Handle up to 8 block layer requests per HW request. These requests
can be processed in parallel on the device leading to better
throughput (and less interrupts). The overhead for additional
requests is small since we don't blindly allocate new aidaws but
try to use what's left of the previous one.
Signed-off-by: NSebastian Ott <sebott@linux.vnet.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

AOBs (the structure describing the HW request) need to be 4K
aligned but very little of that page is actually used. With
this patch we place aidaws at the end of the AOB page and only
allocate a separate page for aidaws when we have to (lists of
aidaws must not cross page boundaries).
Signed-off-by: NSebastian Ott <sebott@linux.vnet.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

We currently use one preallocated page per HW request to store
aidaws. With this patch we use mempool to allocate an aidaw page
whenever we need it.
Signed-off-by: NSebastian Ott <sebott@linux.vnet.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

Refactor direct debug level comparisons with the (internal) s390db->level
member.  Use the debug_level_enabled() function instead.
Signed-off-by: NHendrik Brueckner <brueckner@linux.vnet.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

Stop writing to scm after certain error conditions such as a concurrent
firmware upgrade. Resume to normal state once scm_blk_set_available is
called (due to an scm availability notification).
Reviewed-by: NPeter Oberparleiter <peter.oberparleiter@de.ibm.com>
Signed-off-by: NSebastian Ott <sebott@linux.vnet.ibm.com>
Signed-off-by: NPeter Oberparleiter <peter.oberparleiter@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

Convert the defines for the !CONFIG_SCM* stuff to static inline
functions.
Signed-off-by: NSebastian Ott <sebott@linux.vnet.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

Force writes to Storage Class Memory (SCM) to be in done in clusters.
Signed-off-by: NSebastian Ott <sebott@linux.vnet.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

Block device driver for Storage Class Memory (SCM). This driver
provides a block device interface for each available SCM increment.
Signed-off-by: NSebastian Ott <sebott@linux.vnet.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>