A previous commit dealt with a similar situation, whereby upon enabling
some mutex debug features, a warning about sleep muteces being used in a
/proc file read atomic context was being triggered.

Because in this case replacing the heap mutex with a spinlock isn't
feasible, the fdinfo handler no longer traverses the list of heaps for
every single VM associated with an open DRM file. Instad, when a new heap
chunk is allocated, its size is accumulated into a VM-wide tally, which
also makes the atomic context code path somewhat faster.

Signed-off-by: Adrián Larumbe <adrian.laru...@collabora.com>
Fixes: 3e2c8c718567 ("drm/panthor: Expose size of driver internal BO's over 
fdinfo")
---
 drivers/gpu/drm/panthor/panthor_heap.c | 38 ++++++++------------------
 drivers/gpu/drm/panthor/panthor_heap.h |  2 --
 drivers/gpu/drm/panthor/panthor_mmu.c  | 18 +++++++-----
 drivers/gpu/drm/panthor/panthor_mmu.h  |  1 +
 4 files changed, 23 insertions(+), 36 deletions(-)

diff --git a/drivers/gpu/drm/panthor/panthor_heap.c 
b/drivers/gpu/drm/panthor/panthor_heap.c
index db0285ce5812..686f209f5b09 100644
--- a/drivers/gpu/drm/panthor/panthor_heap.c
+++ b/drivers/gpu/drm/panthor/panthor_heap.c
@@ -127,6 +127,8 @@ static void panthor_free_heap_chunk(struct panthor_vm *vm,
        heap->chunk_count--;
        mutex_unlock(&heap->lock);
 
+       panthor_vm_heaps_accumulate(vm, -heap->chunk_size);
+
        panthor_kernel_bo_destroy(chunk->bo);
        kfree(chunk);
 }
@@ -180,6 +182,8 @@ static int panthor_alloc_heap_chunk(struct panthor_device 
*ptdev,
        heap->chunk_count++;
        mutex_unlock(&heap->lock);
 
+       panthor_vm_heaps_accumulate(vm, heap->chunk_size);
+
        return 0;
 
 err_destroy_bo:
@@ -389,6 +393,7 @@ int panthor_heap_return_chunk(struct panthor_heap_pool 
*pool,
                        removed = chunk;
                        list_del(&chunk->node);
                        heap->chunk_count--;
+                       panthor_vm_heaps_accumulate(chunk->bo->vm, 
-heap->chunk_size);
                        break;
                }
        }
@@ -560,6 +565,8 @@ panthor_heap_pool_create(struct panthor_device *ptdev, 
struct panthor_vm *vm)
        if (ret)
                goto err_destroy_pool;
 
+       panthor_vm_heaps_accumulate(vm, pool->gpu_contexts->obj->size);
+
        return pool;
 
 err_destroy_pool:
@@ -594,8 +601,11 @@ void panthor_heap_pool_destroy(struct panthor_heap_pool 
*pool)
        xa_for_each(&pool->xa, i, heap)
                drm_WARN_ON(&pool->ptdev->base, 
panthor_heap_destroy_locked(pool, i));
 
-       if (!IS_ERR_OR_NULL(pool->gpu_contexts))
+       if (!IS_ERR_OR_NULL(pool->gpu_contexts)) {
+               panthor_vm_heaps_accumulate(pool->gpu_contexts->vm,
+                                           -pool->gpu_contexts->obj->size);
                panthor_kernel_bo_destroy(pool->gpu_contexts);
+       }
 
        /* Reflects the fact the pool has been destroyed. */
        pool->vm = NULL;
@@ -603,29 +613,3 @@ void panthor_heap_pool_destroy(struct panthor_heap_pool 
*pool)
 
        panthor_heap_pool_put(pool);
 }
-
-/**
- * panthor_heap_pool_size() - Calculate size of all chunks across all heaps in 
a pool
- * @pool: Pool whose total chunk size to calculate.
- *
- * This function adds the size of all heap chunks across all heaps in the
- * argument pool. It also adds the size of the gpu contexts kernel bo.
- * It is meant to be used by fdinfo for displaying the size of internal
- * driver BO's that aren't exposed to userspace through a GEM handle.
- *
- */
-size_t panthor_heap_pool_size(struct panthor_heap_pool *pool)
-{
-       struct panthor_heap *heap;
-       unsigned long i;
-       size_t size = 0;
-
-       down_read(&pool->lock);
-       xa_for_each(&pool->xa, i, heap)
-               size += heap->chunk_size * heap->chunk_count;
-       up_read(&pool->lock);
-
-       size += pool->gpu_contexts->obj->size;
-
-       return size;
-}
diff --git a/drivers/gpu/drm/panthor/panthor_heap.h 
b/drivers/gpu/drm/panthor/panthor_heap.h
index e3358d4e8edb..25a5f2bba445 100644
--- a/drivers/gpu/drm/panthor/panthor_heap.h
+++ b/drivers/gpu/drm/panthor/panthor_heap.h
@@ -27,8 +27,6 @@ struct panthor_heap_pool *
 panthor_heap_pool_get(struct panthor_heap_pool *pool);
 void panthor_heap_pool_put(struct panthor_heap_pool *pool);
 
-size_t panthor_heap_pool_size(struct panthor_heap_pool *pool);
-
 int panthor_heap_grow(struct panthor_heap_pool *pool,
                      u64 heap_gpu_va,
                      u32 renderpasses_in_flight,
diff --git a/drivers/gpu/drm/panthor/panthor_mmu.c 
b/drivers/gpu/drm/panthor/panthor_mmu.c
index 0a4e352b5505..aaad1a560805 100644
--- a/drivers/gpu/drm/panthor/panthor_mmu.c
+++ b/drivers/gpu/drm/panthor/panthor_mmu.c
@@ -345,6 +345,10 @@ struct panthor_vm {
 
                /** @heaps.lock: Lock used to protect access to @pool. */
                struct mutex lock;
+
+               /** @heaps.size: Size of all chunks across all heaps in the 
pool. */
+               ssize_t size;
+
        } heaps;
 
        /** @node: Used to insert the VM in the panthor_mmu::vm::list. */
@@ -1539,6 +1543,7 @@ static void panthor_vm_destroy(struct panthor_vm *vm)
        mutex_lock(&vm->heaps.lock);
        panthor_heap_pool_destroy(vm->heaps.pool);
        vm->heaps.pool = NULL;
+       vm->heaps.size = 0;
        mutex_unlock(&vm->heaps.lock);
 
        drm_WARN_ON(&vm->ptdev->base,
@@ -1963,13 +1968,7 @@ void panthor_vm_heaps_sizes(struct panthor_file *pfile, 
struct drm_memory_stats
 
        xa_lock(&pfile->vms->xa);
        xa_for_each(&pfile->vms->xa, i, vm) {
-               size_t size = 0;
-
-               mutex_lock(&vm->heaps.lock);
-               if (vm->heaps.pool)
-                       size = panthor_heap_pool_size(vm->heaps.pool);
-               mutex_unlock(&vm->heaps.lock);
-
+               size_t size = vm->heaps.size;
                stats->resident += size;
                if (vm->as.id >= 0)
                        stats->active += size;
@@ -1977,6 +1976,11 @@ void panthor_vm_heaps_sizes(struct panthor_file *pfile, 
struct drm_memory_stats
        xa_unlock(&pfile->vms->xa);
 }
 
+void panthor_vm_heaps_accumulate(struct panthor_vm *vm, ssize_t acc)
+{
+       vm->heaps.size += acc;
+}
+
 static u64 mair_to_memattr(u64 mair, bool coherent)
 {
        u64 memattr = 0;
diff --git a/drivers/gpu/drm/panthor/panthor_mmu.h 
b/drivers/gpu/drm/panthor/panthor_mmu.h
index fc274637114e..b6686896f8ef 100644
--- a/drivers/gpu/drm/panthor/panthor_mmu.h
+++ b/drivers/gpu/drm/panthor/panthor_mmu.h
@@ -39,6 +39,7 @@ struct panthor_heap_pool *
 panthor_vm_get_heap_pool(struct panthor_vm *vm, bool create);
 
 void panthor_vm_heaps_sizes(struct panthor_file *pfile, struct 
drm_memory_stats *stats);
+void panthor_vm_heaps_accumulate(struct panthor_vm *vm, ssize_t acc);
 
 struct panthor_vm *panthor_vm_get(struct panthor_vm *vm);
 void panthor_vm_put(struct panthor_vm *vm);
-- 
2.47.1

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