Handling magic sysrq included dropping a lock to avoid a deadlock that
happened when cdns_uart_console_write tried to acquire a lock in the
from the sysrq code path. By making the acquisition of the lock in
cdns_uart_console_write depending on port->sysrq, cdns_uart_handle_rx can be
simplified to simply call uart_handle_sysrq.
Suggested-by: Peter Hurley <pe...@hurleysoftware.com>
Signed-off-by: Soren Brinkmann <soren.brinkm...@xilinx.com>
---
v4:
- added this patch
---
drivers/tty/serial/xilinx_uartps.c | 20 +++++---------------
1 file changed, 5 insertions(+), 15 deletions(-)
diff --git a/drivers/tty/serial/xilinx_uartps.c
b/drivers/tty/serial/xilinx_uartps.c
index 7afab0c36528..3b8d15fa5959 100644
--- a/drivers/tty/serial/xilinx_uartps.c
+++ b/drivers/tty/serial/xilinx_uartps.c
@@ -221,20 +221,8 @@ static void cdns_uart_handle_rx(struct uart_port *port,
unsigned int isrstatus)
continue;
}
-#ifdef SUPPORT_SYSRQ
- /*
- * uart_handle_sysrq_char() doesn't work if
- * spinlocked, for some reason
- */
- if (port->sysrq) {
- spin_unlock(&port->lock);
- if (uart_handle_sysrq_char(port, data)) {
- spin_lock(&port->lock);
- continue;
- }
- spin_lock(&port->lock);
- }
-#endif
+ if (uart_handle_sysrq_char(port, data))
+ continue;
port->icount.rx++;
@@ -1121,7 +1109,9 @@ static void cdns_uart_console_write(struct console *co,
const char *s,
unsigned int imr, ctrl;
int locked = 1;
- if (oops_in_progress)
+ if (port->sysrq)
+ locked = 0;
+ else if (oops_in_progress)
locked = spin_trylock_irqsave(&port->lock, flags);
else
spin_lock_irqsave(&port->lock, flags);
--
2.6.3.3.g9bb996a
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