[PATCH v5 1/6] dma-buf: Add dma_buf_{begin,end}_access()

[kernel test robot]

Hi Paul,

kernel test robot noticed the following build warnings:

[auto build test WARNING on usb/usb-testing]
[also build test WARNING on usb/usb-next usb/usb-linus drm-misc/drm-misc-next lwn/docs-next linus/master v6.7 next-20240119]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Paul-Cercueil/dma-buf-Add-dma_buf_-begin-end-_access/20240119-221604
base:   https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing
patch link:    https://lore.kernel.org/r/20240119141402.44262-2-paul%40crapouillou.net
patch subject: [PATCH v5 1/6] dma-buf: Add dma_buf_{begin,end}_access()
config: arm-randconfig-001-20240120 (https://download.01.org/0day-ci/archive/20240121/202401210406.YYgVcAC1-lkp@intel.com/config)
compiler: clang version 18.0.0git (https://github.com/llvm/llvm-project d92ce344bf641e6bb025b41b3f1a77dd25e2b3e9)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20240121/202401210406.YYgVcAC1-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp at intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202401210406.YYgVcAC1-lkp@intel.com/

All warnings (new ones prefixed by >>):

>> drivers/dma-buf/dma-buf.c:1608: warning: Cannot understand  * @dma_buf_begin_access - Call before any hardware access from/to the DMABUF
    on line 1608 - I thought it was a doc line
>> drivers/dma-buf/dma-buf.c:1640: warning: Cannot understand  * @dma_buf_end_access - Call after any hardware access from/to the DMABUF
    on line 1640 - I thought it was a doc line


vim +1608 drivers/dma-buf/dma-buf.c

  1606	
  1607	/**
> 1608	 * @dma_buf_begin_access - Call before any hardware access from/to the DMABUF
  1609	 * @attach:	[in]	attachment used for hardware access
  1610	 * @sg_table:	[in]	scatterlist used for the DMA transfer
  1611	 * @direction:  [in]    direction of DMA transfer
  1612	 */
  1613	int dma_buf_begin_access(struct dma_buf_attachment *attach,
  1614				 struct sg_table *sgt, enum dma_data_direction dir)
  1615	{
  1616		struct dma_buf *dmabuf;
  1617		bool cookie;
  1618		int ret;
  1619	
  1620		if (WARN_ON(!attach))
  1621			return -EINVAL;
  1622	
  1623		dmabuf = attach->dmabuf;
  1624	
  1625		if (!dmabuf->ops->begin_access)
  1626			return 0;
  1627	
  1628		cookie = dma_fence_begin_signalling();
  1629		ret = dmabuf->ops->begin_access(attach, sgt, dir);
  1630		dma_fence_end_signalling(cookie);
  1631	
  1632		if (WARN_ON_ONCE(ret))
  1633			return ret;
  1634	
  1635		return 0;
  1636	}
  1637	EXPORT_SYMBOL_NS_GPL(dma_buf_begin_access, DMA_BUF);
  1638	
  1639	/**
> 1640	 * @dma_buf_end_access - Call after any hardware access from/to the DMABUF
  1641	 * @attach:	[in]	attachment used for hardware access
  1642	 * @sg_table:	[in]	scatterlist used for the DMA transfer
  1643	 * @direction:  [in]    direction of DMA transfer
  1644	 */
  1645	int dma_buf_end_access(struct dma_buf_attachment *attach,
  1646			       struct sg_table *sgt, enum dma_data_direction dir)
  1647	{
  1648		struct dma_buf *dmabuf;
  1649		bool cookie;
  1650		int ret;
  1651	
  1652		if (WARN_ON(!attach))
  1653			return -EINVAL;
  1654	
  1655		dmabuf = attach->dmabuf;
  1656	
  1657		if (!dmabuf->ops->end_access)
  1658			return 0;
  1659	
  1660		cookie = dma_fence_begin_signalling();
  1661		ret = dmabuf->ops->end_access(attach, sgt, dir);
  1662		dma_fence_end_signalling(cookie);
  1663	
  1664		if (WARN_ON_ONCE(ret))
  1665			return ret;
  1666	
  1667		return 0;
  1668	}
  1669	EXPORT_SYMBOL_NS_GPL(dma_buf_end_access, DMA_BUF);
  1670	

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