drivers/gpu/drm/msm/msm_drv.c | 8 +++--- drivers/gpu/drm/msm/msm_gem.c | 49 ----------------------------------- drivers/gpu/drm/msm/msm_gem.h | 3 --- 3 files changed, 5 insertions(+), 55 deletions(-)
The msm driver implements a custom dumb_map_offset callback. This
implementation acquires the msm_gem_lock, but the underlying
drm_gem_create_mmap_offset() function is already thread-safe regarding
the VMA offset manager (it acquires the mgr->vm_lock internally).
Switching to the generic drm_gem_dumb_map_offset() helper provides
several benefits:
1. Removes the unnecessary locking overhead (locking leftovers).
2. Adds a missing check to reject mapping of imported objects, which is
invalid for dumb buffers.
3. Allows for the removal of the msm_gem_dumb_map_offset() wrapper and
the msm_gem_mmap_offset() helper function.
The logic from msm_gem_mmap_offset() has been inlined into
msm_ioctl_gem_info() to maintain functionality without the separate
helper.
This addresses the TODO:
"Documentation/gpu/todo.rst: Remove custom dumb_map_offset implementations"
Signed-off-by: Swaraj Gaikwad <swarajgaikwad1925@gmail.com>
---
Compile-tested only.
drivers/gpu/drm/msm/msm_drv.c | 8 +++---
drivers/gpu/drm/msm/msm_gem.c | 49 -----------------------------------
drivers/gpu/drm/msm/msm_gem.h | 3 ---
3 files changed, 5 insertions(+), 55 deletions(-)
diff --git a/drivers/gpu/drm/msm/msm_drv.c b/drivers/gpu/drm/msm/msm_drv.c
index 7e977fec4100..bf20550c5814 100644
--- a/drivers/gpu/drm/msm/msm_drv.c
+++ b/drivers/gpu/drm/msm/msm_drv.c
@@ -588,7 +588,9 @@ static int msm_ioctl_gem_info(struct drm_device *dev, void *data,
switch (args->info) {
case MSM_INFO_GET_OFFSET:
- args->value = msm_gem_mmap_offset(obj);
+ ret = drm_gem_create_mmap_offset(obj);
+ if (ret == 0)
+ args->value = drm_vma_node_offset_addr(&obj->vma_node);
break;
case MSM_INFO_GET_IOVA:
ret = msm_ioctl_gem_info_iova(dev, file, obj, &args->value);
@@ -836,7 +838,7 @@ static const struct drm_driver msm_driver = {
.open = msm_open,
.postclose = msm_postclose,
.dumb_create = msm_gem_dumb_create,
- .dumb_map_offset = msm_gem_dumb_map_offset,
+ .dumb_map_offset = drm_gem_dumb_map_offset,
.gem_prime_import = msm_gem_prime_import,
.gem_prime_import_sg_table = msm_gem_prime_import_sg_table,
#ifdef CONFIG_DEBUG_FS
@@ -859,7 +861,7 @@ static const struct drm_driver msm_kms_driver = {
.open = msm_open,
.postclose = msm_postclose,
.dumb_create = msm_gem_dumb_create,
- .dumb_map_offset = msm_gem_dumb_map_offset,
+ .dumb_map_offset = drm_gem_dumb_map_offset,
.gem_prime_import_sg_table = msm_gem_prime_import_sg_table,
#ifdef CONFIG_DEBUG_FS
.debugfs_init = msm_debugfs_init,
diff --git a/drivers/gpu/drm/msm/msm_gem.c b/drivers/gpu/drm/msm/msm_gem.c
index 017411a0bf45..da74f1413f94 100644
--- a/drivers/gpu/drm/msm/msm_gem.c
+++ b/drivers/gpu/drm/msm/msm_gem.c
@@ -375,34 +375,6 @@ static vm_fault_t msm_gem_fault(struct vm_fault *vmf)
return ret;
}
-/** get mmap offset */
-static uint64_t mmap_offset(struct drm_gem_object *obj)
-{
- struct drm_device *dev = obj->dev;
- int ret;
-
- msm_gem_assert_locked(obj);
-
- /* Make it mmapable */
- ret = drm_gem_create_mmap_offset(obj);
-
- if (ret) {
- DRM_DEV_ERROR(dev->dev, "could not allocate mmap offset\n");
- return 0;
- }
-
- return drm_vma_node_offset_addr(&obj->vma_node);
-}
-
-uint64_t msm_gem_mmap_offset(struct drm_gem_object *obj)
-{
- uint64_t offset;
-
- msm_gem_lock(obj);
- offset = mmap_offset(obj);
- msm_gem_unlock(obj);
- return offset;
-}
static struct drm_gpuva *lookup_vma(struct drm_gem_object *obj,
struct drm_gpuvm *vm)
@@ -730,27 +702,6 @@ int msm_gem_dumb_create(struct drm_file *file, struct drm_device *dev,
MSM_BO_SCANOUT | MSM_BO_WC, &args->handle, "dumb");
}
-int msm_gem_dumb_map_offset(struct drm_file *file, struct drm_device *dev,
- uint32_t handle, uint64_t *offset)
-{
- struct drm_gem_object *obj;
- int ret = 0;
-
- /* GEM does all our handle to object mapping */
- obj = drm_gem_object_lookup(file, handle);
- if (obj == NULL) {
- ret = -ENOENT;
- goto fail;
- }
-
- *offset = msm_gem_mmap_offset(obj);
-
- drm_gem_object_put(obj);
-
-fail:
- return ret;
-}
-
static void *get_vaddr(struct drm_gem_object *obj, unsigned madv)
{
struct msm_gem_object *msm_obj = to_msm_bo(obj);
diff --git a/drivers/gpu/drm/msm/msm_gem.h b/drivers/gpu/drm/msm/msm_gem.h
index a4cf31853c50..92ada1d69250 100644
--- a/drivers/gpu/drm/msm/msm_gem.h
+++ b/drivers/gpu/drm/msm/msm_gem.h
@@ -262,7 +262,6 @@ struct msm_gem_object {
void msm_gem_vma_get(struct drm_gem_object *obj);
void msm_gem_vma_put(struct drm_gem_object *obj);
-uint64_t msm_gem_mmap_offset(struct drm_gem_object *obj);
int msm_gem_prot(struct drm_gem_object *obj);
int msm_gem_pin_vma_locked(struct drm_gem_object *obj, struct drm_gpuva *vma);
void msm_gem_unpin_locked(struct drm_gem_object *obj);
@@ -285,8 +284,6 @@ struct page **msm_gem_pin_pages_locked(struct drm_gem_object *obj);
void msm_gem_unpin_pages_locked(struct drm_gem_object *obj);
int msm_gem_dumb_create(struct drm_file *file, struct drm_device *dev,
struct drm_mode_create_dumb *args);
-int msm_gem_dumb_map_offset(struct drm_file *file, struct drm_device *dev,
- uint32_t handle, uint64_t *offset);
void *msm_gem_get_vaddr_locked(struct drm_gem_object *obj);
void *msm_gem_get_vaddr(struct drm_gem_object *obj);
void *msm_gem_get_vaddr_active(struct drm_gem_object *obj);
base-commit: 8f0b4cce4481fb22653697cced8d0d04027cb1e8
--
2.52.0On Mon, Dec 15, 2025 at 02:28:50AM +0000, Swaraj Gaikwad wrote: > The msm driver implements a custom dumb_map_offset callback. This > implementation acquires the msm_gem_lock, but the underlying > drm_gem_create_mmap_offset() function is already thread-safe regarding > the VMA offset manager (it acquires the mgr->vm_lock internally). Other pieces are using msm_gem_lock() / msm_gem_unlock(), which translates to dma_resv_lock() / dma_resv_unlock(), so you need to describe, why it's still safe wrt. that code. > > Switching to the generic drm_gem_dumb_map_offset() helper provides > several benefits: > 1. Removes the unnecessary locking overhead (locking leftovers). > 2. Adds a missing check to reject mapping of imported objects, which is > invalid for dumb buffers. > 3. Allows for the removal of the msm_gem_dumb_map_offset() wrapper and > the msm_gem_mmap_offset() helper function. > > The logic from msm_gem_mmap_offset() has been inlined into > msm_ioctl_gem_info() to maintain functionality without the separate > helper. > > This addresses the TODO: > "Documentation/gpu/todo.rst: Remove custom dumb_map_offset implementations" > > Signed-off-by: Swaraj Gaikwad <swarajgaikwad1925@gmail.com> > --- > > Compile-tested only. > -- With best wishes Dmitry
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