Static analyzer can not see balanced locking if the lock is acquired and
released conditionally.
drivers/tty/serial/serial_core.c:131:17: warning: context imbalance in 'uart_stop' - unexpected unlock
include/linux/spinlock.h:362:9: warning: context imbalance in 'uart_start' - unexpected unlock
include/linux/spinlock.h:362:9: warning: context imbalance in 'uart_put_char' - unexpected unlock
include/linux/spinlock.h:362:9: warning: context imbalance in 'uart_write' - unexpected unlock
include/linux/spinlock.h:362:9: warning: context imbalance in 'uart_write_room' - unexpected unlock
include/linux/spinlock.h:362:9: warning: context imbalance in 'uart_chars_in_buffer' - unexpected unlock
include/linux/spinlock.h:362:9: warning: context imbalance in 'uart_flush_buffer' - unexpected unlock
Get rid of macros and implement their functionality in place. This will also
help to enable runtime PM in more clean way later.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
fixup 1 (squash)
Replace macros by their functionality in the callers.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
---
drivers/tty/serial/serial_core.c | 81 ++++++++++++++++++++++++----------------
1 file changed, 48 insertions(+), 33 deletions(-)
diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_core.c
index f2303f3..29e5f70 100644
--- a/drivers/tty/serial/serial_core.c
+++ b/drivers/tty/serial/serial_core.c
@@ -77,22 +77,6 @@ static inline void uart_port_deref(struct uart_port *uport)
wake_up(&uport->state->remove_wait);
}
-#define uart_port_lock(state, flags) \
- ({ \
- struct uart_port *__uport = uart_port_ref(state); \
- if (__uport) \
- spin_lock_irqsave(&__uport->lock, flags); \
- __uport; \
- })
-
-#define uart_port_unlock(uport, flags) \
- ({ \
- struct uart_port *__uport = uport; \
- if (__uport) \
- spin_unlock_irqrestore(&__uport->lock, flags); \
- uart_port_deref(__uport); \
- })
-
static inline struct uart_port *uart_port_check(struct uart_state *state)
{
lockdep_assert_held(&state->port.mutex);
@@ -120,10 +104,14 @@ static void uart_stop(struct tty_struct *tty)
struct uart_port *port;
unsigned long flags;
- port = uart_port_lock(state, flags);
- if (port)
- port->ops->stop_tx(port);
- uart_port_unlock(port, flags);
+ port = uart_port_ref(state);
+ if (!port)
+ return;
+
+ spin_lock_irqsave(&port->lock, flags);
+ port->ops->stop_tx(port);
+ spin_unlock_irqrestore(&port->lock, flags);
+ uart_port_deref(port);
}
static void __uart_start(struct tty_struct *tty)
@@ -141,9 +129,14 @@ static void uart_start(struct tty_struct *tty)
struct uart_port *port;
unsigned long flags;
- port = uart_port_lock(state, flags);
+ port = uart_port_ref(state);
+ if (!port)
+ return;
+
+ spin_lock_irqsave(&port->lock, flags);
__uart_start(tty);
- uart_port_unlock(port, flags);
+ spin_unlock_irqrestore(&port->lock, flags);
+ uart_port_deref(port);
}
static void
@@ -526,13 +519,18 @@ static int uart_put_char(struct tty_struct *tty, unsigned char c)
if (!circ->buf)
return 0;
- port = uart_port_lock(state, flags);
- if (port && uart_circ_chars_free(circ) != 0) {
+ port = uart_port_ref(state);
+ if (!port)
+ return 0;
+
+ spin_lock_irqsave(&port->lock, flags);
+ if (uart_circ_chars_free(circ) != 0) {
circ->buf[circ->head] = c;
circ->head = (circ->head + 1) & (UART_XMIT_SIZE - 1);
ret = 1;
}
- uart_port_unlock(port, flags);
+ spin_unlock_irqrestore(&port->lock, flags);
+ uart_port_deref(port);
return ret;
}
@@ -563,7 +561,11 @@ static int uart_write(struct tty_struct *tty,
if (!circ->buf)
return 0;
- port = uart_port_lock(state, flags);
+ port = uart_port_ref(state);
+ if (!port)
+ return 0;
+
+ spin_lock_irqsave(&port->lock, flags);
while (port) {
c = CIRC_SPACE_TO_END(circ->head, circ->tail, UART_XMIT_SIZE);
if (count < c)
@@ -578,7 +580,8 @@ static int uart_write(struct tty_struct *tty,
}
__uart_start(tty);
- uart_port_unlock(port, flags);
+ spin_unlock_irqrestore(&port->lock, flags);
+ uart_port_deref(port);
return ret;
}
@@ -589,9 +592,14 @@ static int uart_write_room(struct tty_struct *tty)
unsigned long flags;
int ret;
- port = uart_port_lock(state, flags);
+ port = uart_port_ref(state);
+ if (!port)
+ return uart_circ_chars_free(&state->xmit);
+
+ spin_lock_irqsave(&port->lock, flags);
ret = uart_circ_chars_free(&state->xmit);
- uart_port_unlock(port, flags);
+ spin_unlock_irqrestore(&port->lock, flags);
+ uart_port_deref(port);
return ret;
}
@@ -602,9 +610,14 @@ static int uart_chars_in_buffer(struct tty_struct *tty)
unsigned long flags;
int ret;
- port = uart_port_lock(state, flags);
+ port = uart_port_ref(state);
+ if (!port)
+ return uart_circ_chars_pending(&state->xmit);
+
+ spin_lock_irqsave(&port->lock, flags);
ret = uart_circ_chars_pending(&state->xmit);
- uart_port_unlock(port, flags);
+ spin_unlock_irqrestore(&port->lock, flags);
+ uart_port_deref(port);
return ret;
}
@@ -625,13 +638,15 @@ static void uart_flush_buffer(struct tty_struct *tty)
pr_debug("uart_flush_buffer(%d) called\n", tty->index);
- port = uart_port_lock(state, flags);
+ port = uart_port_ref(state);
if (!port)
return;
+ spin_lock_irqsave(&port->lock, flags);
uart_circ_clear(&state->xmit);
if (port->ops->flush_buffer)
port->ops->flush_buffer(port);
- uart_port_unlock(port, flags);
+ spin_unlock_irqrestore(&port->lock, flags);
+ uart_port_deref(port);
tty_port_tty_wakeup(&state->port);
}
--
2.9.3
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