scsi: mpt3sas: Perform additional retries if doorbell read returns 0

commit 4ca10f3e upstream.

The driver retries certain register reads 3 times if the returned value is
0. This was done because the controller could return 0 for certain
registers if other registers were being accessed concurrently by the BMC.

In certain systems with increased BMC interactions, the register values
returned can be 0 for longer than 3 retries. Change the retry count from 3
to 30 for the affected registers to prevent problems with out-of-band
management.

Fixes: b8992029

 ("scsi: mpt3sas: Add separate function for aero doorbell reads")
Cc: stable@vger.kernel.org
Signed-off-by: Ranjan Kumar <ranjan.kumar@broadcom.com>
Link: https://lore.kernel.org/r/20230829090020.5417-2-ranjan.kumar@broadcom.com


Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>