tree 3f3af60351bed04d68f69ccd24f14b85fc2c4f81
parent 879acca58a904c25487c89ab11e23eb556fb13d3
author Sebastian Ott <sebott@linux.vnet.ibm.com> 1267220246 +0100
committer Martin Schwidefsky <sky@mschwide.boeblingen.de.ibm.com> 1267220249 +0100

[S390] cio: wait for channel report

To fetch a pending channel report word (crw) we use a kernel
thread which triggers stcrw and sleeps on a semaphore. The s390
machine check handler uses crw_handle_channel_report to handle
one crw if needed.

This patch replaces the semaphore with a waitqueue (to block the
kernel thread) and an atomic_t (to count the number of pending
requests).

By this we achieve the ability to force this thread to check for
a pending crw (independent on when it is triggered by the machine
check handler) and wait for this action to finish.

Signed-off-by: Sebastian Ott <sebott@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>