scsi: mpi3mr: Synchronize access to ioctl data buffer

scsi: mpi3mr: Synchronize access to ioctl data buffer

[ Upstream commit 367ac16e5ff2dcd6b7f00a8f94e6ba98875cb397 ]

The driver serializes ioctls through a mutex lock but access to the
ioctl data buffer is not guarded by the mutex. This results in multiple
user threads being able to write to the driver's ioctl buffer
simultaneously.

Protect the ioctl buffer with the ioctl mutex.

Signed-off-by: Sumit Saxena <sumit.saxena@broadcom.com>
Signed-off-by: Ranjan Kumar <ranjan.kumar@broadcom.com>
Link: https://lore.kernel.org/r/20241110194405.10108-2-ranjan.kumar@broadcom.com
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>