mm/vmpressure.c: convert to use match_string() helper

The new helper returns index of the matching string in an array.  We are
going to use it here.

Link: http://lkml.kernel.org/r/20180503203206.44046-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 6 insertions, 26 deletions

diff --git a/mm/vmpressure.c b/mm/vmpressure.c
index 7142207224d3..4854584ec436 100644
--- a/mm/vmpressure.c
+++ b/mm/vmpressure.c
@@ -342,26 +342,6 @@ void vmpressure_prio(gfp_t gfp, struct mem_cgroup *memcg, int prio)
         vmpressure(gfp, memcg, true, vmpressure_win, 0);
 }
 
-static enum vmpressure_levels str_to_level(const char *arg)
-{
-        enum vmpressure_levels level;
-
-        for (level = 0; level < VMPRESSURE_NUM_LEVELS; level++)
-                if (!strcmp(vmpressure_str_levels[level], arg))
-                        return level;
-        return -1;
-}
-
-static enum vmpressure_modes str_to_mode(const char *arg)
-{
-        enum vmpressure_modes mode;
-
-        for (mode = 0; mode < VMPRESSURE_NUM_MODES; mode++)
-                if (!strcmp(vmpressure_str_modes[mode], arg))
-                        return mode;
-        return -1;
-}
-
 #define MAX_VMPRESSURE_ARGS_LEN (strlen("critical") + strlen("hierarchy") + 2)
 
 /**
@@ -398,18 +378,18 @@ int vmpressure_register_event(struct mem_cgroup *memcg,
 
         /* Find required level */
         token = strsep(&spec, ",");
-        level = str_to_level(token);
-        if (level == -1) {
-                ret = -EINVAL;
+        level = match_string(vmpressure_str_levels, VMPRESSURE_NUM_LEVELS, token);
+        if (level < 0) {
+                ret = level;
                 goto out;
         }
 
         /* Find optional mode */
         token = strsep(&spec, ",");
         if (token) {
-                mode = str_to_mode(token);
-                if (mode == -1) {
-                        ret = -EINVAL;
+                mode = match_string(vmpressure_str_modes, VMPRESSURE_NUM_MODES, token);
+                if (mode < 0) {
+                        ret = mode;
                         goto out;
                 }
         }