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Message-ID: <20250425111315.1036184-5-jirislaby@kernel.org>
Date: Fri, 25 Apr 2025 13:13:13 +0200
From: "Jiri Slaby (SUSE)" <jirislaby@...nel.org>
To: gregkh@...uxfoundation.org
Cc: linux-serial@...r.kernel.org,
linux-kernel@...r.kernel.org,
"Jiri Slaby (SUSE)" <jirislaby@...nel.org>
Subject: [PATCH 4/6] serial: rename local uart_port_lock() -> uart_port_ref_lock()
uart_port_lock() and uart_port_unlock() are (at the same time) defined
as:
* functions in include/linux/serial_core.h
* macros in drivers/tty/serial/serial_core.c
The former are sane uart port lock wrappers.
The latter _lock() does something completely different: it inspects
a uart_state, obtains a uart_port from it, and increases its reference
count. And if that all succeeded, the port is locked too.
Similarly, the _unlock() counterpart first unlocks and then decrements
the refcount too.
This state is REALLY CONFUSING.
So rename the latter (local .c macros):
* uart_port_lock() -> uart_port_ref_lock(), and
* uart_port_unlock() -> uart_port_unlock_deref().
Now, the forbidden while-at-it part: convert from a macro to an inline
-- do it here as the passed 'flags' have to be pointer to ulong now. So
we avoid doubled changes on identical LOCs.
Signed-off-by: Jiri Slaby (SUSE) <jirislaby@...nel.org>
---
drivers/tty/serial/serial_core.c | 75 ++++++++++++++++----------------
1 file changed, 38 insertions(+), 37 deletions(-)
diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_core.c
index 5bc145643385..52e764be42c4 100644
--- a/drivers/tty/serial/serial_core.c
+++ b/drivers/tty/serial/serial_core.c
@@ -75,22 +75,23 @@ 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) \
- uart_port_lock_irqsave(__uport, &flags); \
- __uport; \
- })
-
-#define uart_port_unlock(uport, flags) \
- ({ \
- struct uart_port *__uport = uport; \
- if (__uport) { \
- uart_port_unlock_irqrestore(__uport, flags); \
- uart_port_deref(__uport); \
- } \
- })
+static inline struct uart_port *uart_port_ref_lock(struct uart_state *state, unsigned long *flags)
+{
+ struct uart_port *uport = uart_port_ref(state);
+
+ if (uport)
+ uart_port_lock_irqsave(uport, flags);
+
+ return uport;
+}
+
+static inline void uart_port_unlock_deref(struct uart_port *uport, unsigned long flags)
+{
+ if (uport) {
+ uart_port_unlock_irqrestore(uport, flags);
+ uart_port_deref(uport);
+ }
+}
static inline struct uart_port *uart_port_check(struct uart_state *state)
{
@@ -127,10 +128,10 @@ static void uart_stop(struct tty_struct *tty)
struct uart_port *port;
unsigned long flags;
- port = uart_port_lock(state, flags);
+ port = uart_port_ref_lock(state, &flags);
if (port)
port->ops->stop_tx(port);
- uart_port_unlock(port, flags);
+ uart_port_unlock_deref(port, flags);
}
static void __uart_start(struct uart_state *state)
@@ -168,9 +169,9 @@ 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_lock(state, &flags);
__uart_start(state);
- uart_port_unlock(port, flags);
+ uart_port_unlock_deref(port, flags);
}
static void
@@ -258,14 +259,14 @@ static int uart_alloc_xmit_buf(struct tty_port *port)
if (!page)
return -ENOMEM;
- uport = uart_port_lock(state, flags);
+ uport = uart_port_ref_lock(state, &flags);
if (!state->port.xmit_buf) {
state->port.xmit_buf = (unsigned char *)page;
kfifo_init(&state->port.xmit_fifo, state->port.xmit_buf,
PAGE_SIZE);
- uart_port_unlock(uport, flags);
+ uart_port_unlock_deref(uport, flags);
} else {
- uart_port_unlock(uport, flags);
+ uart_port_unlock_deref(uport, flags);
/*
* Do not free() the page under the port lock, see
* uart_free_xmit_buf().
@@ -289,11 +290,11 @@ static void uart_free_xmit_buf(struct tty_port *port)
* console driver may need to allocate/free a debug object, which
* can end up in printk() recursion.
*/
- uport = uart_port_lock(state, flags);
+ uport = uart_port_ref_lock(state, &flags);
xmit_buf = port->xmit_buf;
port->xmit_buf = NULL;
INIT_KFIFO(port->xmit_fifo);
- uart_port_unlock(uport, flags);
+ uart_port_unlock_deref(uport, flags);
free_page((unsigned long)xmit_buf);
}
@@ -592,15 +593,15 @@ static int uart_put_char(struct tty_struct *tty, u8 c)
unsigned long flags;
int ret = 0;
- port = uart_port_lock(state, flags);
+ port = uart_port_ref_lock(state, &flags);
if (!state->port.xmit_buf) {
- uart_port_unlock(port, flags);
+ uart_port_unlock_deref(port, flags);
return 0;
}
if (port)
ret = kfifo_put(&state->port.xmit_fifo, c);
- uart_port_unlock(port, flags);
+ uart_port_unlock_deref(port, flags);
return ret;
}
@@ -623,9 +624,9 @@ static ssize_t uart_write(struct tty_struct *tty, const u8 *buf, size_t count)
if (WARN_ON(!state))
return -EL3HLT;
- port = uart_port_lock(state, flags);
+ port = uart_port_ref_lock(state, &flags);
if (!state->port.xmit_buf) {
- uart_port_unlock(port, flags);
+ uart_port_unlock_deref(port, flags);
return 0;
}
@@ -633,7 +634,7 @@ static ssize_t uart_write(struct tty_struct *tty, const u8 *buf, size_t count)
ret = kfifo_in(&state->port.xmit_fifo, buf, count);
__uart_start(state);
- uart_port_unlock(port, flags);
+ uart_port_unlock_deref(port, flags);
return ret;
}
@@ -644,9 +645,9 @@ static unsigned int uart_write_room(struct tty_struct *tty)
unsigned long flags;
unsigned int ret;
- port = uart_port_lock(state, flags);
+ port = uart_port_ref_lock(state, &flags);
ret = kfifo_avail(&state->port.xmit_fifo);
- uart_port_unlock(port, flags);
+ uart_port_unlock_deref(port, flags);
return ret;
}
@@ -657,9 +658,9 @@ static unsigned int uart_chars_in_buffer(struct tty_struct *tty)
unsigned long flags;
unsigned int ret;
- port = uart_port_lock(state, flags);
+ port = uart_port_ref_lock(state, &flags);
ret = kfifo_len(&state->port.xmit_fifo);
- uart_port_unlock(port, flags);
+ uart_port_unlock_deref(port, flags);
return ret;
}
@@ -678,13 +679,13 @@ 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_lock(state, &flags);
if (!port)
return;
kfifo_reset(&state->port.xmit_fifo);
if (port->ops->flush_buffer)
port->ops->flush_buffer(port);
- uart_port_unlock(port, flags);
+ uart_port_unlock_deref(port, flags);
tty_port_tty_wakeup(&state->port);
}
--
2.49.0
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