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From: Dmitry Osipenko <dmitry.osipenko@collabora.com>
To: "Sumit Semwal" <sumit.semwal@linaro.org>,
	"Christian König" <christian.koenig@amd.com>,
	"Benjamin Gaignard" <benjamin.gaignard@collabora.com>,
	"Liam Mark" <lmark@codeaurora.org>,
	"Brian Starkey" <Brian.Starkey@arm.com>,
	"John Stultz" <jstultz@google.com>,
	"Gerd Hoffmann" <kraxel@redhat.com>,
	"Daniel Vetter" <daniel@ffwll.ch>,
	"Jani Nikula" <jani.nikula@linux.intel.com>,
	"Arnd Bergmann" <arnd@arndb.de>,
	"Thomas Zimmermann" <tzimmermann@suse.de>,
	"Tomi Valkeinen" <tomba@kernel.org>,
	"Thierry Reding" <thierry.reding@gmail.com>,
	"Tomasz Figa" <tfiga@chromium.org>,
	"Marek Szyprowski" <m.szyprowski@samsung.com>,
	"Mauro Carvalho Chehab" <mchehab@kernel.org>,
	"Emil Velikov" <emil.l.velikov@gmail.com>
Cc: linux-media@vger.kernel.org, dri-devel@lists.freedesktop.org,
	linux-kernel@vger.kernel.org, intel-gfx@lists.freedesktop.org,
	linux-tegra@vger.kernel.org, kernel@collabora.com
Subject: [PATCH v3 3/6] udmabuf: Don't assert held reservation lock for dma-buf mmapping
Date: Sun, 21 May 2023 23:51:09 +0300	[thread overview]
Message-ID: <20230521205112.150206-4-dmitry.osipenko@collabora.com> (raw)
In-Reply-To: <20230521205112.150206-1-dmitry.osipenko@collabora.com>

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 is
solved by moving the lock down to exporters. This patch prepares udmabuf
for the locking policy update.

Reviewed-by: Emil Velikov <emil.l.velikov@gmail.com>
Signed-off-by: Dmitry Osipenko <dmitry.osipenko@collabora.com>
---
 drivers/dma-buf/udmabuf.c | 2 --
 1 file changed, 2 deletions(-)

diff --git a/drivers/dma-buf/udmabuf.c b/drivers/dma-buf/udmabuf.c
index 01f2e86f3f7c..06729cd60136 100644
--- a/drivers/dma-buf/udmabuf.c
+++ b/drivers/dma-buf/udmabuf.c
@@ -52,8 +52,6 @@ static int mmap_udmabuf(struct dma_buf *buf, struct vm_area_struct *vma)
 {
 	struct udmabuf *ubuf = buf->priv;
 
-	dma_resv_assert_held(buf->resv);
-
 	if ((vma->vm_flags & (VM_SHARED | VM_MAYSHARE)) == 0)
 		return -EINVAL;
 
-- 
2.40.1


  parent reply	other threads:[~2023-05-21 21:00 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-05-21 20:51 [PATCH v3 0/6] Move dma-buf mmap() reservation locking down to exporters Dmitry Osipenko
2023-05-21 20:51 ` [PATCH v3 1/6] media: videobuf2: Don't assert held reservation lock for dma-buf mmapping Dmitry Osipenko
2023-05-21 20:51 ` [PATCH v3 2/6] dma-buf/heaps: " Dmitry Osipenko
2023-05-21 20:51 ` Dmitry Osipenko [this message]
2023-05-21 20:51 ` [PATCH v3 4/6] drm: " Dmitry Osipenko
2023-05-21 20:51 ` [PATCH v3 5/6] dma-buf: Change locking policy for mmap() Dmitry Osipenko
2023-05-21 20:51 ` [PATCH v3 6/6] drm/shmem-helper: Switch to reservation lock Dmitry Osipenko
2023-05-22 13:02   ` Emil Velikov
2023-05-22 13:27     ` Dmitry Osipenko
2023-05-29 22:05     ` Dmitry Osipenko

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