random: remove kernel.random.read_wakeup_threshold

It has no effect any more, so remove it.  We can revert this if
there is some user code that expects to be able to set this sysctl.

Signed-off-by: Andy Lutomirski <luto@kernel.org>
Link: https://lore.kernel.org/r/a74ed2cf0b5a5451428a246a9239f5bc4e29358f.1577088521.git.luto@kernel.org
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

diff --git a/drivers/char/random.c b/drivers/char/random.c
index 1a36a59..b68da8e 100644 (file)
--- a/drivers/char/random.c
+++ b/drivers/char/random.c
@@ -369,12 +369,6 @@
 #define ENTROPY_SHIFT 3
 #define ENTROPY_BITS(r) ((r)->entropy_count >> ENTROPY_SHIFT)
 
-/*
- * The minimum number of bits of entropy before we wake up a read on
- * /dev/random.  Should be enough to do a significant reseed.
- */
-static int random_read_wakeup_bits = 64;
-
 /*
  * If the entropy count falls under this number of bits, then we
  * should wake up processes which are selecting or polling on write
@@ -2054,8 +2048,7 @@ SYSCALL_DEFINE3(getrandom, char __user *, buf, size_t, count,
 
 #include <linux/sysctl.h>
 
-static int min_read_thresh = 8, min_write_thresh;
-static int max_read_thresh = OUTPUT_POOL_WORDS * 32;
+static int min_write_thresh;
 static int max_write_thresh = INPUT_POOL_WORDS * 32;
 static int random_min_urandom_seed = 60;
 static char sysctl_bootid[16];
@@ -2130,15 +2123,6 @@ struct ctl_table random_table[] = {
                .proc_handler   = proc_do_entropy,
                .data           = &input_pool.entropy_count,
        },
-       {
-               .procname       = "read_wakeup_threshold",
-               .data           = &random_read_wakeup_bits,
-               .maxlen         = sizeof(int),
-               .mode           = 0644,
-               .proc_handler   = proc_dointvec_minmax,
-               .extra1         = &min_read_thresh,
-               .extra2         = &max_read_thresh,
-       },
        {
                .procname       = "write_wakeup_threshold",
                .data           = &random_write_wakeup_bits,