mtd: mtd_subpagetest: convert to use prandom library

This removes home-brewed pseudo-random number generator and use
prandom library.
Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Cc: Artem Bityutskiy <dedekind1@gmail.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: "Theodore Ts'o" <tytso@mit.edu>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Laight <david.laight@aculab.com>
Cc: Eilon Greenstein <eilong@broadcom.com>
Cc: Michel Lespinasse <walken@google.com>
Cc: Robert Love <robert.w.love@intel.com>
Cc: Valdis Kletnieks <valdis.kletnieks@vt.edu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/mtd/tests/mtd_subpagetest.c

@@ -28,6 +28,7 @@
 #include <linux/mtd/mtd.h>
 #include <linux/slab.h>
 #include <linux/sched.h>
+#include <linux/random.h>
 
 static int dev = -EINVAL;
 module_param(dev, int, S_IRUGO);
@@ -43,26 +44,7 @@ static int bufsize;
 static int ebcnt;
 static int pgcnt;
 static int errcnt;
-static unsigned long next = 1;
-
-static inline unsigned int simple_rand(void)
-{
-	next = next * 1103515245 + 12345;
-	return (unsigned int)((next / 65536) % 32768);
-}
-
-static inline void simple_srand(unsigned long seed)
-{
-	next = seed;
-}
-
-static void set_random_data(unsigned char *buf, size_t len)
-{
-	size_t i;
-
-	for (i = 0; i < len; ++i)
-		buf[i] = simple_rand();
-}
+static struct rnd_state rnd_state;
 
 static inline void clear_data(unsigned char *buf, size_t len)
 {
@@ -119,7 +101,7 @@ static int write_eraseblock(int ebnum)
 	int err = 0;
 	loff_t addr = ebnum * mtd->erasesize;
 
-	set_random_data(writebuf, subpgsize);
+	prandom_bytes_state(&rnd_state, writebuf, subpgsize);
 	err = mtd_write(mtd, addr, subpgsize, &written, writebuf);
 	if (unlikely(err || written != subpgsize)) {
 		pr_err("error: write failed at %#llx\n",
@@ -133,7 +115,7 @@ static int write_eraseblock(int ebnum)
 
 	addr += subpgsize;
 
-	set_random_data(writebuf, subpgsize);
+	prandom_bytes_state(&rnd_state, writebuf, subpgsize);
 	err = mtd_write(mtd, addr, subpgsize, &written, writebuf);
 	if (unlikely(err || written != subpgsize)) {
 		pr_err("error: write failed at %#llx\n",
@@ -157,7 +139,7 @@ static int write_eraseblock2(int ebnum)
 	for (k = 1; k < 33; ++k) {
 		if (addr + (subpgsize * k) > (ebnum + 1) * mtd->erasesize)
 			break;
-		set_random_data(writebuf, subpgsize * k);
+		prandom_bytes_state(&rnd_state, writebuf, subpgsize * k);
 		err = mtd_write(mtd, addr, subpgsize * k, &written, writebuf);
 		if (unlikely(err || written != subpgsize * k)) {
 			pr_err("error: write failed at %#llx\n",
@@ -193,7 +175,7 @@ static int verify_eraseblock(int ebnum)
 	int err = 0;
 	loff_t addr = ebnum * mtd->erasesize;
 
-	set_random_data(writebuf, subpgsize);
+	prandom_bytes_state(&rnd_state, writebuf, subpgsize);
 	clear_data(readbuf, subpgsize);
 	err = mtd_read(mtd, addr, subpgsize, &read, readbuf);
 	if (unlikely(err || read != subpgsize)) {
@@ -220,7 +202,7 @@ static int verify_eraseblock(int ebnum)
 
 	addr += subpgsize;
 
-	set_random_data(writebuf, subpgsize);
+	prandom_bytes_state(&rnd_state, writebuf, subpgsize);
 	clear_data(readbuf, subpgsize);
 	err = mtd_read(mtd, addr, subpgsize, &read, readbuf);
 	if (unlikely(err || read != subpgsize)) {
@@ -257,7 +239,7 @@ static int verify_eraseblock2(int ebnum)
 	for (k = 1; k < 33; ++k) {
 		if (addr + (subpgsize * k) > (ebnum + 1) * mtd->erasesize)
 			break;
-		set_random_data(writebuf, subpgsize * k);
+		prandom_bytes_state(&rnd_state, writebuf, subpgsize * k);
 		clear_data(readbuf, subpgsize * k);
 		err = mtd_read(mtd, addr, subpgsize * k, &read, readbuf);
 		if (unlikely(err || read != subpgsize * k)) {
@@ -430,7 +412,7 @@ static int __init mtd_subpagetest_init(void)
 		goto out;
 
 	pr_info("writing whole device\n");
-	simple_srand(1);
+	prandom_seed_state(&rnd_state, 1);
 	for (i = 0; i < ebcnt; ++i) {
 		if (bbt[i])
 			continue;
@@ -443,7 +425,7 @@ static int __init mtd_subpagetest_init(void)
 	}
 	pr_info("written %u eraseblocks\n", i);
 
-	simple_srand(1);
+	prandom_seed_state(&rnd_state, 1);
 	pr_info("verifying all eraseblocks\n");
 	for (i = 0; i < ebcnt; ++i) {
 		if (bbt[i])
@@ -466,7 +448,7 @@ static int __init mtd_subpagetest_init(void)
 		goto out;
 
 	/* Write all eraseblocks */
-	simple_srand(3);
+	prandom_seed_state(&rnd_state, 3);
 	pr_info("writing whole device\n");
 	for (i = 0; i < ebcnt; ++i) {
 		if (bbt[i])
@@ -481,7 +463,7 @@ static int __init mtd_subpagetest_init(void)
 	pr_info("written %u eraseblocks\n", i);
 
 	/* Check all eraseblocks */
-	simple_srand(3);
+	prandom_seed_state(&rnd_state, 3);
 	pr_info("verifying all eraseblocks\n");
 	for (i = 0; i < ebcnt; ++i) {
 		if (bbt[i])