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dm mpath: fix uninitialized 'pg_init_wait' waitqueue_head NULL pointer 

Initialize all the scsi_dh related 'struct multipath' members regardless
of whether a scsi_dh is in use or not.

The subtle (and fragile) SCSI-assuming legacy code clearly needs further
decoupling from non-SCSI (and/or developer understanding).

Fixes: 8d47e65948 ("dm mpath: remove unnecessary NVMe branching in favor of scsi_dh checks")
Reported-by: Bart Van Assche <bart.vanassche@wdc.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
This commit is contained in:
Mike Snitzer 2018-03-12 20:30:43 -04:00
parent 0c8efd610b
commit c37366742b
1 changed files with 10 additions and 11 deletions
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21
drivers/md/dm-mpath.c
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@ -223,6 +223,16 @@ static int alloc_multipath_stage2(struct dm_target *ti, struct multipath *m)
dm_table_set_type(ti->table, m->queue_mode);
/*
* Init fields that are only used when a scsi_dh is attached
* - must do this unconditionally (really doesn't hurt non-SCSI uses)
*/
set_bit(MPATHF_QUEUE_IO, &m->flags);
atomic_set(&m->pg_init_in_progress, 0);
atomic_set(&m->pg_init_count, 0);
m->pg_init_delay_msecs = DM_PG_INIT_DELAY_DEFAULT;
init_waitqueue_head(&m->pg_init_wait);
return 0;
}
@ -331,7 +341,6 @@ static void __switch_pg(struct multipath *m, struct priority_group *pg)
set_bit(MPATHF_PG_INIT_REQUIRED, &m->flags);
set_bit(MPATHF_QUEUE_IO, &m->flags);
} else {
/* FIXME: not needed if no scsi_dh is attached */
clear_bit(MPATHF_PG_INIT_REQUIRED, &m->flags);
clear_bit(MPATHF_QUEUE_IO, &m->flags);
}
@ -823,16 +832,6 @@ retain:
*/
kfree(m->hw_handler_name);
m->hw_handler_name = attached_handler_name;
/*
* Init fields that are only used when a scsi_dh is attached
*/
if (!test_and_set_bit(MPATHF_QUEUE_IO, &m->flags)) {
atomic_set(&m->pg_init_in_progress, 0);
atomic_set(&m->pg_init_count, 0);
m->pg_init_delay_msecs = DM_PG_INIT_DELAY_DEFAULT;
init_waitqueue_head(&m->pg_init_wait);
}
}
}