random: remove unused extract_entropy() reserved argument

This argument is always set to zero, as a result of us not caring about
keeping a certain amount reserved in the pool these days. So just remove
it and cleanup the function signatures.

Reviewed-by: Dominik Brodowski <linux@dominikbrodowski.net>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>

diff --git a/drivers/char/random.c b/drivers/char/random.c
index 07354e2..8073443 100644 (file)
--- a/drivers/char/random.c
+++ b/drivers/char/random.c
@@ -519,7 +519,7 @@ struct entropy_store {
 };
 
 static ssize_t extract_entropy(struct entropy_store *r, void *buf,
-                              size_t nbytes, int min, int rsvd);
+                              size_t nbytes, int min);
 static ssize_t _extract_entropy(struct entropy_store *r, void *buf,
                                size_t nbytes);
 
@@ -989,7 +989,7 @@ static void crng_reseed(struct crng_state *crng, struct entropy_store *r)
        } buf;
 
        if (r) {
-               num = extract_entropy(r, &buf, 32, 16, 0);
+               num = extract_entropy(r, &buf, 32, 16);
                if (num == 0)
                        return;
        } else {
@@ -1327,8 +1327,7 @@ EXPORT_SYMBOL_GPL(add_disk_randomness);
  * This function decides how many bytes to actually take from the
  * given pool, and also debits the entropy count accordingly.
  */
-static size_t account(struct entropy_store *r, size_t nbytes, int min,
-                     int reserved)
+static size_t account(struct entropy_store *r, size_t nbytes, int min)
 {
        int entropy_count, orig, have_bytes;
        size_t ibytes, nfrac;
@@ -1342,7 +1341,7 @@ retry:
        /* never pull more than available */
        have_bytes = entropy_count >> (ENTROPY_SHIFT + 3);
 
-       if ((have_bytes -= reserved) < 0)
+       if (have_bytes < 0)
                have_bytes = 0;
        ibytes = min_t(size_t, ibytes, have_bytes);
        if (ibytes < min)
@@ -1448,15 +1447,13 @@ static ssize_t _extract_entropy(struct entropy_store *r, void *buf,
  * returns it in a buffer.
  *
  * The min parameter specifies the minimum amount we can pull before
- * failing to avoid races that defeat catastrophic reseeding while the
- * reserved parameter indicates how much entropy we must leave in the
- * pool after each pull to avoid starving other readers.
+ * failing to avoid races that defeat catastrophic reseeding.
  */
 static ssize_t extract_entropy(struct entropy_store *r, void *buf,
-                                size_t nbytes, int min, int reserved)
+                                size_t nbytes, int min)
 {
        trace_extract_entropy(r->name, nbytes, ENTROPY_BITS(r), _RET_IP_);
-       nbytes = account(r, nbytes, min, reserved);
+       nbytes = account(r, nbytes, min);
        return _extract_entropy(r, buf, nbytes);
 }