scsi: sd: Implement blacklist option for WRITE SAME w/ UNMAP
BugLink: http://bugs.launchpad.net/bugs/1723145
commit
28a0bc4120d38a394499382ba21d6965a67a3703 upstream.
SBC-4 states:
"A MAXIMUM UNMAP LBA COUNT field set to a non-zero value indicates the
maximum number of LBAs that may be unmapped by an UNMAP command"
"A MAXIMUM WRITE SAME LENGTH field set to a non-zero value indicates
the maximum number of contiguous logical blocks that the device server
allows to be unmapped or written in a single WRITE SAME command."
Despite the spec being clear on the topic, some devices incorrectly
expect WRITE SAME commands with the UNMAP bit set to be limited to the
value reported in MAXIMUM UNMAP LBA COUNT in the Block Limits VPD.
Implement a blacklist option that can be used to accommodate devices
with this behavior.
Reported-by: Bill Kuzeja <William.Kuzeja@stratus.com>
Reported-by: Ewan D. Milne <emilne@redhat.com>
Reviewed-by: Ewan D. Milne <emilne@redhat.com>
Tested-by: Laurence Oberman <loberman@redhat.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Seth Forshee <seth.forshee@canonical.com>