On Wed, Jun 21, 2023 at 11:16 AM Dmitry Osipenko <dmitry.osipenko@xxxxxxxxxxxxx> wrote: > > Hi, > > On 6/21/23 20:21, T.J. Mercier wrote: > > On Mon, May 29, 2023 at 3:46 PM Dmitry Osipenko > > <dmitry.osipenko@xxxxxxxxxxxxx> wrote: > >> > >> Don't assert held dma-buf reservation lock on memory mapping of exported > >> buffer. > >> > >> We're going to change dma-buf mmap() locking policy such that exporters > >> will have to handle the lock. The previous locking policy caused deadlock > >> problem for DRM drivers in a case of self-imported dma-bufs once these > >> drivers are moved to use reservation lock universally. The problem > >> solved by moving the lock down to exporters. This patch prepares dma-buf > >> heaps for the locking policy update. > >> > > Hi Dmitry, > > > > I see that in patch 6 of this series calls to > > dma_resv_lock/dma_resv_unlock have been added to the > > drm_gem_shmem_helper functions and some exporters. But I'm curious why > > no dma_resv_lock/dma_resv_unlock calls were added to these two dma-buf > > heap exporters for mmap? > > DMA-buf heaps are exporters, drm_gem_shmem_helper is importer. Locking > rules are different for importers and exporters. > > DMA-heaps use own locking, they can be moved to resv lock in the future. > > DMA-heaps don't protect internal data in theirs mmap() implementations, > nothing to protect there. > Thanks.
