Commit 8284fb19 authored by Michael Ernst's avatar Michael Ernst Committed by Heiko Carstens
Browse files

[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: default avatarMichael Ernst <mernst@de.ibm.com>
Signed-off-by: default avatarMartin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: default avatarHeiko Carstens <heiko.carstens@de.ibm.com>
parent fe6173d9

drivers/s390/cio/chsc.c

+0 −3
Original line number Diff line number Diff line
@@ -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;

}

drivers/s390/cio/css.c

+9 −1
Original line number Diff line number Diff line
@@ -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;