diff options
| author | Thomas Gleixner <tglx@linutronix.de> | 2013-01-09 00:36:51 +0400 |
|---|---|---|
| committer | Minda Chen <minda.chen@starfivetech.com> | 2023-11-06 14:24:52 +0300 |
| commit | 8774a5f2ba0bb295dafa18577cddf1efa72577e5 (patch) | |
| tree | 96806ac631764cc30e39f0368a04cf262b5ddb38 | |
| parent | bc43f1ea53bfa0aa63b2d7b57274adc9366a94fc (diff) | |
| download | linux-8774a5f2ba0bb295dafa18577cddf1efa72577e5.tar.xz | |
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 | 17 |
1 files changed, 11 insertions, 6 deletions
diff --git a/drivers/tty/serial/amba-pl011.c b/drivers/tty/serial/amba-pl011.c index d361cd84ff8c..e1029c108e8e 100644 --- a/drivers/tty/serial/amba-pl011.c +++ b/drivers/tty/serial/amba-pl011.c @@ -2336,18 +2336,24 @@ pl011_console_write(struct console *co, const char *s, unsigned int count) { struct uart_amba_port *uap = amba_ports[co->index]; unsigned int old_cr = 0, new_cr; - unsigned long flags; + unsigned long flags = 0; int locked = 1; 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 @@ -2373,8 +2379,7 @@ pl011_console_write(struct console *co, const char *s, unsigned int count) pl011_write(old_cr, uap, REG_CR); if (locked) - spin_unlock(&uap->port.lock); - local_irq_restore(flags); + spin_unlock_irqrestore(&uap->port.lock, flags); clk_disable(uap->clk); } |