From f80bbd8b92987f55f26691cd53785c4a54622eb0 Mon Sep 17 00:00:00 2001 From: Theodore Ts'o Date: Thu, 3 Oct 2013 12:02:37 -0400 Subject: 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" --- drivers/char/random.c | 52 ++++++++++++++++----------------------------------- 1 file changed, 16 insertions(+), 36 deletions(-) (limited to 'drivers/char') 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 -- cgit v1.2.3