All code paths which populate userptr BOs are fine with the get_pages
function taking the mmap_sem lock. This allows to get rid of the pretty
involved architecture with a worker being scheduled if the mmap_sem
needs to be taken, but instead call GUP directly and allow it to take
the lock if necessary.
This simplifies the code a lot and removes the possibility of this
function returning -EAGAIN, which complicates object population
handling at the callers.
Signed-off-by: Lucas Stach <l.st...@pengutronix.de>
---
drivers/gpu/drm/etnaviv/etnaviv_gem.c | 146 +++++-----------------------------
drivers/gpu/drm/etnaviv/etnaviv_gem.h | 3 +-
2 files changed, 23 insertions(+), 126 deletions(-)
diff --git a/drivers/gpu/drm/etnaviv/etnaviv_gem.c
b/drivers/gpu/drm/etnaviv/etnaviv_gem.c
index a52220eeee45..fcc969fa0e69 100644
--- a/drivers/gpu/drm/etnaviv/etnaviv_gem.c
+++ b/drivers/gpu/drm/etnaviv/etnaviv_gem.c
@@ -705,141 +705,41 @@ int etnaviv_gem_new_private(struct drm_device *dev,
size_t size, u32 flags,
return 0;
}
-struct get_pages_work {
- struct work_struct work;
- struct mm_struct *mm;
- struct task_struct *task;
- struct etnaviv_gem_object *etnaviv_obj;
-};
-
-static struct page **etnaviv_gem_userptr_do_get_pages(
- struct etnaviv_gem_object *etnaviv_obj, struct mm_struct *mm, struct
task_struct *task)
-{
- int ret = 0, pinned, npages = etnaviv_obj->base.size >> PAGE_SHIFT;
- struct page **pvec;
- uintptr_t ptr;
- unsigned int flags = 0;
-
- pvec = kvmalloc_array(npages, sizeof(struct page *), GFP_KERNEL);
- if (!pvec)
- return ERR_PTR(-ENOMEM);
-
- if (!etnaviv_obj->userptr.ro)
- flags |= FOLL_WRITE;
-
- pinned = 0;
- ptr = etnaviv_obj->userptr.ptr;
-
- down_read(&mm->mmap_sem);
- while (pinned < npages) {
- ret = get_user_pages_remote(task, mm, ptr, npages - pinned,
- flags, pvec + pinned, NULL, NULL);
- if (ret < 0)
- break;
-
- ptr += ret * PAGE_SIZE;
- pinned += ret;
- }
- up_read(&mm->mmap_sem);
-
- if (ret < 0) {
- release_pages(pvec, pinned);
- kvfree(pvec);
- return ERR_PTR(ret);
- }
-
- return pvec;
-}
-
-static void __etnaviv_gem_userptr_get_pages(struct work_struct *_work)
-{
- struct get_pages_work *work = container_of(_work, typeof(*work), work);
- struct etnaviv_gem_object *etnaviv_obj = work->etnaviv_obj;
- struct page **pvec;
-
- pvec = etnaviv_gem_userptr_do_get_pages(etnaviv_obj, work->mm,
work->task);
-
- mutex_lock(&etnaviv_obj->lock);
- if (IS_ERR(pvec)) {
- etnaviv_obj->userptr.work = ERR_CAST(pvec);
- } else {
- etnaviv_obj->userptr.work = NULL;
- etnaviv_obj->pages = pvec;
- }
-
- mutex_unlock(&etnaviv_obj->lock);
- drm_gem_object_put_unlocked(&etnaviv_obj->base);
-
- mmput(work->mm);
- put_task_struct(work->task);
- kfree(work);
-}
-
static int etnaviv_gem_userptr_get_pages(struct etnaviv_gem_object
*etnaviv_obj)
{
struct page **pvec = NULL;
- struct get_pages_work *work;
- struct mm_struct *mm;
- int ret, pinned, npages = etnaviv_obj->base.size >> PAGE_SHIFT;
+ struct etnaviv_gem_userptr *userptr = &etnaviv_obj->userptr;
+ int ret, pinned = 0, npages = etnaviv_obj->base.size >> PAGE_SHIFT;
might_lock_read(¤t->mm->mmap_sem);
- if (etnaviv_obj->userptr.work) {
- if (IS_ERR(etnaviv_obj->userptr.work)) {
- ret = PTR_ERR(etnaviv_obj->userptr.work);
- etnaviv_obj->userptr.work = NULL;
- } else {
- ret = -EAGAIN;
- }
- return ret;
- }
+ if (userptr->mm != current->mm)
+ return -EPERM;
- mm = get_task_mm(etnaviv_obj->userptr.task);
- pinned = 0;
- if (mm == current->mm) {
- pvec = kvmalloc_array(npages, sizeof(struct page *),
GFP_KERNEL);
- if (!pvec) {
- mmput(mm);
- return -ENOMEM;
- }
+ pvec = kvmalloc_array(npages, sizeof(struct page *), GFP_KERNEL);
+ if (!pvec)
+ return -ENOMEM;
+
+ do {
+ unsigned num_pages = npages - pinned;
+ uint64_t ptr = userptr->ptr + pinned * PAGE_SIZE;
+ struct page **pages = pvec + pinned;
- pinned = __get_user_pages_fast(etnaviv_obj->userptr.ptr, npages,
- !etnaviv_obj->userptr.ro, pvec);
- if (pinned < 0) {
+ ret = get_user_pages_fast(ptr, num_pages,
+ !userptr->ro ? FOLL_WRITE : 0, pages);
+ if (ret < 0) {
+ release_pages(pvec, pinned);
kvfree(pvec);
- mmput(mm);
- return pinned;
+ return ret;
}
- if (pinned == npages) {
- etnaviv_obj->pages = pvec;
- mmput(mm);
- return 0;
- }
- }
-
- release_pages(pvec, pinned);
- kvfree(pvec);
-
- work = kmalloc(sizeof(*work), GFP_KERNEL);
- if (!work) {
- mmput(mm);
- return -ENOMEM;
- }
-
- get_task_struct(current);
- drm_gem_object_get(&etnaviv_obj->base);
-
- work->mm = mm;
- work->task = current;
- work->etnaviv_obj = etnaviv_obj;
+ pinned += ret;
- etnaviv_obj->userptr.work = &work->work;
- INIT_WORK(&work->work, __etnaviv_gem_userptr_get_pages);
+ } while (pinned < npages);
- etnaviv_queue_work(etnaviv_obj->base.dev, &work->work);
+ etnaviv_obj->pages = pvec;
- return -EAGAIN;
+ return 0;
}
static void etnaviv_gem_userptr_release(struct etnaviv_gem_object *etnaviv_obj)
@@ -855,7 +755,6 @@ static void etnaviv_gem_userptr_release(struct
etnaviv_gem_object *etnaviv_obj)
release_pages(etnaviv_obj->pages, npages);
kvfree(etnaviv_obj->pages);
}
- put_task_struct(etnaviv_obj->userptr.task);
}
static int etnaviv_gem_userptr_mmap_obj(struct etnaviv_gem_object *etnaviv_obj,
@@ -885,9 +784,8 @@ int etnaviv_gem_new_userptr(struct drm_device *dev, struct
drm_file *file,
lockdep_set_class(&etnaviv_obj->lock, &etnaviv_userptr_lock_class);
etnaviv_obj->userptr.ptr = ptr;
- etnaviv_obj->userptr.task = current;
+ etnaviv_obj->userptr.mm = current->mm;
etnaviv_obj->userptr.ro = !(flags & ETNA_USERPTR_WRITE);
- get_task_struct(current);
etnaviv_gem_obj_add(dev, &etnaviv_obj->base);
diff --git a/drivers/gpu/drm/etnaviv/etnaviv_gem.h
b/drivers/gpu/drm/etnaviv/etnaviv_gem.h
index 00bd9c851a02..d1a7d040ac97 100644
--- a/drivers/gpu/drm/etnaviv/etnaviv_gem.h
+++ b/drivers/gpu/drm/etnaviv/etnaviv_gem.h
@@ -26,8 +26,7 @@ struct etnaviv_gem_object;
struct etnaviv_gem_userptr {
uintptr_t ptr;
- struct task_struct *task;
- struct work_struct *work;
+ struct mm_struct *mm;
bool ro;
};
--
2.11.0
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