6.11-stable review patch. If anyone has any objections, please let me know.
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From: Brendan King brendan.king@imgtec.com
commit b04ce1e718bd55302b52d05d6873e233cb3ec7a1 upstream.
When remaining resources are being cleaned up on driver close, outstanding VM mappings may result in resources being leaked, due to an object reference loop, as shown below, with each object (or set of objects) referencing the object below it:
PVR GEM Object GPU scheduler "finished" fence GPU scheduler “scheduled” fence PVR driver “done” fence PVR Context PVR VM Context PVR VM Mappings PVR GEM Object
The reference that the PVR VM Context has on the VM mappings is a soft one, in the sense that the freeing of outstanding VM mappings is done as part of VM context destruction; no reference counts are involved, as is the case for all the other references in the loop.
To break the reference loop during cleanup, free the outstanding VM mappings before destroying the PVR Context associated with the VM context.
Signed-off-by: Brendan King brendan.king@imgtec.com Signed-off-by: Matt Coster matt.coster@imgtec.com Reviewed-by: Frank Binns frank.binns@imgtec.com Cc: stable@vger.kernel.org Link: https://patchwork.freedesktop.org/patch/msgid/8a25924f-1bb7-4d9a-a346-58e871... Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/gpu/drm/imagination/pvr_context.c | 19 +++++++++++++++++++ drivers/gpu/drm/imagination/pvr_context.h | 18 ++++++++++++++++++ drivers/gpu/drm/imagination/pvr_vm.c | 22 ++++++++++++++++++---- drivers/gpu/drm/imagination/pvr_vm.h | 1 + 4 files changed, 56 insertions(+), 4 deletions(-)
--- a/drivers/gpu/drm/imagination/pvr_context.c +++ b/drivers/gpu/drm/imagination/pvr_context.c @@ -450,11 +450,30 @@ pvr_context_destroy(struct pvr_file *pvr */ void pvr_destroy_contexts_for_file(struct pvr_file *pvr_file) { + struct pvr_device *pvr_dev = pvr_file->pvr_dev; struct pvr_context *ctx; unsigned long handle;
xa_for_each(&pvr_file->ctx_handles, handle, ctx) pvr_context_destroy(pvr_file, handle); + + spin_lock(&pvr_dev->ctx_list_lock); + ctx = list_first_entry(&pvr_file->contexts, struct pvr_context, file_link); + + while (!list_entry_is_head(ctx, &pvr_file->contexts, file_link)) { + list_del_init(&ctx->file_link); + + if (pvr_context_get_if_referenced(ctx)) { + spin_unlock(&pvr_dev->ctx_list_lock); + + pvr_vm_unmap_all(ctx->vm_ctx); + + pvr_context_put(ctx); + spin_lock(&pvr_dev->ctx_list_lock); + } + ctx = list_first_entry(&pvr_file->contexts, struct pvr_context, file_link); + } + spin_unlock(&pvr_dev->ctx_list_lock); }
/** --- a/drivers/gpu/drm/imagination/pvr_context.h +++ b/drivers/gpu/drm/imagination/pvr_context.h @@ -127,6 +127,24 @@ pvr_context_get(struct pvr_context *ctx) }
/** + * pvr_context_get_if_referenced() - Take an additional reference on a still + * referenced context. + * @ctx: Context pointer. + * + * Call pvr_context_put() to release. + * + * Returns: + * * True on success, or + * * false if no context pointer passed, or the context wasn't still + * * referenced. + */ +static __always_inline bool +pvr_context_get_if_referenced(struct pvr_context *ctx) +{ + return ctx != NULL && kref_get_unless_zero(&ctx->ref_count) != 0; +} + +/** * pvr_context_lookup() - Lookup context pointer from handle and file. * @pvr_file: Pointer to pvr_file structure. * @handle: Context handle. --- a/drivers/gpu/drm/imagination/pvr_vm.c +++ b/drivers/gpu/drm/imagination/pvr_vm.c @@ -14,6 +14,7 @@ #include <drm/drm_gem.h> #include <drm/drm_gpuvm.h>
+#include <linux/bug.h> #include <linux/container_of.h> #include <linux/err.h> #include <linux/errno.h> @@ -597,12 +598,26 @@ err_free: }
/** - * pvr_vm_context_release() - Teardown a VM context. - * @ref_count: Pointer to reference counter of the VM context. + * pvr_vm_unmap_all() - Unmap all mappings associated with a VM context. + * @vm_ctx: Target VM context. * * This function ensures that no mappings are left dangling by unmapping them * all in order of ascending device-virtual address. */ +void +pvr_vm_unmap_all(struct pvr_vm_context *vm_ctx) +{ + WARN_ON(pvr_vm_unmap(vm_ctx, vm_ctx->gpuvm_mgr.mm_start, + vm_ctx->gpuvm_mgr.mm_range)); +} + +/** + * pvr_vm_context_release() - Teardown a VM context. + * @ref_count: Pointer to reference counter of the VM context. + * + * This function also ensures that no mappings are left dangling by calling + * pvr_vm_unmap_all. + */ static void pvr_vm_context_release(struct kref *ref_count) { @@ -612,8 +627,7 @@ pvr_vm_context_release(struct kref *ref_ if (vm_ctx->fw_mem_ctx_obj) pvr_fw_object_destroy(vm_ctx->fw_mem_ctx_obj);
- WARN_ON(pvr_vm_unmap(vm_ctx, vm_ctx->gpuvm_mgr.mm_start, - vm_ctx->gpuvm_mgr.mm_range)); + pvr_vm_unmap_all(vm_ctx);
pvr_mmu_context_destroy(vm_ctx->mmu_ctx); drm_gem_private_object_fini(&vm_ctx->dummy_gem); --- a/drivers/gpu/drm/imagination/pvr_vm.h +++ b/drivers/gpu/drm/imagination/pvr_vm.h @@ -39,6 +39,7 @@ int pvr_vm_map(struct pvr_vm_context *vm struct pvr_gem_object *pvr_obj, u64 pvr_obj_offset, u64 device_addr, u64 size); int pvr_vm_unmap(struct pvr_vm_context *vm_ctx, u64 device_addr, u64 size); +void pvr_vm_unmap_all(struct pvr_vm_context *vm_ctx);
dma_addr_t pvr_vm_get_page_table_root_addr(struct pvr_vm_context *vm_ctx); struct dma_resv *pvr_vm_get_dma_resv(struct pvr_vm_context *vm_ctx);