s390/cio: allow to reset channel measurement block

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commit 0f5d050cea upstream.

Prior to commit 1bc6664bdf a call to
enable_cmf for a device for which channel measurement was already
enabled resulted in a reset of the measurement data.

What looked like bugs at the time (a 2nd allocation was triggered
but failed, reset was called regardless of previous failures, and
errors have not been reported to userspace) was actually something
at least one userspace tool depended on. Restore that behavior in
a sane way.

Fixes: 1bc6664bdf ("s390/cio: use device_lock during cmb activation")
Signed-off-by: Sebastian Ott <sebott@linux.vnet.ibm.com>
Reviewed-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Reviewed-by: Peter Oberparleiter <oberpar@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

...

This commit is contained in:

Sebastian Ott 2016-07-12 19:57:57 +02:00 • committed by Greg Kroah-Hartman

parent 144941bd99

commit e990e8ba92

1 changed files with 20 additions and 9 deletions

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drivers/s390/cio/cmf.c

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