sysrq: more explicit, less terse help messages

Eliminate sysrq terse help mode; make sysrq help messages more meaningful
(more explicit/verbose).  Make the sysrq action letter clearer by listing
it explicitly in more sysrq help messages (when it is not simple/clear).

The SysRq help message now looks like this:

SysRq : HELP : loglevel(0-9) reBoot terminate-all-tasks(E) memory-full-oom-kill(F) kill-all-tasks(I) saK show-backtrace-all-active-cpus(L) show-memory-usage(M) nice-all-RT-tasks(N) powerOff show-registers(P) show-all-timers(Q) unRaw Sync show-task-states(T) Unmount show-blocked-tasks(W)

Addresses http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=330403.
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Cc: <jidanni@jidanni.org>
Cc: <330403@bugs.debian.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/char/sysrq.c

@@ -82,7 +82,7 @@ static void sysrq_handle_loglevel(int key, struct tty_struct *tty)
 }
 static struct sysrq_key_op sysrq_loglevel_op = {
 	.handler	= sysrq_handle_loglevel,
-	.help_msg	= "loglevel0-8",
+	.help_msg	= "loglevel(0-9)",
 	.action_msg	= "Changing Loglevel",
 	.enable_mask	= SYSRQ_ENABLE_LOG,
 };
@@ -233,7 +233,7 @@ static void sysrq_handle_showallcpus(int key, struct tty_struct *tty)
 
 static struct sysrq_key_op sysrq_showallcpus_op = {
 	.handler	= sysrq_handle_showallcpus,
-	.help_msg	= "aLlcpus",
+	.help_msg	= "show-backtrace-all-active-cpus(L)",
 	.action_msg	= "Show backtrace of all active CPUs",
 	.enable_mask	= SYSRQ_ENABLE_DUMP,
 };
@@ -247,7 +247,7 @@ static void sysrq_handle_showregs(int key, struct tty_struct *tty)
 }
 static struct sysrq_key_op sysrq_showregs_op = {
 	.handler	= sysrq_handle_showregs,
-	.help_msg	= "showPc",
+	.help_msg	= "show-registers(P)",
 	.action_msg	= "Show Regs",
 	.enable_mask	= SYSRQ_ENABLE_DUMP,
 };
@@ -258,7 +258,7 @@ static void sysrq_handle_showstate(int key, struct tty_struct *tty)
 }
 static struct sysrq_key_op sysrq_showstate_op = {
 	.handler	= sysrq_handle_showstate,
-	.help_msg	= "showTasks",
+	.help_msg	= "show-task-states(T)",
 	.action_msg	= "Show State",
 	.enable_mask	= SYSRQ_ENABLE_DUMP,
 };
@@ -269,7 +269,7 @@ static void sysrq_handle_showstate_blocked(int key, struct tty_struct *tty)
 }
 static struct sysrq_key_op sysrq_showstate_blocked_op = {
 	.handler	= sysrq_handle_showstate_blocked,
-	.help_msg	= "shoW-blocked-tasks",
+	.help_msg	= "show-blocked-tasks(W)",
 	.action_msg	= "Show Blocked State",
 	.enable_mask	= SYSRQ_ENABLE_DUMP,
 };
@@ -297,7 +297,7 @@ static void sysrq_handle_showmem(int key, struct tty_struct *tty)
 }
 static struct sysrq_key_op sysrq_showmem_op = {
 	.handler	= sysrq_handle_showmem,
-	.help_msg	= "showMem",
+	.help_msg	= "show-memory-usage(M)",
 	.action_msg	= "Show Memory",
 	.enable_mask	= SYSRQ_ENABLE_DUMP,
 };
@@ -323,7 +323,7 @@ static void sysrq_handle_term(int key, struct tty_struct *tty)
 }
 static struct sysrq_key_op sysrq_term_op = {
 	.handler	= sysrq_handle_term,
-	.help_msg	= "tErm",
+	.help_msg	= "terminate-all-tasks(E)",
 	.action_msg	= "Terminate All Tasks",
 	.enable_mask	= SYSRQ_ENABLE_SIGNAL,
 };
@@ -341,7 +341,7 @@ static void sysrq_handle_moom(int key, struct tty_struct *tty)
 }
 static struct sysrq_key_op sysrq_moom_op = {
 	.handler	= sysrq_handle_moom,
-	.help_msg	= "Full",
+	.help_msg	= "memory-full-oom-kill(F)",
 	.action_msg	= "Manual OOM execution",
 	.enable_mask	= SYSRQ_ENABLE_SIGNAL,
 };
@@ -353,7 +353,7 @@ static void sysrq_handle_kill(int key, struct tty_struct *tty)
 }
 static struct sysrq_key_op sysrq_kill_op = {
 	.handler	= sysrq_handle_kill,
-	.help_msg	= "kIll",
+	.help_msg	= "kill-all-tasks(I)",
 	.action_msg	= "Kill All Tasks",
 	.enable_mask	= SYSRQ_ENABLE_SIGNAL,
 };
@@ -364,7 +364,7 @@ static void sysrq_handle_unrt(int key, struct tty_struct *tty)
 }
 static struct sysrq_key_op sysrq_unrt_op = {
 	.handler	= sysrq_handle_unrt,
-	.help_msg	= "Nice",
+	.help_msg	= "nice-all-RT-tasks(N)",
 	.action_msg	= "Nice All RT Tasks",
 	.enable_mask	= SYSRQ_ENABLE_RTNICE,
 };