Re: [PATCH 2/3] drm/prime: Support importing DMA-BUF without sg_table

[kernel test robot <lkp@intel.com>]

Hi,

kernel test robot noticed the following build warnings:

[auto build test WARNING on jic23-iio/togreg]
[also build test WARNING on char-misc/char-misc-testing char-misc/char-misc-next char-misc/char-misc-linus usb/usb-testing usb/usb-next usb/usb-linus xen-tip/linux-next linus/master v6.15-rc4]
[cannot apply to tegra/for-next drm-xe/drm-xe-next rmk-arm/drm-armada-devel rmk-arm/drm-armada-fixes next-20250430]
[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/oushixiong1025-163-com/drm-prime-Support-importing-DMA-BUF-without-sg_table/20250430-170136
base:   https://git.kernel.org/pub/scm/linux/kernel/git/jic23/iio.git togreg
patch link:    https://lore.kernel.org/r/20250430085658.540746-2-oushixiong1025%40163.com
patch subject: [PATCH 2/3] drm/prime: Support importing DMA-BUF without sg_table
config: arm64-randconfig-003-20250501 (https://download.01.org/0day-ci/archive/20250501/202505011655.qTmh4UA7-lkp@intel.com/config)
compiler: clang version 21.0.0git (https://github.com/llvm/llvm-project f819f46284f2a79790038e1f6649172789734ae8)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250501/202505011655.qTmh4UA7-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@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202505011655.qTmh4UA7-lkp@intel.com/

All warnings (new ones prefixed by >>):

>> drivers/gpu/drm/drm_prime.c:925:24: warning: no previous prototype for function 'drm_gem_prime_import_dev_skip_map' [-Wmissing-prototypes]
     925 | struct drm_gem_object *drm_gem_prime_import_dev_skip_map(struct drm_device *dev,
         |                        ^
   drivers/gpu/drm/drm_prime.c:925:1: note: declare 'static' if the function is not intended to be used outside of this translation unit
     925 | struct drm_gem_object *drm_gem_prime_import_dev_skip_map(struct drm_device *dev,
         | ^
         | static 
   1 warning generated.


vim +/drm_gem_prime_import_dev_skip_map +925 drivers/gpu/drm/drm_prime.c

   913	
   914	/**
   915	 * drm_gem_prime_import_dev_skip_map - core implementation of the import callback
   916	 * @dev: drm_device to import into
   917	 * @dma_buf: dma-buf object to import
   918	 * @attach_dev: struct device to dma_buf attach
   919	 *
   920	 * This function exports a dma-buf without get it's scatter/gather table.
   921	 *
   922	 * Drivers who need to get an scatter/gather table for objects need to call
   923	 * drm_gem_prime_import_dev() instead.
   924	 */
 > 925	struct drm_gem_object *drm_gem_prime_import_dev_skip_map(struct drm_device *dev,
   926								 struct dma_buf *dma_buf,
   927								 struct device *attach_dev)
   928	{
   929		struct dma_buf_attachment *attach;
   930		struct drm_gem_object *obj;
   931		int ret;
   932	
   933		if (dma_buf->ops == &drm_gem_prime_dmabuf_ops) {
   934			obj = dma_buf->priv;
   935			if (obj->dev == dev) {
   936				/*
   937				 * Importing dmabuf exported from our own gem increases
   938				 * refcount on gem itself instead of f_count of dmabuf.
   939				 */
   940				drm_gem_object_get(obj);
   941				return obj;
   942			}
   943		}
   944	
   945		attach = dma_buf_attach(dma_buf, attach_dev, true);
   946		if (IS_ERR(attach))
   947			return ERR_CAST(attach);
   948	
   949		get_dma_buf(dma_buf);
   950	
   951		obj = dev->driver->gem_prime_import_attachment(dev, attach);
   952		if (IS_ERR(obj)) {
   953			ret = PTR_ERR(obj);
   954			goto fail_detach;
   955		}
   956	
   957		obj->import_attach = attach;
   958		obj->resv = dma_buf->resv;
   959	
   960		return obj;
   961	
   962	fail_detach:
   963		dma_buf_detach(dma_buf, attach);
   964		dma_buf_put(dma_buf);
   965	
   966		return ERR_PTR(ret);
   967	}
   968	EXPORT_SYMBOL(drm_gem_prime_import_dev_skip_map);
   969	

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