From: Alan Cox Date: Thu, 5 Nov 2009 13:28:29 +0000 (+0000) Subject: sdio_uart: refcount the tty objects X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=530646f4695b396aeeec2ca912dcc3a9c95e0f52;p=GitHub%2FLineageOS%2FG12%2Fandroid_kernel_amlogic_linux-4.9.git sdio_uart: refcount the tty objects The tty can go away underneath us, so we must refcount it. Do the naïve implementation initially. We will worry about startup shortly. Signed-off-by: Alan Cox Signed-off-by: Greg Kroah-Hartman --- diff --git a/drivers/mmc/card/sdio_uart.c b/drivers/mmc/card/sdio_uart.c index 671fe5efabf3..86ad54341128 100644 --- a/drivers/mmc/card/sdio_uart.c +++ b/drivers/mmc/card/sdio_uart.c @@ -172,8 +172,13 @@ static void sdio_uart_port_remove(struct sdio_uart_port *port) sdio_claim_host(func); port->func = NULL; mutex_unlock(&port->func_lock); - if (port->opened) - tty_hangup(port->port.tty); + if (port->opened) { + struct tty_struct *tty = tty_port_tty_get(&port->port); + /* tty_hangup is async so is this safe as is ?? */ + if (tty) + tty_hangup(tty); + tty_kref_put(tty); + } mutex_unlock(&port->open_lock); sdio_release_irq(func); sdio_disable_func(func); @@ -392,7 +397,7 @@ static void sdio_uart_stop_rx(struct sdio_uart_port *port) static void sdio_uart_receive_chars(struct sdio_uart_port *port, unsigned int *status) { - struct tty_struct *tty = port->port.tty; + struct tty_struct *tty = tty_port_tty_get(&port->port); unsigned int ch, flag; int max_count = 256; @@ -429,25 +434,30 @@ static void sdio_uart_receive_chars(struct sdio_uart_port *port, } if ((*status & port->ignore_status_mask & ~UART_LSR_OE) == 0) - tty_insert_flip_char(tty, ch, flag); + if (tty) + tty_insert_flip_char(tty, ch, flag); /* * Overrun is special. Since it's reported immediately, * it doesn't affect the current character. */ if (*status & ~port->ignore_status_mask & UART_LSR_OE) - tty_insert_flip_char(tty, 0, TTY_OVERRUN); + if (tty) + tty_insert_flip_char(tty, 0, TTY_OVERRUN); *status = sdio_in(port, UART_LSR); } while ((*status & UART_LSR_DR) && (max_count-- > 0)); - tty_flip_buffer_push(tty); + if (tty) { + tty_flip_buffer_push(tty); + tty_kref_put(tty); + } } static void sdio_uart_transmit_chars(struct sdio_uart_port *port) { struct circ_buf *xmit = &port->xmit; int count; - struct tty_struct *tty = port->port.tty; + struct tty_struct *tty; if (port->x_char) { sdio_out(port, UART_TX, port->x_char); @@ -455,8 +465,12 @@ static void sdio_uart_transmit_chars(struct sdio_uart_port *port) port->x_char = 0; return; } - if (circ_empty(xmit) || tty->stopped || tty->hw_stopped) { + + tty = tty_port_tty_get(&port->port); + + if (tty == NULL || circ_empty(xmit) || tty->stopped || tty->hw_stopped) { sdio_uart_stop_tx(port); + tty_kref_put(tty); return; } @@ -474,12 +488,13 @@ static void sdio_uart_transmit_chars(struct sdio_uart_port *port) if (circ_empty(xmit)) sdio_uart_stop_tx(port); + tty_kref_put(tty); } static void sdio_uart_check_modem_status(struct sdio_uart_port *port) { int status; - struct tty_struct *tty = port->port.tty; + struct tty_struct *tty; status = sdio_in(port, UART_MSR); @@ -494,7 +509,8 @@ static void sdio_uart_check_modem_status(struct sdio_uart_port *port) port->icount.dcd++; if (status & UART_MSR_DCTS) { port->icount.cts++; - if (tty->termios->c_cflag & CRTSCTS) { + tty = tty_port_tty_get(&port->port); + if (tty && (tty->termios->c_cflag & CRTSCTS)) { int cts = (status & UART_MSR_CTS); if (tty->hw_stopped) { if (cts) { @@ -509,6 +525,7 @@ static void sdio_uart_check_modem_status(struct sdio_uart_port *port) } } } + tty_kref_put(tty); } } @@ -548,8 +565,10 @@ static void sdio_uart_irq(struct sdio_func *func) static int sdio_uart_startup(struct sdio_uart_port *port) { unsigned long page; - int ret; - struct tty_struct *tty = port->port.tty; + int ret = -ENOMEM; + struct tty_struct *tty = tty_port_tty_get(&port->port); + + /* FIXME: What if it is NULL ?? */ /* * Set the TTY IO error marker - we will only clear this @@ -560,7 +579,7 @@ static int sdio_uart_startup(struct sdio_uart_port *port) /* Initialise and allocate the transmit buffer. */ page = __get_free_page(GFP_KERNEL); if (!page) - return -ENOMEM; + goto err0; port->xmit.buf = (unsigned char *)page; circ_clear(&port->xmit); @@ -614,6 +633,7 @@ static int sdio_uart_startup(struct sdio_uart_port *port) sdio_uart_irq(port->func); sdio_uart_release_func(port); + tty_kref_put(tty); return 0; err3: @@ -622,12 +642,15 @@ err2: sdio_uart_release_func(port); err1: free_page((unsigned long)port->xmit.buf); +err0: + tty_kref_put(tty); return ret; } static void sdio_uart_shutdown(struct sdio_uart_port *port) { int ret; + struct tty_struct *tty; ret = sdio_uart_claim_func(port); if (ret) @@ -637,9 +660,11 @@ static void sdio_uart_shutdown(struct sdio_uart_port *port) /* TODO: wait here for TX FIFO to drain */ + tty = tty_port_tty_get(&port->port); /* Turn off DTR and RTS early. */ - if (port->port.tty->termios->c_cflag & HUPCL) + if (tty && (tty->termios->c_cflag & HUPCL)) sdio_uart_clear_mctrl(port, TIOCM_DTR | TIOCM_RTS); + tty_kref_put(tty); /* Disable interrupts from this port */ sdio_release_irq(port->func); @@ -688,11 +713,11 @@ static int sdio_uart_open(struct tty_struct *tty, struct file *filp) if (!port->opened) { tty->driver_data = port; - port->port.tty = tty; + tty_port_tty_set(&port->port, tty); ret = sdio_uart_startup(port); if (ret) { tty->driver_data = NULL; - port->port.tty = NULL; + tty_port_tty_set(&port->port, NULL); mutex_unlock(&port->open_lock); sdio_uart_port_put(port); return ret; @@ -727,7 +752,7 @@ static void sdio_uart_close(struct tty_struct *tty, struct file * filp) tty->closing = 1; sdio_uart_shutdown(port); tty_ldisc_flush(tty); - port->port.tty = NULL; + tty_port_tty_set(&port->port, NULL); tty->driver_data = NULL; tty->closing = 0; }