Re: [RFC PATCH 10/12] nvme: submisssion/completion of uring_cmd to/from the registered queue

Re: [RFC PATCH 10/12] nvme: submisssion/completion of uring_cmd to/from the registered queue

[kernel test robot]

Hi Kanchan,

[This is a private test report for your RFC patch.]
kernel test robot noticed the following build warnings:

[auto build test WARNING on axboe-block/for-next]
[also build test WARNING on linus/master next-20230428]
[cannot apply to v6.3]
[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/pci-enable-raw_queues-N-module-parameter/20230429-183933
base:   https://git.kernel.org/pub/scm/linux/kernel/git/axboe/linux-block.git for-next
patch link:    https://lore.kernel.org/r/20230429093925.133327-11-joshi.k%40samsung.com
patch subject: [RFC PATCH 10/12] nvme: submisssion/completion of uring_cmd to/from the registered queue
config: arm-randconfig-r032-20230429 (https://download.01.org/0day-ci/archive/20230429/202304292012.oxeNukfB-lkp@intel.com/config)
compiler: clang version 17.0.0 (https://github.com/llvm/llvm-project 437b7602e4a998220871de78afcb020b9c14a661)
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 arm cross compiling tool for clang build
        # apt-get install binutils-arm-linux-gnueabi
        # https://github.com/intel-lab-lkp/linux/commit/e06694e83e548757cf886b603579ce384d95b3ab
        git remote add linux-review https://github.com/intel-lab-lkp/linux
        git fetch --no-tags linux-review Kanchan-Joshi/pci-enable-raw_queues-N-module-parameter/20230429-183933
        git checkout e06694e83e548757cf886b603579ce384d95b3ab
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=arm olddefconfig
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=arm SHELL=/bin/bash drivers/nvme/host/

If you fix the issue, kindly add following tag where applicable
| Reported-by: kernel test robot <lkp@intel.com>
| Link: https://lore.kernel.org/oe-kbuild-all/202304292012.oxeNukfB-lkp@intel.com/

All warnings (new ones prefixed by >>):

   drivers/nvme/host/ioctl.c:812:5: warning: no previous prototype for function 'nvme_uring_cmd_iopoll_qid' [-Wmissing-prototypes]
   int nvme_uring_cmd_iopoll_qid(struct request_queue *q,
       ^
   drivers/nvme/host/ioctl.c:812:1: note: declare 'static' if the function is not intended to be used outside of this translation unit
   int nvme_uring_cmd_iopoll_qid(struct request_queue *q,
   ^
   static 
>> drivers/nvme/host/ioctl.c:1037:28: warning: variable 'q' is uninitialized when used here [-Wuninitialized]
                           if (!percpu_ref_tryget(&q->q_usage_counter))
                                                   ^
   drivers/nvme/host/ioctl.c:1021:25: note: initialize the variable 'q' to silence this warning
           struct request_queue *q;
                                  ^
                                   = NULL
   2 warnings generated.


vim +/q +1037 drivers/nvme/host/ioctl.c

  1010	
  1011	int nvme_ns_head_chr_uring_cmd_iopoll(struct io_uring_cmd *ioucmd,
  1012					      struct io_comp_batch *iob,
  1013					      unsigned int poll_flags)
  1014	{
  1015		struct cdev *cdev = file_inode(ioucmd->file)->i_cdev;
  1016		struct nvme_ns_head *head = container_of(cdev, struct nvme_ns_head, cdev);
  1017		int srcu_idx = srcu_read_lock(&head->srcu);
  1018		struct nvme_ns *ns = nvme_find_path(head);
  1019		struct bio *bio;
  1020		int ret = 0;
  1021		struct request_queue *q;
  1022	
  1023		if (ns) {
  1024			if (!(ioucmd->flags & IORING_URING_CMD_DIRECT)) {
  1025				rcu_read_lock();
  1026				bio = READ_ONCE(ioucmd->cookie);
  1027				q = ns->queue;
  1028				if (test_bit(QUEUE_FLAG_POLL, &q->queue_flags) && bio
  1029						&& bio->bi_bdev)
  1030					ret = bio_poll(bio, iob, poll_flags);
  1031				rcu_read_unlock();
  1032			} else {
  1033				int qid = io_uring_cmd_import_qid(ioucmd);
  1034	
  1035				if (qid <= 0)
  1036					return 0;
> 1037				if (!percpu_ref_tryget(&q->q_usage_counter))
  1038					return 0;
  1039				ret = nvme_uring_cmd_iopoll_qid(q, ioucmd, qid, iob,
  1040								poll_flags);
  1041				percpu_ref_put(&q->q_usage_counter);
  1042			}
  1043		}
  1044		srcu_read_unlock(&head->srcu, srcu_idx);
  1045		return ret;
  1046	}
  1047	#endif /* CONFIG_NVME_MULTIPATH */
  1048	

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https://github.com/intel/lkp-tests