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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>
This commit is contained in:
Jason A. Donenfeld 2017-01-22 16:34:08 +01:00 committed by Theodore Ts'o
parent f5b98461cb
commit c440408cf6
2 changed files with 42 additions and 30 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

55
drivers/char/random.c
View File

@ -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)
static DEFINE_PER_CPU(struct batched_entropy, batched_entropy_u32);
u32 get_random_u32(void)
{
return get_random_long();
}
#else
static DEFINE_PER_CPU(struct batched_entropy, batched_entropy_int);
unsigned int get_random_int(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

17
include/linux/random.h
View File

@ -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);