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locking, printk: Annotate logbuf_lock as raw

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The logbuf_lock lock can be taken in atomic context and therefore
cannot be preempted on -rt - annotate it.

In mainline this change documents the low level nature of
the lock - otherwise there's no functional difference. Lockdep
and Sparse checking will work as usual.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
[ merged and fixed it ]
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Thomas Gleixner 2009-07-25 17:50:36 +02:00 committed by Ingo Molnar
parent 5389f6fad2
commit 07354eb1a7
3 changed files with 28 additions and 28 deletions
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6
include/linux/ratelimit.h
View File

@ -8,7 +8,7 @@
#define DEFAULT_RATELIMIT_BURST 10
struct ratelimit_state {
spinlock_t lock; /* protect the state */
raw_spinlock_t lock; /* protect the state */
int interval;
int burst;
@ -20,7 +20,7 @@ struct ratelimit_state {
#define DEFINE_RATELIMIT_STATE(name, interval_init, burst_init) \
\
struct ratelimit_state name = { \
.lock = __SPIN_LOCK_UNLOCKED(name.lock), \
.lock = __RAW_SPIN_LOCK_UNLOCKED(name.lock), \
.interval = interval_init, \
.burst = burst_init, \
}
@ -28,7 +28,7 @@ struct ratelimit_state {
static inline void ratelimit_state_init(struct ratelimit_state *rs,
int interval, int burst)
{
spin_lock_init(&rs->lock);
raw_spin_lock_init(&rs->lock);
rs->interval = interval;
rs->burst = burst;
rs->printed = 0;

46
kernel/printk.c
View File

@ -100,7 +100,7 @@ static int console_locked, console_suspended;
* It is also used in interesting ways to provide interlocking in
* console_unlock();.
*/
static DEFINE_SPINLOCK(logbuf_lock);
static DEFINE_RAW_SPINLOCK(logbuf_lock);
#define LOG_BUF_MASK (log_buf_len-1)
#define LOG_BUF(idx) (log_buf[(idx) & LOG_BUF_MASK])
@ -212,7 +212,7 @@ void __init setup_log_buf(int early)
return;
}
spin_lock_irqsave(&logbuf_lock, flags);
raw_spin_lock_irqsave(&logbuf_lock, flags);
log_buf_len = new_log_buf_len;
log_buf = new_log_buf;
new_log_buf_len = 0;
@ -230,7 +230,7 @@ void __init setup_log_buf(int early)
log_start -= offset;
con_start -= offset;
log_end -= offset;
spin_unlock_irqrestore(&logbuf_lock, flags);
raw_spin_unlock_irqrestore(&logbuf_lock, flags);
pr_info("log_buf_len: %d\n", log_buf_len);
pr_info("early log buf free: %d(%d%%)\n",
@ -365,18 +365,18 @@ int do_syslog(int type, char __user *buf, int len, bool from_file)
if (error)
goto out;
i = 0;
spin_lock_irq(&logbuf_lock);
raw_spin_lock_irq(&logbuf_lock);
while (!error && (log_start != log_end) && i < len) {
c = LOG_BUF(log_start);
log_start++;
spin_unlock_irq(&logbuf_lock);
raw_spin_unlock_irq(&logbuf_lock);
error = __put_user(c,buf);
buf++;
i++;
cond_resched();
spin_lock_irq(&logbuf_lock);
raw_spin_lock_irq(&logbuf_lock);
}
spin_unlock_irq(&logbuf_lock);
raw_spin_unlock_irq(&logbuf_lock);
if (!error)
error = i;
break;
@ -399,7 +399,7 @@ int do_syslog(int type, char __user *buf, int len, bool from_file)
count = len;
if (count > log_buf_len)
count = log_buf_len;
spin_lock_irq(&logbuf_lock);
raw_spin_lock_irq(&logbuf_lock);
if (count > logged_chars)
count = logged_chars;
if (do_clear)
@ -416,12 +416,12 @@ int do_syslog(int type, char __user *buf, int len, bool from_file)
if (j + log_buf_len < log_end)
break;
c = LOG_BUF(j);
spin_unlock_irq(&logbuf_lock);
raw_spin_unlock_irq(&logbuf_lock);
error = __put_user(c,&buf[count-1-i]);
cond_resched();
spin_lock_irq(&logbuf_lock);
raw_spin_lock_irq(&logbuf_lock);
}
spin_unlock_irq(&logbuf_lock);
raw_spin_unlock_irq(&logbuf_lock);
if (error)
break;
error = i;
@ -689,7 +689,7 @@ static void zap_locks(void)
oops_timestamp = jiffies;
/* If a crash is occurring, make sure we can't deadlock */
spin_lock_init(&logbuf_lock);
raw_spin_lock_init(&logbuf_lock);
/* And make sure that we print immediately */
sema_init(&console_sem, 1);
}
@ -802,9 +802,9 @@ static int console_trylock_for_printk(unsigned int cpu)
}
}
printk_cpu = UINT_MAX;
spin_unlock(&logbuf_lock);
if (wake)
up(&console_sem);
raw_spin_unlock(&logbuf_lock);
return retval;
}
static const char recursion_bug_msg [] =
@ -864,7 +864,7 @@ asmlinkage int vprintk(const char *fmt, va_list args)
}
lockdep_off();
spin_lock(&logbuf_lock);
raw_spin_lock(&logbuf_lock);
printk_cpu = this_cpu;
if (recursion_bug) {
@ -1257,14 +1257,14 @@ void console_unlock(void)
again:
for ( ; ; ) {
spin_lock_irqsave(&logbuf_lock, flags);
raw_spin_lock_irqsave(&logbuf_lock, flags);
wake_klogd |= log_start - log_end;
if (con_start == log_end)
break; /* Nothing to print */
_con_start = con_start;
_log_end = log_end;
con_start = log_end; /* Flush */
spin_unlock(&logbuf_lock);
raw_spin_unlock(&logbuf_lock);
stop_critical_timings(); /* don't trace print latency */
call_console_drivers(_con_start, _log_end);
start_critical_timings();
@ -1276,7 +1276,7 @@ void console_unlock(void)
if (unlikely(exclusive_console))
exclusive_console = NULL;
spin_unlock(&logbuf_lock);
raw_spin_unlock(&logbuf_lock);
up(&console_sem);
@ -1286,13 +1286,13 @@ void console_unlock(void)
* there's a new owner and the console_unlock() from them will do the
* flush, no worries.
*/
spin_lock(&logbuf_lock);
raw_spin_lock(&logbuf_lock);
if (con_start != log_end)
retry = 1;
spin_unlock_irqrestore(&logbuf_lock, flags);
if (retry && console_trylock())
goto again;
raw_spin_unlock_irqrestore(&logbuf_lock, flags);
if (wake_klogd)
wake_up_klogd();
}
@ -1522,9 +1522,9 @@ void register_console(struct console *newcon)
* console_unlock(); will print out the buffered messages
* for us.
*/
spin_lock_irqsave(&logbuf_lock, flags);
raw_spin_lock_irqsave(&logbuf_lock, flags);
con_start = log_start;
spin_unlock_irqrestore(&logbuf_lock, flags);
raw_spin_unlock_irqrestore(&logbuf_lock, flags);
/*
* We're about to replay the log buffer. Only do this to the
* just-registered console to avoid excessive message spam to
@ -1731,10 +1731,10 @@ void kmsg_dump(enum kmsg_dump_reason reason)
/* Theoretically, the log could move on after we do this, but
there's not a lot we can do about that. The new messages
will overwrite the start of what we dump. */
spin_lock_irqsave(&logbuf_lock, flags);
raw_spin_lock_irqsave(&logbuf_lock, flags);
end = log_end & LOG_BUF_MASK;
chars = logged_chars;
spin_unlock_irqrestore(&logbuf_lock, flags);
raw_spin_unlock_irqrestore(&logbuf_lock, flags);
if (chars > end) {
s1 = log_buf + log_buf_len - chars + end;

4
lib/ratelimit.c
View File

@ -39,7 +39,7 @@ int ___ratelimit(struct ratelimit_state *rs, const char *func)
* in addition to the one that will be printed by
* the entity that is holding the lock already:
*/
if (!spin_trylock_irqsave(&rs->lock, flags))
if (!raw_spin_trylock_irqsave(&rs->lock, flags))
return 0;
if (!rs->begin)
@ -60,7 +60,7 @@ int ___ratelimit(struct ratelimit_state *rs, const char *func)
rs->missed++;
ret = 0;
}
spin_unlock_irqrestore(&rs->lock, flags);
raw_spin_unlock_irqrestore(&rs->lock, flags);
return ret;
}