From: Sebastian Ott <sebott@linux.vnet.ibm.com>
Date: Fri, 26 Feb 2010 21:37:26 +0000 (+0100)
Subject: [S390] cio: wait for channel report
X-Git-Tag: v2.6.34-rc1~268^2~30
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=b4563e891a043fe521e62f6f621b928641474ff3;p=pandora-kernel.git

[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>
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