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From: kbuild test robot <lkp@intel.com>
To: kbuild-all@lists.01.org
Subject: Re: [RFC PATCH V3 2/2] scsi: core: don't limit per-LUN queue depth for SSD
Date: Wed, 09 Oct 2019 03:33:43 +0800	[thread overview]
Message-ID: <201910090326.BA2dYjOO%lkp@intel.com> (raw)
In-Reply-To: <20191008100945.24951-3-ming.lei@redhat.com>

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Hi Ming,

[FYI, it's a private test report for your RFC patch.]
[auto build test WARNING on scsi/for-next]
[cannot apply to v5.4-rc2 next-20191008]
[if your patch is applied to the wrong git tree, please drop us a note to help
improve the system. BTW, we also suggest to use '--base' option to specify the
base tree in git format-patch, please see https://stackoverflow.com/a/37406982]

url:    https://github.com/0day-ci/linux/commits/Ming-Lei/scsi-core-avoid-host-wide-host_busy-counter-for-scsi_mq/20191009-015827
base:   https://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi.git for-next
config: i386-defconfig (attached as .config)
compiler: gcc-7 (Debian 7.4.0-13) 7.4.0
reproduce:
        # save the attached .config to linux build tree
        make ARCH=i386 

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

Note: it may well be a FALSE warning. FWIW you are at least aware of it now.
http://gcc.gnu.org/wiki/Better_Uninitialized_Warnings

All warnings (new ones prefixed by >>):

   drivers/scsi/scsi_lib.c: In function 'scsi_mq_get_budget':
>> drivers/scsi/scsi_lib.c:1293:6: warning: 'busy' may be used uninitialized in this function [-Wmaybe-uninitialized]
      if (busy)
         ^
   drivers/scsi/scsi_lib.c:1287:15: note: 'busy' was declared here
     unsigned int busy;
                  ^~~~

vim +/busy +1293 drivers/scsi/scsi_lib.c

7f9a6bc4e9d59e James Bottomley   2007-08-04  1277  
^1da177e4c3f41 Linus Torvalds    2005-04-16  1278  /*
^1da177e4c3f41 Linus Torvalds    2005-04-16  1279   * scsi_dev_queue_ready: if we can send requests to sdev, return 1 else
^1da177e4c3f41 Linus Torvalds    2005-04-16  1280   * return 0.
^1da177e4c3f41 Linus Torvalds    2005-04-16  1281   *
^1da177e4c3f41 Linus Torvalds    2005-04-16  1282   * Called with the queue_lock held.
^1da177e4c3f41 Linus Torvalds    2005-04-16  1283   */
^1da177e4c3f41 Linus Torvalds    2005-04-16  1284  static inline int scsi_dev_queue_ready(struct request_queue *q,
^1da177e4c3f41 Linus Torvalds    2005-04-16  1285  				  struct scsi_device *sdev)
^1da177e4c3f41 Linus Torvalds    2005-04-16  1286  {
71e75c97f97a96 Christoph Hellwig 2014-04-11  1287  	unsigned int busy;
74eb6c22dc70e3 Ming Lei          2019-10-08  1288  	bool bypass = blk_queue_nonrot(sdev->request_queue);
71e75c97f97a96 Christoph Hellwig 2014-04-11  1289  
74eb6c22dc70e3 Ming Lei          2019-10-08  1290  	if (!bypass)
71e75c97f97a96 Christoph Hellwig 2014-04-11  1291  		busy = atomic_inc_return(&sdev->device_busy) - 1;
cd9070c9c512ff Christoph Hellwig 2014-01-23  1292  	if (atomic_read(&sdev->device_blocked)) {
71e75c97f97a96 Christoph Hellwig 2014-04-11 @1293  		if (busy)
71e75c97f97a96 Christoph Hellwig 2014-04-11  1294  			goto out_dec;
71e75c97f97a96 Christoph Hellwig 2014-04-11  1295  
^1da177e4c3f41 Linus Torvalds    2005-04-16  1296  		/*
^1da177e4c3f41 Linus Torvalds    2005-04-16  1297  		 * unblock after device_blocked iterates to zero
^1da177e4c3f41 Linus Torvalds    2005-04-16  1298  		 */
f664a3cc17b7d0 Jens Axboe        2018-11-01  1299  		if (atomic_dec_return(&sdev->device_blocked) > 0)
71e75c97f97a96 Christoph Hellwig 2014-04-11  1300  			goto out_dec;
71e75c97f97a96 Christoph Hellwig 2014-04-11  1301  		SCSI_LOG_MLQUEUE(3, sdev_printk(KERN_INFO, sdev,
71e75c97f97a96 Christoph Hellwig 2014-04-11  1302  				   "unblocking device at zero depth\n"));
^1da177e4c3f41 Linus Torvalds    2005-04-16  1303  	}
71e75c97f97a96 Christoph Hellwig 2014-04-11  1304  
74eb6c22dc70e3 Ming Lei          2019-10-08  1305  	if (bypass)
74eb6c22dc70e3 Ming Lei          2019-10-08  1306  		return 1;
74eb6c22dc70e3 Ming Lei          2019-10-08  1307  
71e75c97f97a96 Christoph Hellwig 2014-04-11  1308  	if (busy >= sdev->queue_depth)
71e75c97f97a96 Christoph Hellwig 2014-04-11  1309  		goto out_dec;
^1da177e4c3f41 Linus Torvalds    2005-04-16  1310  
^1da177e4c3f41 Linus Torvalds    2005-04-16  1311  	return 1;
71e75c97f97a96 Christoph Hellwig 2014-04-11  1312  out_dec:
74eb6c22dc70e3 Ming Lei          2019-10-08  1313  	if (!bypass)
71e75c97f97a96 Christoph Hellwig 2014-04-11  1314  		atomic_dec(&sdev->device_busy);
71e75c97f97a96 Christoph Hellwig 2014-04-11  1315  	return 0;
^1da177e4c3f41 Linus Torvalds    2005-04-16  1316  }
^1da177e4c3f41 Linus Torvalds    2005-04-16  1317  

:::::: The code at line 1293 was first introduced by commit
:::::: 71e75c97f97a9645d25fbf3d8e4165a558f18747 scsi: convert device_busy to atomic_t

:::::: TO: Christoph Hellwig <hch@lst.de>
:::::: CC: Christoph Hellwig <hch@lst.de>

---
0-DAY kernel test infrastructure                Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all                   Intel Corporation

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  reply	other threads:[~2019-10-08 19:33 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-10-08 10:09 [PATCH V3 0/2] scsi: avoid atomic operations in IO path Ming Lei
2019-10-08 10:09 ` [PATCH V3 1/2] scsi: core: avoid host-wide host_busy counter for scsi_mq Ming Lei
2019-10-08 10:09 ` [RFC PATCH V3 2/2] scsi: core: don't limit per-LUN queue depth for SSD Ming Lei
2019-10-08 19:33   ` kbuild test robot [this message]
2019-10-09  8:29   ` Dan Carpenter
2019-10-09  8:29     ` Dan Carpenter
2019-11-04  8:50   ` [scsi] 74eb6c22dc: suspend_stress.fail kernel test robot
2019-11-04  8:50     ` kernel test robot
2019-11-05  3:52     ` Bart Van Assche
2019-11-05  3:52       ` Bart Van Assche
2019-11-05  6:11       ` Ming Lei
2019-11-05  6:11         ` Ming Lei
2019-11-13 17:00         ` Bart Van Assche
2019-11-13 17:00           ` Bart Van Assche
2019-11-14  1:25           ` Ming Lei
2019-11-14  1:25             ` Ming Lei
2019-11-16  8:54     ` Ming Lei
2019-11-16  8:54       ` Ming Lei
2019-11-21  6:50       ` Oliver Sang
2019-11-21  6:50         ` Oliver Sang
2019-11-21  7:36         ` Ming Lei
2019-11-21  7:36           ` Ming Lei

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