scsi: libsas: direct call probe and destruct
In commit 87c8331f ("[SCSI] libsas: prevent domain rediscovery competing with ata error handling") introduced disco mutex to prevent rediscovery competing with ata error handling and put the whole revalidation in the mutex. But the rphy add/remove needs to wait for the error handling which also grabs the disco mutex. This may leads to dead lock.So the probe and destruct event were introduce to do the rphy add/remove asynchronously and out of the lock. The asynchronously processed workers makes the whole discovery process not atomic, the other events may interrupt the process. For example, if a loss of signal event inserted before the probe event, the sas_deform_port() is called and the port will be deleted. And sas_port_delete() may run before the destruct event, but the port-x:x is the top parent of end device or expander. This leads to a kernel WARNING such as: [ 82.042979] sysfs group 'power' not found for kobject 'phy-1:0:22' [ 82.042983] ------------[ cut here ]------------ [ 82.042986] WARNING: CPU: 54 PID: 1714 at fs/sysfs/group.c:237 sysfs_remove_group+0x94/0xa0 [ 82.043059] Call trace: [ 82.043082] [<ffff0000082e7624>] sysfs_remove_group+0x94/0xa0 [ 82.043085] [<ffff00000864e320>] dpm_sysfs_remove+0x60/0x70 [ 82.043086] [<ffff00000863ee10>] device_del+0x138/0x308 [ 82.043089] [<ffff00000869a2d0>] sas_phy_delete+0x38/0x60 [ 82.043091] [<ffff00000869a86c>] do_sas_phy_delete+0x6c/0x80 [ 82.043093] [<ffff00000863dc20>] device_for_each_child+0x58/0xa0 [ 82.043095] [<ffff000008696f80>] sas_remove_children+0x40/0x50 [ 82.043100] [<ffff00000869d1bc>] sas_destruct_devices+0x64/0xa0 [ 82.043102] [<ffff0000080e93bc>] process_one_work+0x1fc/0x4b0 [ 82.043104] [<ffff0000080e96c0>] worker_thread+0x50/0x490 [ 82.043105] [<ffff0000080f0364>] kthread+0xfc/0x128 [ 82.043107] [<ffff0000080836c0>] ret_from_fork+0x10/0x50 Make probe and destruct a direct call in the disco and revalidate function, but put them outside the lock. The whole discovery or revalidate won't be interrupted by other events. And the DISCE_PROBE and DISCE_DESTRUCT event are deleted as a result of the direct call. Introduce a new list to destruct the sas_port and put the port delete after the destruct. This makes sure the right order of destroying the sysfs kobject and fix the warning above. In sas_ex_revalidate_domain() have a loop to find all broadcasted device, and sometimes we have a chance to find the same expander twice. Because the sas_port will be deleted at the end of the whole revalidate process, sas_port with the same name cannot be added before this. Otherwise the sysfs will complain of creating duplicate filename. Since the LLDD will send broadcast for every device change, we can only process one expander's revalidation. [mkp: kbuild test robot warning] Signed-off-by:Jason Yan <yanaijie@huawei.com> CC: John Garry <john.garry@huawei.com> CC: Johannes Thumshirn <jthumshirn@suse.de> CC: Ewan Milne <emilne@redhat.com> CC: Christoph Hellwig <hch@lst.de> CC: Tomas Henzl <thenzl@redhat.com> CC: Dan Williams <dan.j.williams@intel.com> Reviewed-by:
Hannes Reinecke <hare@suse.com> Signed-off-by:
Martin K. Petersen <martin.petersen@oracle.com>
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