diff options
Diffstat (limited to 'target/linux/bcm27xx/patches-5.4/950-0721-udmabuf-fix-dma-buf-cpu-access.patch')
| -rw-r--r-- | target/linux/bcm27xx/patches-5.4/950-0721-udmabuf-fix-dma-buf-cpu-access.patch | 60 |
1 files changed, 0 insertions, 60 deletions
diff --git a/target/linux/bcm27xx/patches-5.4/950-0721-udmabuf-fix-dma-buf-cpu-access.patch b/target/linux/bcm27xx/patches-5.4/950-0721-udmabuf-fix-dma-buf-cpu-access.patch deleted file mode 100644 index 14cfe8aed3..0000000000 --- a/target/linux/bcm27xx/patches-5.4/950-0721-udmabuf-fix-dma-buf-cpu-access.patch +++ /dev/null @@ -1,60 +0,0 @@ -From 153f1e1def226f87cc4c307d2806b000a820f64b Mon Sep 17 00:00:00 2001 -From: Gurchetan Singh <gurchetansingh@chromium.org> -Date: Tue, 17 Dec 2019 15:02:28 -0800 -Subject: [PATCH] udmabuf: fix dma-buf cpu access - -Commit 1ffe09590121fbb3786d6c860acdd200f7ab095c upstream. - -I'm just going to put Chia's review comment here since it sums -the issue rather nicely: - -"(1) Semantically, a dma-buf is in DMA domain. CPU access from the -importer must be surrounded by {begin,end}_cpu_access. This gives the -exporter a chance to move the buffer to the CPU domain temporarily. - -(2) When the exporter itself has other means to do CPU access, it is -only reasonable for the exporter to move the buffer to the CPU domain -before access, and to the DMA domain after access. The exporter can -potentially reuse {begin,end}_cpu_access for that purpose. - -Because of (1), udmabuf does need to implement the -{begin,end}_cpu_access hooks. But "begin" should mean -dma_sync_sg_for_cpu and "end" should mean dma_sync_sg_for_device. - -Because of (2), if userspace wants to continuing accessing through the -memfd mapping, it should call udmabuf's {begin,end}_cpu_access to -avoid cache issues." - -Reported-by: Chia-I Wu <olvaffe@gmail.com> -Suggested-by: Chia-I Wu <olvaffe@gmail.com> -Fixes: 284562e1f348 ("udmabuf: implement begin_cpu_access/end_cpu_access hooks") -Signed-off-by: Gurchetan Singh <gurchetansingh@chromium.org> -Link: http://patchwork.freedesktop.org/patch/msgid/20191217230228.453-1-gurchetansingh@chromium.org -Signed-off-by: Gerd Hoffmann <kraxel@redhat.com> ---- - drivers/dma-buf/udmabuf.c | 7 +++---- - 1 file changed, 3 insertions(+), 4 deletions(-) - ---- a/drivers/dma-buf/udmabuf.c -+++ b/drivers/dma-buf/udmabuf.c -@@ -122,9 +122,8 @@ static int begin_cpu_udmabuf(struct dma_ - if (IS_ERR(ubuf->sg)) - return PTR_ERR(ubuf->sg); - } else { -- dma_sync_sg_for_device(dev, ubuf->sg->sgl, -- ubuf->sg->nents, -- direction); -+ dma_sync_sg_for_cpu(dev, ubuf->sg->sgl, ubuf->sg->nents, -+ direction); - } - - return 0; -@@ -139,7 +138,7 @@ static int end_cpu_udmabuf(struct dma_bu - if (!ubuf->sg) - return -EINVAL; - -- dma_sync_sg_for_cpu(dev, ubuf->sg->sgl, ubuf->sg->nents, direction); -+ dma_sync_sg_for_device(dev, ubuf->sg->sgl, ubuf->sg->nents, direction); - return 0; - } - |