RE: [PATCH v3 3/4] udmabuf: Implement udmabuf rw_file callback

[wangtao <tao.wangtao@honor.com>]

> -----Original Message-----
> From: kernel test robot <lkp@intel.com>
> Sent: Friday, May 30, 2025 10:25 PM
> To: wangtao <tao.wangtao@honor.com>; sumit.semwal@linaro.org;
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> <tao.wangtao@honor.com>
> Subject: Re: [PATCH v3 3/4] udmabuf: Implement udmabuf rw_file callback
> 
> Hi wangtao,
> 
> kernel test robot noticed the following build errors:
> 
> [auto build test ERROR on brauner-vfs/vfs.all] [also build test ERROR on next-
> 20250530] [cannot apply to linus/master v6.15] [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/wangtao/fs-allow-
> cross-FS-copy_file_range-for-memory-backed-files/20250530-184146
> base:   https://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs.git vfs.all
> patch link:    https://lore.kernel.org/r/20250530103941.11092-4-
> tao.wangtao%40honor.com
> patch subject: [PATCH v3 3/4] udmabuf: Implement udmabuf rw_file callback
> config: sparc64-randconfig-002-20250530 (https://download.01.org/0day-
> ci/archive/20250530/202505302235.mDzENMSm-lkp@intel.com/config)
> compiler: sparc64-linux-gcc (GCC) 15.1.0 reproduce (this is a W=1 build):
> (https://download.01.org/0day-
> ci/archive/20250530/202505302235.mDzENMSm-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/202505302235.mDzENMSm-lkp@intel.
> | com/
> 
> All error/warnings (new ones prefixed by >>):
> 
Quick note: I don't have local sparc64 compilation setup, so I'll
explicitly add the header dependencies to ensure safety.

Regards,
Wangtao.
>    drivers/dma-buf/udmabuf.c: In function 'udmabuf_rw_file':
> >> drivers/dma-buf/udmabuf.c:298:25: error: storage size of 'iter' isn't
> >> known
>      298 |         struct iov_iter iter;
>          |                         ^~~~
> >> drivers/dma-buf/udmabuf.c:299:45: error: 'ITER_SOURCE' undeclared
> >> (first use in this function)
>      299 |         unsigned int direction = is_write ? ITER_SOURCE : ITER_DEST;
>          |                                             ^~~~~~~~~~~
>    drivers/dma-buf/udmabuf.c:299:45: note: each undeclared identifier is
> reported only once for each function it appears in
> >> drivers/dma-buf/udmabuf.c:299:59: error: 'ITER_DEST' undeclared
> >> (first use in this function)
>      299 |         unsigned int direction = is_write ? ITER_SOURCE : ITER_DEST;
>          |                                                           ^~~~~~~~~
> >> drivers/dma-buf/udmabuf.c:327:17: error: implicit declaration of
> >> function 'iov_iter_bvec'; did you mean 'bvec_iter_bvec'?
> >> [-Wimplicit-function-declaration]
>      327 |                 iov_iter_bvec(&iter, direction, bvec, bv_idx, bv_total);
>          |                 ^~~~~~~~~~~~~
>          |                 bvec_iter_bvec
> >> drivers/dma-buf/udmabuf.c:298:25: warning: unused variable 'iter'
> >> [-Wunused-variable]
>      298 |         struct iov_iter iter;
>          |                         ^~~~
> 
> 
> vim +298 drivers/dma-buf/udmabuf.c
> 
>    286
>    287	static ssize_t udmabuf_rw_file(struct dma_buf *dmabuf, loff_t
> my_pos,
>    288				struct file *other, loff_t pos,
>    289				size_t count, bool is_write)
>    290	{
>    291		struct udmabuf *ubuf = dmabuf->priv;
>    292		loff_t my_end = my_pos + count, bv_beg, bv_end = 0;
>    293		pgoff_t pg_idx = my_pos / PAGE_SIZE;
>    294		pgoff_t pg_end = DIV_ROUND_UP(my_end, PAGE_SIZE);
>    295		size_t i, bv_off, bv_len, bv_num, bv_idx = 0, bv_total = 0;
>    296		struct bio_vec *bvec;
>    297		struct kiocb kiocb;
>  > 298		struct iov_iter iter;
>  > 299		unsigned int direction = is_write ? ITER_SOURCE : ITER_DEST;
>    300		ssize_t ret = 0, rw_total = 0;
>    301		struct folio *folio;
>    302
>    303		bv_num = min_t(size_t, pg_end - pg_idx + 1, 1024);
>    304		bvec = kvcalloc(bv_num, sizeof(*bvec), GFP_KERNEL);
>    305		if (!bvec)
>    306			return -ENOMEM;
>    307
>    308		init_sync_kiocb(&kiocb, other);
>    309		kiocb.ki_pos = pos;
>    310
>    311		for (i = 0; i < ubuf->nr_pinned && my_pos < my_end; i++) {
>    312			folio = ubuf->pinned_folios[i];
>    313			bv_beg = bv_end;
>    314			bv_end += folio_size(folio);
>    315			if (bv_end <= my_pos)
>    316				continue;
>    317
>    318			bv_len = min(bv_end, my_end) - my_pos;
>    319			bv_off = my_pos - bv_beg;
>    320			my_pos += bv_len;
>    321			bv_total += bv_len;
>    322			bvec_set_page(&bvec[bv_idx], &folio->page, bv_len,
> bv_off);
>    323			if (++bv_idx < bv_num && my_pos < my_end)
>    324				continue;
>    325
>    326			/* start R/W if bvec is full or count reaches zero. */
>  > 327			iov_iter_bvec(&iter, direction, bvec, bv_idx,
> bv_total);
>    328			if (is_write)
>    329				ret = other->f_op->write_iter(&kiocb, &iter);
>    330			else
>    331				ret = other->f_op->read_iter(&kiocb, &iter);
>    332			if (ret <= 0)
>    333				break;
>    334			rw_total += ret;
>    335			if (ret < bv_total || fatal_signal_pending(current))
>    336				break;
>    337
>    338			bv_idx = bv_total = 0;
>    339		}
>    340		kvfree(bvec);
>    341
>    342		return rw_total > 0 ? rw_total : ret;
>    343	}
>    344
> 
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