mm: memtest: convert to memtest_report_meminfo()

It is better to not expose too many internal variables of memtest,
add a helper memtest_report_meminfo() to show memtest results.

Link: https://lkml.kernel.org/r/20230808033359.174986-1-wangkefeng.wang@huawei.comSigned-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Acked-by: Mike Rapoport (IBM) <rppt@kernel.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Tomas Mudrunka <tomas.mudrunka@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

fs/proc/meminfo.c

@@ -133,17 +133,7 @@ static int meminfo_proc_show(struct seq_file *m, void *v)
 	show_val_kb(m, "VmallocChunk:   ", 0ul);
 	show_val_kb(m, "Percpu:         ", pcpu_nr_pages());
 
-#ifdef CONFIG_MEMTEST
-	if (early_memtest_done) {
-		unsigned long early_memtest_bad_size_kb;
-
-		early_memtest_bad_size_kb = early_memtest_bad_size>>10;
-		if (early_memtest_bad_size && !early_memtest_bad_size_kb)
-			early_memtest_bad_size_kb = 1;
-		/* When 0 is reported, it means there actually was a successful test */
-		seq_printf(m, "EarlyMemtestBad:   %5lu kB\n", early_memtest_bad_size_kb);
-	}
-#endif
+	memtest_report_meminfo(m);
 
 #ifdef CONFIG_MEMORY_FAILURE
 	seq_printf(m, "HardwareCorrupted: %5lu kB\n",

include/linux/memblock.h

@@ -594,13 +594,11 @@ extern int hashdist;		/* Distribute hashes across NUMA nodes? */
 #endif
 
 #ifdef CONFIG_MEMTEST
-extern phys_addr_t early_memtest_bad_size;	/* Size of faulty ram found by memtest */
-extern bool early_memtest_done;			/* Was early memtest done? */
-extern void early_memtest(phys_addr_t start, phys_addr_t end);
+void early_memtest(phys_addr_t start, phys_addr_t end);
+void memtest_report_meminfo(struct seq_file *m);
 #else
-static inline void early_memtest(phys_addr_t start, phys_addr_t end)
-{
-}
+static inline void early_memtest(phys_addr_t start, phys_addr_t end) { }
+static inline void memtest_report_meminfo(struct seq_file *m) { }
 #endif
 
 

mm/memtest.c

@@ -3,9 +3,10 @@
 #include <linux/types.h>
 #include <linux/init.h>
 #include <linux/memblock.h>
+#include <linux/seq_file.h>
 
-bool early_memtest_done;
-phys_addr_t early_memtest_bad_size;
+static bool early_memtest_done;
+static phys_addr_t early_memtest_bad_size;
 
 static u64 patterns[] __initdata = {
 	/* The first entry has to be 0 to leave memtest with zeroed memory */
@@ -117,3 +118,20 @@ void __init early_memtest(phys_addr_t start, phys_addr_t end)
 		do_one_pass(patterns[idx], start, end);
 	}
 }
+
+void memtest_report_meminfo(struct seq_file *m)
+{
+	unsigned long early_memtest_bad_size_kb;
+
+	if (!IS_ENABLED(CONFIG_PROC_FS))
+		return;
+
+	if (!early_memtest_done)
+		return;
+
+	early_memtest_bad_size_kb = early_memtest_bad_size >> 10;
+	if (early_memtest_bad_size && !early_memtest_bad_size_kb)
+		early_memtest_bad_size_kb = 1;
+	/* When 0 is reported, it means there actually was a successful test */
+	seq_printf(m, "EarlyMemtestBad:   %5lu kB\n", early_memtest_bad_size_kb);
+}