random: add 8-bit and 16-bit batches

There are numerous places in the kernel that would be sped up by having smaller batches. Currently those callsites do `get_random_u32() & 0xff` or similar. Since these are pretty spread out, and will require patches to multiple different trees, let's get ahead of the curve and lay the foundation for `get_random_u8()` and `get_random_u16()`, so that it's then possible to start submitting conversion patches leisurely. Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
mariux64 · Sep 29, 2022 · 585cd5f · 585cd5f
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diff --git a/drivers/char/random.c b/drivers/char/random.c
@@ -506,6 +506,8 @@ EXPORT_SYMBOL(get_random_ ##type);
 
 DEFINE_BATCHED_ENTROPY(u64)
 DEFINE_BATCHED_ENTROPY(u32)
+DEFINE_BATCHED_ENTROPY(u16)
+DEFINE_BATCHED_ENTROPY(u8)
 
 #ifdef CONFIG_SMP
 /*

diff --git a/include/linux/random.h b/include/linux/random.h
@@ -38,6 +38,8 @@ static inline int unregister_random_vmfork_notifier(struct notifier_block *nb) {
 #endif
 
 void get_random_bytes(void *buf, size_t len);
+u8 get_random_u8(void);
+u16 get_random_u16(void);
 u32 get_random_u32(void);
 u64 get_random_u64(void);
 static inline unsigned int get_random_int(void)