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udmabuf: Ensure to perform cache synchronisation in begin_cpu_udmabuf()

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The message of commit 504e2b4ab9 ("dma-buf/udmabuf: skip redundant cpu sync to
fix cacheline EEXIST warning") says:

> The CPU sync at map/unmap time is also redundant for udmabuf:
> begin_cpu_udmabuf() and end_cpu_udmabuf() already perform explicit
> cache synchronization via dma_sync_sgtable_for_cpu/device() when CPU
> access is requested through the dma-buf interface.

This, however, does not apply to the first time begin_cpu_udmabuf() is
called on an udmabuf, in which case the implementation previously relied on
get_sg_table() to perform the cache synchronisation.

Ensure to call dma_sync_sgtable_for_cpu() in that case as well.

Fixes: 504e2b4ab9 ("dma-buf/udmabuf: skip redundant cpu sync to fix cacheline EEXIST warning")
Signed-off-by: Robert Mader <robert.mader@collabora.com>
Reviewed-by: Mikhail Gavrilov <mikhail.v.gavrilov@gmail.com>
Signed-off-by: Vivek Kasireddy <vivek.kasireddy@intel.com>
Link: https://patch.msgid.link/20260627105725.9083-1-robert.mader@collabora.com
This commit is contained in:
Robert Mader
2026-06-27 12:57:25 +02:00
committed by Vivek Kasireddy
parent cf385cf6e7
commit 1d0e25c1dd
1 changed files with 5 additions and 4 deletions
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9
drivers/dma-buf/udmabuf.c
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@@ -224,21 +224,22 @@ static int begin_cpu_udmabuf(struct dma_buf *buf,
{
struct udmabuf *ubuf = buf->priv;
struct device *dev = ubuf->device->this_device;
int ret = 0;
if (!ubuf->sg) {
ubuf->sg = get_sg_table(dev, buf, direction);
if (IS_ERR(ubuf->sg)) {
int ret;
ret = PTR_ERR(ubuf->sg);
ubuf->sg = NULL;
return ret;
} else {
ubuf->sg_dir = direction;
}
} else {
dma_sync_sgtable_for_cpu(dev, ubuf->sg, direction);
}
return ret;
dma_sync_sgtable_for_cpu(dev, ubuf->sg, direction);
return 0;
}
static int end_cpu_udmabuf(struct dma_buf *buf,