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[85.228.174.190]) by smtp.gmail.com with ESMTPSA id t12sm552600ljj.139.2020.06.02.07.01.25 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 02 Jun 2020 07:01:26 -0700 (PDT) Received: from johan by xi.terra with local (Exim 4.93.0.4) (envelope-from ) id 1jg7Ti-0000y4-Tg; Tue, 02 Jun 2020 16:01:18 +0200 From: Johan Hovold To: Greg Kroah-Hartman Cc: Jiri Slaby , Dmitry Safonov <0x7f454c46@gmail.com>, Andy Shevchenko , linux-serial@vger.kernel.org, linux-kernel@vger.kernel.org, Johan Hovold Subject: [PATCH 3/4] serial: core: fix sysrq overhead regression Date: Tue, 2 Jun 2020 16:00:57 +0200 Message-Id: <20200602140058.3656-4-johan@kernel.org> X-Mailer: git-send-email 2.26.2 In-Reply-To: <20200602140058.3656-1-johan@kernel.org> References: <20200602140058.3656-1-johan@kernel.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-serial-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-serial@vger.kernel.org Commit 8e20fc391711 ("serial_core: Move sysrq functions from header file") converted the inline sysrq helpers to exported functions which are now called for every received character and break signal also on systems without CONFIG_MAGIC_SYSRQ_SERIAL instead of being optimised away by the compiler. Inlining these helpers again also avoids the function call overhead when CONFIG_MAGIC_SYSRQ_SERIAL is enabled. Fixes: 8e20fc391711 ("serial_core: Move sysrq functions from header file") Cc: Dmitry Safonov <0x7f454c46@gmail.com> Signed-off-by: Johan Hovold --- drivers/tty/serial/serial_core.c | 80 +----------------------------- include/linux/serial_core.h | 85 ++++++++++++++++++++++++++++++-- 2 files changed, 84 insertions(+), 81 deletions(-) diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_core.c index f6cf9cc4ce69..a714402dcf4e 100644 --- a/drivers/tty/serial/serial_core.c +++ b/drivers/tty/serial/serial_core.c @@ -41,8 +41,6 @@ static struct lock_class_key port_lock_key; #define HIGH_BITS_OFFSET ((sizeof(long)-sizeof(int))*8) -#define SYSRQ_TIMEOUT (HZ * 5) - static void uart_change_speed(struct tty_struct *tty, struct uart_state *state, struct ktermios *old_termios); static void uart_wait_until_sent(struct tty_struct *tty, int timeout); @@ -3163,7 +3161,7 @@ static DECLARE_WORK(sysrq_enable_work, uart_sysrq_on); * Returns false if @ch is out of enabling sequence and should be * handled some other way, true if @ch was consumed. */ -static bool uart_try_toggle_sysrq(struct uart_port *port, unsigned int ch) +bool uart_try_toggle_sysrq(struct uart_port *port, unsigned int ch) { int sysrq_toggle_seq_len = strlen(sysrq_toggle_seq); @@ -3186,83 +3184,9 @@ static bool uart_try_toggle_sysrq(struct uart_port *port, unsigned int ch) port->sysrq = 0; return true; } -#else -static inline bool uart_try_toggle_sysrq(struct uart_port *port, unsigned int ch) -{ - return false; -} +EXPORT_SYMBOL_GPL(uart_try_toggle_sysrq); #endif -int uart_handle_sysrq_char(struct uart_port *port, unsigned int ch) -{ - if (!IS_ENABLED(CONFIG_MAGIC_SYSRQ_SERIAL)) - return 0; - - if (!port->has_sysrq || !port->sysrq) - return 0; - - if (ch && time_before(jiffies, port->sysrq)) { - if (sysrq_mask()) { - handle_sysrq(ch); - port->sysrq = 0; - return 1; - } - if (uart_try_toggle_sysrq(port, ch)) - return 1; - } - port->sysrq = 0; - - return 0; -} -EXPORT_SYMBOL_GPL(uart_handle_sysrq_char); - -int uart_prepare_sysrq_char(struct uart_port *port, unsigned int ch) -{ - if (!IS_ENABLED(CONFIG_MAGIC_SYSRQ_SERIAL)) - return 0; - - if (!port->has_sysrq || !port->sysrq) - return 0; - - if (ch && time_before(jiffies, port->sysrq)) { - if (sysrq_mask()) { - port->sysrq_ch = ch; - port->sysrq = 0; - return 1; - } - if (uart_try_toggle_sysrq(port, ch)) - return 1; - } - port->sysrq = 0; - - return 0; -} -EXPORT_SYMBOL_GPL(uart_prepare_sysrq_char); - -/* - * We do the SysRQ and SAK checking like this... - */ -int uart_handle_break(struct uart_port *port) -{ - struct uart_state *state = port->state; - - if (port->handle_break) - port->handle_break(port); - - if (port->has_sysrq && uart_console(port)) { - if (!port->sysrq) { - port->sysrq = jiffies + SYSRQ_TIMEOUT; - return 1; - } - port->sysrq = 0; - } - - if (port->flags & UPF_SAK) - do_SAK(state->port.tty); - return 0; -} -EXPORT_SYMBOL_GPL(uart_handle_break); - EXPORT_SYMBOL(uart_write_wakeup); EXPORT_SYMBOL(uart_register_driver); EXPORT_SYMBOL(uart_unregister_driver); diff --git a/include/linux/serial_core.h b/include/linux/serial_core.h index 858c5dd926ad..a8a213b71553 100644 --- a/include/linux/serial_core.h +++ b/include/linux/serial_core.h @@ -460,8 +460,49 @@ extern void uart_handle_cts_change(struct uart_port *uport, extern void uart_insert_char(struct uart_port *port, unsigned int status, unsigned int overrun, unsigned int ch, unsigned int flag); -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); +#ifdef CONFIG_MAGIC_SYSRQ_SERIAL + +#define SYSRQ_TIMEOUT (HZ * 5) + +bool uart_try_toggle_sysrq(struct uart_port *port, unsigned int ch); + +static inline int uart_handle_sysrq_char(struct uart_port *port, unsigned int ch) +{ + if (!port->has_sysrq || !port->sysrq) + return 0; + + if (ch && time_before(jiffies, port->sysrq)) { + if (sysrq_mask()) { + handle_sysrq(ch); + port->sysrq = 0; + return 1; + } + if (uart_try_toggle_sysrq(port, ch)) + return 1; + } + port->sysrq = 0; + + return 0; +} + +static inline int uart_prepare_sysrq_char(struct uart_port *port, unsigned int ch) +{ + if (!port->has_sysrq || !port->sysrq) + return 0; + + if (ch && time_before(jiffies, port->sysrq)) { + if (sysrq_mask()) { + port->sysrq_ch = ch; + port->sysrq = 0; + return 1; + } + if (uart_try_toggle_sysrq(port, ch)) + return 1; + } + port->sysrq = 0; + + return 0; +} static inline void uart_unlock_and_check_sysrq(struct uart_port *port, unsigned long irqflags) { @@ -480,8 +521,46 @@ static inline void uart_unlock_and_check_sysrq(struct uart_port *port, unsigned if (sysrq_ch) handle_sysrq(sysrq_ch); } +#else /* CONFIG_MAGIC_SYSRQ_SERIAL */ +static inline int uart_handle_sysrq_char(struct uart_port *port, unsigned int ch) +{ + return 0; +} -extern int uart_handle_break(struct uart_port *port); +static inline int uart_prepare_sysrq_char(struct uart_port *port, unsigned int ch) +{ + return 0; +} + +static inline void uart_unlock_and_check_sysrq(struct uart_port *port, unsigned long irqflags) +{ + spin_unlock_irqrestore(&port->lock, irqflags); +} +#endif /* CONFIG_MAGIC_SYSRQ_SERIAL */ + +/* + * We do the SysRQ and SAK checking like this... + */ +static inline int uart_handle_break(struct uart_port *port) +{ + struct uart_state *state = port->state; + + if (port->handle_break) + port->handle_break(port); + +#ifdef CONFIG_MAGIC_SYSRQ_SERIAL + if (port->has_sysrq && uart_console(port)) { + if (!port->sysrq) { + port->sysrq = jiffies + SYSRQ_TIMEOUT; + return 1; + } + port->sysrq = 0; + } +#endif + if (port->flags & UPF_SAK) + do_SAK(state->port.tty); + return 0; +} /* * UART_ENABLE_MS - determine if port should enable modem status irqs -- 2.26.2