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From: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
To: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	linux-serial@vger.kernel.org,
	Dmitry Safonov <0x7f454c46@gmail.com>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Subject: [PATCH v2 4/4] serial: core: Refactor uart_unlock_and_check_sysrq()
Date: Tue, 10 Mar 2020 19:43:37 +0200	[thread overview]
Message-ID: <20200310174337.74109-4-andriy.shevchenko@linux.intel.com> (raw)
In-Reply-To: <20200310174337.74109-1-andriy.shevchenko@linux.intel.com>

Refactor uart_unlock_and_check_sysrq() to:

  - explicitly show that we release a port lock which makes
    static analyzers happy:

CHECK   drivers/tty/serial/serial_core.c
.../serial_core.c:3290:17: warning: context imbalance in 'uart_unlock_and_check_sysrq' - unexpected unlock

  - use flags instead of irqflags to avoid confusion with IRQ flags

  - provide one return point

  - be more compact

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
---
v2: move sysrq_ch declaration inside branch (Dmitry)
 drivers/tty/serial/serial_core.c | 23 ++++++++++-------------
 include/linux/serial_core.h      |  3 +--
 2 files changed, 11 insertions(+), 15 deletions(-)

diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_core.c
index e3f8e641e3a7..203697465afc 100644
--- a/drivers/tty/serial/serial_core.c
+++ b/drivers/tty/serial/serial_core.c
@@ -3286,22 +3286,19 @@ int uart_prepare_sysrq_char(struct uart_port *port, unsigned int ch)
 }
 EXPORT_SYMBOL_GPL(uart_prepare_sysrq_char);
 
-void uart_unlock_and_check_sysrq(struct uart_port *port, unsigned long irqflags)
+void uart_unlock_and_check_sysrq(struct uart_port *port, unsigned long flags)
+__releases(&port->lock)
 {
-	int sysrq_ch;
+	if (port->has_sysrq) {
+		int sysrq_ch = port->sysrq_ch;
 
-	if (!port->has_sysrq) {
-		spin_unlock_irqrestore(&port->lock, irqflags);
-		return;
+		port->sysrq_ch = 0;
+		spin_unlock_irqrestore(&port->lock, flags);
+		if (sysrq_ch)
+			handle_sysrq(sysrq_ch);
+	} else {
+		spin_unlock_irqrestore(&port->lock, flags);
 	}
-
-	sysrq_ch = port->sysrq_ch;
-	port->sysrq_ch = 0;
-
-	spin_unlock_irqrestore(&port->lock, irqflags);
-
-	if (sysrq_ch)
-		handle_sysrq(sysrq_ch);
 }
 EXPORT_SYMBOL_GPL(uart_unlock_and_check_sysrq);
 
diff --git a/include/linux/serial_core.h b/include/linux/serial_core.h
index 7a025042e0bb..cab896c60e35 100644
--- a/include/linux/serial_core.h
+++ b/include/linux/serial_core.h
@@ -447,8 +447,7 @@ extern void uart_insert_char(struct uart_port *port, unsigned int status,
 
 extern int uart_handle_sysrq_char(struct uart_port *port, unsigned int ch);
 extern int uart_prepare_sysrq_char(struct uart_port *port, unsigned int ch);
-extern void uart_unlock_and_check_sysrq(struct uart_port *port,
-					unsigned long irqflags);
+extern void uart_unlock_and_check_sysrq(struct uart_port *port, unsigned long flags);
 extern int uart_handle_break(struct uart_port *port);
 
 /*
-- 
2.25.1


  parent reply	other threads:[~2020-03-10 17:43 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-03-10 17:43 [PATCH v2 1/4] serial: core: Use string length for SysRq magic sequence Andy Shevchenko
2020-03-10 17:43 ` [PATCH v2 2/4] serial: core: Print escaped SysRq Magic sequence if enabled Andy Shevchenko
2020-03-10 17:43 ` [PATCH v2 3/4] serial: core: Use uart_console() helper in SysRq code Andy Shevchenko
2020-03-10 17:43 ` Andy Shevchenko [this message]
2020-03-10 17:45   ` [PATCH v2 4/4] serial: core: Refactor uart_unlock_and_check_sysrq() Dmitry Safonov

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