Merge branch 'next' into for-linus

Prepare first round of input updates for 3.17.

1 files changed, 19 insertions, 10 deletions

diff --git a/drivers/tty/sysrq.c b/drivers/tty/sysrq.c
index ce396ecdf412..454b65898e2c 100644
--- a/drivers/tty/sysrq.c
+++ b/drivers/tty/sysrq.c
@@ -46,6 +46,7 @@
 #include <linux/jiffies.h>
 #include <linux/syscalls.h>
 #include <linux/of.h>
+#include <linux/rcupdate.h>
 
 #include <asm/ptrace.h>
 #include <asm/irq_regs.h>
@@ -88,7 +89,7 @@ static void sysrq_handle_loglevel(int key)
 	int i;
 
 	i = key - '0';
-	console_loglevel = 7;
+	console_loglevel = CONSOLE_LOGLEVEL_DEFAULT;
 	printk("Loglevel set to %d\n", i);
 	console_loglevel = i;
 }
@@ -343,7 +344,7 @@ static void send_sig_all(int sig)
 static void sysrq_handle_term(int key)
 {
 	send_sig_all(SIGTERM);
-	console_loglevel = 8;
+	console_loglevel = CONSOLE_LOGLEVEL_DEBUG;
 }
 static struct sysrq_key_op sysrq_term_op = {
 	.handler	= sysrq_handle_term,
@@ -387,7 +388,7 @@ static struct sysrq_key_op sysrq_thaw_op = {
 static void sysrq_handle_kill(int key)
 {
 	send_sig_all(SIGKILL);
-	console_loglevel = 8;
+	console_loglevel = CONSOLE_LOGLEVEL_DEBUG;
 }
 static struct sysrq_key_op sysrq_kill_op = {
 	.handler	= sysrq_handle_kill,
@@ -510,9 +511,9 @@ void __handle_sysrq(int key, bool check_mask)
 	struct sysrq_key_op *op_p;
 	int orig_log_level;
 	int i;
-	unsigned long flags;
 
-	spin_lock_irqsave(&sysrq_key_table_lock, flags);
+	rcu_sysrq_start();
+	rcu_read_lock();
 	/*
 	 * Raise the apparent loglevel to maximum so that the sysrq header
 	 * is shown to provide the user with positive feedback.  We do not
@@ -520,7 +521,7 @@ void __handle_sysrq(int key, bool check_mask)
 	 * routing in the consumers of /proc/kmsg.
 	 */
 	orig_log_level = console_loglevel;
-	console_loglevel = 7;
+	console_loglevel = CONSOLE_LOGLEVEL_DEFAULT;
 	printk(KERN_INFO "SysRq : ");
 
         op_p = __sysrq_get_key_op(key);
@@ -554,7 +555,8 @@ void __handle_sysrq(int key, bool check_mask)
 		printk("\n");
 		console_loglevel = orig_log_level;
 	}
-	spin_unlock_irqrestore(&sysrq_key_table_lock, flags);
+	rcu_read_unlock();
+	rcu_sysrq_end();
 }
 
 void handle_sysrq(int key)
@@ -1043,16 +1045,23 @@ static int __sysrq_swap_key_ops(int key, struct sysrq_key_op *insert_op_p,
                                 struct sysrq_key_op *remove_op_p)
 {
 	int retval;
-	unsigned long flags;
 
-	spin_lock_irqsave(&sysrq_key_table_lock, flags);
+	spin_lock(&sysrq_key_table_lock);
 	if (__sysrq_get_key_op(key) == remove_op_p) {
 		__sysrq_put_key_op(key, insert_op_p);
 		retval = 0;
 	} else {
 		retval = -1;
 	}
-	spin_unlock_irqrestore(&sysrq_key_table_lock, flags);
+	spin_unlock(&sysrq_key_table_lock);
+
+	/*
+	 * A concurrent __handle_sysrq either got the old op or the new op.
+	 * Wait for it to go away before returning, so the code for an old
+	 * op is not freed (eg. on module unload) while it is in use.
+	 */
+	synchronize_rcu();
+
 	return retval;
 }