tree 741f394a7159c15ed73281ce563d5d8e3d176f9a
parent 23dcfa61bac244e1200ff9ad19c6e9144dcb6bb5
author sreekanth.reddy@lsi.com <sreekanth.reddy@lsi.com> 1342520825 +0530
committer James Bottomley <JBottomley@Parallels.com> 1345613929 +0400

[SCSI] mpt2sas: Fix for Driver oops, when loading driver with max_queue_depth command line option to a very small value

If the specified max_queue_depth setting is less than the
expected number of internal commands, then driver will calculate
the queue depth size to a negitive number. This negitive number
is actually a very large number because variable is unsigned
16bit integer. So, the driver will ask for a very large amount of
memory for message frames and resulting into oops as memory
allocation routines will not able to handle such a large request.

So, in order to limit this kind of oops, The driver need to set
the max_queue_depth to a scsi mid layer's can_queue value. Then
the overall message frames required for IO is minimum of either
(max_queue_depth plus internal commands) or the IOC global
credits.

Signed-off-by: Sreekanth Reddy <sreekanth.reddy@lsi.com>
Cc: <stable@kernel.org>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>