From 9d898966c4a07e4a5092215b5a2829d0ef02baa2 Mon Sep 17 00:00:00 2001 From: Thadeu Lima de Souza Cascardo Date: Wed, 24 Aug 2011 13:14:22 -0300 Subject: [PATCH] jsm: remove buggy write queue jsm uses a write queue that copies from uart_core circular buffer. This copying however has some bugs, like not wrapping the head counter. Since this write queue is also a circular buffer, the consumer function is ready to use the uart_core circular buffer directly. This buggy copying function was making some bytes be dropped when transmitting to a raw tty, doing something like this. [root@hostname ~]$ cat /dev/ttyn1 > cascardo/dump & [1] 2658 [root@hostname ~]$ cat /proc/tty/drivers > /dev/ttyn0 [root@hostname ~]$ cat /proc/tty/drivers /dev/tty /dev/tty 5 0 system:/dev/tty /dev/console /dev/console 5 1 system:console /dev/ptmx /dev/ptmx 5 2 system /dev/vc/0 /dev/vc/0 4 0 system:vtmaster jsm /dev/ttyn 250 0-31 serial serial /dev/ttyS 4 64-95 serial hvc /dev/hvc 229 0-7 system pty_slave /dev/pts 136 0-1048575 pty:slave pty_master /dev/ptm 128 0-1048575 pty:master unknown /dev/tty 4 1-63 console [root@hostname ~]$ cat cascardo/dump /dev/tty /dev/tty 5 0 system:/dev/tty /dev/console /dev/console 5 1 system:console /dev/ptmx /dev/ptmx 5 2 system /dev/vc/0 /dev/vc/0 4 0 system:vtmaste[root@hostname ~]$ This patch drops the driver write queue entirely, using the circular buffer from uart_core only. Signed-off-by: Thadeu Lima de Souza Cascardo Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/jsm/jsm.h | 7 --- drivers/tty/serial/jsm/jsm_driver.c | 1 - drivers/tty/serial/jsm/jsm_neo.c | 29 ++++----- drivers/tty/serial/jsm/jsm_tty.c | 94 ++++------------------------- 4 files changed, 28 insertions(+), 103 deletions(-) diff --git a/drivers/tty/serial/jsm/jsm.h b/drivers/tty/serial/jsm/jsm.h index cd53bdda77ce..529bec6edaf8 100644 --- a/drivers/tty/serial/jsm/jsm.h +++ b/drivers/tty/serial/jsm/jsm.h @@ -180,10 +180,8 @@ struct jsm_board /* Our Read/Error/Write queue sizes */ #define RQUEUEMASK 0x1FFF /* 8 K - 1 */ #define EQUEUEMASK 0x1FFF /* 8 K - 1 */ -#define WQUEUEMASK 0x0FFF /* 4 K - 1 */ #define RQUEUESIZE (RQUEUEMASK + 1) #define EQUEUESIZE RQUEUESIZE -#define WQUEUESIZE (WQUEUEMASK + 1) /************************************************************************ @@ -223,10 +221,6 @@ struct jsm_channel { u16 ch_e_head; /* Head location of the error queue */ u16 ch_e_tail; /* Tail location of the error queue */ - u8 *ch_wqueue; /* Our write queue buffer - malloc'ed */ - u16 ch_w_head; /* Head location of the write queue */ - u16 ch_w_tail; /* Tail location of the write queue */ - u64 ch_rxcount; /* total of data received so far */ u64 ch_txcount; /* total of data transmitted so far */ @@ -375,7 +369,6 @@ extern int jsm_debug; * Prototypes for non-static functions used in more than one module * *************************************************************************/ -int jsm_tty_write(struct uart_port *port); int jsm_tty_init(struct jsm_board *); int jsm_uart_port_init(struct jsm_board *); int jsm_remove_uart_port(struct jsm_board *); diff --git a/drivers/tty/serial/jsm/jsm_driver.c b/drivers/tty/serial/jsm/jsm_driver.c index 1cc8cf602af8..648b6a3efa32 100644 --- a/drivers/tty/serial/jsm/jsm_driver.c +++ b/drivers/tty/serial/jsm/jsm_driver.c @@ -194,7 +194,6 @@ static void __devexit jsm_remove_one(struct pci_dev *pdev) if (brd->channels[i]) { kfree(brd->channels[i]->ch_rqueue); kfree(brd->channels[i]->ch_equeue); - kfree(brd->channels[i]->ch_wqueue); kfree(brd->channels[i]); } } diff --git a/drivers/tty/serial/jsm/jsm_neo.c b/drivers/tty/serial/jsm/jsm_neo.c index 4538c3e3646e..bd6e84699e11 100644 --- a/drivers/tty/serial/jsm/jsm_neo.c +++ b/drivers/tty/serial/jsm/jsm_neo.c @@ -496,12 +496,15 @@ static void neo_copy_data_from_queue_to_uart(struct jsm_channel *ch) int s; int qlen; u32 len_written = 0; + struct circ_buf *circ; if (!ch) return; + circ = &ch->uart_port.state->xmit; + /* No data to write to the UART */ - if (ch->ch_w_tail == ch->ch_w_head) + if (uart_circ_empty(circ)) return; /* If port is "stopped", don't send any data to the UART */ @@ -517,11 +520,10 @@ static void neo_copy_data_from_queue_to_uart(struct jsm_channel *ch) if (ch->ch_cached_lsr & UART_LSR_THRE) { ch->ch_cached_lsr &= ~(UART_LSR_THRE); - writeb(ch->ch_wqueue[ch->ch_w_tail], &ch->ch_neo_uart->txrx); + writeb(circ->buf[circ->tail], &ch->ch_neo_uart->txrx); jsm_printk(WRITE, INFO, &ch->ch_bd->pci_dev, - "Tx data: %x\n", ch->ch_wqueue[ch->ch_w_head]); - ch->ch_w_tail++; - ch->ch_w_tail &= WQUEUEMASK; + "Tx data: %x\n", circ->buf[circ->head]); + circ->tail = (circ->tail + 1) & (UART_XMIT_SIZE - 1); ch->ch_txcount++; } return; @@ -536,36 +538,36 @@ static void neo_copy_data_from_queue_to_uart(struct jsm_channel *ch) n = UART_17158_TX_FIFOSIZE - ch->ch_t_tlevel; /* cache head and tail of queue */ - head = ch->ch_w_head & WQUEUEMASK; - tail = ch->ch_w_tail & WQUEUEMASK; - qlen = (head - tail) & WQUEUEMASK; + head = circ->head & (UART_XMIT_SIZE - 1); + tail = circ->tail & (UART_XMIT_SIZE - 1); + qlen = uart_circ_chars_pending(circ); /* Find minimum of the FIFO space, versus queue length */ n = min(n, qlen); while (n > 0) { - s = ((head >= tail) ? head : WQUEUESIZE) - tail; + s = ((head >= tail) ? head : UART_XMIT_SIZE) - tail; s = min(s, n); if (s <= 0) break; - memcpy_toio(&ch->ch_neo_uart->txrxburst, ch->ch_wqueue + tail, s); + memcpy_toio(&ch->ch_neo_uart->txrxburst, circ->buf + tail, s); /* Add and flip queue if needed */ - tail = (tail + s) & WQUEUEMASK; + tail = (tail + s) & (UART_XMIT_SIZE - 1); n -= s; ch->ch_txcount += s; len_written += s; } /* Update the final tail */ - ch->ch_w_tail = tail & WQUEUEMASK; + circ->tail = tail & (UART_XMIT_SIZE - 1); if (len_written >= ch->ch_t_tlevel) ch->ch_flags &= ~(CH_TX_FIFO_EMPTY | CH_TX_FIFO_LWM); - if (!jsm_tty_write(&ch->uart_port)) + if (uart_circ_empty(circ)) uart_write_wakeup(&ch->uart_port); } @@ -946,7 +948,6 @@ static void neo_param(struct jsm_channel *ch) if ((ch->ch_c_cflag & (CBAUD)) == 0) { ch->ch_r_head = ch->ch_r_tail = 0; ch->ch_e_head = ch->ch_e_tail = 0; - ch->ch_w_head = ch->ch_w_tail = 0; neo_flush_uart_write(ch); neo_flush_uart_read(ch); diff --git a/drivers/tty/serial/jsm/jsm_tty.c b/drivers/tty/serial/jsm/jsm_tty.c index 7a4a914ecff0..434bd881fcae 100644 --- a/drivers/tty/serial/jsm/jsm_tty.c +++ b/drivers/tty/serial/jsm/jsm_tty.c @@ -118,6 +118,19 @@ static void jsm_tty_set_mctrl(struct uart_port *port, unsigned int mctrl) udelay(10); } +/* + * jsm_tty_write() + * + * Take data from the user or kernel and send it out to the FEP. + * In here exists all the Transparent Print magic as well. + */ +static void jsm_tty_write(struct uart_port *port) +{ + struct jsm_channel *channel; + channel = container_of(port, struct jsm_channel, uart_port); + channel->ch_bd->bd_ops->copy_data_from_queue_to_uart(channel); +} + static void jsm_tty_start_tx(struct uart_port *port) { struct jsm_channel *channel = (struct jsm_channel *)port; @@ -216,14 +229,6 @@ static int jsm_tty_open(struct uart_port *port) return -ENOMEM; } } - if (!channel->ch_wqueue) { - channel->ch_wqueue = kzalloc(WQUEUESIZE, GFP_KERNEL); - if (!channel->ch_wqueue) { - jsm_printk(INIT, ERR, &channel->ch_bd->pci_dev, - "unable to allocate write queue buf"); - return -ENOMEM; - } - } channel->ch_flags &= ~(CH_OPENING); /* @@ -237,7 +242,6 @@ static int jsm_tty_open(struct uart_port *port) */ channel->ch_r_head = channel->ch_r_tail = 0; channel->ch_e_head = channel->ch_e_tail = 0; - channel->ch_w_head = channel->ch_w_tail = 0; brd->bd_ops->flush_uart_write(channel); brd->bd_ops->flush_uart_read(channel); @@ -836,75 +840,3 @@ void jsm_check_queue_flow_control(struct jsm_channel *ch) } } } - -/* - * jsm_tty_write() - * - * Take data from the user or kernel and send it out to the FEP. - * In here exists all the Transparent Print magic as well. - */ -int jsm_tty_write(struct uart_port *port) -{ - int bufcount; - int data_count = 0,data_count1 =0; - u16 head; - u16 tail; - u16 tmask; - u32 remain; - int temp_tail = port->state->xmit.tail; - struct jsm_channel *channel = (struct jsm_channel *)port; - - tmask = WQUEUEMASK; - head = (channel->ch_w_head) & tmask; - tail = (channel->ch_w_tail) & tmask; - - if ((bufcount = tail - head - 1) < 0) - bufcount += WQUEUESIZE; - - bufcount = min(bufcount, 56); - remain = WQUEUESIZE - head; - - data_count = 0; - if (bufcount >= remain) { - bufcount -= remain; - while ((port->state->xmit.head != temp_tail) && - (data_count < remain)) { - channel->ch_wqueue[head++] = - port->state->xmit.buf[temp_tail]; - - temp_tail++; - temp_tail &= (UART_XMIT_SIZE - 1); - data_count++; - } - if (data_count == remain) head = 0; - } - - data_count1 = 0; - if (bufcount > 0) { - remain = bufcount; - while ((port->state->xmit.head != temp_tail) && - (data_count1 < remain)) { - channel->ch_wqueue[head++] = - port->state->xmit.buf[temp_tail]; - - temp_tail++; - temp_tail &= (UART_XMIT_SIZE - 1); - data_count1++; - - } - } - - port->state->xmit.tail = temp_tail; - - data_count += data_count1; - if (data_count) { - head &= tmask; - channel->ch_w_head = head; - } - - if (data_count) { - channel->ch_bd->bd_ops->copy_data_from_queue_to_uart(channel); - } - - return data_count; -}