On 02/24/2017 01:20 AM, Thierry Reding wrote:
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On Mon, Jan 30, 2017 at 09:03:07PM +0100, Thierry Reding wrote:
From: Thierry Reding <treding@xxxxxxxxxx>
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@xxxxxxxxxx>
---
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@xxxxxxxxxx>
Tested-by: Alexandre Courbot <acourbot@xxxxxxxxxx>
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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