Re: [PATCH 2/2] scsi:target:tcmu: reduce once copy by using uio ioctl

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

Hi Guixin,

Thank you for the patch! Perhaps something to improve:

[auto build test WARNING on char-misc/char-misc-testing]
[also build test WARNING on mkp-scsi/for-next linux/master linus/master v5.17-rc4 next-20220216]
[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]

url:    https://github.com/0day-ci/linux/commits/Guixin-Liu/uio-add-ioctl-to-uio/20220217-103120
base:   https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc.git e6cb9c167eeb8f90ab924666c573e69e85e700a0
config: riscv-randconfig-r042-20220217 (https://download.01.org/0day-ci/archive/20220217/202202171541.grdjAOIT-lkp@intel.com/config)
compiler: clang version 15.0.0 (https://github.com/llvm/llvm-project 0bad7cb56526f2572c74449fcf97c1fcda42b41d)
reproduce (this is a W=1 build):
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # install riscv cross compiling tool for clang build
        # apt-get install binutils-riscv64-linux-gnu
        # https://github.com/0day-ci/linux/commit/c604d03c2be8ca4b3533bb151bcd2d10379debff
        git remote add linux-review https://github.com/0day-ci/linux
        git fetch --no-tags linux-review Guixin-Liu/uio-add-ioctl-to-uio/20220217-103120
        git checkout c604d03c2be8ca4b3533bb151bcd2d10379debff
        # save the config file to linux build tree
        mkdir build_dir
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=riscv SHELL=/bin/bash drivers/target/

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>

All warnings (new ones prefixed by >>):

>> drivers/target/target_core_user.c:1987:6: warning: no previous prototype for function 'tcmu_ioctl_copy_between_sgl_and_iovec' [-Wmissing-prototypes]
   long tcmu_ioctl_copy_between_sgl_and_iovec(struct tcmu_cmd *tcmu_cmd,
        ^
   drivers/target/target_core_user.c:1987:1: note: declare 'static' if the function is not intended to be used outside of this translation unit
   long tcmu_ioctl_copy_between_sgl_and_iovec(struct tcmu_cmd *tcmu_cmd,
   ^
   static 
>> drivers/target/target_core_user.c:2031:6: warning: no previous prototype for function 'tcmu_ioctl' [-Wmissing-prototypes]
   long tcmu_ioctl(struct uio_info *info, unsigned int cmd, unsigned long arg)
        ^
   drivers/target/target_core_user.c:2031:1: note: declare 'static' if the function is not intended to be used outside of this translation unit
   long tcmu_ioctl(struct uio_info *info, unsigned int cmd, unsigned long arg)
   ^
   static 
   2 warnings generated.


vim +/tcmu_ioctl_copy_between_sgl_and_iovec +1987 drivers/target/target_core_user.c

  1986	
> 1987	long tcmu_ioctl_copy_between_sgl_and_iovec(struct tcmu_cmd *tcmu_cmd,
  1988				struct iovec __user *uiovec,
  1989				unsigned long vcnt,
  1990				bool is_copy_to_sgl)
  1991	{
  1992		struct iovec iovstack[UIO_FASTIOV];
  1993		struct iovec *iov = iovstack;
  1994		struct iov_iter iter;
  1995		ssize_t ret;
  1996		struct se_cmd *se_cmd = tcmu_cmd->se_cmd;
  1997		struct scatterlist *data_sg, *sg;
  1998		int i;
  1999		unsigned int data_nents;
  2000		long copy_ret = 0;
  2001	
  2002		if (se_cmd->se_cmd_flags & SCF_BIDI) {
  2003			data_sg = se_cmd->t_bidi_data_sg;
  2004			data_nents = se_cmd->t_bidi_data_nents;
  2005		} else {
  2006			data_sg = se_cmd->t_data_sg;
  2007			data_nents = se_cmd->t_data_nents;
  2008		}
  2009	
  2010		ret = import_iovec(READ, uiovec, vcnt, ARRAY_SIZE(iovstack), &iov, &iter);
  2011		if (ret < 0) {
  2012			pr_err("import iovec failed.\n");
  2013			return -EFAULT;
  2014		}
  2015	
  2016		for_each_sg(data_sg, sg, data_nents, i) {
  2017			if (is_copy_to_sgl)
  2018				ret = copy_page_from_iter(sg_page(sg), sg->offset, sg->length, &iter);
  2019			else
  2020				ret = copy_page_to_iter(sg_page(sg), sg->offset, sg->length, &iter);
  2021			if (ret < 0) {
  2022				pr_err("copy failed.\n");
  2023				copy_ret = -EFAULT;
  2024				break;
  2025			}
  2026		}
  2027		kfree(iov);
  2028		return copy_ret;
  2029	}
  2030	
> 2031	long tcmu_ioctl(struct uio_info *info, unsigned int cmd, unsigned long arg)
  2032	{
  2033		struct tcmu_dev *udev = container_of(info, struct tcmu_dev, uio_info);
  2034		struct tcmu_data_xfer __user *uxfer = (struct tcmu_data_xfer __user *)arg;
  2035		struct tcmu_data_xfer xfer;
  2036		struct tcmu_cmd *tcmu_cmd;
  2037	
  2038		if (!test_bit(TCMU_DEV_BIT_BYPASS_DATA_AREA, &udev->flags))
  2039			return -EINVAL;
  2040	
  2041		if (copy_from_user(&xfer, uxfer, sizeof(xfer)))
  2042			return -EFAULT;
  2043	
  2044		tcmu_cmd = xa_load(&udev->commands, xfer.cmd_id);
  2045		if (!tcmu_cmd) {
  2046			set_bit(TCMU_DEV_BIT_BROKEN, &udev->flags);
  2047			return -EFAULT;
  2048		}
  2049	
  2050		if (test_bit(TCMU_CMD_BIT_EXPIRED, &tcmu_cmd->flags))
  2051			return -EFAULT;
  2052	
  2053		switch (cmd) {
  2054		case TCMU_IOCTL_CMD_COPY_TO_SGL:
  2055			return tcmu_ioctl_copy_between_sgl_and_iovec(tcmu_cmd, xfer.iovec,
  2056								     xfer.iov_cnt, true);
  2057		case TCMU_IOCTL_CMD_COPY_FROM_SGL:
  2058			return tcmu_ioctl_copy_between_sgl_and_iovec(tcmu_cmd, xfer.iovec,
  2059								     xfer.iov_cnt, false);
  2060		default:
  2061			return -EINVAL;
  2062		}
  2063	}
  2064	

---
0-DAY CI Kernel Test Service, Intel Corporation
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