From 18b862dcd57a3e23e34c8cd1e939f68548c1209a Mon Sep 17 00:00:00 2001 From: Chris Wilson Date: Fri, 18 Mar 2016 20:02:39 +0000 Subject: dma-buf, drm, ion: Propagate error code from dma_buf_start_cpu_access() MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Drivers, especially i915.ko, can fail during the initial migration of a dma-buf for CPU access. However, the error code from the driver was not being propagated back to ioctl and so userspace was blissfully ignorant of the failure. Rendering corruption ensues. Whilst fixing the ioctl to return the error code from dma_buf_start_cpu_access(), also do the same for dma_buf_end_cpu_access(). For most drivers, dma_buf_end_cpu_access() cannot fail. i915.ko however, as most drivers would, wants to avoid being uninterruptible (as would be required to guarrantee no failure when flushing the buffer to the device). As userspace already has to handle errors from the SYNC_IOCTL, take advantage of this to be able to restart the syscall across signals. This fixes a coherency issue for i915.ko as well as reducing the uninterruptible hold upon its BKL, the struct_mutex. Fixes commit c11e391da2a8fe973c3c2398452000bed505851e Author: Daniel Vetter Date: Thu Feb 11 20:04:51 2016 -0200 dma-buf: Add ioctls to allow userspace to flush Testcase: igt/gem_concurrent_blit/*dmabuf*interruptible Testcase: igt/prime_mmap_coherency/ioctl-errors Signed-off-by: Chris Wilson Cc: Tiago Vignatti Cc: Stéphane Marchesin Cc: David Herrmann Cc: Sumit Semwal Cc: Daniel Vetter CC: linux-media@vger.kernel.org Cc: dri-devel@lists.freedesktop.org Cc: linaro-mm-sig@lists.linaro.org Cc: intel-gfx@lists.freedesktop.org Cc: devel@driverdev.osuosl.org Signed-off-by: Daniel Vetter Link: http://patchwork.freedesktop.org/patch/msgid/1458331359-2634-1-git-send-email-chris@chris-wilson.co.uk --- drivers/staging/android/ion/ion.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) (limited to 'drivers/staging') diff --git a/drivers/staging/android/ion/ion.c b/drivers/staging/android/ion/ion.c index 0754a37c9674..49436b4510f4 100644 --- a/drivers/staging/android/ion/ion.c +++ b/drivers/staging/android/ion/ion.c @@ -1075,14 +1075,16 @@ static int ion_dma_buf_begin_cpu_access(struct dma_buf *dmabuf, return PTR_ERR_OR_ZERO(vaddr); } -static void ion_dma_buf_end_cpu_access(struct dma_buf *dmabuf, - enum dma_data_direction direction) +static int ion_dma_buf_end_cpu_access(struct dma_buf *dmabuf, + enum dma_data_direction direction) { struct ion_buffer *buffer = dmabuf->priv; mutex_lock(&buffer->lock); ion_buffer_kmap_put(buffer); mutex_unlock(&buffer->lock); + + return 0; } static struct dma_buf_ops dma_buf_ops = { -- cgit v1.2.3-59-g8ed1b