[PATCH 4.9 105/264] random: access input_pool_data directly rather than through pointer

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

From: "Jason A. Donenfeld" <Jason@zx2c4.com>

commit 6c0eace6e1499712583b6ee62d95161e8b3449f5 upstream.

This gets rid of another abstraction we no longer need. It would be nice
if we could instead make pool an array rather than a pointer, but the
latent entropy plugin won't be able to do its magic in that case. So
instead we put all accesses to the input pool's actual data through the
input_pool_data array directly.

Reviewed-by: Dominik Brodowski <linux@dominikbrodowski.net>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/char/random.c |  217 +++++++++++++++++++++++---------------------------
 1 file changed, 101 insertions(+), 116 deletions(-)

--- a/drivers/char/random.c
+++ b/drivers/char/random.c
@@ -124,7 +124,7 @@
  *
  * The primary kernel interface is
  *
- * 	void get_random_bytes(void *buf, int nbytes);
+ *	void get_random_bytes(void *buf, int nbytes);
  *
  * This interface will return the requested number of random bytes,
  * and place it in the requested buffer.  This is equivalent to a
@@ -132,10 +132,10 @@
  *
  * For less critical applications, there are the functions:
  *
- * 	u32 get_random_u32()
- * 	u64 get_random_u64()
- * 	unsigned int get_random_int()
- * 	unsigned long get_random_long()
+ *	u32 get_random_u32()
+ *	u64 get_random_u64()
+ *	unsigned int get_random_int()
+ *	unsigned long get_random_long()
  *
  * These are produced by a cryptographic RNG seeded from get_random_bytes,
  * and so do not deplete the entropy pool as much.  These are recommended
@@ -197,10 +197,10 @@
  * from the devices are:
  *
  *	void add_device_randomness(const void *buf, unsigned int size);
- * 	void add_input_randomness(unsigned int type, unsigned int code,
+ *	void add_input_randomness(unsigned int type, unsigned int code,
  *                                unsigned int value);
  *	void add_interrupt_randomness(int irq);
- * 	void add_disk_randomness(struct gendisk *disk);
+ *	void add_disk_randomness(struct gendisk *disk);
  *	void add_hwgenerator_randomness(const char *buffer, size_t count,
  *					size_t entropy);
  *	void add_bootloader_randomness(const void *buf, unsigned int size);
@@ -296,8 +296,8 @@
  * /dev/random and /dev/urandom created already, they can be created
  * by using the commands:
  *
- * 	mknod /dev/random c 1 8
- * 	mknod /dev/urandom c 1 9
+ *	mknod /dev/random c 1 8
+ *	mknod /dev/urandom c 1 9
  *
  * Acknowledgements:
  * =================
@@ -444,9 +444,9 @@ static DEFINE_SPINLOCK(random_ready_list
 static LIST_HEAD(random_ready_list);
 
 struct crng_state {
-	u32		state[16];
-	unsigned long	init_time;
-	spinlock_t	lock;
+	u32 state[16];
+	unsigned long init_time;
+	spinlock_t lock;
 };
 
 static struct crng_state primary_crng = {
@@ -470,7 +470,7 @@ static bool crng_need_final_init = false
 #define crng_ready() (likely(crng_init > 1))
 static int crng_init_cnt = 0;
 static unsigned long crng_global_init_time = 0;
-#define CRNG_INIT_CNT_THRESH (2*CHACHA20_KEY_SIZE)
+#define CRNG_INIT_CNT_THRESH (2 * CHACHA20_KEY_SIZE)
 static void _extract_crng(struct crng_state *crng, u8 out[CHACHA20_BLOCK_SIZE]);
 static void _crng_backtrack_protect(struct crng_state *crng,
 				    u8 tmp[CHACHA20_BLOCK_SIZE], int used);
@@ -497,17 +497,12 @@ MODULE_PARM_DESC(ratelimit_disable, "Dis
 static u32 input_pool_data[POOL_WORDS] __latent_entropy;
 
 static struct {
-	/* read-only data: */
-	u32 *pool;
-
-	/* read-write data: */
 	spinlock_t lock;
 	u16 add_ptr;
 	u16 input_rotate;
 	int entropy_count;
 } input_pool = {
 	.lock = __SPIN_LOCK_UNLOCKED(input_pool.lock),
-	.pool = input_pool_data
 };
 
 static ssize_t extract_entropy(void *buf, size_t nbytes, int min);
@@ -515,7 +510,7 @@ static ssize_t _extract_entropy(void *bu
 
 static void crng_reseed(struct crng_state *crng, bool use_input_pool);
 
-static u32 const twist_table[8] = {
+static const u32 twist_table[8] = {
 	0x00000000, 0x3b6e20c8, 0x76dc4190, 0x4db26158,
 	0xedb88320, 0xd6d6a3e8, 0x9b64c2b0, 0xa00ae278 };
 
@@ -545,15 +540,15 @@ static void _mix_pool_bytes(const void *
 		i = (i - 1) & POOL_WORDMASK;
 
 		/* XOR in the various taps */
-		w ^= input_pool.pool[i];
-		w ^= input_pool.pool[(i + POOL_TAP1) & POOL_WORDMASK];
-		w ^= input_pool.pool[(i + POOL_TAP2) & POOL_WORDMASK];
-		w ^= input_pool.pool[(i + POOL_TAP3) & POOL_WORDMASK];
-		w ^= input_pool.pool[(i + POOL_TAP4) & POOL_WORDMASK];
-		w ^= input_pool.pool[(i + POOL_TAP5) & POOL_WORDMASK];
+		w ^= input_pool_data[i];
+		w ^= input_pool_data[(i + POOL_TAP1) & POOL_WORDMASK];
+		w ^= input_pool_data[(i + POOL_TAP2) & POOL_WORDMASK];
+		w ^= input_pool_data[(i + POOL_TAP3) & POOL_WORDMASK];
+		w ^= input_pool_data[(i + POOL_TAP4) & POOL_WORDMASK];
+		w ^= input_pool_data[(i + POOL_TAP5) & POOL_WORDMASK];
 
 		/* Mix the result back in with a twist */
-		input_pool.pool[i] = (w >> 3) ^ twist_table[w & 7];
+		input_pool_data[i] = (w >> 3) ^ twist_table[w & 7];
 
 		/*
 		 * Normally, we add 7 bits of rotation to the pool.
@@ -585,10 +580,10 @@ static void mix_pool_bytes(const void *i
 }
 
 struct fast_pool {
-	u32		pool[4];
-	unsigned long	last;
-	u16		reg_idx;
-	u8		count;
+	u32 pool[4];
+	unsigned long last;
+	u16 reg_idx;
+	u8 count;
 };
 
 /*
@@ -716,7 +711,7 @@ static int credit_entropy_bits_safe(int
 		return -EINVAL;
 
 	/* Cap the value to avoid overflows */
-	nbits = min(nbits,  POOL_BITS);
+	nbits = min(nbits, POOL_BITS);
 
 	credit_entropy_bits(nbits);
 	return 0;
@@ -728,7 +723,7 @@ static int credit_entropy_bits_safe(int
  *
  *********************************************************************/
 
-#define CRNG_RESEED_INTERVAL (300*HZ)
+#define CRNG_RESEED_INTERVAL (300 * HZ)
 
 static DECLARE_WAIT_QUEUE_HEAD(crng_init_wait);
 
@@ -751,9 +746,9 @@ early_param("random.trust_cpu", parse_tr
 
 static bool crng_init_try_arch(struct crng_state *crng)
 {
-	int		i;
-	bool		arch_init = true;
-	unsigned long	rv;
+	int i;
+	bool arch_init = true;
+	unsigned long rv;
 
 	for (i = 4; i < 16; i++) {
 		if (!arch_get_random_seed_long(&rv) &&
@@ -769,9 +764,9 @@ static bool crng_init_try_arch(struct cr
 
 static bool __init crng_init_try_arch_early(struct crng_state *crng)
 {
-	int		i;
-	bool		arch_init = true;
-	unsigned long	rv;
+	int i;
+	bool arch_init = true;
+	unsigned long rv;
 
 	for (i = 4; i < 16; i++) {
 		if (!arch_get_random_seed_long_early(&rv) &&
@@ -841,7 +836,7 @@ static void do_numa_crng_init(struct wor
 	struct crng_state *crng;
 	struct crng_state **pool;
 
-	pool = kcalloc(nr_node_ids, sizeof(*pool), GFP_KERNEL|__GFP_NOFAIL);
+	pool = kcalloc(nr_node_ids, sizeof(*pool), GFP_KERNEL | __GFP_NOFAIL);
 	for_each_online_node(i) {
 		crng = kmalloc_node(sizeof(struct crng_state),
 				    GFP_KERNEL | __GFP_NOFAIL, i);
@@ -897,7 +892,7 @@ static size_t crng_fast_load(const u8 *c
 		spin_unlock_irqrestore(&primary_crng.lock, flags);
 		return 0;
 	}
-	p = (u8 *) &primary_crng.state[4];
+	p = (u8 *)&primary_crng.state[4];
 	while (len > 0 && crng_init_cnt < CRNG_INIT_CNT_THRESH) {
 		p[crng_init_cnt % CHACHA20_KEY_SIZE] ^= *cp;
 		cp++; crng_init_cnt++; len--; ret++;
@@ -978,12 +973,12 @@ static struct crng_state *select_crng(vo
  */
 static int crng_slow_load(const u8 *cp, size_t len)
 {
-	unsigned long		flags;
-	static u8		lfsr = 1;
-	u8			tmp;
-	unsigned int		i, max = CHACHA20_KEY_SIZE;
-	const u8 *		src_buf = cp;
-	u8 *			dest_buf = (u8 *) &primary_crng.state[4];
+	unsigned long flags;
+	static u8 lfsr = 1;
+	u8 tmp;
+	unsigned int i, max = CHACHA20_KEY_SIZE;
+	const u8 *src_buf = cp;
+	u8 *dest_buf = (u8 *)&primary_crng.state[4];
 
 	if (!spin_trylock_irqsave(&primary_crng.lock, flags))
 		return 0;
@@ -994,7 +989,7 @@ static int crng_slow_load(const u8 *cp,
 	if (len > max)
 		max = len;
 
-	for (i = 0; i < max ; i++) {
+	for (i = 0; i < max; i++) {
 		tmp = lfsr;
 		lfsr >>= 1;
 		if (tmp & 1)
@@ -1009,11 +1004,11 @@ static int crng_slow_load(const u8 *cp,
 
 static void crng_reseed(struct crng_state *crng, bool use_input_pool)
 {
-	unsigned long	flags;
-	int		i, num;
+	unsigned long flags;
+	int i, num;
 	union {
-		u8	block[CHACHA20_BLOCK_SIZE];
-		u32	key[8];
+		u8 block[CHACHA20_BLOCK_SIZE];
+		u32 key[8];
 	} buf;
 
 	if (use_input_pool) {
@@ -1027,11 +1022,11 @@ static void crng_reseed(struct crng_stat
 	}
 	spin_lock_irqsave(&crng->lock, flags);
 	for (i = 0; i < 8; i++) {
-		unsigned long	rv;
+		unsigned long rv;
 		if (!arch_get_random_seed_long(&rv) &&
 		    !arch_get_random_long(&rv))
 			rv = random_get_entropy();
-		crng->state[i+4] ^= buf.key[i] ^ rv;
+		crng->state[i + 4] ^= buf.key[i] ^ rv;
 	}
 	memzero_explicit(&buf, sizeof(buf));
 	WRITE_ONCE(crng->init_time, jiffies);
@@ -1039,8 +1034,7 @@ static void crng_reseed(struct crng_stat
 	crng_finalize_init(crng);
 }
 
-static void _extract_crng(struct crng_state *crng,
-			  u8 out[CHACHA20_BLOCK_SIZE])
+static void _extract_crng(struct crng_state *crng, u8 out[CHACHA20_BLOCK_SIZE])
 {
 	unsigned long flags, init_time;
 
@@ -1069,9 +1063,9 @@ static void extract_crng(u8 out[CHACHA20
 static void _crng_backtrack_protect(struct crng_state *crng,
 				    u8 tmp[CHACHA20_BLOCK_SIZE], int used)
 {
-	unsigned long	flags;
-	u32		*s, *d;
-	int		i;
+	unsigned long flags;
+	u32 *s, *d;
+	int i;
 
 	used = round_up(used, sizeof(u32));
 	if (used + CHACHA20_KEY_SIZE > CHACHA20_BLOCK_SIZE) {
@@ -1079,9 +1073,9 @@ static void _crng_backtrack_protect(stru
 		used = 0;
 	}
 	spin_lock_irqsave(&crng->lock, flags);
-	s = (u32 *) &tmp[used];
+	s = (u32 *)&tmp[used];
 	d = &crng->state[4];
-	for (i=0; i < 8; i++)
+	for (i = 0; i < 8; i++)
 		*d++ ^= *s++;
 	spin_unlock_irqrestore(&crng->lock, flags);
 }
@@ -1126,7 +1120,6 @@ static ssize_t extract_crng_user(void __
 	return ret;
 }
 
-
 /*********************************************************************
  *
  * Entropy input management
@@ -1221,11 +1214,11 @@ static void add_timer_randomness(struct
 	 * Round down by 1 bit on general principles,
 	 * and limit entropy estimate to 12 bits.
 	 */
-	credit_entropy_bits(min_t(int, fls(delta>>1), 11));
+	credit_entropy_bits(min_t(int, fls(delta >> 1), 11));
 }
 
 void add_input_randomness(unsigned int type, unsigned int code,
-				 unsigned int value)
+			  unsigned int value)
 {
 	static unsigned char last_value;
 
@@ -1245,19 +1238,19 @@ static DEFINE_PER_CPU(struct fast_pool,
 #ifdef ADD_INTERRUPT_BENCH
 static unsigned long avg_cycles, avg_deviation;
 
-#define AVG_SHIFT 8     /* Exponential average factor k=1/256 */
-#define FIXED_1_2 (1 << (AVG_SHIFT-1))
+#define AVG_SHIFT 8 /* Exponential average factor k=1/256 */
+#define FIXED_1_2 (1 << (AVG_SHIFT - 1))
 
 static void add_interrupt_bench(cycles_t start)
 {
-        long delta = random_get_entropy() - start;
+	long delta = random_get_entropy() - start;
 
-        /* Use a weighted moving average */
-        delta = delta - ((avg_cycles + FIXED_1_2) >> AVG_SHIFT);
-        avg_cycles += delta;
-        /* And average deviation */
-        delta = abs(delta) - ((avg_deviation + FIXED_1_2) >> AVG_SHIFT);
-        avg_deviation += delta;
+	/* Use a weighted moving average */
+	delta = delta - ((avg_cycles + FIXED_1_2) >> AVG_SHIFT);
+	avg_cycles += delta;
+	/* And average deviation */
+	delta = abs(delta) - ((avg_deviation + FIXED_1_2) >> AVG_SHIFT);
+	avg_deviation += delta;
 }
 #else
 #define add_interrupt_bench(x)
@@ -1265,7 +1258,7 @@ static void add_interrupt_bench(cycles_t
 
 static u32 get_reg(struct fast_pool *f, struct pt_regs *regs)
 {
-	u32 *ptr = (u32 *) regs;
+	u32 *ptr = (u32 *)regs;
 	unsigned int idx;
 
 	if (regs == NULL)
@@ -1280,12 +1273,12 @@ static u32 get_reg(struct fast_pool *f,
 
 void add_interrupt_randomness(int irq)
 {
-	struct fast_pool	*fast_pool = this_cpu_ptr(&irq_randomness);
-	struct pt_regs		*regs = get_irq_regs();
-	unsigned long		now = jiffies;
-	cycles_t		cycles = random_get_entropy();
-	u32			c_high, j_high;
-	u64			ip;
+	struct fast_pool *fast_pool = this_cpu_ptr(&irq_randomness);
+	struct pt_regs *regs = get_irq_regs();
+	unsigned long now = jiffies;
+	cycles_t cycles = random_get_entropy();
+	u32 c_high, j_high;
+	u64 ip;
 
 	if (cycles == 0)
 		cycles = get_reg(fast_pool, regs);
@@ -1295,8 +1288,8 @@ void add_interrupt_randomness(int irq)
 	fast_pool->pool[1] ^= now ^ c_high;
 	ip = regs ? instruction_pointer(regs) : _RET_IP_;
 	fast_pool->pool[2] ^= ip;
-	fast_pool->pool[3] ^= (sizeof(ip) > 4) ? ip >> 32 :
-		get_reg(fast_pool, regs);
+	fast_pool->pool[3] ^=
+		(sizeof(ip) > 4) ? ip >> 32 : get_reg(fast_pool, regs);
 
 	fast_mix(fast_pool);
 	add_interrupt_bench(cycles);
@@ -1310,8 +1303,7 @@ void add_interrupt_randomness(int irq)
 		return;
 	}
 
-	if ((fast_pool->count < 64) &&
-	    !time_after(now, fast_pool->last + HZ))
+	if ((fast_pool->count < 64) && !time_after(now, fast_pool->last + HZ))
 		return;
 
 	if (!spin_trylock(&input_pool.lock))
@@ -1375,7 +1367,7 @@ retry:
 		entropy_count = 0;
 	}
 	nfrac = ibytes << (POOL_ENTROPY_SHIFT + 3);
-	if ((size_t) entropy_count > nfrac)
+	if ((size_t)entropy_count > nfrac)
 		entropy_count -= nfrac;
 	else
 		entropy_count = 0;
@@ -1420,7 +1412,7 @@ static void extract_buf(u8 *out)
 
 	/* Generate a hash across the pool */
 	spin_lock_irqsave(&input_pool.lock, flags);
-	blake2s_update(&state, (const u8 *)input_pool.pool, POOL_BYTES);
+	blake2s_update(&state, (const u8 *)input_pool_data, POOL_BYTES);
 	blake2s_final(&state, hash); /* final zeros out state */
 
 	/*
@@ -1478,10 +1470,9 @@ static ssize_t extract_entropy(void *buf
 }
 
 #define warn_unseeded_randomness(previous) \
-	_warn_unseeded_randomness(__func__, (void *) _RET_IP_, (previous))
+	_warn_unseeded_randomness(__func__, (void *)_RET_IP_, (previous))
 
-static void _warn_unseeded_randomness(const char *func_name, void *caller,
-				      void **previous)
+static void _warn_unseeded_randomness(const char *func_name, void *caller, void **previous)
 {
 #ifdef CONFIG_WARN_ALL_UNSEEDED_RANDOM
 	const bool print_once = false;
@@ -1489,8 +1480,7 @@ static void _warn_unseeded_randomness(co
 	static bool print_once __read_mostly;
 #endif
 
-	if (print_once ||
-	    crng_ready() ||
+	if (print_once || crng_ready() ||
 	    (previous && (caller == READ_ONCE(*previous))))
 		return;
 	WRITE_ONCE(*previous, caller);
@@ -1542,7 +1532,6 @@ void get_random_bytes(void *buf, int nby
 }
 EXPORT_SYMBOL(get_random_bytes);
 
-
 /*
  * Each time the timer fires, we expect that we got an unpredictable
  * jump in the cycle counter. Even if the timer is running on another
@@ -1581,7 +1570,7 @@ static void try_to_generate_entropy(void
 	__setup_timer_on_stack(&stack.timer, entropy_timer, 0, 0);
 	while (!crng_ready()) {
 		if (!timer_pending(&stack.timer))
-			mod_timer(&stack.timer, jiffies+1);
+			mod_timer(&stack.timer, jiffies + 1);
 		mix_pool_bytes(&stack.now, sizeof(stack.now));
 		schedule();
 		stack.now = random_get_entropy();
@@ -1791,9 +1780,8 @@ void rand_initialize_disk(struct gendisk
 }
 #endif
 
-static ssize_t
-urandom_read_nowarn(struct file *file, char __user *buf, size_t nbytes,
-		    loff_t *ppos)
+static ssize_t urandom_read_nowarn(struct file *file, char __user *buf,
+				   size_t nbytes, loff_t *ppos)
 {
 	int ret;
 
@@ -1803,8 +1791,8 @@ urandom_read_nowarn(struct file *file, c
 	return ret;
 }
 
-static ssize_t
-urandom_read(struct file *file, char __user *buf, size_t nbytes, loff_t *ppos)
+static ssize_t urandom_read(struct file *file, char __user *buf, size_t nbytes,
+			    loff_t *ppos)
 {
 	static int maxwarn = 10;
 
@@ -1818,8 +1806,8 @@ urandom_read(struct file *file, char __u
 	return urandom_read_nowarn(file, buf, nbytes, ppos);
 }
 
-static ssize_t
-random_read(struct file *file, char __user *buf, size_t nbytes, loff_t *ppos)
+static ssize_t random_read(struct file *file, char __user *buf, size_t nbytes,
+			   loff_t *ppos)
 {
 	int ret;
 
@@ -1829,8 +1817,7 @@ random_read(struct file *file, char __us
 	return urandom_read_nowarn(file, buf, nbytes, ppos);
 }
 
-static unsigned int
-random_poll(struct file *file, poll_table * wait)
+static unsigned int random_poll(struct file *file, poll_table *wait)
 {
 	unsigned int mask;
 
@@ -1844,8 +1831,7 @@ random_poll(struct file *file, poll_tabl
 	return mask;
 }
 
-static int
-write_pool(const char __user *buffer, size_t count)
+static int write_pool(const char __user *buffer, size_t count)
 {
 	size_t bytes;
 	u32 t, buf[16];
@@ -1947,35 +1933,35 @@ static int random_fasync(int fd, struct
 }
 
 const struct file_operations random_fops = {
-	.read  = random_read,
+	.read = random_read,
 	.write = random_write,
-	.poll  = random_poll,
+	.poll = random_poll,
 	.unlocked_ioctl = random_ioctl,
 	.fasync = random_fasync,
 	.llseek = noop_llseek,
 };
 
 const struct file_operations urandom_fops = {
-	.read  = urandom_read,
+	.read = urandom_read,
 	.write = random_write,
 	.unlocked_ioctl = random_ioctl,
 	.fasync = random_fasync,
 	.llseek = noop_llseek,
 };
 
-SYSCALL_DEFINE3(getrandom, char __user *, buf, size_t, count,
-		unsigned int, flags)
+SYSCALL_DEFINE3(getrandom, char __user *, buf, size_t, count, unsigned int,
+		flags)
 {
 	int ret;
 
-	if (flags & ~(GRND_NONBLOCK|GRND_RANDOM|GRND_INSECURE))
+	if (flags & ~(GRND_NONBLOCK | GRND_RANDOM | GRND_INSECURE))
 		return -EINVAL;
 
 	/*
 	 * Requesting insecure and blocking randomness at the same time makes
 	 * no sense.
 	 */
-	if ((flags & (GRND_INSECURE|GRND_RANDOM)) == (GRND_INSECURE|GRND_RANDOM))
+	if ((flags & (GRND_INSECURE | GRND_RANDOM)) == (GRND_INSECURE | GRND_RANDOM))
 		return -EINVAL;
 
 	if (count > INT_MAX)
@@ -2123,7 +2109,7 @@ struct ctl_table random_table[] = {
 #endif
 	{ }
 };
-#endif 	/* CONFIG_SYSCTL */
+#endif	/* CONFIG_SYSCTL */
 
 struct batched_entropy {
 	union {
@@ -2143,7 +2129,7 @@ struct batched_entropy {
  * point prior.
  */
 static DEFINE_PER_CPU(struct batched_entropy, batched_entropy_u64) = {
-	.batch_lock	= __SPIN_LOCK_UNLOCKED(batched_entropy_u64.lock),
+	.batch_lock = __SPIN_LOCK_UNLOCKED(batched_entropy_u64.lock),
 };
 
 u64 get_random_u64(void)
@@ -2168,7 +2154,7 @@ u64 get_random_u64(void)
 EXPORT_SYMBOL(get_random_u64);
 
 static DEFINE_PER_CPU(struct batched_entropy, batched_entropy_u32) = {
-	.batch_lock	= __SPIN_LOCK_UNLOCKED(batched_entropy_u32.lock),
+	.batch_lock = __SPIN_LOCK_UNLOCKED(batched_entropy_u32.lock),
 };
 u32 get_random_u32(void)
 {
@@ -2200,7 +2186,7 @@ static void invalidate_batched_entropy(v
 	int cpu;
 	unsigned long flags;
 
-	for_each_possible_cpu (cpu) {
+	for_each_possible_cpu(cpu) {
 		struct batched_entropy *batched_entropy;
 
 		batched_entropy = per_cpu_ptr(&batched_entropy_u32, cpu);
@@ -2229,8 +2215,7 @@ static void invalidate_batched_entropy(v
  * Return: A page aligned address within [start, start + range).  On error,
  * @start is returned.
  */
-unsigned long
-randomize_page(unsigned long start, unsigned long range)
+unsigned long randomize_page(unsigned long start, unsigned long range)
 {
 	if (!PAGE_ALIGNED(start)) {
 		range -= PAGE_ALIGN(start) - start;