Reding wrote:
> On Mon, Jun 26, 2023 at 10:33:30PM +0800, Sui Jingfeng wrote:
> > Return -ENOMEM if tegra_bo_mmap() fails.
> >
> > Signed-off-by: Sui Jingfeng <suijingfeng@loongson.cn>
> > ---
> > drivers/gpu/drm/tegra/gem.c | 2 ++
> > 1 file changed, 2 insertions(+)
>
> Sorry, this fell through the cracks. I think it'd be better if
> tegra_bo_mmap() were to be improved to always return either an ERR_PTR()
> encoded error code or a valid pointer. Throwing NULL into the mix isn't
> useful because it typically means something like -ENOMEM anyway. Error
> codes are more explicit, so since we're already using them for some
> cases, might as well return them for all.
>
> Actually, looks like tegra_bo_mmap() never actually returns an ERR_PTR()
> encoded error code. It's either obj->vaddr, the return value of vmap()
> (which is either NULL or the address of the mapping), or the address
> obtained from dma_buf_vmap_unlocked() (i.e. map.vaddr) or NULL on
> failure. So I think it would equally make sense to keep your patch and
> to remove the IS_ERR() check below it.
>
> I would slightly prefer the first option, but either is fine.
How about the attached patch?
Thierry
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From b34a09efcf7b1d2c25d3baf8c6d91c5ca09b4e0f Mon Sep 17 00:00:00 2001
From: Thierry Reding <treding@nvidia.com>
Date: Tue, 10 Oct 2023 17:26:14 +0200
Subject: [PATCH] drm/tegra: gem: Do not return NULL in tegra_bo_mmap()
It's confusing for a function to return NULL and ERR_PTR()-encoded error
codes on failure. Make sure we only ever return the latter since that's
what callers already expect.
Signed-off-by: Thierry Reding <treding@nvidia.com>
---
drivers/gpu/drm/tegra/gem.c | 13 +++++++++++--
1 file changed, 11 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/tegra/gem.c b/drivers/gpu/drm/tegra/gem.c
index 11296de59c5a..679460e05c05 100644
--- a/drivers/gpu/drm/tegra/gem.c
+++ b/drivers/gpu/drm/tegra/gem.c
@@ -178,6 +178,7 @@ static void *tegra_bo_mmap(struct host1x_bo *bo)
{
struct tegra_bo *obj = host1x_to_tegra_bo(bo);
struct iosys_map map;
+ void *vaddr;
int ret;
if (obj->vaddr)
@@ -185,10 +186,18 @@ static void *tegra_bo_mmap(struct host1x_bo *bo)
if (obj->gem.import_attach) {
ret = dma_buf_vmap_unlocked(obj->gem.import_attach->dmabuf, &map);
- return ret ? NULL : map.vaddr;
+ if (ret < 0)
+ return ERR_PTR(ret);
+
+ return map.vaddr;
}
- return vmap(obj->pages, obj->num_pages, VM_MAP, pgprot_writecombine(PAGE_KERNEL));
+ vaddr = vmap(obj->pages, obj->num_pages, VM_MAP,
+ pgprot_writecombine(PAGE_KERNEL));
+ if (!vaddr)
+ return -ENOMEM;
+
+ return vaddr;
}
static void tegra_bo_munmap(struct host1x_bo *bo, void *addr)
--
2.42.0
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^ permalink raw reply related [flat|nested] 7+ messages in thread
* Re: [PATCH 1/2] drm/tegra: Return an error code if fails
2023-10-10 15:31 ` Thierry Reding
@ 2023-10-11 3:06 ` Sui Jingfeng
0 siblings, 0 replies; 7+ messages in thread
From: Sui Jingfeng @ 2023-10-11 3:06 UTC (permalink / raw)
To: Thierry Reding
Cc: linux-kernel, dri-devel, Jonathan Hunter, linux-tegra, Mikko Perttunen
Hi,
On 2023/10/10 23:31, Thierry Reding wrote:
> On Tue, Oct 10, 2023 at 03:22:56PM +0200, Thierry Reding wrote:
>> On Mon, Jun 26, 2023 at 10:33:30PM +0800, Sui Jingfeng wrote:
>>> Return -ENOMEM if tegra_bo_mmap() fails.
>>>
>>> Signed-off-by: Sui Jingfeng <suijingfeng@loongson.cn>
>>> ---
>>> drivers/gpu/drm/tegra/gem.c | 2 ++
>>> 1 file changed, 2 insertions(+)
>> Sorry, this fell through the cracks. I think it'd be better if
>> tegra_bo_mmap() were to be improved to always return either an ERR_PTR()
>> encoded error code or a valid pointer. Throwing NULL into the mix isn't
>> useful because it typically means something like -ENOMEM anyway. Error
>> codes are more explicit, so since we're already using them for some
>> cases, might as well return them for all.
>>
>> Actually, looks like tegra_bo_mmap() never actually returns an ERR_PTR()
>> encoded error code. It's either obj->vaddr, the return value of vmap()
>> (which is either NULL or the address of the mapping), or the address
>> obtained from dma_buf_vmap_unlocked() (i.e. map.vaddr) or NULL on
>> failure. So I think it would equally make sense to keep your patch and
>> to remove the IS_ERR() check below it.
>>
>> I would slightly prefer the first option, but either is fine.
> How about the attached patch?
I also prefer the prefer the first option.
The attached patch is more better, because it solve the problem at lower level.
Reviewed-by: Sui Jingfeng <suijingfeng@loongson.cn>
> Thierry
^ permalink raw reply [flat|nested] 7+ messages in thread
end of thread, other threads:[~2023-10-11 3:06 UTC | newest]
Thread overview: 7+ messages (download: mbox.gz / follow: Atom feed)
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2023-06-26 14:33 [PATCH 1/2] drm/tegra: Return an error code if fails Sui Jingfeng
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2023-10-10 15:28 ` Thierry Reding
2023-07-27 10:02 ` [1/2] drm/tegra: Return an error code if fails suijingfeng
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