From: Robert Mader Date: Sat, 27 Jun 2026 10:57:25 +0000 (+0200) Subject: udmabuf: Ensure to perform cache synchronisation in begin_cpu_udmabuf() X-Git-Tag: v7.2-rc4~13^2~3^2~15 X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=1d0e25c1ddf2063c499264fb2ba0fa6a3e4f8a00;p=thirdparty%2Fkernel%2Flinux.git udmabuf: Ensure to perform cache synchronisation in begin_cpu_udmabuf() The message of commit 504e2b4ab97a ("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: 504e2b4ab97a ("dma-buf/udmabuf: skip redundant cpu sync to fix cacheline EEXIST warning") Signed-off-by: Robert Mader Reviewed-by: Mikhail Gavrilov Signed-off-by: Vivek Kasireddy Link: https://patch.msgid.link/20260627105725.9083-1-robert.mader@collabora.com --- diff --git a/drivers/dma-buf/udmabuf.c b/drivers/dma-buf/udmabuf.c index bced421c0d65..08f57bc1294d 100644 --- a/drivers/dma-buf/udmabuf.c +++ b/drivers/dma-buf/udmabuf.c @@ -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,