[PATCH 1/9] random32: introduce random32_get_bytes() and prandom32_get_bytes()

[PATCH 1/9] random32: introduce random32_get_bytes() and prandom32_get_bytes()

[Akinobu Mita]

Add functions to get the requested number of pseudo-random bytes.

The difference from get_random_bytes() is that it uses pseudo-random
numbers generated by random32.  It is fast, suitable for generating
random bytes for testing, and reproducible if prandom32 interface is used.

Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Cc: "Theodore Ts'o" <tytso@mit.edu>
Cc: Artem Bityutskiy <dedekind1@gmail.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: linux-mtd@lists.infradead.org
---
 include/linux/random.h |  2 ++
 lib/random32.c         | 38 ++++++++++++++++++++++++++++++++++++++
 2 files changed, 40 insertions(+)

diff --git a/include/linux/random.h b/include/linux/random.h
index 6330ed4..eedf429b 100644
--- a/include/linux/random.h
+++ b/include/linux/random.h
@@ -27,8 +27,10 @@ unsigned long randomize_range(unsigned long start, unsigned long end, unsigned l
 
 u32 random32(void);
 void srandom32(u32 seed);
+void random32_get_bytes(void *buf, int nbytes);
 
 u32 prandom32(struct rnd_state *);
+void prandom32_get_bytes(struct rnd_state *state, void *buf, int nbytes);
 
 /*
  * Handle minimum values for seeds
diff --git a/lib/random32.c b/lib/random32.c
index 938bde5..aee87dd 100644
--- a/lib/random32.c
+++ b/lib/random32.c
@@ -61,6 +61,44 @@ u32 prandom32(struct rnd_state *state)
 EXPORT_SYMBOL(prandom32);
 
 /**
+ *	prandom32_get_bytes - get the requested number of pseudo-random bytes
+ *	@state: pointer to state structure holding seeded state.
+ *	@buf: where to copy the pseudo-random bytes to
+ *	@bytes: the requested number of bytes
+ *
+ *	This is used for pseudo-randomness with no outside seeding.
+ *	For more random results, use random32_get_bytes().
+ */
+void prandom32_get_bytes(struct rnd_state *state, void *buf, int bytes)
+{
+	unsigned char *p = buf;
+
+	for (; bytes > 0 && ((unsigned long)p) % sizeof(u32); bytes--, p++)
+		*p = prandom32(state);
+
+	for (; bytes > sizeof(u32) - 1; bytes -= sizeof(u32), p += sizeof(u32))
+		*(u32 *)p = prandom32(state);
+
+	for (; bytes > 0; bytes--, p++)
+		*p = prandom32(state);
+}
+EXPORT_SYMBOL(prandom32_get_bytes);
+
+/**
+ *	random32_get_bytes - get the requested number of pseudo-random bytes
+ *	@buf: where to copy the pseudo-random bytes to
+ *	@bytes: the requested number of bytes
+ */
+void random32_get_bytes(void *buf, int bytes)
+{
+	struct rnd_state *state = &get_cpu_var(net_rand_state);
+
+	prandom32_get_bytes(state, buf, bytes);
+	put_cpu_var(state);
+}
+EXPORT_SYMBOL(random32_get_bytes);
+
+/**
  *	random32 - pseudo random number generator
  *
  *	A 32 bit pseudo-random number is generated using a fast
-- 
1.7.11.7

[PATCH 3/9] mtd: mtd_nandecctest: use random32_get_bytes instead of get_random_bytes()

[Akinobu Mita]

Using random32_get_bytes() is enough.  Because this data is only used
for testing, not used for cryptographic use.

Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Cc: Artem Bityutskiy <dedekind1@gmail.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: linux-mtd@lists.infradead.org
---
 drivers/mtd/tests/mtd_nandecctest.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/mtd/tests/mtd_nandecctest.c b/drivers/mtd/tests/mtd_nandecctest.c
index a5fb9b0..0ddcbec 100644
--- a/drivers/mtd/tests/mtd_nandecctest.c
+++ b/drivers/mtd/tests/mtd_nandecctest.c
@@ -253,7 +253,7 @@ static int nand_ecc_test_run(const size_t size)
 		goto error;
 	}
 
-	get_random_bytes(correct_data, size);
+	random32_get_bytes(correct_data, size);
 	__nand_calculate_ecc(correct_data, size, correct_ecc);
 
 	for (i = 0; i < ARRAY_SIZE(nand_ecc_test); i++) {
-- 
1.7.11.7

[PATCH 4/9] mtd: nandsim: use random32_get_bytes

[Akinobu Mita]

This also removes unnecessary memset call which is immediately overwritten
with random bytes.

Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Cc: Artem Bityutskiy <dedekind1@gmail.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: linux-mtd@lists.infradead.org
---
 drivers/mtd/nand/nandsim.c | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/drivers/mtd/nand/nandsim.c b/drivers/mtd/nand/nandsim.c
index a932c48..d074b4c 100644
--- a/drivers/mtd/nand/nandsim.c
+++ b/drivers/mtd/nand/nandsim.c
@@ -1397,10 +1397,7 @@ int do_read_error(struct nandsim *ns, int num)
 	unsigned int page_no = ns->regs.row;
 
 	if (read_error(page_no)) {
-		int i;
-		memset(ns->buf.byte, 0xFF, num);
-		for (i = 0; i < num; ++i)
-			ns->buf.byte[i] = random32();
+		random32_get_bytes(ns->buf.byte, num);
 		NS_WARN("simulating read error in page %u\n", page_no);
 		return 1;
 	}
-- 
1.7.11.7

[PATCH 5/9] ubifs: use random32_get_bytes

[Akinobu Mita]

This also converts filling memory loop to use memset.

Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Cc: Artem Bityutskiy <dedekind1@gmail.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: linux-mtd@lists.infradead.org
---
 fs/ubifs/debug.c | 8 +++-----
 1 file changed, 3 insertions(+), 5 deletions(-)

diff --git a/fs/ubifs/debug.c b/fs/ubifs/debug.c
index 6291163..f3e4a25 100644
--- a/fs/ubifs/debug.c
+++ b/fs/ubifs/debug.c
@@ -2560,7 +2560,7 @@ static int power_cut_emulated(struct ubifs_info *c, int lnum, int write)
 static int corrupt_data(const struct ubifs_info *c, const void *buf,
 			unsigned int len)
 {
-	unsigned int from, to, i, ffs = chance(1, 2);
+	unsigned int from, to, ffs = chance(1, 2);
 	unsigned char *p = (void *)buf;
 
 	from = random32() % (len + 1);
@@ -2571,11 +2571,9 @@ static int corrupt_data(const struct ubifs_info *c, const void *buf,
 		   ffs ? "0xFFs" : "random data");
 
 	if (ffs)
-		for (i = from; i < to; i++)
-			p[i] = 0xFF;
+		memset(p + from, 0xFF, to - from);
 	else
-		for (i = from; i < to; i++)
-			p[i] = random32() % 0x100;
+		random32_get_bytes(p + from, to - from);
 
 	return to;
 }
-- 
1.7.11.7

[PATCH 6/9] mtd: mtd_oobtest: convert to use prandom32_get_bytes()

[Akinobu Mita]

This removes home-brewed pseudo-random number generator and use
prandom32_get_bytes().

Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Cc: Artem Bityutskiy <dedekind1@gmail.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: linux-mtd@lists.infradead.org
---
 drivers/mtd/tests/mtd_oobtest.c | 49 ++++++++++++++---------------------------
 1 file changed, 16 insertions(+), 33 deletions(-)

diff --git a/drivers/mtd/tests/mtd_oobtest.c b/drivers/mtd/tests/mtd_oobtest.c
index ed9b628..41670ed 100644
--- a/drivers/mtd/tests/mtd_oobtest.c
+++ b/drivers/mtd/tests/mtd_oobtest.c
@@ -27,6 +27,7 @@
 #include <linux/mtd/mtd.h>
 #include <linux/slab.h>
 #include <linux/sched.h>
+#include <linux/random.h>
 
 #define PRINT_PREF KERN_INFO "mtd_oobtest: "
 
@@ -46,26 +47,7 @@ static int use_offset;
 static int use_len;
 static int use_len_max;
 static int vary_offset;
-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 int erase_eraseblock(int ebnum)
 {
@@ -130,7 +112,7 @@ static int write_eraseblock(int ebnum)
 	loff_t addr = ebnum * mtd->erasesize;
 
 	for (i = 0; i < pgcnt; ++i, addr += mtd->writesize) {
-		set_random_data(writebuf, use_len);
+		prandom32_get_bytes(&rnd_state, writebuf, use_len);
 		ops.mode      = MTD_OPS_AUTO_OOB;
 		ops.len       = 0;
 		ops.retlen    = 0;
@@ -183,7 +165,7 @@ static int verify_eraseblock(int ebnum)
 	loff_t addr = ebnum * mtd->erasesize;
 
 	for (i = 0; i < pgcnt; ++i, addr += mtd->writesize) {
-		set_random_data(writebuf, use_len);
+		prandom32_get_bytes(&rnd_state, writebuf, use_len);
 		ops.mode      = MTD_OPS_AUTO_OOB;
 		ops.len       = 0;
 		ops.retlen    = 0;
@@ -275,7 +257,7 @@ static int verify_eraseblock_in_one_go(int ebnum)
 	loff_t addr = ebnum * mtd->erasesize;
 	size_t len = mtd->ecclayout->oobavail * pgcnt;
 
-	set_random_data(writebuf, len);
+	prandom32_get_bytes(&rnd_state, writebuf, len);
 	ops.mode      = MTD_OPS_AUTO_OOB;
 	ops.len       = 0;
 	ops.retlen    = 0;
@@ -426,12 +408,12 @@ static int __init mtd_oobtest_init(void)
 	if (err)
 		goto out;
 
-	simple_srand(1);
+	prandom32_seed(&rnd_state, 1);
 	err = write_whole_device();
 	if (err)
 		goto out;
 
-	simple_srand(1);
+	prandom32_seed(&rnd_state, 1);
 	err = verify_all_eraseblocks();
 	if (err)
 		goto out;
@@ -446,13 +428,13 @@ static int __init mtd_oobtest_init(void)
 	if (err)
 		goto out;
 
-	simple_srand(3);
+	prandom32_seed(&rnd_state, 3);
 	err = write_whole_device();
 	if (err)
 		goto out;
 
 	/* Check all eraseblocks */
-	simple_srand(3);
+	prandom32_seed(&rnd_state, 3);
 	printk(PRINT_PREF "verifying all eraseblocks\n");
 	for (i = 0; i < ebcnt; ++i) {
 		if (bbt[i])
@@ -481,7 +463,7 @@ static int __init mtd_oobtest_init(void)
 	use_len = mtd->ecclayout->oobavail;
 	use_len_max = mtd->ecclayout->oobavail;
 	vary_offset = 1;
-	simple_srand(5);
+	prandom32_seed(&rnd_state, 5);
 
 	err = write_whole_device();
 	if (err)
@@ -492,7 +474,7 @@ static int __init mtd_oobtest_init(void)
 	use_len = mtd->ecclayout->oobavail;
 	use_len_max = mtd->ecclayout->oobavail;
 	vary_offset = 1;
-	simple_srand(5);
+	prandom32_seed(&rnd_state, 5);
 	err = verify_all_eraseblocks();
 	if (err)
 		goto out;
@@ -651,7 +633,7 @@ static int __init mtd_oobtest_init(void)
 		goto out;
 
 	/* Write all eraseblocks */
-	simple_srand(11);
+	prandom32_seed(&rnd_state, 11);
 	printk(PRINT_PREF "writing OOBs of whole device\n");
 	for (i = 0; i < ebcnt - 1; ++i) {
 		int cnt = 2;
@@ -661,7 +643,7 @@ static int __init mtd_oobtest_init(void)
 			continue;
 		addr = (i + 1) * mtd->erasesize - mtd->writesize;
 		for (pg = 0; pg < cnt; ++pg) {
-			set_random_data(writebuf, sz);
+			prandom32_get_bytes(&rnd_state, writebuf, sz);
 			ops.mode      = MTD_OPS_AUTO_OOB;
 			ops.len       = 0;
 			ops.retlen    = 0;
@@ -683,12 +665,13 @@ static int __init mtd_oobtest_init(void)
 	printk(PRINT_PREF "written %u eraseblocks\n", i);
 
 	/* Check all eraseblocks */
-	simple_srand(11);
+	prandom32_seed(&rnd_state, 11);
 	printk(PRINT_PREF "verifying all eraseblocks\n");
 	for (i = 0; i < ebcnt - 1; ++i) {
 		if (bbt[i] || bbt[i + 1])
 			continue;
-		set_random_data(writebuf, mtd->ecclayout->oobavail * 2);
+		prandom32_get_bytes(&rnd_state, writebuf,
+					mtd->ecclayout->oobavail * 2);
 		addr = (i + 1) * mtd->erasesize - mtd->writesize;
 		ops.mode      = MTD_OPS_AUTO_OOB;
 		ops.len       = 0;
-- 
1.7.11.7

[PATCH 7/9] mtd: mtd_pagetest: convert to use prandom32_get_bytes()

[Akinobu Mita]

This removes home-brewed pseudo-random number generator and use
prandom32_get_bytes().

Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Cc: Artem Bityutskiy <dedekind1@gmail.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: linux-mtd@lists.infradead.org
---
 drivers/mtd/tests/mtd_pagetest.c | 43 ++++++++++++----------------------------
 1 file changed, 13 insertions(+), 30 deletions(-)

diff --git a/drivers/mtd/tests/mtd_pagetest.c b/drivers/mtd/tests/mtd_pagetest.c
index 252ddb0..ae390c3 100644
--- a/drivers/mtd/tests/mtd_pagetest.c
+++ b/drivers/mtd/tests/mtd_pagetest.c
@@ -27,6 +27,7 @@
 #include <linux/mtd/mtd.h>
 #include <linux/slab.h>
 #include <linux/sched.h>
+#include <linux/random.h>
 
 #define PRINT_PREF KERN_INFO "mtd_pagetest: "
 
@@ -45,26 +46,7 @@ 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 int erase_eraseblock(int ebnum)
 {
@@ -98,7 +80,7 @@ static int write_eraseblock(int ebnum)
 	size_t written;
 	loff_t addr = ebnum * mtd->erasesize;
 
-	set_random_data(writebuf, mtd->erasesize);
+	prandom32_get_bytes(&rnd_state, writebuf, mtd->erasesize);
 	cond_resched();
 	err = mtd_write(mtd, addr, mtd->erasesize, &written, writebuf);
 	if (err || written != mtd->erasesize)
@@ -124,7 +106,7 @@ static int verify_eraseblock(int ebnum)
 	for (i = 0; i < ebcnt && bbt[ebcnt - i - 1]; ++i)
 		addrn -= mtd->erasesize;
 
-	set_random_data(writebuf, mtd->erasesize);
+	prandom32_get_bytes(&rnd_state, writebuf, mtd->erasesize);
 	for (j = 0; j < pgcnt - 1; ++j, addr += pgsize) {
 		/* Do a read to set the internal dataRAMs to different data */
 		err = mtd_read(mtd, addr0, bufsize, &read, twopages);
@@ -160,7 +142,8 @@ static int verify_eraseblock(int ebnum)
 	}
 	/* Check boundary between eraseblocks */
 	if (addr <= addrn - pgsize - pgsize && !bbt[ebnum + 1]) {
-		unsigned long oldnext = next;
+		struct rnd_state old_state = rnd_state;
+
 		/* Do a read to set the internal dataRAMs to different data */
 		err = mtd_read(mtd, addr0, bufsize, &read, twopages);
 		if (mtd_is_bitflip(err))
@@ -188,13 +171,13 @@ static int verify_eraseblock(int ebnum)
 			return err;
 		}
 		memcpy(boundary, writebuf + mtd->erasesize - pgsize, pgsize);
-		set_random_data(boundary + pgsize, pgsize);
+		prandom32_get_bytes(&rnd_state, boundary + pgsize, pgsize);
 		if (memcmp(twopages, boundary, bufsize)) {
 			printk(PRINT_PREF "error: verify failed at %#llx\n",
 			       (long long)addr);
 			errcnt += 1;
 		}
-		next = oldnext;
+		rnd_state = old_state;
 	}
 	return err;
 }
@@ -326,7 +309,7 @@ static int erasecrosstest(void)
 		return err;
 
 	printk(PRINT_PREF "writing 1st page of block %d\n", ebnum);
-	set_random_data(writebuf, pgsize);
+	prandom32_get_bytes(&rnd_state, writebuf, pgsize);
 	strcpy(writebuf, "There is no data like this!");
 	err = mtd_write(mtd, addr0, pgsize, &written, writebuf);
 	if (err || written != pgsize) {
@@ -359,7 +342,7 @@ static int erasecrosstest(void)
 		return err;
 
 	printk(PRINT_PREF "writing 1st page of block %d\n", ebnum);
-	set_random_data(writebuf, pgsize);
+	prandom32_get_bytes(&rnd_state, writebuf, pgsize);
 	strcpy(writebuf, "There is no data like this!");
 	err = mtd_write(mtd, addr0, pgsize, &written, writebuf);
 	if (err || written != pgsize) {
@@ -417,7 +400,7 @@ static int erasetest(void)
 		return err;
 
 	printk(PRINT_PREF "writing 1st page of block %d\n", ebnum);
-	set_random_data(writebuf, pgsize);
+	prandom32_get_bytes(&rnd_state, writebuf, pgsize);
 	err = mtd_write(mtd, addr0, pgsize, &written, writebuf);
 	if (err || written != pgsize) {
 		printk(PRINT_PREF "error: write failed at %#llx\n",
@@ -565,7 +548,7 @@ static int __init mtd_pagetest_init(void)
 	printk(PRINT_PREF "erased %u eraseblocks\n", i);
 
 	/* Write all eraseblocks */
-	simple_srand(1);
+	prandom32_seed(&rnd_state, 1);
 	printk(PRINT_PREF "writing whole device\n");
 	for (i = 0; i < ebcnt; ++i) {
 		if (bbt[i])
@@ -580,7 +563,7 @@ static int __init mtd_pagetest_init(void)
 	printk(PRINT_PREF "written %u eraseblocks\n", i);
 
 	/* Check all eraseblocks */
-	simple_srand(1);
+	prandom32_seed(&rnd_state, 1);
 	printk(PRINT_PREF "verifying all eraseblocks\n");
 	for (i = 0; i < ebcnt; ++i) {
 		if (bbt[i])
-- 
1.7.11.7

[PATCH 8/9] mtd: mtd_speedtest: use random32_get_bytes

[Akinobu Mita]

Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Cc: Artem Bityutskiy <dedekind1@gmail.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: linux-mtd@lists.infradead.org
---
 drivers/mtd/tests/mtd_speedtest.c | 9 +--------
 1 file changed, 1 insertion(+), 8 deletions(-)

diff --git a/drivers/mtd/tests/mtd_speedtest.c b/drivers/mtd/tests/mtd_speedtest.c
index 42b0f74..57f0383 100644
--- a/drivers/mtd/tests/mtd_speedtest.c
+++ b/drivers/mtd/tests/mtd_speedtest.c
@@ -49,13 +49,6 @@ static int pgcnt;
 static int goodebcnt;
 static struct timeval start, finish;
 
-static void set_random_data(unsigned char *buf, size_t len)
-{
-	size_t i;
-
-	for (i = 0; i < len; ++i)
-		buf[i] = random32();
-}
 
 static int erase_eraseblock(int ebnum)
 {
@@ -396,7 +389,7 @@ static int __init mtd_speedtest_init(void)
 		goto out;
 	}
 
-	set_random_data(iobuf, mtd->erasesize);
+	random32_get_bytes(iobuf, mtd->erasesize);
 
 	err = scan_for_bad_eraseblocks();
 	if (err)
-- 
1.7.11.7

[PATCH 9/9] mtd: mtd_subpagetest: convert to use prandom32_get_bytes()

[Akinobu Mita]

This removes home-brewed pseudo-random number generator and use
prandom32_get_bytes().

Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Cc: Artem Bityutskiy <dedekind1@gmail.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: linux-mtd@lists.infradead.org
---
 drivers/mtd/tests/mtd_subpagetest.c | 42 +++++++++++--------------------------
 1 file changed, 12 insertions(+), 30 deletions(-)

diff --git a/drivers/mtd/tests/mtd_subpagetest.c b/drivers/mtd/tests/mtd_subpagetest.c
index 9667bf5..86a7140 100644
--- a/drivers/mtd/tests/mtd_subpagetest.c
+++ b/drivers/mtd/tests/mtd_subpagetest.c
@@ -26,6 +26,7 @@
 #include <linux/mtd/mtd.h>
 #include <linux/slab.h>
 #include <linux/sched.h>
+#include <linux/random.h>
 
 #define PRINT_PREF KERN_INFO "mtd_subpagetest: "
 
@@ -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);
+	prandom32_get_bytes(&rnd_state, writebuf, subpgsize);
 	err = mtd_write(mtd, addr, subpgsize, &written, writebuf);
 	if (unlikely(err || written != subpgsize)) {
 		printk(PRINT_PREF "error: write failed at %#llx\n",
@@ -133,7 +115,7 @@ static int write_eraseblock(int ebnum)
 
 	addr += subpgsize;
 
-	set_random_data(writebuf, subpgsize);
+	prandom32_get_bytes(&rnd_state, writebuf, subpgsize);
 	err = mtd_write(mtd, addr, subpgsize, &written, writebuf);
 	if (unlikely(err || written != subpgsize)) {
 		printk(PRINT_PREF "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);
+		prandom32_get_bytes(&rnd_state, writebuf, subpgsize * k);
 		err = mtd_write(mtd, addr, subpgsize * k, &written, writebuf);
 		if (unlikely(err || written != subpgsize * k)) {
 			printk(PRINT_PREF "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);
+	prandom32_get_bytes(&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);
+	prandom32_get_bytes(&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);
+		prandom32_get_bytes(&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;
 
 	printk(PRINT_PREF "writing whole device\n");
-	simple_srand(1);
+	prandom32_seed(&rnd_state, 1);
 	for (i = 0; i < ebcnt; ++i) {
 		if (bbt[i])
 			continue;
@@ -443,7 +425,7 @@ static int __init mtd_subpagetest_init(void)
 	}
 	printk(PRINT_PREF "written %u eraseblocks\n", i);
 
-	simple_srand(1);
+	prandom32_seed(&rnd_state, 1);
 	printk(PRINT_PREF "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);
+	prandom32_seed(&rnd_state, 3);
 	printk(PRINT_PREF "writing whole device\n");
 	for (i = 0; i < ebcnt; ++i) {
 		if (bbt[i])
@@ -481,7 +463,7 @@ static int __init mtd_subpagetest_init(void)
 	printk(PRINT_PREF "written %u eraseblocks\n", i);
 
 	/* Check all eraseblocks */
-	simple_srand(3);
+	prandom32_seed(&rnd_state, 3);
 	printk(PRINT_PREF "verifying all eraseblocks\n");
 	for (i = 0; i < ebcnt; ++i) {
 		if (bbt[i])
-- 
1.7.11.7

Re: [PATCH 1/9] random32: introduce random32_get_bytes() and prandom32_get_bytes()

[Theodore Ts'o]

On Sun, Oct 28, 2012 at 04:18:58PM +0900, Akinobu Mita wrote:
>  /**
> + *	prandom32_get_bytes - get the requested number of pseudo-random bytes
> + *	@state: pointer to state structure holding seeded state.
> + *	@buf: where to copy the pseudo-random bytes to
> + *	@bytes: the requested number of bytes
> + *
> + *	This is used for pseudo-randomness with no outside seeding.
> + *	For more random results, use random32_get_bytes().
> + */
> +
> +/**
> + *	random32_get_bytes - get the requested number of pseudo-random bytes
> + *	@buf: where to copy the pseudo-random bytes to
> + *	@bytes: the requested number of bytes
> + */

This naming scheme is going to be very confusing.  If the function is
going to return a pseudo-random number, it *must* have a "prandom"
suffix.  Otherwise some kernel developer, somewhere, will get confused
between get_random_bytes() and random32_get_bytes(), and the result
may be a very embarassing security exposure.

How about prandom32_get_bytes_state() and prandom32_get_bytes() instead?

						- Ted

Re: [PATCH 1/9] random32: introduce random32_get_bytes() and prandom32_get_bytes()

[Akinobu Mita]

2012/10/30 Theodore Ts'o <tytso@mit.edu>:
> On Sun, Oct 28, 2012 at 04:18:58PM +0900, Akinobu Mita wrote:
>>  /**
>> + *   prandom32_get_bytes - get the requested number of pseudo-random bytes
>> + *   @state: pointer to state structure holding seeded state.
>> + *   @buf: where to copy the pseudo-random bytes to
>> + *   @bytes: the requested number of bytes
>> + *
>> + *   This is used for pseudo-randomness with no outside seeding.
>> + *   For more random results, use random32_get_bytes().
>> + */
>> +
>> +/**
>> + *   random32_get_bytes - get the requested number of pseudo-random bytes
>> + *   @buf: where to copy the pseudo-random bytes to
>> + *   @bytes: the requested number of bytes
>> + */
>
> This naming scheme is going to be very confusing.  If the function is
> going to return a pseudo-random number, it *must* have a "prandom"
> suffix.  Otherwise some kernel developer, somewhere, will get confused
> between get_random_bytes() and random32_get_bytes(), and the result
> may be a very embarassing security exposure.
>
> How about prandom32_get_bytes_state() and prandom32_get_bytes() instead?

I agree with your suggestion.  I'll rename them and try again.

By the way, should we also rename the existing random32() and
prandom32() in the future?

Specifically, rename random32() to prandom32(), and prandom32() to
prandom32_state().  As a result, it will cause a little confusion
between old and new prandom32(). But the number of arguments will
be changed from 3 to 2, so gcc can detect the misuse of prandom32().

Is there any other idea of renaming? Or should we keep them as is?

Re: [PATCH 1/9] random32: introduce random32_get_bytes() and prandom32_get_bytes()

[Akinobu Mita]

2012/10/30 Akinobu Mita <akinobu.mita@gmail.com>:
> 2012/10/30 Theodore Ts'o <tytso@mit.edu>:
>> On Sun, Oct 28, 2012 at 04:18:58PM +0900, Akinobu Mita wrote:
>>>  /**
>>> + *   prandom32_get_bytes - get the requested number of pseudo-random bytes
>>> + *   @state: pointer to state structure holding seeded state.
>>> + *   @buf: where to copy the pseudo-random bytes to
>>> + *   @bytes: the requested number of bytes
>>> + *
>>> + *   This is used for pseudo-randomness with no outside seeding.
>>> + *   For more random results, use random32_get_bytes().
>>> + */
>>> +
>>> +/**
>>> + *   random32_get_bytes - get the requested number of pseudo-random bytes
>>> + *   @buf: where to copy the pseudo-random bytes to
>>> + *   @bytes: the requested number of bytes
>>> + */
>>
>> This naming scheme is going to be very confusing.  If the function is
>> going to return a pseudo-random number, it *must* have a "prandom"
>> suffix.  Otherwise some kernel developer, somewhere, will get confused
>> between get_random_bytes() and random32_get_bytes(), and the result
>> may be a very embarassing security exposure.
>>
>> How about prandom32_get_bytes_state() and prandom32_get_bytes() instead?
>
> I agree with your suggestion.  I'll rename them and try again.
>
> By the way, should we also rename the existing random32() and
> prandom32() in the future?
>
> Specifically, rename random32() to prandom32(), and prandom32() to
> prandom32_state().  As a result, it will cause a little confusion
> between old and new prandom32(). But the number of arguments will
> be changed from 3 to 2, so gcc can detect the misuse of prandom32().

Oops, I intended to say "the number of arguments of prandom32() will be
changed from 1 to 0". And I realized that the exisiting srandom32() also should
be renamed to sprandom32().

Re: [PATCH 1/9] random32: introduce random32_get_bytes() and prandom32_get_bytes()

[Theodore Ts'o]

On Tue, Oct 30, 2012 at 08:12:39PM +0900, Akinobu Mita wrote:
> >>
> >> How about prandom32_get_bytes_state() and prandom32_get_bytes() instead?
> >
> > I agree with your suggestion.  I'll rename them and try again.
> >
> > By the way, should we also rename the existing random32() and
> > prandom32() in the future?

I suppose the other way to go is to just use random32 as the common
prefix, and just have random32() and random32_state().  My concern was
that people might assume that prandom32() and random32() might imply
that only prandom32() was the one using a pseudo-random number
generator.  This might be easier since there are large number of uses
of random32() in the source tree, but only a relative few using
prandom32().

    	   	     	    	     - Ted

Re: [PATCH 1/9] random32: introduce random32_get_bytes() and prandom32_get_bytes()

[Akinobu Mita]

2012/10/31 Theodore Ts'o <tytso@mit.edu>:
> On Tue, Oct 30, 2012 at 08:12:39PM +0900, Akinobu Mita wrote:
>> >>
>> >> How about prandom32_get_bytes_state() and prandom32_get_bytes() instead?
>> >
>> > I agree with your suggestion.  I'll rename them and try again.
>> >
>> > By the way, should we also rename the existing random32() and
>> > prandom32() in the future?
>
> I suppose the other way to go is to just use random32 as the common
> prefix, and just have random32() and random32_state().  My concern was
> that people might assume that prandom32() and random32() might imply
> that only prandom32() was the one using a pseudo-random number
> generator.  This might be easier since there are large number of uses
> of random32() in the source tree, but only a relative few using
> prandom32().

Using random32 as the common prefix sounds good idea.  I'm going to
prepare the following patch set:

[patch 1] rename prandom32 to randome32_state
[patch 2] introduce random32_get_bytes and random32_get_bytes_state
[patch 3-] proliferate random32_get_bytes and random32_get_bytes_state