scsi: scsi_dh_alua: Avoid crash during alua_bus_detach()

alua_bus_detach() might be running concurrently with alua_rtpg_work(), so
we might trip over h->sdev == NULL and call BUG_ON().  The correct way of
handling it is to not set h->sdev to NULL in alua_bus_detach(), and call
rcu_synchronize() before the final delete to ensure that all concurrent
threads have left the critical section.  Then we can get rid of the
BUG_ON() and replace it with a simple if condition.

Link: https://lore.kernel.org/r/[email protected]
Link: https://lore.kernel.org/r/[email protected]
Cc: Brian Bunker <[email protected]>
Acked-by: Brian Bunker <[email protected]>
Tested-by: Jitendra Khasdev <[email protected]>
Reviewed-by: Jitendra Khasdev <[email protected]>
Signed-off-by: Hannes Reinecke <[email protected]>
Signed-off-by: Martin K. Petersen <[email protected]>

0 files changed, 0 insertions, 0 deletions