Merge branch 'next' (accumulated 3.16 merge window patches) into master

Now that 3.15 is released, this merges the 'next' branch into 'master',
bringing us to the normal situation where my 'master' branch is the
merge window.

* accumulated work in next: (6809 commits)
  ufs: sb mutex merge + mutex_destroy
  powerpc: update comments for generic idle conversion
  cris: update comments for generic idle conversion
  idle: remove cpu_idle() forward declarations
  nbd: zero from and len fields in NBD_CMD_DISCONNECT.
  mm: convert some level-less printks to pr_*
  MAINTAINERS: adi-buildroot-devel is moderated
  MAINTAINERS: add linux-api for review of API/ABI changes
  mm/kmemleak-test.c: use pr_fmt for logging
  fs/dlm/debug_fs.c: replace seq_printf by seq_puts
  fs/dlm/lockspace.c: convert simple_str to kstr
  fs/dlm/config.c: convert simple_str to kstr
  mm: mark remap_file_pages() syscall as deprecated
  mm: memcontrol: remove unnecessary memcg argument from soft limit functions
  mm: memcontrol: clean up memcg zoneinfo lookup
  mm/memblock.c: call kmemleak directly from memblock_(alloc|free)
  mm/mempool.c: update the kmemleak stack trace for mempool allocations
  lib/radix-tree.c: update the kmemleak stack trace for radix tree allocations
  mm: introduce kmemleak_update_trace()
  mm/kmemleak.c: use %u to print ->checksum
  ...

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;
 }