* [PATCH] drm/nouveau: gk20a: Turn instmem lock into mutex
@ 2017-01-30 20:03 Thierry Reding
2017-02-23 16:20 ` Thierry Reding
0 siblings, 1 reply; 3+ messages in thread
From: Thierry Reding @ 2017-01-30 20:03 UTC (permalink / raw)
To: Ben Skeggs; +Cc: nouveau, dri-devel
From: Thierry Reding <treding@nvidia.com>
The gk20a implementation of instance memory uses vmap()/vunmap() to map
memory regions into the kernel's virtual address space. These functions
may sleep, so protecting them by a spin lock is not safe. This triggers
a warning if the DEBUG_ATOMIC_SLEEP Kconfig option is enabled. Fix this
by using a mutex instead.
Signed-off-by: Thierry Reding <treding@nvidia.com>
---
drivers/gpu/drm/nouveau/nvkm/subdev/instmem/gk20a.c | 19 ++++++++-----------
1 file changed, 8 insertions(+), 11 deletions(-)
diff --git a/drivers/gpu/drm/nouveau/nvkm/subdev/instmem/gk20a.c b/drivers/gpu/drm/nouveau/nvkm/subdev/instmem/gk20a.c
index a6a7fa0d7679..7f5244d57d2f 100644
--- a/drivers/gpu/drm/nouveau/nvkm/subdev/instmem/gk20a.c
+++ b/drivers/gpu/drm/nouveau/nvkm/subdev/instmem/gk20a.c
@@ -94,7 +94,7 @@ struct gk20a_instmem {
struct nvkm_instmem base;
/* protects vaddr_* and gk20a_instobj::vaddr* */
- spinlock_t lock;
+ struct mutex lock;
/* CPU mappings LRU */
unsigned int vaddr_use;
@@ -184,11 +184,10 @@ gk20a_instobj_acquire_iommu(struct nvkm_memory *memory)
struct gk20a_instmem *imem = node->base.imem;
struct nvkm_ltc *ltc = imem->base.subdev.device->ltc;
const u64 size = nvkm_memory_size(memory);
- unsigned long flags;
nvkm_ltc_flush(ltc);
- spin_lock_irqsave(&imem->lock, flags);
+ mutex_lock(&imem->lock);
if (node->base.vaddr) {
if (!node->use_cpt) {
@@ -216,7 +215,7 @@ gk20a_instobj_acquire_iommu(struct nvkm_memory *memory)
out:
node->use_cpt++;
- spin_unlock_irqrestore(&imem->lock, flags);
+ mutex_unlock(&imem->lock);
return node->base.vaddr;
}
@@ -239,9 +238,8 @@ gk20a_instobj_release_iommu(struct nvkm_memory *memory)
struct gk20a_instobj_iommu *node = gk20a_instobj_iommu(memory);
struct gk20a_instmem *imem = node->base.imem;
struct nvkm_ltc *ltc = imem->base.subdev.device->ltc;
- unsigned long flags;
- spin_lock_irqsave(&imem->lock, flags);
+ mutex_lock(&imem->lock);
/* we should at least have one user to release... */
if (WARN_ON(node->use_cpt == 0))
@@ -252,7 +250,7 @@ gk20a_instobj_release_iommu(struct nvkm_memory *memory)
list_add_tail(&node->vaddr_node, &imem->vaddr_lru);
out:
- spin_unlock_irqrestore(&imem->lock, flags);
+ mutex_unlock(&imem->lock);
wmb();
nvkm_ltc_invalidate(ltc);
@@ -306,19 +304,18 @@ gk20a_instobj_dtor_iommu(struct nvkm_memory *memory)
struct gk20a_instmem *imem = node->base.imem;
struct device *dev = imem->base.subdev.device->dev;
struct nvkm_mm_node *r;
- unsigned long flags;
int i;
if (unlikely(list_empty(&node->base.mem.regions)))
goto out;
- spin_lock_irqsave(&imem->lock, flags);
+ mutex_lock(&imem->lock);
/* vaddr has already been recycled */
if (node->base.vaddr)
gk20a_instobj_iommu_recycle_vaddr(node);
- spin_unlock_irqrestore(&imem->lock, flags);
+ mutex_unlock(&imem->lock);
r = list_first_entry(&node->base.mem.regions, struct nvkm_mm_node,
rl_entry);
@@ -580,7 +577,7 @@ gk20a_instmem_new(struct nvkm_device *device, int index,
if (!(imem = kzalloc(sizeof(*imem), GFP_KERNEL)))
return -ENOMEM;
nvkm_instmem_ctor(&gk20a_instmem, device, index, &imem->base);
- spin_lock_init(&imem->lock);
+ mutex_init(&imem->lock);
*pimem = &imem->base;
/* do not allow more than 1MB of CPU-mapped instmem */
--
2.11.0
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^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH] drm/nouveau: gk20a: Turn instmem lock into mutex
2017-01-30 20:03 [PATCH] drm/nouveau: gk20a: Turn instmem lock into mutex Thierry Reding
@ 2017-02-23 16:20 ` Thierry Reding
2017-02-24 7:25 ` Alexandre Courbot
0 siblings, 1 reply; 3+ messages in thread
From: Thierry Reding @ 2017-02-23 16:20 UTC (permalink / raw)
To: Ben Skeggs; +Cc: nouveau, dri-devel
[-- Attachment #1.1: Type: text/plain, Size: 3770 bytes --]
On Mon, Jan 30, 2017 at 09:03:07PM +0100, Thierry Reding wrote:
> From: Thierry Reding <treding@nvidia.com>
>
> The gk20a implementation of instance memory uses vmap()/vunmap() to map
> memory regions into the kernel's virtual address space. These functions
> may sleep, so protecting them by a spin lock is not safe. This triggers
> a warning if the DEBUG_ATOMIC_SLEEP Kconfig option is enabled. Fix this
> by using a mutex instead.
>
> Signed-off-by: Thierry Reding <treding@nvidia.com>
> ---
> drivers/gpu/drm/nouveau/nvkm/subdev/instmem/gk20a.c | 19 ++++++++-----------
> 1 file changed, 8 insertions(+), 11 deletions(-)
Alex, could you take a look at this?
Thanks,
Thierry
> diff --git a/drivers/gpu/drm/nouveau/nvkm/subdev/instmem/gk20a.c b/drivers/gpu/drm/nouveau/nvkm/subdev/instmem/gk20a.c
> index a6a7fa0d7679..7f5244d57d2f 100644
> --- a/drivers/gpu/drm/nouveau/nvkm/subdev/instmem/gk20a.c
> +++ b/drivers/gpu/drm/nouveau/nvkm/subdev/instmem/gk20a.c
> @@ -94,7 +94,7 @@ struct gk20a_instmem {
> struct nvkm_instmem base;
>
> /* protects vaddr_* and gk20a_instobj::vaddr* */
> - spinlock_t lock;
> + struct mutex lock;
>
> /* CPU mappings LRU */
> unsigned int vaddr_use;
> @@ -184,11 +184,10 @@ gk20a_instobj_acquire_iommu(struct nvkm_memory *memory)
> struct gk20a_instmem *imem = node->base.imem;
> struct nvkm_ltc *ltc = imem->base.subdev.device->ltc;
> const u64 size = nvkm_memory_size(memory);
> - unsigned long flags;
>
> nvkm_ltc_flush(ltc);
>
> - spin_lock_irqsave(&imem->lock, flags);
> + mutex_lock(&imem->lock);
>
> if (node->base.vaddr) {
> if (!node->use_cpt) {
> @@ -216,7 +215,7 @@ gk20a_instobj_acquire_iommu(struct nvkm_memory *memory)
>
> out:
> node->use_cpt++;
> - spin_unlock_irqrestore(&imem->lock, flags);
> + mutex_unlock(&imem->lock);
>
> return node->base.vaddr;
> }
> @@ -239,9 +238,8 @@ gk20a_instobj_release_iommu(struct nvkm_memory *memory)
> struct gk20a_instobj_iommu *node = gk20a_instobj_iommu(memory);
> struct gk20a_instmem *imem = node->base.imem;
> struct nvkm_ltc *ltc = imem->base.subdev.device->ltc;
> - unsigned long flags;
>
> - spin_lock_irqsave(&imem->lock, flags);
> + mutex_lock(&imem->lock);
>
> /* we should at least have one user to release... */
> if (WARN_ON(node->use_cpt == 0))
> @@ -252,7 +250,7 @@ gk20a_instobj_release_iommu(struct nvkm_memory *memory)
> list_add_tail(&node->vaddr_node, &imem->vaddr_lru);
>
> out:
> - spin_unlock_irqrestore(&imem->lock, flags);
> + mutex_unlock(&imem->lock);
>
> wmb();
> nvkm_ltc_invalidate(ltc);
> @@ -306,19 +304,18 @@ gk20a_instobj_dtor_iommu(struct nvkm_memory *memory)
> struct gk20a_instmem *imem = node->base.imem;
> struct device *dev = imem->base.subdev.device->dev;
> struct nvkm_mm_node *r;
> - unsigned long flags;
> int i;
>
> if (unlikely(list_empty(&node->base.mem.regions)))
> goto out;
>
> - spin_lock_irqsave(&imem->lock, flags);
> + mutex_lock(&imem->lock);
>
> /* vaddr has already been recycled */
> if (node->base.vaddr)
> gk20a_instobj_iommu_recycle_vaddr(node);
>
> - spin_unlock_irqrestore(&imem->lock, flags);
> + mutex_unlock(&imem->lock);
>
> r = list_first_entry(&node->base.mem.regions, struct nvkm_mm_node,
> rl_entry);
> @@ -580,7 +577,7 @@ gk20a_instmem_new(struct nvkm_device *device, int index,
> if (!(imem = kzalloc(sizeof(*imem), GFP_KERNEL)))
> return -ENOMEM;
> nvkm_instmem_ctor(&gk20a_instmem, device, index, &imem->base);
> - spin_lock_init(&imem->lock);
> + mutex_init(&imem->lock);
> *pimem = &imem->base;
>
> /* do not allow more than 1MB of CPU-mapped instmem */
> --
> 2.11.0
>
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^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] drm/nouveau: gk20a: Turn instmem lock into mutex
2017-02-23 16:20 ` Thierry Reding
@ 2017-02-24 7:25 ` Alexandre Courbot
0 siblings, 0 replies; 3+ messages in thread
From: Alexandre Courbot @ 2017-02-24 7:25 UTC (permalink / raw)
To: Thierry Reding, Ben Skeggs; +Cc: nouveau, dri-devel
On 02/24/2017 01:20 AM, Thierry Reding wrote:
> * PGP Signed by an unknown key
>
> On Mon, Jan 30, 2017 at 09:03:07PM +0100, Thierry Reding wrote:
>> From: Thierry Reding <treding@nvidia.com>
>>
>> The gk20a implementation of instance memory uses vmap()/vunmap() to map
>> memory regions into the kernel's virtual address space. These functions
>> may sleep, so protecting them by a spin lock is not safe. This triggers
>> a warning if the DEBUG_ATOMIC_SLEEP Kconfig option is enabled. Fix this
>> by using a mutex instead.
>>
>> Signed-off-by: Thierry Reding <treding@nvidia.com>
>> ---
>> drivers/gpu/drm/nouveau/nvkm/subdev/instmem/gk20a.c | 19 ++++++++-----------
>> 1 file changed, 8 insertions(+), 11 deletions(-)
>
> Alex, could you take a look at this?
Sorry! Yes, using a mutex here should be safe since vmap() can sleep
anyway. And I don't think this code can ever be reached in atomic
context (Ben can confirm that last point). Tested this patch and it
seems to work like a charm.
Reviewed-by: Alexandre Courbot <acourbot@nvidia.com>
Tested-by: Alexandre Courbot <acourbot@nvidia.com>
>
> Thanks,
> Thierry
>
>> diff --git a/drivers/gpu/drm/nouveau/nvkm/subdev/instmem/gk20a.c b/drivers/gpu/drm/nouveau/nvkm/subdev/instmem/gk20a.c
>> index a6a7fa0d7679..7f5244d57d2f 100644
>> --- a/drivers/gpu/drm/nouveau/nvkm/subdev/instmem/gk20a.c
>> +++ b/drivers/gpu/drm/nouveau/nvkm/subdev/instmem/gk20a.c
>> @@ -94,7 +94,7 @@ struct gk20a_instmem {
>> struct nvkm_instmem base;
>>
>> /* protects vaddr_* and gk20a_instobj::vaddr* */
>> - spinlock_t lock;
>> + struct mutex lock;
>>
>> /* CPU mappings LRU */
>> unsigned int vaddr_use;
>> @@ -184,11 +184,10 @@ gk20a_instobj_acquire_iommu(struct nvkm_memory *memory)
>> struct gk20a_instmem *imem = node->base.imem;
>> struct nvkm_ltc *ltc = imem->base.subdev.device->ltc;
>> const u64 size = nvkm_memory_size(memory);
>> - unsigned long flags;
>>
>> nvkm_ltc_flush(ltc);
>>
>> - spin_lock_irqsave(&imem->lock, flags);
>> + mutex_lock(&imem->lock);
>>
>> if (node->base.vaddr) {
>> if (!node->use_cpt) {
>> @@ -216,7 +215,7 @@ gk20a_instobj_acquire_iommu(struct nvkm_memory *memory)
>>
>> out:
>> node->use_cpt++;
>> - spin_unlock_irqrestore(&imem->lock, flags);
>> + mutex_unlock(&imem->lock);
>>
>> return node->base.vaddr;
>> }
>> @@ -239,9 +238,8 @@ gk20a_instobj_release_iommu(struct nvkm_memory *memory)
>> struct gk20a_instobj_iommu *node = gk20a_instobj_iommu(memory);
>> struct gk20a_instmem *imem = node->base.imem;
>> struct nvkm_ltc *ltc = imem->base.subdev.device->ltc;
>> - unsigned long flags;
>>
>> - spin_lock_irqsave(&imem->lock, flags);
>> + mutex_lock(&imem->lock);
>>
>> /* we should at least have one user to release... */
>> if (WARN_ON(node->use_cpt == 0))
>> @@ -252,7 +250,7 @@ gk20a_instobj_release_iommu(struct nvkm_memory *memory)
>> list_add_tail(&node->vaddr_node, &imem->vaddr_lru);
>>
>> out:
>> - spin_unlock_irqrestore(&imem->lock, flags);
>> + mutex_unlock(&imem->lock);
>>
>> wmb();
>> nvkm_ltc_invalidate(ltc);
>> @@ -306,19 +304,18 @@ gk20a_instobj_dtor_iommu(struct nvkm_memory *memory)
>> struct gk20a_instmem *imem = node->base.imem;
>> struct device *dev = imem->base.subdev.device->dev;
>> struct nvkm_mm_node *r;
>> - unsigned long flags;
>> int i;
>>
>> if (unlikely(list_empty(&node->base.mem.regions)))
>> goto out;
>>
>> - spin_lock_irqsave(&imem->lock, flags);
>> + mutex_lock(&imem->lock);
>>
>> /* vaddr has already been recycled */
>> if (node->base.vaddr)
>> gk20a_instobj_iommu_recycle_vaddr(node);
>>
>> - spin_unlock_irqrestore(&imem->lock, flags);
>> + mutex_unlock(&imem->lock);
>>
>> r = list_first_entry(&node->base.mem.regions, struct nvkm_mm_node,
>> rl_entry);
>> @@ -580,7 +577,7 @@ gk20a_instmem_new(struct nvkm_device *device, int index,
>> if (!(imem = kzalloc(sizeof(*imem), GFP_KERNEL)))
>> return -ENOMEM;
>> nvkm_instmem_ctor(&gk20a_instmem, device, index, &imem->base);
>> - spin_lock_init(&imem->lock);
>> + mutex_init(&imem->lock);
>> *pimem = &imem->base;
>>
>> /* do not allow more than 1MB of CPU-mapped instmem */
>> --
>> 2.11.0
>>
>
> * Unknown Key
> * 0x7F3EB3A1
>
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2017-01-30 20:03 [PATCH] drm/nouveau: gk20a: Turn instmem lock into mutex Thierry Reding
2017-02-23 16:20 ` Thierry Reding
2017-02-24 7:25 ` Alexandre Courbot
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