Merge tag 'v3.15-rc1' into patchwork

Linux 3.15-rc1

* tag 'v3.15-rc1': (12180 commits)
  Linux 3.15-rc1
  mm: Initialize error in shmem_file_aio_read()
  cifs: Use min_t() when comparing "size_t" and "unsigned long"
  sym53c8xx_2: Set DID_REQUEUE return code when aborting squeue
  powerpc: Don't try to set LPCR unless we're in hypervisor mode
  futex: update documentation for ordering guarantees
  ceph: fix pr_fmt() redefinition
  vti: don't allow to add the same tunnel twice
  gre: don't allow to add the same tunnel twice
  drivers: net: xen-netfront: fix array initialization bug
  missing bits of "splice: fix racy pipe->buffers uses"
  cifs: fix the race in cifs_writev()
  ceph_sync_{,direct_}write: fix an oops on ceph_osdc_new_request() failure
  pktgen: be friendly to LLTX devices
  r8152: check RTL8152_UNPLUG
  net: sun4i-emac: add promiscuous support
  net/apne: replace IS_ERR and PTR_ERR with PTR_ERR_OR_ZERO
  blackfin: cleanup board files
  bf609: clock: drop unused clock bit set/clear functions
  Blackfin: bf537: rename "CONFIG_ADT75"
  ...

1 files changed, 51 insertions, 38 deletions

diff --git a/lib/random32.c b/lib/random32.c
index 1e5b2df4429..fa5da61ce7a 100644
--- a/lib/random32.c
+++ b/lib/random32.c
@@ -1,37 +1,35 @@
 /*
-  This is a maximally equidistributed combined Tausworthe generator
-  based on code from GNU Scientific Library 1.5 (30 Jun 2004)
-
-  lfsr113 version:
-
-   x_n = (s1_n ^ s2_n ^ s3_n ^ s4_n)
-
-   s1_{n+1} = (((s1_n & 4294967294) << 18) ^ (((s1_n <<  6) ^ s1_n) >> 13))
-   s2_{n+1} = (((s2_n & 4294967288) <<  2) ^ (((s2_n <<  2) ^ s2_n) >> 27))
-   s3_{n+1} = (((s3_n & 4294967280) <<  7) ^ (((s3_n << 13) ^ s3_n) >> 21))
-   s4_{n+1} = (((s4_n & 4294967168) << 13) ^ (((s4_n <<  3) ^ s4_n) >> 12))
-
-   The period of this generator is about 2^113 (see erratum paper).
-
-   From: P. L'Ecuyer, "Maximally Equidistributed Combined Tausworthe
-   Generators", Mathematics of Computation, 65, 213 (1996), 203--213:
-   http://www.iro.umontreal.ca/~lecuyer/myftp/papers/tausme.ps
-   ftp://ftp.iro.umontreal.ca/pub/simulation/lecuyer/papers/tausme.ps
-
-   There is an erratum in the paper "Tables of Maximally
-   Equidistributed Combined LFSR Generators", Mathematics of
-   Computation, 68, 225 (1999), 261--269:
-   http://www.iro.umontreal.ca/~lecuyer/myftp/papers/tausme2.ps
-
-        ... the k_j most significant bits of z_j must be non-
-        zero, for each j. (Note: this restriction also applies to the
-        computer code given in [4], but was mistakenly not mentioned in
-        that paper.)
-
-   This affects the seeding procedure by imposing the requirement
-   s1 > 1, s2 > 7, s3 > 15, s4 > 127.
-
-*/
+ * This is a maximally equidistributed combined Tausworthe generator
+ * based on code from GNU Scientific Library 1.5 (30 Jun 2004)
+ *
+ * lfsr113 version:
+ *
+ * x_n = (s1_n ^ s2_n ^ s3_n ^ s4_n)
+ *
+ * s1_{n+1} = (((s1_n & 4294967294) << 18) ^ (((s1_n <<  6) ^ s1_n) >> 13))
+ * s2_{n+1} = (((s2_n & 4294967288) <<  2) ^ (((s2_n <<  2) ^ s2_n) >> 27))
+ * s3_{n+1} = (((s3_n & 4294967280) <<  7) ^ (((s3_n << 13) ^ s3_n) >> 21))
+ * s4_{n+1} = (((s4_n & 4294967168) << 13) ^ (((s4_n <<  3) ^ s4_n) >> 12))
+ *
+ * The period of this generator is about 2^113 (see erratum paper).
+ *
+ * From: P. L'Ecuyer, "Maximally Equidistributed Combined Tausworthe
+ * Generators", Mathematics of Computation, 65, 213 (1996), 203--213:
+ * http://www.iro.umontreal.ca/~lecuyer/myftp/papers/tausme.ps
+ * ftp://ftp.iro.umontreal.ca/pub/simulation/lecuyer/papers/tausme.ps
+ *
+ * There is an erratum in the paper "Tables of Maximally Equidistributed
+ * Combined LFSR Generators", Mathematics of Computation, 68, 225 (1999),
+ * 261--269: http://www.iro.umontreal.ca/~lecuyer/myftp/papers/tausme2.ps
+ *
+ *      ... the k_j most significant bits of z_j must be non-zero,
+ *      for each j. (Note: this restriction also applies to the
+ *      computer code given in [4], but was mistakenly not mentioned
+ *      in that paper.)
+ *
+ * This affects the seeding procedure by imposing the requirement
+ * s1 > 1, s2 > 7, s3 > 15, s4 > 127.
+ */
 
 #include <linux/types.h>
 #include <linux/percpu.h>
@@ -75,15 +73,17 @@ EXPORT_SYMBOL(prandom_u32_state);
  */
 u32 prandom_u32(void)
 {
-	unsigned long r;
 	struct rnd_state *state = &get_cpu_var(net_rand_state);
-	r = prandom_u32_state(state);
+	u32 res;
+
+	res = prandom_u32_state(state);
 	put_cpu_var(state);
-	return r;
+
+	return res;
 }
 EXPORT_SYMBOL(prandom_u32);
 
-/*
+/**
  *	prandom_bytes_state - get the requested number of pseudo-random bytes
  *
  *	@state: pointer to state structure holding seeded state.
@@ -204,6 +204,7 @@ static int __init prandom_init(void)
 		prandom_seed_very_weak(state, (i + jiffies) ^ random_get_entropy());
 		prandom_warmup(state);
 	}
+
 	return 0;
 }
 core_initcall(prandom_init);
@@ -244,10 +245,22 @@ static void __prandom_reseed(bool late)
 	static bool latch = false;
 	static DEFINE_SPINLOCK(lock);
 
+	/* Asking for random bytes might result in bytes getting
+	 * moved into the nonblocking pool and thus marking it
+	 * as initialized. In this case we would double back into
+	 * this function and attempt to do a late reseed.
+	 * Ignore the pointless attempt to reseed again if we're
+	 * already waiting for bytes when the nonblocking pool
+	 * got initialized.
+	 */
+
 	/* only allow initial seeding (late == false) once */
-	spin_lock_irqsave(&lock, flags);
+	if (!spin_trylock_irqsave(&lock, flags))
+		return;
+
 	if (latch && !late)
 		goto out;
+
 	latch = true;
 
 	for_each_possible_cpu(i) {