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authorAndy Lutomirski <luto@kernel.org>2019-12-23 00:20:45 -0800
committerTheodore Ts'o <tytso@mit.edu>2020-01-07 16:07:00 -0500
commitc6f1deb158789abba02a7eba600747843eeb3a57 (patch)
tree2e8e5715d3dd2705531cf17fa13b0ce7814396df /drivers/char
parent4c8d062186d9923c09488716b2fb1b829b5b8006 (diff)
random: Add a urandom_read_nowait() for random APIs that don't warn
/dev/random and getrandom() never warn. Split the meat of urandom_read() into urandom_read_nowarn() and leave the warning code in urandom_read(). This has no effect on kernel behavior, but it makes subsequent patches more straightforward. It also makes the fact that getrandom() never warns more obvious. Signed-off-by: Andy Lutomirski <luto@kernel.org> Link: https://lore.kernel.org/r/c87ab200588de746431d9f916501ef11e5242b13.1577088521.git.luto@kernel.org Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Diffstat (limited to 'drivers/char')
-rw-r--r--drivers/char/random.c21
1 files changed, 15 insertions, 6 deletions
diff --git a/drivers/char/random.c b/drivers/char/random.c
index 502e37141c72..91954c0091a5 100644
--- a/drivers/char/random.c
+++ b/drivers/char/random.c
@@ -2020,11 +2020,22 @@ random_read(struct file *file, char __user *buf, size_t nbytes, loff_t *ppos)
}
static ssize_t
+urandom_read_nowarn(struct file *file, char __user *buf, size_t nbytes,
+ loff_t *ppos)
+{
+ int ret;
+
+ nbytes = min_t(size_t, nbytes, INT_MAX >> (ENTROPY_SHIFT + 3));
+ ret = extract_crng_user(buf, nbytes);
+ trace_urandom_read(8 * nbytes, 0, ENTROPY_BITS(&input_pool));
+ return ret;
+}
+
+static ssize_t
urandom_read(struct file *file, char __user *buf, size_t nbytes, loff_t *ppos)
{
unsigned long flags;
static int maxwarn = 10;
- int ret;
if (!crng_ready() && maxwarn > 0) {
maxwarn--;
@@ -2036,10 +2047,8 @@ urandom_read(struct file *file, char __user *buf, size_t nbytes, loff_t *ppos)
crng_init_cnt = 0;
spin_unlock_irqrestore(&primary_crng.lock, flags);
}
- nbytes = min_t(size_t, nbytes, INT_MAX >> (ENTROPY_SHIFT + 3));
- ret = extract_crng_user(buf, nbytes);
- trace_urandom_read(8 * nbytes, 0, ENTROPY_BITS(&input_pool));
- return ret;
+
+ return urandom_read_nowarn(file, buf, nbytes, ppos);
}
static __poll_t
@@ -2201,7 +2210,7 @@ SYSCALL_DEFINE3(getrandom, char __user *, buf, size_t, count,
if (unlikely(ret))
return ret;
}
- return urandom_read(NULL, buf, count, NULL);
+ return urandom_read_nowarn(NULL, buf, count, NULL);
}
/********************************************************************