linux-kernel - [PATCH] ipm: fix mutex use

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Date:	Fri, 14 May 2010 18:56:37 +0200
From:	Tomas Henzl <thenzl@...hat.com>
To:	"'linux-kernel@...r.kernel.org'" <linux-kernel@...r.kernel.org>,
	"'akpm@...l.org'" <akpm@...l.org>
CC:	minyard@....org, mjg@...hat.com,
	openipmi-developer@...ts.sourceforge.net
Subject: [PATCH] ipm: fix mutex use

It looks like there is an unbalance with the mutexes after the latest 
IPMI patchset applied. For example in 
"static __devinit int init_ipmi_si(void)"
....
	list_for_each_entry(e, &smi_infos, link) {
		if (!e->irq && (!type || e->addr_source == type)) {
			if (!try_smi_init(e)) {
				type = e->addr_source;
			}
		}
	}
	mutex_unlock(&smi_infos_lock);

we are calling mutex_unlock twice, because the mutex_unlock(&smi_infos_lock)
is also called from try_smi_init.

If the lock in try_smi_init is not needed this can be then solved
by removing the mutex_unlock(&smi_infos_lock) from try_smi_init.

Signed-off-by: Tomas Henzl <thenzl@...hat.com>

---
diff --git a/drivers/char/ipmi/ipmi_si_intf.c b/drivers/char/ipmi/ipmi_si_intf.c
index 8d7b879..c6af8e0 100644
--- a/drivers/char/ipmi/ipmi_si_intf.c
+++ b/drivers/char/ipmi/ipmi_si_intf.c
@@ -3060,8 +3060,6 @@ static int try_smi_init(struct smi_info *new_smi)
 		goto out_err_stop_timer;
 	}
 
-	mutex_unlock(&smi_infos_lock);
-
 	printk(KERN_INFO "IPMI %s interface initialized\n",
 	       si_to_str[new_smi->si_type]);
 
@@ -3111,8 +3109,6 @@ static int try_smi_init(struct smi_info *new_smi)
 		new_smi->dev_registered = 0;
 	}
 
-	mutex_unlock(&smi_infos_lock);
-
 	return rv;
 }
 


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