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5 hours, 32 minutes

[PATCH 0/6] drm/panthor: Use guards

by Boris Brezillon

Turn the mixed bag of manual locks and guards into something more consistent. This patchset takes care of locks that already have guards available, but also adds new guards for resv, drm_dev_enter/exit and the custom panthor_device_resume_and_get() helper we have around runtime PM. I've intentionally placed the patch transition all locks with readily available guards first so we can merge it even if the new guards face some controversy. Signed-off-by: Boris Brezillon <boris.brezillon(a)collabora.com> --- Boris Brezillon (6): drm/panthor: Driver-wide xxx_[un]lock -> [scoped_]guard replacement dma-resv: Define guards for context-less dma_resv locks drm: Define a conditional guard for drm_dev_{enter,exit}() drm/panthor: Use guards for resv locking drm/panthor: Use the drm_dev_access guard drm/panthor: Add a new guard for our custom resume_and_get() PM helper drivers/gpu/drm/panthor/panthor_devfreq.c | 29 +- drivers/gpu/drm/panthor/panthor_device.c | 163 +++++----- drivers/gpu/drm/panthor/panthor_device.h | 10 +- drivers/gpu/drm/panthor/panthor_drv.c | 62 ++-- drivers/gpu/drm/panthor/panthor_gem.c | 102 +++---- drivers/gpu/drm/panthor/panthor_gpu.c | 40 +-- drivers/gpu/drm/panthor/panthor_heap.c | 139 ++++----- drivers/gpu/drm/panthor/panthor_mmu.c | 480 ++++++++++++++---------------- drivers/gpu/drm/panthor/panthor_pwr.c | 8 +- drivers/gpu/drm/panthor/panthor_sched.c | 254 ++++++++-------- include/drm/drm_drv.h | 9 + include/linux/dma-resv.h | 5 + 12 files changed, 589 insertions(+), 712 deletions(-) --- base-commit: ac5ac0acf11df04295eb1811066097b7022d6c7f change-id: 20260512-panthor-guard-refactor-f1c6bc30c321 prerequisite-message-id: 20260512-panthor-signal-from-irq-v2-0-95c614a739cb(a)collabora.com prerequisite-patch-id: e3cfd6399b2dc5439687932c6e961d845369562a prerequisite-patch-id: 79820e6740c0c456efc1dfa273de04e495515a1c prerequisite-patch-id: a3611a7c9551c606aaf87125782e6d18b6a6549e prerequisite-patch-id: 6e9dc83a60e53e7b0d84030727ad9b1921e4b2ca prerequisite-patch-id: eabd36064a01418a6ada3176b996a4038a314c21 prerequisite-patch-id: ca3a30182b71bf66c51ed2b6411d7ed8dc761c8e prerequisite-patch-id: 6e549dd0ee9e3e0c8866da72dcabc82209d88360 prerequisite-patch-id: 5217700df7026ef533a2f273ea2535f9fc1274ac prerequisite-patch-id: 8d57abec9f92bcbb21108d3005805b7c155a48f6 prerequisite-patch-id: 0bf98de955fce577ff8d4fb82c02dc04684beca6 prerequisite-patch-id: a9e0d90a64dfd5950a69b857af3867404be1ab45 Best regards, -- Boris Brezillon <boris.brezillon(a)collabora.com>

10 hours, 39 minutes

[PATCH v4] drm/virtio: use uninterruptible resv lock for plane updates

by Deepanshu Kartikey

virtio_gpu_cursor_plane_update() and virtio_gpu_resource_flush() lock the framebuffer BO's dma_resv via virtio_gpu_array_lock_resv() and ignore its return value. The function can fail with -EINTR from dma_resv_lock_interruptible() (signal during lock wait) or with -ENOMEM from dma_resv_reserve_fences() (fence slot allocation), leaving the resv lock not held. The queue path then walks the object array and calls dma_resv_add_fence(), which requires the lock held; with lockdep enabled this trips dma_resv_assert_held(): WARNING: drivers/dma-buf/dma-resv.c:296 at dma_resv_add_fence+0x71e/0x840 Call Trace: virtio_gpu_array_add_fence virtio_gpu_queue_ctrl_sgs virtio_gpu_queue_fenced_ctrl_buffer virtio_gpu_cursor_plane_update drm_atomic_helper_commit_planes drm_atomic_helper_commit_tail commit_tail drm_atomic_helper_commit drm_atomic_commit drm_atomic_helper_update_plane __setplane_atomic drm_mode_cursor_universal drm_mode_cursor_common drm_mode_cursor_ioctl drm_ioctl __x64_sys_ioctl Beyond the WARN, mutating the dma_resv fence list without the lock races with concurrent readers/writers and can corrupt the list. Both call sites run inside the .atomic_update plane callback, which DRM atomic helpers do not allow to fail (by the time it runs, the commit has been signed off to userspace and there is no clean rollback path). Moving the lock acquisition to .prepare_fb was rejected because the broader lock scope deadlocks against other BO locking paths in the same atomic commit. Introduce virtio_gpu_lock_one_resv_uninterruptible() that uses dma_resv_lock() instead of dma_resv_lock_interruptible(). This eliminates the -EINTR failure mode -- the realistic syzbot trigger -- without extending the lock hold across the commit. The helper locks a single BO and rejects nents > 1 with -EINVAL; both fix sites lock exactly one BO. Use it from virtio_gpu_cursor_plane_update() and virtio_gpu_resource_flush(); check the return value to handle the remaining -ENOMEM case from dma_resv_reserve_fences() by freeing the objs and skipping the plane update for that frame. The framebuffer BOs touched here are not shared with other contexts and lock contention is expected to be brief, so the loss of signal-interruptibility is acceptable. Other callers of virtio_gpu_array_lock_resv() (the ioctl paths) continue to use the interruptible variant. The bug was reported by syzbot, triggered via fault injection (fail_nth) on the DRM_IOCTL_MODE_CURSOR path, which forces the -ENOMEM branch in dma_resv_reserve_fences(). Reported-by: syzbot+72bd3dd3a5d5f39a0271(a)syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=72bd3dd3a5d5f39a0271 Fixes: 5cfd31c5b3a3 ("drm/virtio: fix virtio_gpu_cursor_plane_update().") Cc: stable(a)vger.kernel.org Signed-off-by: Deepanshu Kartikey <kartikey406(a)gmail.com> --- v4: Rename the helper to virtio_gpu_lock_one_resv_uninterruptible() and reject objs->nents > 1 with -EINVAL. The v3 helper's multi-object branch used drm_gem_lock_reservations(), which is interruptible, contradicting the "uninterruptible" name; both fix sites lock a single BO so the multi-object path is dropped. (Dmitry Osipenko) v3: Drop the prepare_fb/cleanup_fb approach from v2 (it deadlocked against virtio_gpu_resource_flush(), which also locks the BO in the same atomic commit). Instead add an uninterruptible variant of the resv lock helper and use it in both virtio_gpu_cursor_plane_update() and virtio_gpu_resource_flush(). (Dmitry Osipenko) v2: Move resv lock acquisition from .atomic_update (which must not fail) to .prepare_fb (which may), per maintainer review of v1. The v1 approach of silently skipping the cursor update on lock failure violated the atomic-commit contract with userspace. --- drivers/gpu/drm/virtio/virtgpu_drv.h | 1 + drivers/gpu/drm/virtio/virtgpu_gem.c | 17 +++++++++++++++++ drivers/gpu/drm/virtio/virtgpu_plane.c | 10 ++++++++-- 3 files changed, 26 insertions(+), 2 deletions(-) diff --git a/drivers/gpu/drm/virtio/virtgpu_drv.h b/drivers/gpu/drm/virtio/virtgpu_drv.h index f17660a71a3e..2f3531950aa4 100644 --- a/drivers/gpu/drm/virtio/virtgpu_drv.h +++ b/drivers/gpu/drm/virtio/virtgpu_drv.h @@ -317,6 +317,7 @@ virtio_gpu_array_from_handles(struct drm_file *drm_file, u32 *handles, u32 nents void virtio_gpu_array_add_obj(struct virtio_gpu_object_array *objs, struct drm_gem_object *obj); int virtio_gpu_array_lock_resv(struct virtio_gpu_object_array *objs); +int virtio_gpu_lock_one_resv_uninterruptible(struct virtio_gpu_object_array *objs); void virtio_gpu_array_unlock_resv(struct virtio_gpu_object_array *objs); void virtio_gpu_array_add_fence(struct virtio_gpu_object_array *objs, struct dma_fence *fence); diff --git a/drivers/gpu/drm/virtio/virtgpu_gem.c b/drivers/gpu/drm/virtio/virtgpu_gem.c index f22dc5c21cd4..435d37d36034 100644 --- a/drivers/gpu/drm/virtio/virtgpu_gem.c +++ b/drivers/gpu/drm/virtio/virtgpu_gem.c @@ -238,6 +238,23 @@ int virtio_gpu_array_lock_resv(struct virtio_gpu_object_array *objs) return ret; } +int virtio_gpu_lock_one_resv_uninterruptible(struct virtio_gpu_object_array *objs) +{ + int ret; + + if (objs->nents != 1) + return -EINVAL; + + dma_resv_lock(objs->objs[0]->resv, NULL); + + ret = dma_resv_reserve_fences(objs->objs[0]->resv, 1); + if (ret) { + virtio_gpu_array_unlock_resv(objs); + return ret; + } + return 0; +} + void virtio_gpu_array_unlock_resv(struct virtio_gpu_object_array *objs) { if (objs->nents == 1) { diff --git a/drivers/gpu/drm/virtio/virtgpu_plane.c b/drivers/gpu/drm/virtio/virtgpu_plane.c index a126d1b25f46..652352424744 100644 --- a/drivers/gpu/drm/virtio/virtgpu_plane.c +++ b/drivers/gpu/drm/virtio/virtgpu_plane.c @@ -215,7 +215,10 @@ static void virtio_gpu_resource_flush(struct drm_plane *plane, if (!objs) return; virtio_gpu_array_add_obj(objs, vgfb->base.obj[0]); - virtio_gpu_array_lock_resv(objs); + if (virtio_gpu_lock_one_resv_uninterruptible(objs)) { + virtio_gpu_array_put_free(objs); + return; + } virtio_gpu_cmd_resource_flush(vgdev, bo->hw_res_handle, x, y, width, height, objs, vgplane_st->fence); @@ -459,7 +462,10 @@ static void virtio_gpu_cursor_plane_update(struct drm_plane *plane, if (!objs) return; virtio_gpu_array_add_obj(objs, vgfb->base.obj[0]); - virtio_gpu_array_lock_resv(objs); + if (virtio_gpu_lock_one_resv_uninterruptible(objs)) { + virtio_gpu_array_put_free(objs); + return; + } virtio_gpu_cmd_transfer_to_host_2d (vgdev, 0, plane->state->crtc_w, -- 2.43.0

11 hours, 5 minutes

[PATCH] drm/amdgpu: fix recursive ww_mutex acquire in amdgpu_devcoredump_format

by Mikhail Gavrilov

When dumping IB contents from a hung job, amdgpu_devcoredump_format() acquires the VM root PD's reservation lock via amdgpu_vm_lock_by_pasid() and then, for each IB referenced by the job, calls amdgpu_bo_reserve() on the BO that backs the IB. Both reservations are taken on reservation_ww_class_mutex objects but neither uses a ww_acquire_ctx, which trips lockdep: WARNING: possible recursive locking detected -------------------------------------------- kworker/u128:0 is trying to acquire lock: ffff88838b16e1f0 (reservation_ww_class_mutex){+.+.}-{4:4}, at: amdgpu_devcoredump_format+0x1594/0x23f0 [amdgpu] but task is already holding lock: ffff8882f82681f0 (reservation_ww_class_mutex){+.+.}-{4:4}, at: amdgpu_devcoredump_format+0x1594/0x23f0 [amdgpu] Possible unsafe locking scenario: CPU0 ---- lock(reservation_ww_class_mutex); lock(reservation_ww_class_mutex); *** DEADLOCK *** May be due to missing lock nesting notation Workqueue: events_unbound amdgpu_devcoredump_deferred_work [amdgpu] Call Trace: __ww_mutex_lock.constprop.0 ww_mutex_lock amdgpu_bo_reserve amdgpu_devcoredump_format+0x1594 [amdgpu] amdgpu_devcoredump_deferred_work+0xea [amdgpu] process_one_work worker_thread kthread The two reservations are on different BOs in the captured trace, so the splat is a lockdep-correctness warning, not an observed deadlock. It becomes a real self-deadlock whenever the IB BO shares its dma_resv with the root PD (the always-valid case, see amdgpu_vm_is_bo_always_valid()): amdgpu_bo_reserve(abo) re-acquires the same ww_mutex without a ticket and blocks forever. With amdgpu.gpu_recovery=0 the timeout handler refires every ~2 s and each invocation produces this splat, drowning the kernel ring buffer. Fix it by collecting the per-IB BO references under the root PD's reservation, then releasing the root before reserving each IB BO individually. The walk over the VM mapping tree must remain under the root lock (mappings can be torn down without it), but the actual content copies do not need to nest inside it. Each per-IB reservation is now an independent top-level acquire, eliminating the nested ww_mutex. The collect/release logic is factored out into two small helpers (amdgpu_devcoredump_collect_ib_refs / amdgpu_devcoredump_release_ib_refs) to keep the main function's indentation reasonable. This also fixes a BO refcount leak in the original code: when amdgpu_bo_reserve() failed, control jumped to free_ib_content without running amdgpu_bo_unref(). In the new structure the per-IB BO refs are released unconditionally in the cleanup helper. Reproducer (~150 LoC libdrm_amdgpu): submit a single GFX IB containing PACKET3_INDIRECT_BUFFER chained at GPU VA 0 and wait for the fence. The TDR fires within ~10 s and the deferred coredump worker produces the splat above on every invocation. Fixes: 7b15fc2d1f1a ("drm/amdgpu: dump job ibs in the devcoredump") Cc: stable(a)vger.kernel.org # 7.1 Signed-off-by: Mikhail Gavrilov <mikhail.v.gavrilov(a)gmail.com> --- .../gpu/drm/amd/amdgpu/amdgpu_dev_coredump.c | 147 +++++++++++++----- 1 file changed, 110 insertions(+), 37 deletions(-) diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_dev_coredump.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_dev_coredump.c index d386bc775d03..f6bb968de756 100644 --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_dev_coredump.c +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_dev_coredump.c @@ -207,6 +207,72 @@ static void amdgpu_devcoredump_fw_info(struct amdgpu_device *adev, } } +struct amdgpu_devcoredump_ib_ref { + struct amdgpu_bo *bo; + u64 offset; +}; + +/* + * Walk the VM's mapping tree under the root PD's reservation to obtain the BO + * that backs each IB and pin it with a refcount. The root PD reservation is + * dropped before this function returns; the caller can then reserve each IB + * BO individually without nesting ww_mutex acquires on + * reservation_ww_class_mutex. + * + * Returns an array of num_ibs entries (each ib_refs[i].bo may be NULL if its + * mapping was not found), or NULL on allocation failure / VM lookup failure. + * The caller must release the BO refs and free the array. + */ +static struct amdgpu_devcoredump_ib_ref * +amdgpu_devcoredump_collect_ib_refs(struct amdgpu_device *adev, + struct amdgpu_coredump_info *coredump) +{ + struct amdgpu_devcoredump_ib_ref *ib_refs; + struct amdgpu_bo_va_mapping *mapping; + struct amdgpu_bo *root; + struct amdgpu_vm *vm; + u64 va_start; + + ib_refs = kcalloc(coredump->num_ibs, sizeof(*ib_refs), GFP_KERNEL); + if (!ib_refs) + return NULL; + + vm = amdgpu_vm_lock_by_pasid(adev, &root, coredump->pasid); + if (!vm) { + kfree(ib_refs); + return NULL; + } + + for (int i = 0; i < coredump->num_ibs; i++) { + va_start = coredump->ibs[i].gpu_addr & AMDGPU_GMC_HOLE_MASK; + mapping = amdgpu_vm_bo_lookup_mapping(vm, va_start / AMDGPU_GPU_PAGE_SIZE); + if (!mapping) + continue; + + ib_refs[i].bo = amdgpu_bo_ref(mapping->bo_va->base.bo); + ib_refs[i].offset = va_start - + mapping->start * AMDGPU_GPU_PAGE_SIZE; + } + + amdgpu_bo_unreserve(root); + amdgpu_bo_unref(&root); + + return ib_refs; +} + +static void +amdgpu_devcoredump_release_ib_refs(struct amdgpu_devcoredump_ib_ref *ib_refs, + int num_ibs) +{ + if (!ib_refs) + return; + + for (int i = 0; i < num_ibs; i++) + if (ib_refs[i].bo) + amdgpu_bo_unref(&ib_refs[i].bo); + kfree(ib_refs); +} + static ssize_t amdgpu_devcoredump_format(char *buffer, size_t count, struct amdgpu_coredump_info *coredump) { @@ -214,13 +280,11 @@ amdgpu_devcoredump_format(char *buffer, size_t count, struct amdgpu_coredump_inf struct drm_printer p; struct drm_print_iterator iter; struct amdgpu_vm_fault_info *fault_info; - struct amdgpu_bo_va_mapping *mapping; struct amdgpu_ip_block *ip_block; struct amdgpu_res_cursor cursor; - struct amdgpu_bo *abo, *root; - uint64_t va_start, offset; + struct amdgpu_bo *abo; + uint64_t offset; struct amdgpu_ring *ring; - struct amdgpu_vm *vm; u32 *ib_content; uint8_t *kptr; int ver, i, j, r; @@ -343,43 +407,52 @@ amdgpu_devcoredump_format(char *buffer, size_t count, struct amdgpu_coredump_inf drm_printf(&p, "VRAM is lost due to GPU reset!\n"); if (coredump->num_ibs) { - /* Don't try to lookup the VM or map the BOs when calculating the - * size required to store the devcoredump. + struct amdgpu_devcoredump_ib_ref *ib_refs = NULL; + + /* + * Snapshot per-IB BO references under the root PD's reservation, + * then release the root before reserving each IB BO individually + * to copy its contents. + * + * Reserving an IB BO while the root PD is still reserved would + * be a nested ww_mutex acquire on reservation_ww_class_mutex + * without a ww_acquire_ctx, which trips lockdep's recursive- + * locking check and self-deadlocks for IB BOs that share their + * dma_resv with the root PD (always-valid BOs). + * + * Skip lookup/reservation entirely on the sizing pass: it does + * not write IB content, and the size estimate doesn't depend on + * whether the BOs are reachable. */ - if (sizing_pass) - vm = NULL; - else - vm = amdgpu_vm_lock_by_pasid(adev, &root, coredump->pasid); + if (!sizing_pass) + ib_refs = amdgpu_devcoredump_collect_ib_refs(adev, coredump); - for (int i = 0; i < coredump->num_ibs && (sizing_pass || vm); i++) { + for (int i = 0; i < coredump->num_ibs; i++) { ib_content = kvmalloc_array(coredump->ibs[i].ib_size_dw, 4, GFP_KERNEL); if (!ib_content) continue; - /* vm=NULL can only happen when 'sizing_pass' is true. Skip to the - * drm_printf() calls (ib_content doesn't need to be initialized - * as its content won't be written anywhere). - */ - if (!vm) + if (sizing_pass) goto output_ib_content; - va_start = coredump->ibs[i].gpu_addr & AMDGPU_GMC_HOLE_MASK; - mapping = amdgpu_vm_bo_lookup_mapping(vm, va_start / AMDGPU_GPU_PAGE_SIZE); - if (!mapping) - goto free_ib_content; + if (!ib_refs || !ib_refs[i].bo) + goto output_ib_content; + + abo = ib_refs[i].bo; + offset = ib_refs[i].offset; - offset = va_start - (mapping->start * AMDGPU_GPU_PAGE_SIZE); - abo = amdgpu_bo_ref(mapping->bo_va->base.bo); r = amdgpu_bo_reserve(abo, false); if (r) - goto free_ib_content; + goto output_ib_content; if (abo->flags & AMDGPU_GEM_CREATE_NO_CPU_ACCESS) { off = 0; - if (abo->tbo.resource->mem_type != TTM_PL_VRAM) - goto unreserve_abo; + if (abo->tbo.resource->mem_type != TTM_PL_VRAM) { + amdgpu_bo_unreserve(abo); + goto output_ib_content; + } amdgpu_res_first(abo->tbo.resource, offset, coredump->ibs[i].ib_size_dw * 4, @@ -395,8 +468,10 @@ amdgpu_devcoredump_format(char *buffer, size_t count, struct amdgpu_coredump_inf r = ttm_bo_kmap(&abo->tbo, 0, PFN_UP(abo->tbo.base.size), &abo->kmap); - if (r) - goto unreserve_abo; + if (r) { + amdgpu_bo_unreserve(abo); + goto output_ib_content; + } kptr = amdgpu_bo_kptr(abo); kptr += offset; @@ -406,21 +481,19 @@ amdgpu_devcoredump_format(char *buffer, size_t count, struct amdgpu_coredump_inf amdgpu_bo_kunmap(abo); } + amdgpu_bo_unreserve(abo); + output_ib_content: drm_printf(&p, "\nIB #%d 0x%llx %d dw\n", i, coredump->ibs[i].gpu_addr, coredump->ibs[i].ib_size_dw); - for (int j = 0; j < coredump->ibs[i].ib_size_dw; j++) - drm_printf(&p, "0x%08x\n", ib_content[j]); -unreserve_abo: - if (vm) - amdgpu_bo_unreserve(abo); -free_ib_content: + if (!sizing_pass && ib_refs && ib_refs[i].bo) { + for (int j = 0; j < coredump->ibs[i].ib_size_dw; j++) + drm_printf(&p, "0x%08x\n", ib_content[j]); + } kvfree(ib_content); } - if (vm) { - amdgpu_bo_unreserve(root); - amdgpu_bo_unref(&root); - } + + amdgpu_devcoredump_release_ib_refs(ib_refs, coredump->num_ibs); } return count - iter.remain; -- 2.54.0

11 hours, 5 minutes

[PATCH 00/15] accel/qda: Qualcomm DSP Accelerator driver

by Ekansh Gupta via B4 Relay

This patch series introduces the Qualcomm DSP Accelerator (QDA) driver, a DRM-based accelerator driver for Qualcomm DSPs. The driver provides a standardized interface for offloading computational tasks to DSPs found on Qualcomm SoCs, supporting all DSP domains. The QDA driver implements the FastRPC protocol over the DRM accel subsystem. It uses the same device-tree node structure as the existing fastrpc driver in drivers/misc/. The approach for binding the QDA driver to device-tree nodes while coexisting with the fastrpc driver is an open item described below. RFC thread: https://lore.kernel.org/dri-devel/20260224-qda-firstpost-v1-0-fe46a9c1a046@… User-space staging branch ========================= https://github.com/qualcomm/fastrpc/tree/accel/staging Key Features ============ * Standard DRM accelerator interface via /dev/accel/accelN * GEM-based buffer management with DMA-BUF import/export (PRIME) * IOMMU-based memory isolation using per-process context banks * FastRPC protocol implementation for DSP communication * RPMsg transport layer for reliable message passing * Support for all DSP domains (ADSP, CDSP, SDSP, GDSP) * DRM IOCTL interface for DSP session management, buffer allocation, and remote procedure invocation Architecture ============ 1. DRM Accelerator Framework Integration The driver registers as a DRM accel device, exposing a standard /dev/accel/accelN character device node. This provides established DRM infrastructure for device management, file operations, and IOCTL dispatch. 2. Memory Management Buffers are managed as GEM objects with full PRIME support for DMA-BUF import/export. This enables seamless buffer sharing with other DRM drivers (GPU, camera, video) using standard kernel mechanisms. 3. IOMMU Context Bank Management IOMMU context banks (CBs) are represented as proper struct device instances on a custom virtual bus (qda-compute-cb). Each CB device is registered with the IOMMU subsystem and receives its own IOMMU domain, enabling per-session address space isolation. The custom bus was introduced because IOMMU context banks are synthetic constructs — not real platform devices — and to ensure CB device lifetime is strictly subordinate to the parent QDA device. See also: https://lore.kernel.org/all/245d602f-3037-4ae3-9af9-d98f37258aae@oss.qualco… 4. Memory Manager Architecture A pluggable memory manager coordinates IOMMU device assignment and buffer allocation. The current implementation uses a DMA-coherent backend with SID-prefixed DMA addresses for DSP firmware compatibility. 5. Transport Layer RPMsg communication is handled in a dedicated transport layer (qda_rpmsg.c), separate from the core DRM driver logic. 6. Code Organization The driver is organized across multiple files (~4600 lines total): * qda_drv.c: Core driver and DRM integration * qda_rpmsg.c: RPMsg transport layer * qda_cb.c: Context bank device management * qda_compute_bus.c: Custom virtual bus for CB devices * qda_gem.c: GEM object management * qda_prime.c: DMA-BUF import (PRIME) * qda_memory_manager.c: IOMMU device registry and allocation * qda_memory_dma.c: DMA-coherent allocation backend * qda_fastrpc.c: FastRPC protocol implementation * qda_ioctl.c: IOCTL dispatch 7. UAPI Design The driver exposes DRM-style IOCTLs defined in include/uapi/drm/qda_accel.h, following DRM UAPI conventions (__u32/__u64 types, C++ guard, GPL-2.0-only WITH Linux-syscall-note). Patch Series Organization ========================== Patch 01: MAINTAINERS entry Patch 02: Driver documentation (Documentation/accel/qda/) Patches 03-04: Core driver skeleton and compute bus Patch 05: iommu: Register qda-compute-cb bus with IOMMU subsystem Patches 06-07: CB device enumeration and memory manager Patch 08: QUERY IOCTL and UAPI header Patches 09-11: GEM buffer management and PRIME import Patches 12-15: FastRPC protocol (invoke, session create/release, map/unmap) Open Items =========== 1. Device-Tree Compatible String The QDA driver uses the same device-tree node structure and properties as the existing fastrpc driver in drivers/misc/. A mechanism is needed to allow the QDA driver to bind to its device node independently of the fastrpc driver. The intended coexistence model is: platforms that require the complete fastrpc feature set continue to use "qcom,fastrpc"; new platforms where a feature available only in QDA takes priority, or where QDA's current feature set is sufficient, use a QDA-specific compatible string. New feature development is directed toward QDA rather than the existing fastrpc driver. As QDA matures toward feature parity with fastrpc, platforms can adopt the QDA-specific compatible string exclusively. The options under consideration are: a) Add a new "qcom,qda" compatible string to the existing qcom,fastrpc.yaml binding, since the DT node structure and properties are identical. This avoids a separate binding file but adds a QDA-specific string to a fastrpc binding. b) Introduce a separate qcom,qda.yaml binding that references or inherits the fastrpc binding properties. Seeking guidance from DT binding maintainers on the preferred approach. 2. Privilege Level Management Currently, daemon processes and user processes have the same access level as both use the same accel device node. This needs to be addressed as daemons attach to privileged DSP protection domains and require higher privilege levels for system-level operations. Seeking guidance on the best approach: separate device nodes, capability-based checks, or DRM master/authentication mechanisms. 3. UAPI Compatibility Layer A compatibility layer is needed to facilitate migration of client applications from the existing FastRPC UAPI to the new QDA UAPI, ensuring a smooth transition for existing userspace code. Seeking guidance on the preferred implementation approach: in-kernel translation layer, userspace wrapper library, or hybrid solution. An initial evaluation of an in-kernel translation shim was performed, where legacy FastRPC device nodes (/dev/fastrpc-*) are exposed and requests are internally routed to the QDA accel driver. The goal was to keep the compatibility layer minimal, reuse existing QDA helper paths (attach, buffer allocation, mapping, etc.), and avoid duplication of GEM and buffer management logic. However, the following challenges were identified: a) Dependency on drm_file for QDA helpers QDA relies on GEM-backed allocations and per-client handle namespaces, which require a valid struct drm_file. Since GEM handles are scoped per drm_file, the compatibility layer cannot directly reuse QDA helper paths without establishing a proper drm_file context for each client. b) Lack of public API for drm_file creation Creating a drm_file directly (similar to mock_drm_getfile()-style approaches) is not feasible, as the required helpers (drm_file_alloc(), drm_file_free(), etc.) are internal to the DRM core and not exported. This prevents external drivers from safely constructing and managing drm_file instances. c) VFS-based open is not a viable solution Opening the underlying accel device (/dev/accel/accelN) from the compatibility driver via filp_open() does provide a valid drm_file, but introduces reliance on userspace-visible device paths, lack of stability in containerized or chroot environments, and no clean mapping between legacy device nodes and accel devices. d) Userspace proxy limitations (CUSE) A CUSE-based userspace proxy was evaluated. However, DMA-buf file descriptors passed by legacy applications cannot be directly reused in the CUSE daemon (file descriptors are process-specific), which breaks buffer sharing semantics. e) drm_client-based approaches do not match requirements drm_client APIs (used for fbdev emulation) rely on a shared drm_file and do not provide the per-client isolation required by FastRPC semantics. Due to the above constraints, it is currently unclear how to implement an in-kernel compatibility layer that correctly handles per-client drm_file contexts without relying on VFS paths or non-exported DRM internals. 4. Documentation Improvements Add detailed IOCTL usage examples, document DSP firmware interface requirements, and create a migration guide from the existing FastRPC driver. 5. Per-Session Memory Allocation Develop a userspace API to support memory allocation on a per-session basis, enabling session-specific memory management. 6. Audio and Sensors PD Support The current series does not handle Audio PD and Sensors PD functionalities. These specialized protection domains require additional support for real-time constraints and power management. Interface Compatibility ======================== The QDA driver uses the same device-tree node structure and child node layout (including "qcom,fastrpc-compute-cb" child nodes) as the existing fastrpc driver. The underlying FastRPC protocol and DSP firmware interface are compatible with the existing fastrpc driver, ensuring that DSP firmware and libraries continue to work without modification. References ========== Previous discussions on this migration: - https://lkml.org/lkml/2024/6/24/479 - https://lkml.org/lkml/2024/6/21/1252 Testing ======= The driver has been tested on Qualcomm platforms with: - Basic FastRPC attach/release operations - DSP process creation and initialization - Memory mapping/unmapping operations - Dynamic invocation with various buffer types - GEM buffer allocation and mmap - PRIME buffer import from other subsystems Signed-off-by: Ekansh Gupta <ekansh.gupta(a)oss.qualcomm.com> --- Ekansh Gupta (15): MAINTAINERS: Add entry for Qualcomm DSP Accelerator (QDA) driver accel/qda: Add QDA driver documentation accel/qda: Add initial QDA DRM accelerator driver accel/qda: Add compute bus for QDA context banks iommu: Add QDA compute context bank bus to iommu_buses accel/qda: Create compute context bank devices on QDA compute bus accel/qda: Add memory manager for CB devices accel/qda: Add QUERY IOCTL and QDA UAPI header accel/qda: Add DMA-backed GEM objects and memory manager integration accel/qda: Add GEM_CREATE and GEM_MMAP_OFFSET IOCTLs accel/qda: Add PRIME DMA-BUF import support accel/qda: Add FastRPC invocation support accel/qda: Add DSP process creation and release accel/qda: Add remote memory mapping to DSP address space accel/qda: Add remote memory unmap from DSP address space Documentation/accel/index.rst | 1 + Documentation/accel/qda/index.rst | 13 + Documentation/accel/qda/qda.rst | 146 +++++ MAINTAINERS | 9 + drivers/accel/Kconfig | 1 + drivers/accel/Makefile | 2 + drivers/accel/qda/Kconfig | 34 + drivers/accel/qda/Makefile | 19 + drivers/accel/qda/qda_cb.c | 146 +++++ drivers/accel/qda/qda_cb.h | 32 + drivers/accel/qda/qda_compute_bus.c | 68 ++ drivers/accel/qda/qda_drv.c | 192 ++++++ drivers/accel/qda/qda_drv.h | 91 +++ drivers/accel/qda/qda_fastrpc.c | 1058 ++++++++++++++++++++++++++++++++ drivers/accel/qda/qda_fastrpc.h | 390 ++++++++++++ drivers/accel/qda/qda_gem.c | 177 ++++++ drivers/accel/qda/qda_gem.h | 62 ++ drivers/accel/qda/qda_ioctl.c | 296 +++++++++ drivers/accel/qda/qda_ioctl.h | 19 + drivers/accel/qda/qda_memory_dma.c | 110 ++++ drivers/accel/qda/qda_memory_dma.h | 17 + drivers/accel/qda/qda_memory_manager.c | 380 ++++++++++++ drivers/accel/qda/qda_memory_manager.h | 75 +++ drivers/accel/qda/qda_prime.c | 184 ++++++ drivers/accel/qda/qda_prime.h | 18 + drivers/accel/qda/qda_rpmsg.c | 248 ++++++++ drivers/accel/qda/qda_rpmsg.h | 30 + drivers/iommu/iommu.c | 4 + include/linux/qda_compute_bus.h | 32 + include/uapi/drm/qda_accel.h | 229 +++++++ 30 files changed, 4083 insertions(+) --- base-commit: 80dd246accce631c328ea43294e53b2b2dd2aa32 change-id: 20260519-qda-series-78c2bf0ed78b Best regards, -- Ekansh Gupta <ekansh.gupta(a)oss.qualcomm.com>

11 hours, 53 minutes

Re: [PATCH 00/12] misc/syncobj: add /dev/syncobj device

by Christian König

On 5/20/26 14:33, Xaver Hugl wrote: > Am Mi., 20. Mai 2026 um 10:08 Uhr schrieb Christian König > <christian.koenig(a)amd.com>: >> Well I would say the other way around is a pretty common use case. >> >> In other words the compositors uses the internal GPU for composing and displaying the picture. And the client uses the external GPU for fast rendering. > Sure, but that's not what I'm talking about. Yeah sorry for that, I wasn't sure if I misunderstood your use case because it's usually the other way around. >>> - the buffers from the client stay valid >> >> Buffers from the hot plugged GPU don't stay valid. Accessing CPU mappings either result in a SIGBUS or are redirected to a dummy page. > Again, not what I wrote about. The buffers are on the integrated GPU. General rule of thumb is that as long as the exporter stays around the buffers stay around as well. >>> - the syncobj stays valid on the client side >>> - the syncobj becomes invalid on the compositor side >> >> Nope that's not correct. The syncobj itself stays valid even if you completely hot plug the device. >> >> It can just be that the fences inside the syncobj are terminated with an error. > What about eventfd created for a point on the syncobj? The eventfd unfortunately doesn't has error handling as far as I know, so when a fence signals with an error condition then the eventfd you only sees that it is signaled. > Another (future) problem with hotplugs will be if the sync file hasn't > materialized for the timeline point when the device is hotunplugged, > since there can't be an error on the fence if there isn't one. Or > could userspace somehow set an 'artificial' fence with an error in > that case? In general the answer is yes, userspace needs to take care of inserting fences when wait before signal is used and the work can not be submitted to the HW for some reason. Currently we only have an IOCTL to insert the signaled dummy fence at some timeline sequence, but it should be trivial as well to insert a signaled fence with an error code. But the compositor needs to be able to handle that case anyway, because it can be that a malicious or just buggy client just never inserts the fence. So that a device is hot plugged is not different to just a client not inserting the fence in the first place. >>> "invalid" there means either >>> - the acquire point of the client is marked as signaled, before >>> rendering on the client side is completed >>> - the acquire point of the client is never signaled. Since the >>> compositor waits for the acquire point, the Wayland surface is stuck >>> forever >> >> Both of those would be a *massive* violation of documented kernel rules for hot-plugging which could lead to random data corruption and/or deadlocks. >> >> If you see any HW driver showing behavior like that please open up a bug report and ping the relevant maintainers immediately. > If there are no error codes with syncobj yet, then to userspace, the > latter behavior is exactly what we get, isn't it? No, from userspace side you just see a signaled fence. It's just that you need to export the timeline point of the syncobj to a syncfile and then you can call the QUERY IOCTL on the syncfile to see the error code. >> When a hotplug happens all operations of the device should return an -ENODEV error, even when exposed to other devices/application through syncobj or syncfile. > Okay, that at least gives us a way to fail imports somewhat > gracefully. Normally, failing to import a syncobj is a fatal error in > the Wayland protocol. So the task at hand would be to avoid importing the syncobj into a driver. That should be relatively trivial. The only real problem I see is if you want to create a syncobj without having any device whatsoever. >> One problem is that only syncfile allows for querying such error codes at the moment, we have patches pending to add that to syncobj as well but we lack a compositor with support for that as userspace client. > As long as the error case can be detected with an eventfd, Yeah that's the problem. The eventfd only tells you if the operation is completed (or at least has materialized). To query the error you would need to ask the underlying syncobj or syncfile directly. > implementing that in KWin shouldn't be a challenge. > >> Well the question here is if the device the compositor is using or the client is using is gone? >> >> If the client device is hot removed the compositor should be perfectly capable to import the syncobj. >> >> If the compositor device is gone then you don't have a device to display anything any more, so generating the next frame doesn't seem to make sense either. >> >> What could be is that you want the compositor to be kept alive even when the display device is gone to switch over to vkms or whatever so that a VNC session or other remote desktop still works. > There are two GPUs in the example I gave. The compositor can use both > for rendering (in cosmic-comp's case) or switch between them (what I'm > trying to do with KWin), or use one device for rendering, and another > for importing the syncobj. Ah! I think I got the problem now. You basically want to avoid importing the syncobj because when the wrong device goes away you are busted. The reason we didn't considered having the IOCTLs on the FD is because if you don't import them and instead keep them around you can run out file descriptors quite quickly. When you have an use case where you receive an FD from the client and do a one shot conversion to an eventfd that will probably work, but for keeping them in the long run you need some kind of container for the syncobjs, don't you? >>>>>>> 3. It removes the need to translate between syncobjs fds and handles. >>>>>> >>>>>> That's a pretty big no-go as well. The differentiation between FDs and handles is completely intentional. >>>>> Could you expand on why it's needed? For compositors, the handle is >>>>> just an intermediary thing when translating between file descriptors. >>>> >>>> Well what we could do is to add an IOCTL to directly attach an syncobj file descriptor to an eventfd. >>> That would be nice. >> >> Take a look at drm_syncobj_file_fops and how drm_syncobj_add_eventfd() is used. Adding that functionality shouldn't be more than a typing exercise. > Yeah, this patchset already adds that functionality (on the new device). > >> Do I see it right that this would already solve most problems in the compositor side? > Skipping the syncobj handle step would only reduce the amounts of > ioctls the compositor does, but afaict it wouldn't solve any > compositor problems. At least not as long as it's still tied to a drm > device. Yeah, you need something like a syncobj container or dummy DRM device. > For device hotplugs, the only new thing we need for correctly handling > syncobj is a way to receive errors on the eventfd. I need to look into the eventfd code, could be that this is somehow possible but it's clearly not something I used before. > A device-independent way to create and use syncobj would still be > useful to us though, both to simplify the compositor and to improve > the software rendering use cases. Yeah not sure how to cleanly do that. We could have a dummy /dev/dri/rendersync or something like that, but that would be quite a hack. At least I understand the requirement now. Thanks, Christian. > > - Xaver

12 hours, 16 minutes

Re: [PATCH 00/12] misc/syncobj: add /dev/syncobj device

by Christian König

On 5/19/26 17:31, Xaver Hugl wrote: > Am Di., 19. Mai 2026 um 15:29 Uhr schrieb Christian König > <christian.koenig(a)amd.com>: >>> 1. This series makes the ability to manipulate syncobjs available >>> independently of attached hardware. >>> 2. It makes it available under a consistent path /dev/syncobj. >> >> Exactly that is a big no-go. This has to be under /dev/dri. > FWIW udmabuf is also under /dev directly, but I don't think any > compositor developer would complain about a different path. > What are the rules for that? Could this simply be put in /dev/dri/syncobj? The syncobj are actually the DRM specific way of doing things. The general kernel wide way is to use sync files (see drivers/dma-buf/sync_file.c). But there has already been tons of problems with those sync files. E.g. they doesn't support your use case at all since they don't have wait before submit behavior. So there are already ways to do this, but the Linux kernel so far told everybody that this is forbidden. The DRM syncobj wait before signal functionality is much better, but then basically the second try to do this. > The part where we get this independent of attached hardware is quite > important for us though, since we can't just ignore explicit sync once > the device we previously imported the syncobj into is disconnected. Can you elaborate more on this? > Buffers can be from any device or allocated in system memory and > access should be synchronized properly in all cases. > > How exactly it's made available isn't all that critical. > >>> 3. It removes the need to translate between syncobjs fds and handles. >> >> That's a pretty big no-go as well. The differentiation between FDs and handles is completely intentional. > Could you expand on why it's needed? For compositors, the handle is > just an intermediary thing when translating between file descriptors. Well what we could do is to add an IOCTL to directly attach an syncobj file descriptor to an eventfd. > FTR for me at least, this part would be merely nice to have, since it > slightly reduces the amount of ioctls a compositor needs to call, but > it's not important. > >>>> What about using VGEM for this? >>> >>> If the vgem render node were made available unconditionally under, >> >> Software rendering is a complete corner case, I don't think that this will be enabled by default. > That simply makes vgem unsuitable for solving the problems we face in > compositors. Thinking more about it vgem also has the same issues as sync file mentioned above. So that is really also not doable. Maybe Simona or David have another idea. Regards, Christian. > > - Xaver

14 hours, 37 minutes

[PATCH v3 00/10] Add dmabuf read/write via io_uring

by Pavel Begunkov

The patch set allows to register a dmabuf to an io_uring instance for a specified file and use it with io_uring read / write requests. The infrastructure is not tied to io_uring and there could be more users in the future. A similar idea was attempted some years ago by Keith [1], from where I borrowed a good number of changes, and later was brough up by Tushar and Vishal from Intel. It's an opt-in feature for files, and they need to implement a new file operation to use it. Only NVMe block devices are supported in this series. The user API is built on top of io_uring's "registered buffers", where a dmabuf is registered in a special way, but after it can be used as any other "registered buffer" with IORING_OP_{READ,WRITE}_FIXED requests. It's created via a new file operation and the resulted map is then passed through the I/O stack in a new iterator type. There is some additional infrastructure to bind it all, which also counts requests using a dmabuf map and managing lifetimes, which is used to implement map invalidation. It was tested for GPU <-> NVMe transfers. Also, as it maintains a long-term dma mapping, it helps with the IOMMU cost. The numbers below are for udmabuf reads previously run by Anuj for different IOMMU modes: - STRICT: before = 570 KIOPS, after = 5.01 MIOPS - LAZY: before = 1.93 MIOPS, after = 5.01 MIOPS - PASSTHROUGH: before = 5.01 MIOPS, after = 5.01 MIOPS There are some liburing tests that can serve as an example: git: https://github.com/isilence/liburing.git rw-dmabuf-tests-v3 url: https://github.com/isilence/liburing/tree/rw-dmabuf-tests-v3 [1] https://lore.kernel.org/io-uring/20220805162444.3985535-1-kbusch@fb.com/ v3: - Rework io_uring registration - Move token/map infrastructure code out of blk-mq - Simplify callbacks: remove a separate blk-mq table, which was mostly just forwarding calls (to nvme). - Don't skip dma sync depending on request direction - Fix a couple of hangs - Rename s/dma/dmabuf/ - Other small changes v2: - Don't pass raw dma addresses, wrap it into a driver specific object - Split into two objects: token and map - Implement move_notify Pavel Begunkov (10): file: add callback for creating long-term dmabuf maps iov_iter: add iterator type for dmabuf maps block: move bvec init into __bio_clone block: introduce dma map backed bio type lib: add dmabuf token infrastructure block: forward create_dmabuf_token to drivers nvme-pci: implement dma_token backed requests io_uring/rsrc: introduce buf registration structure io_uring/rsrc: extend buffer update io_uring/rsrc: add dmabuf backed registered buffers block/bio.c | 28 +++- block/blk-merge.c | 14 ++ block/blk.h | 3 +- block/fops.c | 16 ++ drivers/nvme/host/pci.c | 282 ++++++++++++++++++++++++++++++++ include/linux/bio.h | 19 ++- include/linux/blk-mq.h | 9 + include/linux/blk_types.h | 8 +- include/linux/fs.h | 2 + include/linux/io_dmabuf_token.h | 92 +++++++++++ include/linux/io_uring_types.h | 5 + include/linux/uio.h | 11 ++ include/uapi/linux/io_uring.h | 31 +++- io_uring/io_uring.c | 3 +- io_uring/rsrc.c | 266 +++++++++++++++++++++++++----- io_uring/rsrc.h | 30 +++- io_uring/rw.c | 4 +- lib/Kconfig | 4 + lib/Makefile | 2 + lib/io_dmabuf_token.c | 272 ++++++++++++++++++++++++++++++ lib/iov_iter.c | 29 +++- 21 files changed, 1071 insertions(+), 59 deletions(-) create mode 100644 include/linux/io_dmabuf_token.h create mode 100644 lib/io_dmabuf_token.c -- 2.53.0

17 hours, 52 minutes

Re: [PATCH 00/12] misc/syncobj: add /dev/syncobj device

by Christian König

On 5/19/26 19:08, Xaver Hugl wrote: >>> The part where we get this independent of attached hardware is quite >>> important for us though, since we can't just ignore explicit sync once >>> the device we previously imported the syncobj into is disconnected. >> >> Can you elaborate more on this? > > In Wayland, the client is allowed to attach dmabuf and syncobj > independently, they don't have to be from the same device (and the > compositor wouldn't be able to verify the opposite anyways). The > compositor will usually import both into the same drm device, but > especially with compositors that render on multiple devices, that's > not necessarily the case either. > > If for example we had a system with one internal GPU and one external > GPU, the client renders on the internal GPU and the compositor uses > the external one. Now when the user yanks the USB C cable, afaiu Well I would say the other way around is a pretty common use case. In other words the compositors uses the internal GPU for composing and displaying the picture. And the client uses the external GPU for fast rendering. > - the buffers from the client stay valid Buffers from the hot plugged GPU don't stay valid. Accessing CPU mappings either result in a SIGBUS or are redirected to a dummy page. DMA operations to hot plugged buffers from other GPUs (or rather more general other devices) are waited on before the underlying resource is removed (e.g. system memory or PCIe address space or whatever is backing that). But no new DMA operations are usually permitted to start. > - the syncobj stays valid on the client side > - the syncobj becomes invalid on the compositor side Nope that's not correct. The syncobj itself stays valid even if you completely hot plug the device. It can just be that the fences inside the syncobj are terminated with an error. > "invalid" there means either > - the acquire point of the client is marked as signaled, before > rendering on the client side is completed > - the acquire point of the client is never signaled. Since the > compositor waits for the acquire point, the Wayland surface is stuck > forever Both of those would be a *massive* violation of documented kernel rules for hot-plugging which could lead to random data corruption and/or deadlocks. If you see any HW driver showing behavior like that please open up a bug report and ping the relevant maintainers immediately. When a hotplug happens all operations of the device should return an -ENODEV error, even when exposed to other devices/application through syncobj or syncfile. One problem is that only syncfile allows for querying such error codes at the moment, we have patches pending to add that to syncobj as well but we lack a compositor with support for that as userspace client. > Afaik the latter is currently the case. The former wouldn't be much > better though, not when it's preventable. > > This is admittedly an edge case, but GPU hotunplug is something we try > to support as well as possible in Plasma, and all the edge cases cause > a lot of problems in combination and are a lot of headaches to handle > (or really work around) in the compositor. Well exactly that design is used in the Tesla 3 infotainment system for example. So GPU hotplug is actually a pretty common use case. > Another edge case is when the client asks the compositor to import the > syncobj, which can fail when a hotunplug is in process, and ends up > disconnecting the client for no fault of either client or compositor. Well the question here is if the device the compositor is using or the client is using is gone? If the client device is hot removed the compositor should be perfectly capable to import the syncobj. If the compositor device is gone then you don't have a device to display anything any more, so generating the next frame doesn't seem to make sense either. What could be is that you want the compositor to be kept alive even when the display device is gone to switch over to vkms or whatever so that a VNC session or other remote desktop still works. >>>>> 3. It removes the need to translate between syncobjs fds and handles. >>>> >>>> That's a pretty big no-go as well. The differentiation between FDs and handles is completely intentional. >>> Could you expand on why it's needed? For compositors, the handle is >>> just an intermediary thing when translating between file descriptors. >> >> Well what we could do is to add an IOCTL to directly attach an syncobj file descriptor to an eventfd. > That would be nice. Take a look at drm_syncobj_file_fops and how drm_syncobj_add_eventfd() is used. Adding that functionality shouldn't be more than a typing exercise. Do I see it right that this would already solve most problems in the compositor side? Regards, Christian. > > - Xaver

18 hours, 14 minutes

[PATCH] dma-buf: system_heap: Use LIST_HEAD() to initialize on stack list head

by Jisheng Zhang

Use LIST_HEAD to initialize on stack list head. No intentional functional impact. Change generated with below coccinelle script: @@ identifier name; @@ - struct list_head name; + LIST_HEAD(name); ... when != name - INIT_LIST_HEAD(&name); Signed-off-by: Jisheng Zhang <jszhang(a)kernel.org> --- drivers/dma-buf/heaps/system_heap.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/drivers/dma-buf/heaps/system_heap.c b/drivers/dma-buf/heaps/system_heap.c index 03c2b87cb111..6f8b7138ff56 100644 --- a/drivers/dma-buf/heaps/system_heap.c +++ b/drivers/dma-buf/heaps/system_heap.c @@ -409,7 +409,7 @@ static struct dma_buf *system_heap_allocate(struct dma_heap *heap, struct dma_buf *dmabuf; struct sg_table *table; struct scatterlist *sg; - struct list_head pages; + LIST_HEAD(pages); struct page *page, *tmp_page; int i, ret = -ENOMEM; @@ -423,7 +423,6 @@ static struct dma_buf *system_heap_allocate(struct dma_heap *heap, buffer->len = len; buffer->cc_shared = cc_shared; - INIT_LIST_HEAD(&pages); i = 0; while (size_remaining > 0) { /* -- 2.53.0

1 day, 3 hours

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