ANDROID: mm: introduce gcma_stat_get function

Introduce helper function to get gcma stats and move enum gcma_stat_type
to include/linux/gcma.h. For debugging purposes, I'd like to print usage
status of gcma area into kernel log via show_mem vendor hook and add gcma
stats in /proc/meminfo via meminfo vendor hook.
So let's export this helper function.

Bug: 410432482
Change-Id: I1e4fd209c8a3037fba69ab2ed190f4c308477835
Signed-off-by: Sooyong Suk <s.suk@samsung.corp-partner.google.com>

include/linux/gcma.h

@@ -5,6 +5,21 @@
 #include <linux/types.h>
 
 #ifdef CONFIG_GCMA
+enum gcma_stat_type {
+	STORED_PAGE,
+	LOADED_PAGE,
+	EVICTED_PAGE,
+	CACHED_PAGE,
+	DISCARDED_PAGE,
+	NUM_OF_GCMA_STAT,
+};
+
+#ifdef CONFIG_GCMA_SYSFS
+u64 gcma_stat_get(enum gcma_stat_type type);
+#else
+static inline u64 gcma_stat_get(enum gcma_stat_type type) { return 0; }
+#endif
+
 extern void gcma_alloc_range(unsigned long start_pfn, unsigned long end_pfn);
 extern void gcma_free_range(unsigned long start_pfn, unsigned long end_pfn);
 extern int register_gcma_area(const char *name, phys_addr_t base,

mm/gcma_sysfs.c

@@ -1,5 +1,6 @@
 #include <linux/kobject.h>
 #include <linux/sysfs.h>
+#include <linux/gcma.h>
 #include "gcma_sysfs.h"
 
 extern struct kobject *vendor_mm_kobj;
@@ -22,6 +23,12 @@ void gcma_stat_add(enum gcma_stat_type type, unsigned long delta)
 	atomic64_add(delta, &gcma_stats[type]);
 }
 
+u64 gcma_stat_get(enum gcma_stat_type type)
+{
+	return (u64)atomic64_read(&gcma_stats[type]);
+}
+EXPORT_SYMBOL_GPL(gcma_stat_get);
+
 /*
  * This all compiles without CONFIG_SYSFS, but is a waste of space.
  */

mm/gcma_sysfs.h

@@ -2,15 +2,6 @@
 #ifndef __GCMA_SYSFS_H__
 #define __GCMA_SYSFS_H__
 
-enum gcma_stat_type {
-        STORED_PAGE,
-        LOADED_PAGE,
-        EVICTED_PAGE,
-        CACHED_PAGE,
-        DISCARDED_PAGE,
-        NUM_OF_GCMA_STAT,
-};
-
 #ifdef CONFIG_GCMA_SYSFS
 void gcma_stat_inc(enum gcma_stat_type type);
 void gcma_stat_dec(enum gcma_stat_type type);