[203/272] memsw: handle swapaccount kernel parameter correctly

[Greg KH]

2.6.37-stable review patch.  If anyone has any objections, please let us know.

------------------

From: Michal Hocko <mhocko@xxxxxxx>

commit fceda1bf498677501befc7da72fd2e4de7f18466 upstream.

__setup based kernel command line parameters handlers which are handled in
obsolete_checksetup are provided with the parameter value including =
(more precisely everything right after the parameter name).

This means that the current implementation of swapaccount[=1|0] doesn't
work at all because if there is a value for the parameter then we are
testing for "0" resp.  "1" but we are getting "=0" resp.  "=1" and if
there is no parameter value we are getting an empty string rather than
NULL.

The original noswapccount parameter, which doesn't care about the value,
works correctly.

Signed-off-by: Michal Hocko <mhocko@xxxxxxx>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx>
Cc: Daisuke Nishimura <nishimura@xxxxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>

---
 mm/memcontrol.c |    6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -4930,9 +4930,9 @@ struct cgroup_subsys mem_cgroup_subsys =
 static int __init enable_swap_account(char *s)
 {
 	/* consider enabled if no parameter or 1 is given */
-	if (!s || !strcmp(s, "1"))
+	if (!(*s) || !strcmp(s, "=1"))
 		really_do_swap_account = 1;
-	else if (!strcmp(s, "0"))
+	else if (!strcmp(s, "=0"))
 		really_do_swap_account = 0;
 	return 1;
 }
@@ -4940,7 +4940,7 @@ __setup("swapaccount", enable_swap_accou
 
 static int __init disable_swap_account(char *s)
 {
-	enable_swap_account("0");
+	enable_swap_account("=0");
 	return 1;
 }
 __setup("noswapaccount", disable_swap_account);


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