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authorTheodore Ts'o <tytso@mit.edu>2013-10-03 12:02:37 -0400
committerTheodore Ts'o <tytso@mit.edu>2013-10-10 14:32:23 -0400
commitf80bbd8b92987f55f26691cd53785c4a54622eb0 (patch)
tree390c761123de9fe3784c147a01be2f3be8f7b7e0 /drivers/char
parent6265e169cd313d6f3aad3c33d0a5b0d9624f69f5 (diff)
downloadlinux-linaro-stable-f80bbd8b92987f55f26691cd53785c4a54622eb0.tar.gz
random: convert DEBUG_ENT to tracepoints
Instead of using the random driver's ad-hoc DEBUG_ENT() mechanism, use tracepoints instead. This allows for a much more fine-grained control of which debugging mechanism which a developer might need, and unifies the debugging messages with all of the existing tracepoints. Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Diffstat (limited to 'drivers/char')
-rw-r--r--drivers/char/random.c52
1 files changed, 16 insertions, 36 deletions
diff --git a/drivers/char/random.c b/drivers/char/random.c
index 84c576ec20e9..f126bd2f69fe 100644
--- a/drivers/char/random.c
+++ b/drivers/char/random.c
@@ -404,17 +404,6 @@ static DECLARE_WAIT_QUEUE_HEAD(random_read_wait);
static DECLARE_WAIT_QUEUE_HEAD(random_write_wait);
static struct fasync_struct *fasync;
-static bool debug;
-module_param(debug, bool, 0644);
-#define DEBUG_ENT(fmt, arg...) do { \
- if (debug) \
- printk(KERN_DEBUG "random %04d %04d %04d: " \
- fmt,\
- input_pool.entropy_count,\
- blocking_pool.entropy_count,\
- nonblocking_pool.entropy_count,\
- ## arg); } while (0)
-
/**********************************************************************
*
* OS independent entropy store. Here are the functions which handle
@@ -612,7 +601,6 @@ static void credit_entropy_bits(struct entropy_store *r, int nbits)
if (!nbits)
return;
- DEBUG_ENT("added %d entropy credits to %s\n", nbits, r->name);
retry:
entropy_count = orig = ACCESS_ONCE(r->entropy_count);
if (nfrac < 0) {
@@ -655,7 +643,9 @@ retry:
}
if (entropy_count < 0) {
- DEBUG_ENT("negative entropy/overflow\n");
+ pr_warn("random: negative entropy/overflow: pool %s count %d\n",
+ r->name, entropy_count);
+ WARN_ON(1);
entropy_count = 0;
} else if (entropy_count > pool_size)
entropy_count = pool_size;
@@ -832,10 +822,10 @@ void add_input_randomness(unsigned int type, unsigned int code,
if (value == last_value)
return;
- DEBUG_ENT("input event\n");
last_value = value;
add_timer_randomness(&input_timer_state,
(type << 4) ^ code ^ (code >> 4) ^ value);
+ trace_add_input_randomness(ENTROPY_BITS(&input_pool));
}
EXPORT_SYMBOL_GPL(add_input_randomness);
@@ -890,10 +880,8 @@ void add_disk_randomness(struct gendisk *disk)
if (!disk || !disk->random)
return;
/* first major is 1, so we get >= 0x200 here */
- DEBUG_ENT("disk event %d:%d\n",
- MAJOR(disk_devt(disk)), MINOR(disk_devt(disk)));
-
add_timer_randomness(disk->random, 0x100 + disk_devt(disk));
+ trace_add_disk_randomness(disk_devt(disk), ENTROPY_BITS(&input_pool));
}
#endif
@@ -941,10 +929,8 @@ static void _xfer_secondary_pool(struct entropy_store *r, size_t nbytes)
/* but never more than the buffer size */
bytes = min_t(int, bytes, sizeof(tmp));
- DEBUG_ENT("going to reseed %s with %d bits (%zu of %d requested)\n",
- r->name, bytes * 8, nbytes * 8,
- r->entropy_count >> ENTROPY_SHIFT);
-
+ trace_xfer_secondary_pool(r->name, bytes * 8, nbytes * 8,
+ ENTROPY_BITS(r), ENTROPY_BITS(r->pull));
bytes = extract_entropy(r->pull, tmp, bytes,
random_read_wakeup_thresh / 8, rsvd);
mix_pool_bytes(r, tmp, bytes, NULL);
@@ -992,8 +978,6 @@ static size_t account(struct entropy_store *r, size_t nbytes, int min,
spin_lock_irqsave(&r->lock, flags);
BUG_ON(r->entropy_count > r->poolinfo->poolfracbits);
- DEBUG_ENT("trying to extract %zu bits from %s\n",
- nbytes * 8, r->name);
/* Can we pull enough? */
retry:
@@ -1019,12 +1003,9 @@ retry:
< random_write_wakeup_thresh)
wakeup_write = 1;
}
-
- DEBUG_ENT("debiting %zu entropy credits from %s%s\n",
- ibytes * 8, r->name, r->limit ? "" : " (unlimited)");
-
spin_unlock_irqrestore(&r->lock, flags);
+ trace_debit_entropy(r->name, 8 * ibytes);
if (wakeup_write) {
wake_up_interruptible(&random_write_wait);
kill_fasync(&fasync, SIGIO, POLL_OUT);
@@ -1303,8 +1284,6 @@ random_read(struct file *file, char __user *buf, size_t nbytes, loff_t *ppos)
if (n > SEC_XFER_SIZE)
n = SEC_XFER_SIZE;
- DEBUG_ENT("reading %zu bits\n", n*8);
-
n = extract_entropy_user(&blocking_pool, buf, n);
if (n < 0) {
@@ -1312,8 +1291,9 @@ random_read(struct file *file, char __user *buf, size_t nbytes, loff_t *ppos)
break;
}
- DEBUG_ENT("read got %zd bits (%zd still needed)\n",
- n*8, (nbytes-n)*8);
+ trace_random_read(n*8, (nbytes-n)*8,
+ ENTROPY_BITS(&blocking_pool),
+ ENTROPY_BITS(&input_pool));
if (n == 0) {
if (file->f_flags & O_NONBLOCK) {
@@ -1321,14 +1301,10 @@ random_read(struct file *file, char __user *buf, size_t nbytes, loff_t *ppos)
break;
}
- DEBUG_ENT("sleeping?\n");
-
wait_event_interruptible(random_read_wait,
ENTROPY_BITS(&input_pool) >=
random_read_wakeup_thresh);
- DEBUG_ENT("awake\n");
-
if (signal_pending(current)) {
retval = -ERESTARTSYS;
break;
@@ -1350,7 +1326,11 @@ random_read(struct file *file, char __user *buf, size_t nbytes, loff_t *ppos)
static ssize_t
urandom_read(struct file *file, char __user *buf, size_t nbytes, loff_t *ppos)
{
- return extract_entropy_user(&nonblocking_pool, buf, nbytes);
+ int ret = extract_entropy_user(&nonblocking_pool, buf, nbytes);
+
+ trace_urandom_read(8 * nbytes, ENTROPY_BITS(&nonblocking_pool),
+ ENTROPY_BITS(&input_pool));
+ return ret;
}
static unsigned int