Merge tag 'random-6.1-rc1-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/crng/random

Pull more random number generator updates from Jason Donenfeld:
 "This time with some large scale treewide cleanups.

  The intent of this pull is to clean up the way callers fetch random
  integers. The current rules for doing this right are:

   - If you want a secure or an insecure random u64, use get_random_u64()

   - If you want a secure or an insecure random u32, use get_random_u32()

     The old function prandom_u32() has been deprecated for a while
     now and is just a wrapper around get_random_u32(). Same for
     get_random_int().

   - If you want a secure or an insecure random u16, use get_random_u16()

   - If you want a secure or an insecure random u8, use get_random_u8()

   - If you want secure or insecure random bytes, use get_random_bytes().

     The old function prandom_bytes() has been deprecated for a while
     now and has long been a wrapper around get_random_bytes()

   - If you want a non-uniform random u32, u16, or u8 bounded by a
     certain open interval maximum, use prandom_u32_max()

     I say "non-uniform", because it doesn't do any rejection sampling
     or divisions. Hence, it stays within the prandom_*() namespace, not
     the get_random_*() namespace.

     I'm currently investigating a "uniform" function for 6.2. We'll see
     what comes of that.

  By applying these rules uniformly, we get several benefits:

   - By using prandom_u32_max() with an upper-bound that the compiler
     can prove at compile-time is ≤65536 or ≤256, internally
     get_random_u16() or get_random_u8() is used, which wastes fewer
     batched random bytes, and hence has higher throughput.

   - By using prandom_u32_max() instead of %, when the upper-bound is
     not a constant, division is still avoided, because
     prandom_u32_max() uses a faster multiplication-based trick instead.

   - By using get_random_u16() or get_random_u8() in cases where the
     return value is intended to indeed be a u16 or a u8, we waste fewer
     batched random bytes, and hence have higher throughput.

  This series was originally done by hand while I was on an airplane
  without Internet. Later, Kees and I worked on retroactively figuring
  out what could be done with Coccinelle and what had to be done
  manually, and then we split things up based on that.

  So while this touches a lot of files, the actual amount of code that's
  hand fiddled is comfortably small"

* tag 'random-6.1-rc1-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/crng/random:
  prandom: remove unused functions
  treewide: use get_random_bytes() when possible
  treewide: use get_random_u32() when possible
  treewide: use get_random_{u8,u16}() when possible, part 2
  treewide: use get_random_{u8,u16}() when possible, part 1
  treewide: use prandom_u32_max() when possible, part 2
  treewide: use prandom_u32_max() when possible, part 1

6 files changed, 4 insertions, 21 deletions

diff --git a/include/linux/nodemask.h b/include/linux/nodemask.h
index 378956c93c94..efef68c9352a 100644
--- a/include/linux/nodemask.h
+++ b/include/linux/nodemask.h
@@ -516,7 +516,7 @@ static inline int node_random(const nodemask_t *maskp)
 		bit = first_node(*maskp);
 		break;
 	default:
-		bit = find_nth_bit(maskp->bits, MAX_NUMNODES, get_random_int() % w);
+		bit = find_nth_bit(maskp->bits, MAX_NUMNODES, prandom_u32_max(w));
 		break;
 	}
 	return bit;
diff --git a/include/linux/prandom.h b/include/linux/prandom.h
index 78db003bc290..e0a0759dd09c 100644
--- a/include/linux/prandom.h
+++ b/include/linux/prandom.h
@@ -12,18 +12,6 @@
 #include <linux/percpu.h>
 #include <linux/random.h>
 
-/* Deprecated: use get_random_u32 instead. */
-static inline u32 prandom_u32(void)
-{
-	return get_random_u32();
-}
-
-/* Deprecated: use get_random_bytes instead. */
-static inline void prandom_bytes(void *buf, size_t nbytes)
-{
-	return get_random_bytes(buf, nbytes);
-}
-
 struct rnd_state {
 	__u32 s1, s2, s3, s4;
 };
diff --git a/include/linux/random.h b/include/linux/random.h
index 08322f700cdc..147a5e0d0b8e 100644
--- a/include/linux/random.h
+++ b/include/linux/random.h
@@ -42,10 +42,6 @@ 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)
-{
-	return get_random_u32();
-}
 static inline unsigned long get_random_long(void)
 {
 #if BITS_PER_LONG == 64
@@ -100,7 +96,6 @@ declare_get_random_var_wait(u8, u8)
 declare_get_random_var_wait(u16, u16)
 declare_get_random_var_wait(u32, u32)
 declare_get_random_var_wait(u64, u32)
-declare_get_random_var_wait(int, unsigned int)
 declare_get_random_var_wait(long, unsigned long)
 #undef declare_get_random_var
 
diff --git a/include/net/netfilter/nf_queue.h b/include/net/netfilter/nf_queue.h
index 980daa6e1e3a..c81021ab07aa 100644
--- a/include/net/netfilter/nf_queue.h
+++ b/include/net/netfilter/nf_queue.h
@@ -43,7 +43,7 @@ void nf_queue_entry_free(struct nf_queue_entry *entry);
 static inline void init_hashrandom(u32 *jhash_initval)
 {
 	while (*jhash_initval == 0)
-		*jhash_initval = prandom_u32();
+		*jhash_initval = get_random_u32();
 }
 
 static inline u32 hash_v4(const struct iphdr *iph, u32 initval)
diff --git a/include/net/red.h b/include/net/red.h
index 454ac2b65d8c..425364de0df7 100644
--- a/include/net/red.h
+++ b/include/net/red.h
@@ -363,7 +363,7 @@ static inline unsigned long red_calc_qavg(const struct red_parms *p,
 
 static inline u32 red_random(const struct red_parms *p)
 {
-	return reciprocal_divide(prandom_u32(), p->max_P_reciprocal);
+	return reciprocal_divide(get_random_u32(), p->max_P_reciprocal);
 }
 
 static inline int red_mark_probability(const struct red_parms *p,
diff --git a/include/net/sock.h b/include/net/sock.h
index 08038a385ef2..9e464f6409a7 100644
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -2109,7 +2109,7 @@ static inline kuid_t sock_net_uid(const struct net *net, const struct sock *sk)
 
 static inline u32 net_tx_rndhash(void)
 {
-	u32 v = prandom_u32();
+	u32 v = get_random_u32();
 
 	return v ?: 1;
 }