Re: [PATCH v5 02/10] block: Add copy offload support infrastructure

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

:::::: 
:::::: Manual check reason: "low confidence static check warning: block/blk-lib.c:464:6: warning: Redundant initialization for 'ret'. The initialized value is overwritten before it is read. [redundantInitialization]"
:::::: 

BCC: lkp@intel.com
CC: oe-kbuild-all@lists.linux.dev
In-Reply-To: <20221123055827.26996-3-nj.shetty@samsung.com>
References: <20221123055827.26996-3-nj.shetty@samsung.com>
TO: Nitesh Shetty <nj.shetty@samsung.com>
TO: axboe@kernel.dk
TO: agk@redhat.com
TO: snitzer@kernel.org
TO: dm-devel@redhat.com
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TO: naohiro.aota@wdc.com
TO: jth@kernel.org
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CC: linux-block@vger.kernel.org
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CC: nitheshshetty@gmail.com
CC: gost.dev@samsung.com
CC: Nitesh Shetty <nj.shetty@samsung.com>

Hi Nitesh,

Thank you for the patch! Perhaps something to improve:

[auto build test WARNING on axboe-block/for-next]
[also build test WARNING on next-20221206]
[cannot apply to device-mapper-dm/for-next linus/master v6.1-rc8]
[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/Nitesh-Shetty/block-Introduce-queue-limits-for-copy-offload-support/20221123-145837
base:   https://git.kernel.org/pub/scm/linux/kernel/git/axboe/linux-block.git for-next
patch link:    https://lore.kernel.org/r/20221123055827.26996-3-nj.shetty%40samsung.com
patch subject: [PATCH v5 02/10] block: Add copy offload support infrastructure
:::::: branch date: 2 weeks ago
:::::: commit date: 2 weeks ago
compiler: loongarch64-linux-gcc (GCC) 12.1.0
reproduce (cppcheck warning):
        # apt-get install cppcheck
        git checkout 101fd213e34571287d11546f15a89f06ae9b9746
        cppcheck --quiet --enable=style,performance,portability --template=gcc FILE

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


cppcheck possible warnings: (new ones prefixed by >>, may not real problems)

>> block/blk-lib.c:464:6: warning: Redundant initialization for 'ret'. The initialized value is overwritten before it is read. [redundantInitialization]
    ret = blk_copy_sanity_check(src_bdev, dst_bdev, ranges, nr);
        ^
   block/blk-lib.c:462:10: note: ret is initialized
    int ret = -EINVAL;
            ^
   block/blk-lib.c:464:6: note: ret is overwritten
    ret = blk_copy_sanity_check(src_bdev, dst_bdev, ranges, nr);
        ^

vim +/ret +464 block/blk-lib.c

101fd213e34571 Nitesh Shetty 2022-11-23  436  
101fd213e34571 Nitesh Shetty 2022-11-23  437  /*
101fd213e34571 Nitesh Shetty 2022-11-23  438   * blkdev_issue_copy - queue a copy
101fd213e34571 Nitesh Shetty 2022-11-23  439   * @src_bdev:	source block device
101fd213e34571 Nitesh Shetty 2022-11-23  440   * @dst_bdev:	destination block device
101fd213e34571 Nitesh Shetty 2022-11-23  441   * @ranges:	array of source/dest/len,
101fd213e34571 Nitesh Shetty 2022-11-23  442   *		ranges are expected to be allocated/freed by caller
101fd213e34571 Nitesh Shetty 2022-11-23  443   * @nr:		number of source ranges to copy
101fd213e34571 Nitesh Shetty 2022-11-23  444   * @end_io:	end_io function to be called on completion of copy operation,
101fd213e34571 Nitesh Shetty 2022-11-23  445   *		for synchronous operation this should be NULL
101fd213e34571 Nitesh Shetty 2022-11-23  446   * @private:	end_io function will be called with this private data, should be
101fd213e34571 Nitesh Shetty 2022-11-23  447   *		NULL, if operation is synchronous in nature
101fd213e34571 Nitesh Shetty 2022-11-23  448   * @gfp_mask:   memory allocation flags (for bio_alloc)
101fd213e34571 Nitesh Shetty 2022-11-23  449   *
101fd213e34571 Nitesh Shetty 2022-11-23  450   * Description:
101fd213e34571 Nitesh Shetty 2022-11-23  451   *	Copy source ranges from source block device to destination block
101fd213e34571 Nitesh Shetty 2022-11-23  452   *	device. length of a source range cannot be zero. Max total length of
101fd213e34571 Nitesh Shetty 2022-11-23  453   *	copy is limited to MAX_COPY_TOTAL_LENGTH and also maximum number of
101fd213e34571 Nitesh Shetty 2022-11-23  454   *	entries is limited to MAX_COPY_NR_RANGE
101fd213e34571 Nitesh Shetty 2022-11-23  455   */
101fd213e34571 Nitesh Shetty 2022-11-23  456  int blkdev_issue_copy(struct block_device *src_bdev,
101fd213e34571 Nitesh Shetty 2022-11-23  457  	struct block_device *dst_bdev, struct range_entry *ranges, int nr,
101fd213e34571 Nitesh Shetty 2022-11-23  458  	cio_iodone_t end_io, void *private, gfp_t gfp_mask)
101fd213e34571 Nitesh Shetty 2022-11-23  459  {
101fd213e34571 Nitesh Shetty 2022-11-23  460  	struct request_queue *src_q = bdev_get_queue(src_bdev);
101fd213e34571 Nitesh Shetty 2022-11-23  461  	struct request_queue *dst_q = bdev_get_queue(dst_bdev);
101fd213e34571 Nitesh Shetty 2022-11-23  462  	int ret = -EINVAL;
101fd213e34571 Nitesh Shetty 2022-11-23  463  
101fd213e34571 Nitesh Shetty 2022-11-23 @464  	ret = blk_copy_sanity_check(src_bdev, dst_bdev, ranges, nr);
101fd213e34571 Nitesh Shetty 2022-11-23  465  	if (ret)
101fd213e34571 Nitesh Shetty 2022-11-23  466  		return ret;
101fd213e34571 Nitesh Shetty 2022-11-23  467  
101fd213e34571 Nitesh Shetty 2022-11-23  468  	if (blk_check_copy_offload(src_q, dst_q))
101fd213e34571 Nitesh Shetty 2022-11-23  469  		ret = blk_copy_offload(src_bdev, dst_bdev, ranges, nr,
101fd213e34571 Nitesh Shetty 2022-11-23  470  				end_io, private, gfp_mask);
101fd213e34571 Nitesh Shetty 2022-11-23  471  
101fd213e34571 Nitesh Shetty 2022-11-23  472  	return ret;
101fd213e34571 Nitesh Shetty 2022-11-23  473  }
101fd213e34571 Nitesh Shetty 2022-11-23  474  EXPORT_SYMBOL_GPL(blkdev_issue_copy);
101fd213e34571 Nitesh Shetty 2022-11-23  475  

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