From 6e94dbc7a4e49a028b81302d755bba1a518f973b Mon Sep 17 00:00:00 2001 From: Jiri Slaby Date: Wed, 5 May 2021 11:19:05 +0200 Subject: tty: cumulate and document tty_struct::flow* members Group the flow flags under a single struct called flow. The new struct contains 'stopped' and 'tco_stopped' bools which used to be bits in a bitfield. The struct also contains the lock protecting them to potentially share the same cache line. Note that commit c545b66c6922b (tty: Serialize tcflow() with other tty flow control changes) added a padding to the original bitfield. It was for the bitfield to occupy a whole 64b word to avoid interferring stores on Alpha (cannot we evaporate this arch with weird implications to C code yet?). But it doesn't work as expected as the padding (tty_struct::unused) is aligned to a 8B boundary too and occupies some bytes from the next word. So make it reliable by: 1) setting __aligned of the struct -- that aligns the start, and 2) making 'unsigned long unused[0]' as the last member of the struct -- pads the end. This is also the perfect time to start the documentation of tty_struct where all this lives. So we start by documenting what these bools actually serve for. And why we do all the alignment dances. Only the few up-to-date information from the Theodore's comment made it into this new Kerneldoc comment. Signed-off-by: Jiri Slaby Cc: "David S. Miller" Cc: Jakub Kicinski Cc: Jonathan Corbet Cc: Arnd Bergmann Cc: Ulf Hansson Cc: Heiko Carstens Cc: Vasily Gorbik Cc: Christian Borntraeger Cc: Shawn Guo Cc: Sascha Hauer Cc: Vineet Gupta Cc: "Maciej W. Rozycki" Link: https://lore.kernel.org/r/20210505091928.22010-13-jslaby@suse.cz Signed-off-by: Greg Kroah-Hartman --- drivers/mmc/core/sdio_uart.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'drivers/mmc') diff --git a/drivers/mmc/core/sdio_uart.c b/drivers/mmc/core/sdio_uart.c index be4067281caa..dbcac2b7f2fe 100644 --- a/drivers/mmc/core/sdio_uart.c +++ b/drivers/mmc/core/sdio_uart.c @@ -439,7 +439,7 @@ static void sdio_uart_transmit_chars(struct sdio_uart_port *port) tty = tty_port_tty_get(&port->port); if (tty == NULL || !kfifo_len(xmit) || - tty->stopped || tty->hw_stopped) { + tty->flow.stopped || tty->hw_stopped) { sdio_uart_stop_tx(port); tty_kref_put(tty); return; -- cgit v1.2.3 From 03b3b1a2405ccd71570cd5ec1fe4abd7bb4891cb Mon Sep 17 00:00:00 2001 From: Jiri Slaby Date: Wed, 5 May 2021 11:19:15 +0200 Subject: tty: make tty_operations::write_room return uint Line disciplines expect a positive value or zero returned from tty->ops->write_room (invoked by tty_write_room). So make this assumption explicit by using unsigned int as a return value. Both of tty->ops->write_room and tty_write_room. Signed-off-by: Jiri Slaby Acked-by: Laurentiu Tudor Acked-by: Alex Elder Acked-by: Max Filippov # xtensa Acked-by: David Sterba Acked-By: Anton Ivanov Acked-by: Geert Uytterhoeven Cc: Richard Henderson Cc: Ivan Kokshaysky Cc: Matt Turner Cc: "James E.J. Bottomley" Cc: Helge Deller Cc: Jeff Dike Cc: Richard Weinberger Cc: Chris Zankel Cc: Arnd Bergmann Cc: Samuel Iglesias Gonsalvez Cc: Jens Taprogge Cc: Karsten Keil Cc: Scott Branden Cc: Ulf Hansson Cc: "David S. Miller" Cc: Jakub Kicinski Cc: Heiko Carstens Cc: Vasily Gorbik Cc: Christian Borntraeger Cc: David Lin Cc: Johan Hovold Cc: Jiri Kosina Cc: Shawn Guo Cc: Sascha Hauer Cc: Oliver Neukum Cc: Felipe Balbi Cc: Mathias Nyman Cc: Marcel Holtmann Cc: Johan Hedberg Cc: Luiz Augusto von Dentz Link: https://lore.kernel.org/r/20210505091928.22010-23-jslaby@suse.cz Signed-off-by: Greg Kroah-Hartman --- drivers/mmc/core/sdio_uart.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'drivers/mmc') diff --git a/drivers/mmc/core/sdio_uart.c b/drivers/mmc/core/sdio_uart.c index dbcac2b7f2fe..c8f4eca7aad4 100644 --- a/drivers/mmc/core/sdio_uart.c +++ b/drivers/mmc/core/sdio_uart.c @@ -797,7 +797,7 @@ static int sdio_uart_write(struct tty_struct *tty, const unsigned char *buf, return ret; } -static int sdio_uart_write_room(struct tty_struct *tty) +static unsigned int sdio_uart_write_room(struct tty_struct *tty) { struct sdio_uart_port *port = tty->driver_data; return FIFO_SIZE - kfifo_len(&port->xmit_fifo); -- cgit v1.2.3 From fff4ef17a9400fcd276b5c3a00ce5793f6c465e6 Mon Sep 17 00:00:00 2001 From: Jiri Slaby Date: Wed, 5 May 2021 11:19:19 +0200 Subject: tty: make tty_operations::chars_in_buffer return uint tty_operations::chars_in_buffer is another hook which is expected to return values >= 0. So make it explicit by the return type too -- use unsigned int. Signed-off-by: Jiri Slaby Acked-By: Anton Ivanov Acked-by: David Sterba Cc: Jeff Dike Cc: Richard Weinberger Cc: Arnd Bergmann Cc: Samuel Iglesias Gonsalvez Cc: Jens Taprogge Cc: Karsten Keil Cc: Ulf Hansson Cc: "David S. Miller" Cc: Jakub Kicinski Cc: Heiko Carstens Cc: Vasily Gorbik Cc: Christian Borntraeger Cc: David Lin Cc: Johan Hovold Cc: Alex Elder Cc: Jiri Kosina Cc: Shawn Guo Cc: Sascha Hauer Cc: Oliver Neukum Cc: Felipe Balbi Cc: Mathias Nyman Cc: Marcel Holtmann Cc: Johan Hedberg Cc: Luiz Augusto von Dentz Link: https://lore.kernel.org/r/20210505091928.22010-27-jslaby@suse.cz Signed-off-by: Greg Kroah-Hartman --- drivers/mmc/core/sdio_uart.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'drivers/mmc') diff --git a/drivers/mmc/core/sdio_uart.c b/drivers/mmc/core/sdio_uart.c index c8f4eca7aad4..c36242b86b1d 100644 --- a/drivers/mmc/core/sdio_uart.c +++ b/drivers/mmc/core/sdio_uart.c @@ -803,7 +803,7 @@ static unsigned int sdio_uart_write_room(struct tty_struct *tty) return FIFO_SIZE - kfifo_len(&port->xmit_fifo); } -static int sdio_uart_chars_in_buffer(struct tty_struct *tty) +static unsigned int sdio_uart_chars_in_buffer(struct tty_struct *tty) { struct sdio_uart_port *port = tty->driver_data; return kfifo_len(&port->xmit_fifo); -- cgit v1.2.3