random: convert get_random_int/long into get_random_u32/u64

Many times, when a user wants a random number, he wants a random number
of a guaranteed size. So, thinking of get_random_int and get_random_long
in terms of get_random_u32 and get_random_u64 makes it much easier to
achieve this. It also makes the code simpler.

On 32-bit platforms, get_random_int and get_random_long are both aliased
to get_random_u32. On 64-bit platforms, int->u32 and long->u64.

Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

diff --git a/drivers/char/random.c b/drivers/char/random.c
index b800e5479b7dc8065ce0e12a6a521ba04f188667..066ae125f2c83e7b548632d18e3058a6d208e60f 100644 (file)
--- a/drivers/char/random.c
+++ b/drivers/char/random.c
@@ -2018,8 +2018,8 @@ struct ctl_table random_table[] = {
 
 struct batched_entropy {
        union {
-               unsigned long entropy_long[CHACHA20_BLOCK_SIZE / sizeof(unsigned long)];
-               unsigned int entropy_int[CHACHA20_BLOCK_SIZE / sizeof(unsigned int)];
+               u64 entropy_u64[CHACHA20_BLOCK_SIZE / sizeof(u64)];
+               u32 entropy_u32[CHACHA20_BLOCK_SIZE / sizeof(u32)];
        };
        unsigned int position;
 };
@@ -2029,52 +2029,51 @@ struct batched_entropy {
  * number is either as good as RDRAND or as good as /dev/urandom, with the
  * goal of being quite fast and not depleting entropy.
  */
-static DEFINE_PER_CPU(struct batched_entropy, batched_entropy_long);
-unsigned long get_random_long(void)
+static DEFINE_PER_CPU(struct batched_entropy, batched_entropy_u64);
+u64 get_random_u64(void)
 {
-       unsigned long ret;
+       u64 ret;
        struct batched_entropy *batch;
 
-       if (arch_get_random_long(&ret))
+#if BITS_PER_LONG == 64
+       if (arch_get_random_long((unsigned long *)&ret))
                return ret;
+#else
+       if (arch_get_random_long((unsigned long *)&ret) &&
+           arch_get_random_long((unsigned long *)&ret + 1))
+           return ret;
+#endif
 
-       batch = &get_cpu_var(batched_entropy_long);
-       if (batch->position % ARRAY_SIZE(batch->entropy_long) == 0) {
-               extract_crng((u8 *)batch->entropy_long);
+       batch = &get_cpu_var(batched_entropy_u64);
+       if (batch->position % ARRAY_SIZE(batch->entropy_u64) == 0) {
+               extract_crng((u8 *)batch->entropy_u64);
                batch->position = 0;
        }
-       ret = batch->entropy_long[batch->position++];
-       put_cpu_var(batched_entropy_long);
+       ret = batch->entropy_u64[batch->position++];
+       put_cpu_var(batched_entropy_u64);
        return ret;
 }
-EXPORT_SYMBOL(get_random_long);
+EXPORT_SYMBOL(get_random_u64);
 
-#if BITS_PER_LONG == 32
-unsigned int get_random_int(void)
-{
-       return get_random_long();
-}
-#else
-static DEFINE_PER_CPU(struct batched_entropy, batched_entropy_int);
-unsigned int get_random_int(void)
+static DEFINE_PER_CPU(struct batched_entropy, batched_entropy_u32);
+u32 get_random_u32(void)
 {
-       unsigned int ret;
+       u32 ret;
        struct batched_entropy *batch;
 
        if (arch_get_random_int(&ret))
                return ret;
 
-       batch = &get_cpu_var(batched_entropy_int);
-       if (batch->position % ARRAY_SIZE(batch->entropy_int) == 0) {
-               extract_crng((u8 *)batch->entropy_int);
+       batch = &get_cpu_var(batched_entropy_u32);
+       if (batch->position % ARRAY_SIZE(batch->entropy_u32) == 0) {
+               extract_crng((u8 *)batch->entropy_u32);
                batch->position = 0;
        }
-       ret = batch->entropy_int[batch->position++];
-       put_cpu_var(batched_entropy_int);
+       ret = batch->entropy_u32[batch->position++];
+       put_cpu_var(batched_entropy_u32);
        return ret;
 }
-#endif
-EXPORT_SYMBOL(get_random_int);
+EXPORT_SYMBOL(get_random_u32);
 
 /**
  * randomize_page - Generate a random, page aligned address

diff --git a/include/linux/random.h b/include/linux/random.h
index 16ab429735a783f0d68943437d19162c62032b07..ed5c3838780de5ba9509071bef56e8d521dc5782 100644 (file)
--- a/include/linux/random.h
+++ b/include/linux/random.h
@@ -42,8 +42,21 @@ extern void get_random_bytes_arch(void *buf, int nbytes);
 extern const struct file_operations random_fops, urandom_fops;
 #endif
 
-unsigned int get_random_int(void);
-unsigned long get_random_long(void);
+u32 get_random_u32(void);
+u64 get_random_u64(void);
+static inline unsigned int get_random_int(void)
+{
+       return get_random_u32();
+}
+static inline unsigned long get_random_long(void)
+{
+#if BITS_PER_LONG == 64
+       return get_random_u64();
+#else
+       return get_random_u32();
+#endif
+}
+
 unsigned long randomize_page(unsigned long start, unsigned long range);
 
 u32 prandom_u32(void);