Change the ccwrequest infrastructure to use more than one channel
path per start I/O. A flag "singlepath" is added to struct
ccw_request - if set, the old behavior is used. This flag is set
for all exploiters of the ccwrequest infrastructure - so there
is no functional change through this patch.
Signed-off-by: Sebastian Ott <sebott@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Log the response from the unit check handler which triggers further
cio internal i/o processing.
Signed-off-by: Michael Ernst <mernst@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Send unit checks that occur during internal I/O to the device driver
and react according to its return code.
Signed-off-by: Michael Ernst <mernst@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Use asm offsets to make sure the offset defines to struct _lowcore and
its layout don't get out of sync.
Also add a BUILD_BUG_ON() which checks that the size of the structure
is sane.
And while being at it change those sites which use odd casts to access
the current lowcore. These should use S390_lowcore instead.
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Channel path vary is currently broken: channel paths which are varied
offline are still used by Linux. The reason for this is that:
* the path mask indicating which paths of an I/O device can be used
is reset by each internal I/O request
* the logic that checks if a path group is already in its designated
target state incorrectly interprets the result "is correctly set"
as "is correctly set and available"
Fix this by resetting the path mask only for internal I/O requests
which affect the path mask and by correcting the pgid check logic.
Signed-off-by: Peter Oberparleiter <peter.oberparleiter@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Improve error recovery for internal I/Os by repeating each I/O
256 times per path to cope with long-running non-permanent error
conditions. Also retry each path twice to cope with link flapping,
i.e. single paths becoming unavailable in the order in which they
are tried.
Signed-off-by: Peter Oberparleiter <peter.oberparleiter@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Reduce code duplication by introducing a central infrastructure to
perform an internal I/O operation on a CCW device.
Signed-off-by: Peter Oberparleiter <peter.oberparleiter@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
