[PATCH 4/4] nvme: wire up async polling for io passthrough commands

[kernel test robot]

Hi Kanchan,

Thank you for the patch! Perhaps something to improve:

[auto build test WARNING on axboe-block/for-next]
[also build test WARNING on linus/master next-20220805]
[cannot apply to hch-configfs/for-next v5.19]
[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/Kanchan-Joshi/fs-add-file_operations-uring_cmd_iopoll/20220806-004320
base:   https://git.kernel.org/pub/scm/linux/kernel/git/axboe/linux-block.git for-next
config: i386-randconfig-a002 (https://download.01.org/0day-ci/archive/20220806/202208060733.GCwasLXB-lkp@intel.com/config)
compiler: clang version 16.0.0 (https://github.com/llvm/llvm-project 26dd42705c2af0b8f6e5d6cdb32c9bd5ed9524eb)
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
        # https://github.com/intel-lab-lkp/linux/commit/0964795577fbf09d8b315269504b5e87b5ac492b
        git remote add linux-review https://github.com/intel-lab-lkp/linux
        git fetch --no-tags linux-review Kanchan-Joshi/fs-add-file_operations-uring_cmd_iopoll/20220806-004320
        git checkout 0964795577fbf09d8b315269504b5e87b5ac492b
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=i386 SHELL=/bin/bash drivers/nvme/host/

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

All warnings (new ones prefixed by >>):

>> drivers/nvme/host/ioctl.c:638:6: warning: variable 'ret' is used uninitialized whenever 'if' condition is false [-Wsometimes-uninitialized]
           if (test_bit(QUEUE_FLAG_POLL, &q->queue_flags) && bio && bio->bi_bdev)
               ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   drivers/nvme/host/ioctl.c:641:9: note: uninitialized use occurs here
           return ret;
                  ^~~
   drivers/nvme/host/ioctl.c:638:2: note: remove the 'if' if its condition is always true
           if (test_bit(QUEUE_FLAG_POLL, &q->queue_flags) && bio && bio->bi_bdev)
           ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>> drivers/nvme/host/ioctl.c:638:6: warning: variable 'ret' is used uninitialized whenever '&&' condition is false [-Wsometimes-uninitialized]
           if (test_bit(QUEUE_FLAG_POLL, &q->queue_flags) && bio && bio->bi_bdev)
               ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   drivers/nvme/host/ioctl.c:641:9: note: uninitialized use occurs here
           return ret;
                  ^~~
   drivers/nvme/host/ioctl.c:638:6: note: remove the '&&' if its condition is always true
           if (test_bit(QUEUE_FLAG_POLL, &q->queue_flags) && bio && bio->bi_bdev)
               ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>> drivers/nvme/host/ioctl.c:638:6: warning: variable 'ret' is used uninitialized whenever '&&' condition is false [-Wsometimes-uninitialized]
           if (test_bit(QUEUE_FLAG_POLL, &q->queue_flags) && bio && bio->bi_bdev)
               ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   drivers/nvme/host/ioctl.c:641:9: note: uninitialized use occurs here
           return ret;
                  ^~~
   drivers/nvme/host/ioctl.c:638:6: note: remove the '&&' if its condition is always true
           if (test_bit(QUEUE_FLAG_POLL, &q->queue_flags) && bio && bio->bi_bdev)
               ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   drivers/nvme/host/ioctl.c:629:9: note: initialize the variable 'ret' to silence this warning
           int ret;
                  ^
                   = 0
   3 warnings generated.


vim +638 drivers/nvme/host/ioctl.c

   625	
   626	int nvme_ns_chr_uring_cmd_iopoll(struct io_uring_cmd *ioucmd)
   627	{
   628		struct bio *bio;
   629		int ret;
   630		struct nvme_ns *ns;
   631		struct request_queue *q;
   632	
   633		rcu_read_lock();
   634		bio = READ_ONCE(ioucmd->cookie);
   635		ns = container_of(file_inode(ioucmd->file)->i_cdev,
   636				struct nvme_ns, cdev);
   637		q = ns->queue;
 > 638		if (test_bit(QUEUE_FLAG_POLL, &q->queue_flags) && bio && bio->bi_bdev)
   639			ret = bio_poll(bio, 0, 0);
   640		rcu_read_unlock();
   641		return ret;
   642	}
   643	#ifdef CONFIG_NVME_MULTIPATH
   644	static int nvme_ns_head_ctrl_ioctl(struct nvme_ns *ns, unsigned int cmd,
   645			void __user *argp, struct nvme_ns_head *head, int srcu_idx)
   646		__releases(&head->srcu)
   647	{
   648		struct nvme_ctrl *ctrl = ns->ctrl;
   649		int ret;
   650	
   651		nvme_get_ctrl(ns->ctrl);
   652		srcu_read_unlock(&head->srcu, srcu_idx);
   653		ret = nvme_ctrl_ioctl(ns->ctrl, cmd, argp);
   654	
   655		nvme_put_ctrl(ctrl);
   656		return ret;
   657	}
   658	

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