[4/5] ibmvfc: complete commands outside the host/queue lock

Drain the command queue and place all commands on a completion list.
Perform command completion on that list outside the host/queue locks.
Further, move purged command compeletions outside the host_lock as well.

Signed-off-by: Tyrel Datwyler <tyreld@linux.ibm.com>
Reviewed-by: Brian King <brking@linux.vnet.ibm.com>
---
 drivers/scsi/ibmvscsi/ibmvfc.c | 58 ++++++++++++++++++++++++++--------
 drivers/scsi/ibmvscsi/ibmvfc.h |  3 +-
 2 files changed, 47 insertions(+), 14 deletions(-)

Hi Tyrel,

I love your patch! Perhaps something to improve:

[auto build test WARNING on next-20201218]
[also build test WARNING on v5.11-rc1]
[cannot apply to powerpc/next v5.10 v5.10-rc7 v5.10-rc6]
[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/Tyrel-Datwyler/ibmvfc-MQ-preparatory-locking-work/20201219-072334
base:    0d52778b8710eb11cb616761a02aee0a7fd60425
config: powerpc-allyesconfig (attached as .config)
compiler: powerpc64-linux-gcc (GCC) 9.3.0
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/0day-ci/linux/commit/2609a2691baaf1f06d8306a56575ae2eb076f625
        git remote add linux-review https://github.com/0day-ci/linux
        git fetch --no-tags linux-review Tyrel-Datwyler/ibmvfc-MQ-preparatory-locking-work/20201219-072334
        git checkout 2609a2691baaf1f06d8306a56575ae2eb076f625
        # save the attached .config to linux build tree
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross ARCH=powerpc 

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/scsi/ibmvscsi/ibmvfc.c:1418:6: warning: no previous prototype for 'ibmvfc_locked_done' [-Wmissing-prototypes]

    1418 | void ibmvfc_locked_done(struct ibmvfc_event *evt)
         |      ^~~~~~~~~~~~~~~~~~
   In file included from arch/powerpc/include/asm/paca.h:15,
                    from arch/powerpc/include/asm/current.h:13,
                    from include/linux/thread_info.h:21,
                    from include/asm-generic/preempt.h:5,
                    from ./arch/powerpc/include/generated/asm/preempt.h:1,
                    from include/linux/preempt.h:78,
                    from include/linux/spinlock.h:51,
                    from include/linux/mmzone.h:8,
                    from include/linux/gfp.h:6,
                    from include/linux/umh.h:4,
                    from include/linux/kmod.h:9,
                    from include/linux/module.h:16,
                    from drivers/scsi/ibmvscsi/ibmvfc.c:10:
   In function 'strncpy',
       inlined from 'ibmvfc_gather_partition_info' at drivers/scsi/ibmvscsi/ibmvfc.c:1267:3,
       inlined from 'ibmvfc_npiv_login' at drivers/scsi/ibmvscsi/ibmvfc.c:4538:2:
   include/linux/string.h:291:30: warning: '__builtin_strncpy' specified bound 97 equals destination size [-Wstringop-truncation]
     291 | #define __underlying_strncpy __builtin_strncpy
         |                              ^
   include/linux/string.h:301:9: note: in expansion of macro '__underlying_strncpy'
     301 |  return __underlying_strncpy(p, q, size);
         |         ^~~~~~~~~~~~~~~~~~~~
   In function 'strncpy',
       inlined from 'ibmvfc_set_login_info' at drivers/scsi/ibmvscsi/ibmvfc.c:1307:2,
       inlined from 'ibmvfc_npiv_login' at drivers/scsi/ibmvscsi/ibmvfc.c:4539:2:
   include/linux/string.h:291:30: warning: '__builtin_strncpy' specified bound 256 equals destination size [-Wstringop-truncation]
     291 | #define __underlying_strncpy __builtin_strncpy
         |                              ^
   include/linux/string.h:301:9: note: in expansion of macro '__underlying_strncpy'
     301 |  return __underlying_strncpy(p, q, size);
         |         ^~~~~~~~~~~~~~~~~~~~
   In function 'strncpy',
       inlined from 'ibmvfc_set_login_info' at drivers/scsi/ibmvscsi/ibmvfc.c:1312:2,
       inlined from 'ibmvfc_npiv_login' at drivers/scsi/ibmvscsi/ibmvfc.c:4539:2:
   include/linux/string.h:291:30: warning: '__builtin_strncpy' specified bound 256 equals destination size [-Wstringop-truncation]
     291 | #define __underlying_strncpy __builtin_strncpy
         |                              ^
   include/linux/string.h:301:9: note: in expansion of macro '__underlying_strncpy'
     301 |  return __underlying_strncpy(p, q, size);
         |         ^~~~~~~~~~~~~~~~~~~~


vim +/ibmvfc_locked_done +1418 drivers/scsi/ibmvscsi/ibmvfc.c

  1409	
  1410	/**
  1411	 * ibmvfc_locked_done - Calls evt completion with host_lock held
  1412	 * @evt:	ibmvfc evt to complete
  1413	 *
  1414	 * All non-scsi command completion callbacks have the expectation that the
  1415	 * host_lock is held. This callback is used by ibmvfc_init_event to wrap a
  1416	 * MAD evt with the host_lock.
  1417	 **/
> 1418	void ibmvfc_locked_done(struct ibmvfc_event *evt)

  1419	{
  1420		unsigned long flags;
  1421	
  1422		spin_lock_irqsave(evt->vhost->host->host_lock, flags);
  1423		evt->_done(evt);
  1424		spin_unlock_irqrestore(evt->vhost->host->host_lock, flags);
  1425	}
  1426	

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org

On 1/4/21 2:17 PM, Tyrel Datwyler wrote:
> The drivers queuecommand routine is still wrapped to hold the host lock

> for the duration of the call. This will become problematic when moving

> to multiple queues due to the lock contention preventing asynchronous

> submissions to mulitple queues. There is no real legatimate reason to

> hold the host lock, and previous patches have insured proper protection

> of moving ibmvfc_event objects between free and sent lists.

> 

> Signed-off-by: Tyrel Datwyler <tyreld@linux.ibm.com>

> Reviewed-by: Brian King <brking@linux.vnet.ibm.com>

> ---


Ignore. This is the wrong updated patch.

-Tyrel