From: Michael Ernst Date: Thu, 17 Apr 2008 05:46:01 +0000 (+0200) Subject: [S390] cio: fix parallel cm_enable processing. X-Git-Tag: v2.6.26-rc1~1158^2~30 X-Git-Url: http://pilppa.com/gitweb/?a=commitdiff_plain;h=8284fb19efa1f11ea8dd213e9e227fc1fcb20586;p=linux-2.6-omap-h63xx.git [S390] cio: fix parallel cm_enable processing. It is now possible to trigger cm_enable processing several times in parallel without causing a kernel panic. Signed-off-by: Michael Ernst Signed-off-by: Martin Schwidefsky Signed-off-by: Heiko Carstens --- diff --git a/drivers/s390/cio/chsc.c b/drivers/s390/cio/chsc.c index b6a40c20780..5de86908b0d 100644 --- a/drivers/s390/cio/chsc.c +++ b/drivers/s390/cio/chsc.c @@ -766,7 +766,6 @@ chsc_secm(struct channel_subsystem *css, int enable) if (!secm_area) return -ENOMEM; - mutex_lock(&css->mutex); if (enable && !css->cm_enabled) { css->cub_addr1 = (void *)get_zeroed_page(GFP_KERNEL | GFP_DMA); css->cub_addr2 = (void *)get_zeroed_page(GFP_KERNEL | GFP_DMA); @@ -774,7 +773,6 @@ chsc_secm(struct channel_subsystem *css, int enable) free_page((unsigned long)css->cub_addr1); free_page((unsigned long)css->cub_addr2); free_page((unsigned long)secm_area); - mutex_unlock(&css->mutex); return -ENOMEM; } } @@ -795,7 +793,6 @@ chsc_secm(struct channel_subsystem *css, int enable) free_page((unsigned long)css->cub_addr1); free_page((unsigned long)css->cub_addr2); } - mutex_unlock(&css->mutex); free_page((unsigned long)secm_area); return ret; } diff --git a/drivers/s390/cio/css.c b/drivers/s390/cio/css.c index 3e829c82749..c1afab5f72d 100644 --- a/drivers/s390/cio/css.c +++ b/drivers/s390/cio/css.c @@ -689,10 +689,14 @@ css_cm_enable_show(struct device *dev, struct device_attribute *attr, char *buf) { struct channel_subsystem *css = to_css(dev); + int ret; if (!css) return 0; - return sprintf(buf, "%x\n", css->cm_enabled); + mutex_lock(&css->mutex); + ret = sprintf(buf, "%x\n", css->cm_enabled); + mutex_unlock(&css->mutex); + return ret; } static ssize_t @@ -702,6 +706,7 @@ css_cm_enable_store(struct device *dev, struct device_attribute *attr, struct channel_subsystem *css = to_css(dev); int ret; + mutex_lock(&css->mutex); switch (buf[0]) { case '0': ret = css->cm_enabled ? chsc_secm(css, 0) : 0; @@ -712,6 +717,7 @@ css_cm_enable_store(struct device *dev, struct device_attribute *attr, default: ret = -EINVAL; } + mutex_unlock(&css->mutex); return ret < 0 ? ret : count; } @@ -758,9 +764,11 @@ static int css_reboot_event(struct notifier_block *this, struct channel_subsystem *css; css = channel_subsystems[i]; + mutex_lock(&css->mutex); if (css->cm_enabled) if (chsc_secm(css, 0)) ret = NOTIFY_BAD; + mutex_unlock(&css->mutex); } return ret;