diff options
| author | Thomas Gleixner <tglx@linutronix.de> | 2013-01-08 21:36:51 +0100 |
|---|---|---|
| committer | Sebastian Andrzej Siewior <bigeasy@linutronix.de> | 2016-02-13 00:36:10 +0100 |
| commit | 7dcb1286a60b23cd081d0e473bf379dc67864f36 (patch) | |
| tree | c8433123b992e4ef13c6f5adbf2e0e2fd3aab125 | |
| parent | 85e15b9ea60536f769419a5654f0f391ceefda40 (diff) | |
| download | rt-linux-7dcb1286a60b23cd081d0e473bf379dc67864f36.tar.gz | |
tty/serial/pl011: Make the locking work on RT
The lock is a sleeping lock and local_irq_save() is not the optimsation
we are looking for. Redo it to make it work on -RT and non-RT.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
| -rw-r--r-- | drivers/tty/serial/amba-pl011.c | 15 |
1 files changed, 10 insertions, 5 deletions
diff --git a/drivers/tty/serial/amba-pl011.c b/drivers/tty/serial/amba-pl011.c index 899a77187bdea..3ff6363b3751d 100644 --- a/drivers/tty/serial/amba-pl011.c +++ b/drivers/tty/serial/amba-pl011.c @@ -2067,13 +2067,19 @@ pl011_console_write(struct console *co, const char *s, unsigned int count) clk_enable(uap->clk); - local_irq_save(flags); + /* + * local_irq_save(flags); + * + * This local_irq_save() is nonsense. If we come in via sysrq + * handling then interrupts are already disabled. Aside of + * that the port.sysrq check is racy on SMP regardless. + */ if (uap->port.sysrq) locked = 0; else if (oops_in_progress) - locked = spin_trylock(&uap->port.lock); + locked = spin_trylock_irqsave(&uap->port.lock, flags); else - spin_lock(&uap->port.lock); + spin_lock_irqsave(&uap->port.lock, flags); /* * First save the CR then disable the interrupts @@ -2098,8 +2104,7 @@ pl011_console_write(struct console *co, const char *s, unsigned int count) writew(old_cr, uap->port.membase + UART011_CR); if (locked) - spin_unlock(&uap->port.lock); - local_irq_restore(flags); + spin_unlock_irqrestore(&uap->port.lock, flags); clk_disable(uap->clk); } |