Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
From:   Dmitry Osipenko <dmitry.osipenko@collabora.com>
To:     Sumit Semwal <sumit.semwal@linaro.org>,
        =?UTF-8?q?Christian=20K=C3=B6nig?= <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>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        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>,
        Srinivas Kandagatla <srinivas.kandagatla@linaro.org>,
        Amol Maheshwari <amahesh@qti.qualcomm.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, linux-arm-msm@vger.kernel.org,
        kernel@collabora.com
Subject: [PATCH v1 4/7] Revert "fastrpc: Assert held reservation lock for dma-buf mmapping"
Date:   Sun,  2 Apr 2023 19:48:23 +0300
Message-Id: <20230402164826.752842-5-dmitry.osipenko@collabora.com>
In-Reply-To: <20230402164826.752842-1-dmitry.osipenko@collabora.com>
References: <20230402164826.752842-1-dmitry.osipenko@collabora.com>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

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, it's solved
by moving the lock down to exporters.

Fixes: 265751a513ad ("fastrpc: Assert held reservation lock for dma-buf mmapping")
Signed-off-by: Dmitry Osipenko <dmitry.osipenko@collabora.com>
---
 drivers/misc/fastrpc.c | 3 ---
 1 file changed, 3 deletions(-)

diff --git a/drivers/misc/fastrpc.c b/drivers/misc/fastrpc.c
index a701132638cf..7e9c9ad37fd9 100644
--- a/drivers/misc/fastrpc.c
+++ b/drivers/misc/fastrpc.c
@@ -6,7 +6,6 @@
 #include <linux/device.h>
 #include <linux/dma-buf.h>
 #include <linux/dma-mapping.h>
-#include <linux/dma-resv.h>
 #include <linux/idr.h>
 #include <linux/list.h>
 #include <linux/miscdevice.h>
@@ -733,8 +732,6 @@ static int fastrpc_mmap(struct dma_buf *dmabuf,
 	struct fastrpc_buf *buf = dmabuf->priv;
 	size_t size = vma->vm_end - vma->vm_start;
 
-	dma_resv_assert_held(dmabuf->resv);
-
 	return dma_mmap_coherent(buf->dev, vma, buf->virt,
 				 FASTRPC_PHYS(buf->phys), size);
 }
-- 
2.39.2