random: simplify fips mode

Rather than dynamically allocate 10 bytes, move it to static allocation.
This saves space and avoids the need for error checking.

Signed-off-by: Matt Mackall <mpm@selenic.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

1 files changed, 3 insertions, 7 deletions

diff --git a/drivers/char/random.c b/drivers/char/random.c
index 2fd3d39995d5..8d85587b6d4f 100644
--- a/drivers/char/random.c
+++ b/drivers/char/random.c
@@ -257,6 +257,7 @@
 #define INPUT_POOL_WORDS 128
 #define OUTPUT_POOL_WORDS 32
 #define SEC_XFER_SIZE 512
+#define EXTRACT_SIZE 10
 
 /*
  * The minimum number of bits of entropy before we wake up a read on
@@ -414,7 +415,7 @@ struct entropy_store {
         unsigned add_ptr;
         int entropy_count;
         int input_rotate;
-        __u8 *last_data;
+        __u8 last_data[EXTRACT_SIZE];
 };
 
 static __u32 input_pool_data[INPUT_POOL_WORDS];
@@ -714,8 +715,6 @@ void add_disk_randomness(struct gendisk *disk)
 }
 #endif
 
-#define EXTRACT_SIZE 10
-
 /*********************************************************************
  *
  * Entropy extraction routines
@@ -862,7 +861,7 @@ static ssize_t extract_entropy(struct entropy_store *r, void *buf,
         while (nbytes) {
                 extract_buf(r, tmp);
 
-                if (r->last_data) {
+                if (fips_enabled) {
                         spin_lock_irqsave(&r->lock, flags);
                         if (!memcmp(tmp, r->last_data, EXTRACT_SIZE))
                                 panic("Hardware RNG duplicated output!\n");
@@ -951,9 +950,6 @@ static void init_std_data(struct entropy_store *r)
         now = ktime_get_real();
         mix_pool_bytes(r, &now, sizeof(now));
         mix_pool_bytes(r, utsname(), sizeof(*(utsname())));
-        /* Enable continuous test in fips mode */
-        if (fips_enabled)
-                r->last_data = kmalloc(EXTRACT_SIZE, GFP_KERNEL);
 }
 
 static int rand_initialize(void)