On Wed, Nov 20, 2019 at 3:07 AM Rob Clark robdclark@gmail.com wrote:
On Tue, Nov 19, 2019 at 1:08 PM Daniel Vetter daniel.vetter@ffwll.ch wrote:
For locking semantics it really doesn't matter when we grab the ticket. But for lockdep validation it does: the acquire ctx is a fake lockdep. Since other drivers might want to do a full multi-lock dance in their fault-handler, not just lock a single dma_resv. Therefore we must init the acquire_ctx only after we've done all the copy_*_user or anything else that might trigger a pagefault. For msm this means we need to move it past submit_lookup_objects.
seems reasonable.. but maybe a comment would be useful to prevent future-me from "cleaning-this-up" back to the way it was
I'll add a comment.
with that, r-b
Well I spotted a bug for the error handling, I'll need to respin. -Daniel
Aside: Why is msm still using struct_mutex, it seems to be using dma_resv_lock for general buffer state protection?
only because I (or anyone else) hasn't had time to revisit the struct_mutex usage since we moved to per-object-locks.. the downside, I suppose, of kernel generally working ok and this not being a big enough fire to bubble up to the top of my todo list
BR, -R
Signed-off-by: Daniel Vetter daniel.vetter@intel.com Cc: Rob Clark robdclark@gmail.com Cc: Sean Paul sean@poorly.run Cc: linux-arm-msm@vger.kernel.org Cc: freedreno@lists.freedesktop.org
drivers/gpu/drm/msm/msm_gem_submit.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/msm/msm_gem_submit.c b/drivers/gpu/drm/msm/msm_gem_submit.c index fb1fdd7fa3ef..126b2f62bfe7 100644 --- a/drivers/gpu/drm/msm/msm_gem_submit.c +++ b/drivers/gpu/drm/msm/msm_gem_submit.c @@ -54,7 +54,6 @@ static struct msm_gem_submit *submit_create(struct drm_device *dev,
INIT_LIST_HEAD(&submit->node); INIT_LIST_HEAD(&submit->bo_list);
ww_acquire_init(&submit->ticket, &reservation_ww_class); return submit;} @@ -489,6 +488,7 @@ int msm_ioctl_gem_submit(struct drm_device *dev, void *data, if (ret) goto out;
ww_acquire_init(&submit->ticket, &reservation_ww_class); ret = submit_lock_objects(submit); if (ret) goto out;-- 2.24.0