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>,
"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 v4 5/6] dma-buf: Change locking policy for mmap()
Date: Tue, 30 May 2023 01:39:34 +0300 [thread overview]
Message-ID: <20230529223935.2672495-6-dmitry.osipenko@collabora.com> (raw)
In-Reply-To: <20230529223935.2672495-1-dmitry.osipenko@collabora.com>
Change locking policy of mmap() callback, making exporters responsible
for handling dma-buf reservation locking. Previous locking policy stated
that dma-buf is locked for both importers and exporters by the dma-buf
core, which caused a deadlock problem for DRM drivers in a case of
self-imported dma-bufs which required to take the lock from the DRM
exporter side.
Reviewed-by: Emil Velikov <emil.l.velikov@gmail.com>
Signed-off-by: Dmitry Osipenko <dmitry.osipenko@collabora.com>
---
drivers/dma-buf/dma-buf.c | 17 +++--------------
1 file changed, 3 insertions(+), 14 deletions(-)
diff --git a/drivers/dma-buf/dma-buf.c b/drivers/dma-buf/dma-buf.c
index aa4ea8530cb3..21916bba77d5 100644
--- a/drivers/dma-buf/dma-buf.c
+++ b/drivers/dma-buf/dma-buf.c
@@ -131,7 +131,6 @@ static struct file_system_type dma_buf_fs_type = {
static int dma_buf_mmap_internal(struct file *file, struct vm_area_struct *vma)
{
struct dma_buf *dmabuf;
- int ret;
if (!is_dma_buf_file(file))
return -EINVAL;
@@ -147,11 +146,7 @@ static int dma_buf_mmap_internal(struct file *file, struct vm_area_struct *vma)
dmabuf->size >> PAGE_SHIFT)
return -EINVAL;
- dma_resv_lock(dmabuf->resv, NULL);
- ret = dmabuf->ops->mmap(dmabuf, vma);
- dma_resv_unlock(dmabuf->resv);
-
- return ret;
+ return dmabuf->ops->mmap(dmabuf, vma);
}
static loff_t dma_buf_llseek(struct file *file, loff_t offset, int whence)
@@ -850,6 +845,7 @@ static struct sg_table * __map_dma_buf(struct dma_buf_attachment *attach,
* - &dma_buf_ops.release()
* - &dma_buf_ops.begin_cpu_access()
* - &dma_buf_ops.end_cpu_access()
+ * - &dma_buf_ops.mmap()
*
* 2. These &dma_buf_ops callbacks are invoked with locked dma-buf
* reservation and exporter can't take the lock:
@@ -858,7 +854,6 @@ static struct sg_table * __map_dma_buf(struct dma_buf_attachment *attach,
* - &dma_buf_ops.unpin()
* - &dma_buf_ops.map_dma_buf()
* - &dma_buf_ops.unmap_dma_buf()
- * - &dma_buf_ops.mmap()
* - &dma_buf_ops.vmap()
* - &dma_buf_ops.vunmap()
*
@@ -1463,8 +1458,6 @@ EXPORT_SYMBOL_NS_GPL(dma_buf_end_cpu_access, DMA_BUF);
int dma_buf_mmap(struct dma_buf *dmabuf, struct vm_area_struct *vma,
unsigned long pgoff)
{
- int ret;
-
if (WARN_ON(!dmabuf || !vma))
return -EINVAL;
@@ -1485,11 +1478,7 @@ int dma_buf_mmap(struct dma_buf *dmabuf, struct vm_area_struct *vma,
vma_set_file(vma, dmabuf->file);
vma->vm_pgoff = pgoff;
- dma_resv_lock(dmabuf->resv, NULL);
- ret = dmabuf->ops->mmap(dmabuf, vma);
- dma_resv_unlock(dmabuf->resv);
-
- return ret;
+ return dmabuf->ops->mmap(dmabuf, vma);
}
EXPORT_SYMBOL_NS_GPL(dma_buf_mmap, DMA_BUF);
--
2.40.1
next prev parent reply other threads:[~2023-05-29 22:46 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-05-29 22:39 [PATCH v4 0/6] Move dma-buf mmap() reservation locking down to exporters Dmitry Osipenko
2023-05-29 22:39 ` [PATCH v4 1/6] media: videobuf2: Don't assert held reservation lock for dma-buf mmapping Dmitry Osipenko
2023-05-29 22:39 ` [PATCH v4 2/6] dma-buf/heaps: " Dmitry Osipenko
2023-06-21 17:21 ` T.J. Mercier
2023-06-21 18:16 ` Dmitry Osipenko
2023-06-21 19:24 ` T.J. Mercier
2023-05-29 22:39 ` [PATCH v4 3/6] udmabuf: " Dmitry Osipenko
2023-05-29 22:39 ` [PATCH v4 4/6] drm: " Dmitry Osipenko
2023-05-29 22:39 ` Dmitry Osipenko [this message]
[not found] ` <91466907-d4e1-1619-27a8-a49a01cbc8f1@collabora.com>
2023-06-20 15:58 ` [PATCH v4 5/6] dma-buf: Change locking policy for mmap() Dmitry Osipenko
2023-06-21 5:42 ` Christian König
2023-06-21 18:17 ` Dmitry Osipenko
2023-05-29 22:39 ` [PATCH v4 6/6] drm/shmem-helper: Switch to reservation lock Dmitry Osipenko
2023-06-26 9:40 ` Boris Brezillon
2023-06-26 9:57 ` Boris Brezillon
2023-06-26 13:05 ` Dmitry Osipenko
2023-06-26 13:05 ` Dmitry Osipenko
2023-06-21 19:13 ` [PATCH v4 0/6] Move dma-buf mmap() reservation locking down to exporters Dmitry Osipenko
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