centos man page for dma_buf_begin_cpu_access

DMA_BUF_BEGIN_CPU_AC(9) 				   Device drivers infrastructure				   DMA_BUF_BEGIN_CPU_AC(9)

NAME
       dma_buf_begin_cpu_access - Must be called before accessing a dma_buf from the cpu in the kernel context. Calls begin_cpu_access to allow
       exporter-specific preparations. Coherency is only guaranteed in the specified range for the specified access direction.

SYNOPSIS
       int dma_buf_begin_cpu_access(struct dma_buf * dmabuf, size_t start, size_t len, enum dma_data_direction direction);

ARGUMENTS
       dmabuf
	   [in] buffer to prepare cpu access for.

       start
	   [in] start of range for cpu access.

       len
	   [in] length of range for cpu access.

       direction
	   [in] length of range for cpu access.

DESCRIPTION
       Can return negative error values, returns 0 on success.

COPYRIGHT
Kernel Hackers Manual 3.10					     June 2014						   DMA_BUF_BEGIN_CPU_AC(9)