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drm: Add helpers for locking an array of BO reservations.

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Now that we have the reservation object in the GEM object, it's easy
to provide a helper for this common case.  Noticed while reviewing
panfrost and lima drivers.  This particular version came out of v3d,
which in turn was a copy from vc4.

v2: Fix kerneldoc warnings.

Signed-off-by: Eric Anholt <eric@anholt.net>
Link: https://patchwork.freedesktop.org/patch/msgid/20190308161716.2466-2-eric@anholt.net
Acked-by: Rob Herring <robh@kernel.org> (v1)
This commit is contained in:
Eric Anholt 2019-03-08 08:17:13 -08:00
parent f435fe83d5
commit 7edc3e3b97
2 changed files with 82 additions and 0 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

78
drivers/gpu/drm/drm_gem.c
View file

@ -1233,3 +1233,81 @@ void drm_gem_vunmap(struct drm_gem_object *obj, void *vaddr)
obj->dev->driver->gem_prime_vunmap(obj, vaddr);
}
EXPORT_SYMBOL(drm_gem_vunmap);
/**
* drm_gem_lock_reservations - Sets up the ww context and acquires
* the lock on an array of GEM objects.
*
* Once you've locked your reservations, you'll want to set up space
* for your shared fences (if applicable), submit your job, then
* drm_gem_unlock_reservations().
*
* @objs: drm_gem_objects to lock
* @count: Number of objects in @objs
* @acquire_ctx: struct ww_acquire_ctx that will be initialized as
* part of tracking this set of locked reservations.
*/
int
drm_gem_lock_reservations(struct drm_gem_object **objs, int count,
struct ww_acquire_ctx *acquire_ctx)
{
int contended = -1;
int i, ret;
ww_acquire_init(acquire_ctx, &reservation_ww_class);
retry:
if (contended != -1) {
struct drm_gem_object *obj = objs[contended];
ret = ww_mutex_lock_slow_interruptible(&obj->resv->lock,
acquire_ctx);
if (ret) {
ww_acquire_done(acquire_ctx);
return ret;
}
}
for (i = 0; i < count; i++) {
if (i == contended)
continue;
ret = ww_mutex_lock_interruptible(&objs[i]->resv->lock,
acquire_ctx);
if (ret) {
int j;
for (j = 0; j < i; j++)
ww_mutex_unlock(&objs[j]->resv->lock);
if (contended != -1 && contended >= i)
ww_mutex_unlock(&objs[contended]->resv->lock);
if (ret == -EDEADLK) {
contended = i;
goto retry;
}
ww_acquire_done(acquire_ctx);
return ret;
}
}
ww_acquire_done(acquire_ctx);
return 0;
}
EXPORT_SYMBOL(drm_gem_lock_reservations);
void
drm_gem_unlock_reservations(struct drm_gem_object **objs, int count,
struct ww_acquire_ctx *acquire_ctx)
{
int i;
for (i = 0; i < count; i++)
ww_mutex_unlock(&objs[i]->resv->lock);
ww_acquire_fini(acquire_ctx);
}
EXPORT_SYMBOL(drm_gem_unlock_reservations);

4
include/drm/drm_gem.h
View file

@ -384,6 +384,10 @@ void drm_gem_put_pages(struct drm_gem_object *obj, struct page **pages,
struct drm_gem_object *drm_gem_object_lookup(struct drm_file *filp, u32 handle);
long drm_gem_reservation_object_wait(struct drm_file *filep, u32 handle,
bool wait_all, unsigned long timeout);
int drm_gem_lock_reservations(struct drm_gem_object **objs, int count,
struct ww_acquire_ctx *acquire_ctx);
void drm_gem_unlock_reservations(struct drm_gem_object **objs, int count,
struct ww_acquire_ctx *acquire_ctx);
int drm_gem_dumb_map_offset(struct drm_file *file, struct drm_device *dev,
u32 handle, u64 *offset);
int drm_gem_dumb_destroy(struct drm_file *file,