6.14-stable review patch. If anyone has any objections, please let me know.
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From: Adrián Larumbe adrian.larumbe@collabora.com
[ Upstream commit c63c3bfdde2656a3ead50ac3ce4a51a634e22dab ]
Commit 434e5ca5b5d7 ("drm/panthor: Expose size of driver internal BO's over fdinfo") locks the VMS xarray, to avoid UAF errors when the same VM is being concurrently destroyed by another thread. However, that puts the current thread in atomic context, which means taking the VMS' heap locks will trigger a warning as the thread is no longer allowed to sleep.
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. Instead, when a new heap chunk is allocated, its size is accumulated into a pool-wide tally, which also makes the atomic context code path somewhat faster.
Signed-off-by: Adrián Larumbe adrian.larumbe@collabora.com Fixes: 434e5ca5b5d7 ("drm/panthor: Expose size of driver internal BO's over fdinfo") Reviewed-by: Boris Brezillon boris.brezillon@collabora.com Reviewed-by: Steven Price steven.price@arm.com Signed-off-by: Steven Price steven.price@arm.com Link: https://patchwork.freedesktop.org/patch/msgid/20250303190923.1639985-2-adria... Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/gpu/drm/panthor/panthor_heap.c | 62 +++++++++++++------------- drivers/gpu/drm/panthor/panthor_mmu.c | 8 +--- 2 files changed, 31 insertions(+), 39 deletions(-)
diff --git a/drivers/gpu/drm/panthor/panthor_heap.c b/drivers/gpu/drm/panthor/panthor_heap.c index db0285ce58126..3bdf61c142644 100644 --- a/drivers/gpu/drm/panthor/panthor_heap.c +++ b/drivers/gpu/drm/panthor/panthor_heap.c @@ -97,6 +97,9 @@ struct panthor_heap_pool {
/** @gpu_contexts: Buffer object containing the GPU heap contexts. */ struct panthor_kernel_bo *gpu_contexts; + + /** @size: Size of all chunks across all heaps in the pool. */ + atomic_t size; };
static int panthor_heap_ctx_stride(struct panthor_device *ptdev) @@ -118,7 +121,7 @@ static void *panthor_get_heap_ctx(struct panthor_heap_pool *pool, int id) panthor_get_heap_ctx_offset(pool, id); }
-static void panthor_free_heap_chunk(struct panthor_vm *vm, +static void panthor_free_heap_chunk(struct panthor_heap_pool *pool, struct panthor_heap *heap, struct panthor_heap_chunk *chunk) { @@ -127,12 +130,13 @@ static void panthor_free_heap_chunk(struct panthor_vm *vm, heap->chunk_count--; mutex_unlock(&heap->lock);
+ atomic_sub(heap->chunk_size, &pool->size); + panthor_kernel_bo_destroy(chunk->bo); kfree(chunk); }
-static int panthor_alloc_heap_chunk(struct panthor_device *ptdev, - struct panthor_vm *vm, +static int panthor_alloc_heap_chunk(struct panthor_heap_pool *pool, struct panthor_heap *heap, bool initial_chunk) { @@ -144,7 +148,7 @@ static int panthor_alloc_heap_chunk(struct panthor_device *ptdev, if (!chunk) return -ENOMEM;
- chunk->bo = panthor_kernel_bo_create(ptdev, vm, heap->chunk_size, + chunk->bo = panthor_kernel_bo_create(pool->ptdev, pool->vm, heap->chunk_size, DRM_PANTHOR_BO_NO_MMAP, DRM_PANTHOR_VM_BIND_OP_MAP_NOEXEC, PANTHOR_VM_KERNEL_AUTO_VA); @@ -180,6 +184,8 @@ static int panthor_alloc_heap_chunk(struct panthor_device *ptdev, heap->chunk_count++; mutex_unlock(&heap->lock);
+ atomic_add(heap->chunk_size, &pool->size); + return 0;
err_destroy_bo: @@ -191,17 +197,16 @@ static int panthor_alloc_heap_chunk(struct panthor_device *ptdev, return ret; }
-static void panthor_free_heap_chunks(struct panthor_vm *vm, +static void panthor_free_heap_chunks(struct panthor_heap_pool *pool, struct panthor_heap *heap) { struct panthor_heap_chunk *chunk, *tmp;
list_for_each_entry_safe(chunk, tmp, &heap->chunks, node) - panthor_free_heap_chunk(vm, heap, chunk); + panthor_free_heap_chunk(pool, heap, chunk); }
-static int panthor_alloc_heap_chunks(struct panthor_device *ptdev, - struct panthor_vm *vm, +static int panthor_alloc_heap_chunks(struct panthor_heap_pool *pool, struct panthor_heap *heap, u32 chunk_count) { @@ -209,7 +214,7 @@ static int panthor_alloc_heap_chunks(struct panthor_device *ptdev, u32 i;
for (i = 0; i < chunk_count; i++) { - ret = panthor_alloc_heap_chunk(ptdev, vm, heap, true); + ret = panthor_alloc_heap_chunk(pool, heap, true); if (ret) return ret; } @@ -226,7 +231,7 @@ panthor_heap_destroy_locked(struct panthor_heap_pool *pool, u32 handle) if (!heap) return -EINVAL;
- panthor_free_heap_chunks(pool->vm, heap); + panthor_free_heap_chunks(pool, heap); mutex_destroy(&heap->lock); kfree(heap); return 0; @@ -308,8 +313,7 @@ int panthor_heap_create(struct panthor_heap_pool *pool, heap->max_chunks = max_chunks; heap->target_in_flight = target_in_flight;
- ret = panthor_alloc_heap_chunks(pool->ptdev, vm, heap, - initial_chunk_count); + ret = panthor_alloc_heap_chunks(pool, heap, initial_chunk_count); if (ret) goto err_free_heap;
@@ -342,7 +346,7 @@ int panthor_heap_create(struct panthor_heap_pool *pool, return id;
err_free_heap: - panthor_free_heap_chunks(pool->vm, heap); + panthor_free_heap_chunks(pool, heap); mutex_destroy(&heap->lock); kfree(heap);
@@ -389,6 +393,7 @@ int panthor_heap_return_chunk(struct panthor_heap_pool *pool, removed = chunk; list_del(&chunk->node); heap->chunk_count--; + atomic_sub(heap->chunk_size, &pool->size); break; } } @@ -466,7 +471,7 @@ int panthor_heap_grow(struct panthor_heap_pool *pool, * further jobs in this queue fail immediately instead of having to * wait for the job timeout. */ - ret = panthor_alloc_heap_chunk(pool->ptdev, pool->vm, heap, false); + ret = panthor_alloc_heap_chunk(pool, heap, false); if (ret) goto out_unlock;
@@ -560,6 +565,8 @@ panthor_heap_pool_create(struct panthor_device *ptdev, struct panthor_vm *vm) if (ret) goto err_destroy_pool;
+ atomic_add(pool->gpu_contexts->obj->size, &pool->size); + return pool;
err_destroy_pool: @@ -594,8 +601,10 @@ 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)) { + atomic_sub(pool->gpu_contexts->obj->size, &pool->size); panthor_kernel_bo_destroy(pool->gpu_contexts); + }
/* Reflects the fact the pool has been destroyed. */ pool->vm = NULL; @@ -605,27 +614,16 @@ void panthor_heap_pool_destroy(struct panthor_heap_pool *pool) }
/** - * panthor_heap_pool_size() - Calculate size of all chunks across all heaps in a pool - * @pool: Pool whose total chunk size to calculate. + * panthor_heap_pool_size() - Get a heap pool's total size + * @pool: Pool whose total chunks size to return * - * 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. + * Returns the aggregated size of all chunks for all heaps in the pool * */ 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; + if (!pool) + return 0;
- return size; + return atomic_read(&pool->size); } diff --git a/drivers/gpu/drm/panthor/panthor_mmu.c b/drivers/gpu/drm/panthor/panthor_mmu.c index 11771ca8147f9..1202de8811c2a 100644 --- a/drivers/gpu/drm/panthor/panthor_mmu.c +++ b/drivers/gpu/drm/panthor/panthor_mmu.c @@ -1960,13 +1960,7 @@ 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 = panthor_heap_pool_size(vm->heaps.pool); stats->resident += size; if (vm->as.id >= 0) stats->active += size;