cyclades: push down tty_port_tty_get

Now, the tty is not needed at all places in the ISR. So we can just
request in on demand when really needed.

This cleans TX and RX paths a bit as the indentation level can be
dropped by two now when we also invert the char_count if condition.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 115 insertions, 122 deletions

diff --git a/drivers/tty/cyclades.c b/drivers/tty/cyclades.c
index 42a329b8af9f..345bd0e0884e 100644
--- a/drivers/tty/cyclades.c
+++ b/drivers/tty/cyclades.c
@@ -917,7 +917,7 @@ cyz_issue_cmd(struct cyclades_card *cinfo,
         return 0;
 }                               /* cyz_issue_cmd */
 
-static void cyz_handle_rx(struct cyclades_port *info, struct tty_struct *tty)
+static void cyz_handle_rx(struct cyclades_port *info)
 {
         struct BUF_CTRL __iomem *buf_ctrl = info->u.cyz.buf_ctrl;
         struct cyclades_card *cinfo = info->card;
@@ -940,80 +940,77 @@ static void cyz_handle_rx(struct cyclades_port *info, struct tty_struct *tty)
         else
                 char_count = rx_put - rx_get + rx_bufsize;
 
-        if (char_count) {
+        if (!char_count)
+                return;
+
 #ifdef CY_ENABLE_MONITORING
-                info->mon.int_count++;
-                info->mon.char_count += char_count;
-                if (char_count > info->mon.char_max)
-                        info->mon.char_max = char_count;
-                info->mon.char_last = char_count;
+        info->mon.int_count++;
+        info->mon.char_count += char_count;
+        if (char_count > info->mon.char_max)
+                info->mon.char_max = char_count;
+        info->mon.char_last = char_count;
 #endif
-                if (tty == NULL) {
-                        /* flush received characters */
-                        new_rx_get = (new_rx_get + char_count) &
-                                        (rx_bufsize - 1);
-                        info->rflush_count++;
-                } else {
+
 #ifdef BLOCKMOVE
-                /* we'd like to use memcpy(t, f, n) and memset(s, c, count)
-                   for performance, but because of buffer boundaries, there
-                   may be several steps to the operation */
-                        while (1) {
-                                len = tty_prepare_flip_string(port, &buf,
-                                                char_count);
-                                if (!len)
-                                        break;
+        /* we'd like to use memcpy(t, f, n) and memset(s, c, count)
+           for performance, but because of buffer boundaries, there
+           may be several steps to the operation */
+        while (1) {
+                len = tty_prepare_flip_string(port, &buf,
+                                char_count);
+                if (!len)
+                        break;
 
-                                len = min_t(unsigned int, min(len, char_count),
-                                                rx_bufsize - new_rx_get);
+                len = min_t(unsigned int, min(len, char_count),
+                                rx_bufsize - new_rx_get);
 
-                                memcpy_fromio(buf, cinfo->base_addr +
-                                                rx_bufaddr + new_rx_get, len);
+                memcpy_fromio(buf, cinfo->base_addr +
+                                rx_bufaddr + new_rx_get, len);
 
-                                new_rx_get = (new_rx_get + len) &
-                                                (rx_bufsize - 1);
-                                char_count -= len;
-                                info->icount.rx += len;
-                                info->idle_stats.recv_bytes += len;
-                        }
+                new_rx_get = (new_rx_get + len) &
+                                (rx_bufsize - 1);
+                char_count -= len;
+                info->icount.rx += len;
+                info->idle_stats.recv_bytes += len;
+        }
 #else
-                        len = tty_buffer_request_room(port, char_count);
-                        while (len--) {
-                                data = readb(cinfo->base_addr + rx_bufaddr +
-                                                new_rx_get);
-                                new_rx_get = (new_rx_get + 1) &
-                                                        (rx_bufsize - 1);
-                                tty_insert_flip_char(port, data, TTY_NORMAL);
-                                info->idle_stats.recv_bytes++;
-                                info->icount.rx++;
-                        }
+        len = tty_buffer_request_room(port, char_count);
+        while (len--) {
+                data = readb(cinfo->base_addr + rx_bufaddr +
+                                new_rx_get);
+                new_rx_get = (new_rx_get + 1) &
+                                        (rx_bufsize - 1);
+                tty_insert_flip_char(port, data, TTY_NORMAL);
+                info->idle_stats.recv_bytes++;
+                info->icount.rx++;
+        }
 #endif
 #ifdef CONFIG_CYZ_INTR
-                /* Recalculate the number of chars in the RX buffer and issue
-                   a cmd in case it's higher than the RX high water mark */
-                        rx_put = readl(&buf_ctrl->rx_put);
-                        if (rx_put >= rx_get)
-                                char_count = rx_put - rx_get;
-                        else
-                                char_count = rx_put - rx_get + rx_bufsize;
-                        if (char_count >= readl(&buf_ctrl->rx_threshold) &&
-                                        !timer_pending(&cyz_rx_full_timer[
-                                                        info->line]))
-                                mod_timer(&cyz_rx_full_timer[info->line],
-                                                jiffies + 1);
+        /* Recalculate the number of chars in the RX buffer and issue
+           a cmd in case it's higher than the RX high water mark */
+        rx_put = readl(&buf_ctrl->rx_put);
+        if (rx_put >= rx_get)
+                char_count = rx_put - rx_get;
+        else
+                char_count = rx_put - rx_get + rx_bufsize;
+        if (char_count >= readl(&buf_ctrl->rx_threshold) &&
+                        !timer_pending(&cyz_rx_full_timer[
+                                        info->line]))
+                mod_timer(&cyz_rx_full_timer[info->line],
+                                jiffies + 1);
 #endif
-                        info->idle_stats.recv_idle = jiffies;
-                        tty_schedule_flip(&info->port);
-                }
-                /* Update rx_get */
-                cy_writel(&buf_ctrl->rx_get, new_rx_get);
-        }
+        info->idle_stats.recv_idle = jiffies;
+        tty_schedule_flip(&info->port);
+
+        /* Update rx_get */
+        cy_writel(&buf_ctrl->rx_get, new_rx_get);
 }
 
-static void cyz_handle_tx(struct cyclades_port *info, struct tty_struct *tty)
+static void cyz_handle_tx(struct cyclades_port *info)
 {
         struct BUF_CTRL __iomem *buf_ctrl = info->u.cyz.buf_ctrl;
         struct cyclades_card *cinfo = info->card;
+        struct tty_struct *tty;
         u8 data;
         unsigned int char_count;
 #ifdef BLOCKMOVE
@@ -1033,63 +1030,63 @@ static void cyz_handle_tx(struct cyclades_port *info, struct tty_struct *tty)
         else
                 char_count = tx_get - tx_put - 1;
 
-        if (char_count) {
-
-                if (tty == NULL)
-                        goto ztxdone;
+        if (!char_count)
+                return;
+                
+        tty = tty_port_tty_get(&info->port);
+        if (tty == NULL)
+                goto ztxdone;
 
-                if (info->x_char) {     /* send special char */
-                        data = info->x_char;
+        if (info->x_char) {     /* send special char */
+                data = info->x_char;
 
-                        cy_writeb(cinfo->base_addr + tx_bufaddr + tx_put, data);
-                        tx_put = (tx_put + 1) & (tx_bufsize - 1);
-                        info->x_char = 0;
-                        char_count--;
-                        info->icount.tx++;
-                }
+                cy_writeb(cinfo->base_addr + tx_bufaddr + tx_put, data);
+                tx_put = (tx_put + 1) & (tx_bufsize - 1);
+                info->x_char = 0;
+                char_count--;
+                info->icount.tx++;
+        }
 #ifdef BLOCKMOVE
-                while (0 < (small_count = min_t(unsigned int,
-                                tx_bufsize - tx_put, min_t(unsigned int,
-                                        (SERIAL_XMIT_SIZE - info->xmit_tail),
-                                        min_t(unsigned int, info->xmit_cnt,
-                                                char_count))))) {
-
-                        memcpy_toio((char *)(cinfo->base_addr + tx_bufaddr +
-                                        tx_put),
-                                        &info->port.xmit_buf[info->xmit_tail],
-                                        small_count);
-
-                        tx_put = (tx_put + small_count) & (tx_bufsize - 1);
-                        char_count -= small_count;
-                        info->icount.tx += small_count;
-                        info->xmit_cnt -= small_count;
-                        info->xmit_tail = (info->xmit_tail + small_count) &
-                                        (SERIAL_XMIT_SIZE - 1);
-                }
+        while (0 < (small_count = min_t(unsigned int,
+                        tx_bufsize - tx_put, min_t(unsigned int,
+                                (SERIAL_XMIT_SIZE - info->xmit_tail),
+                                min_t(unsigned int, info->xmit_cnt,
+                                        char_count))))) {
+
+                memcpy_toio((char *)(cinfo->base_addr + tx_bufaddr + tx_put),
+                                &info->port.xmit_buf[info->xmit_tail],
+                                small_count);
+
+                tx_put = (tx_put + small_count) & (tx_bufsize - 1);
+                char_count -= small_count;
+                info->icount.tx += small_count;
+                info->xmit_cnt -= small_count;
+                info->xmit_tail = (info->xmit_tail + small_count) &
+                                (SERIAL_XMIT_SIZE - 1);
+        }
 #else
-                while (info->xmit_cnt && char_count) {
-                        data = info->port.xmit_buf[info->xmit_tail];
-                        info->xmit_cnt--;
-                        info->xmit_tail = (info->xmit_tail + 1) &
-                                        (SERIAL_XMIT_SIZE - 1);
-
-                        cy_writeb(cinfo->base_addr + tx_bufaddr + tx_put, data);
-                        tx_put = (tx_put + 1) & (tx_bufsize - 1);
-                        char_count--;
-                        info->icount.tx++;
-                }
+        while (info->xmit_cnt && char_count) {
+                data = info->port.xmit_buf[info->xmit_tail];
+                info->xmit_cnt--;
+                info->xmit_tail = (info->xmit_tail + 1) &
+                                (SERIAL_XMIT_SIZE - 1);
+
+                cy_writeb(cinfo->base_addr + tx_bufaddr + tx_put, data);
+                tx_put = (tx_put + 1) & (tx_bufsize - 1);
+                char_count--;
+                info->icount.tx++;
+        }
 #endif
-                tty_wakeup(tty);
+        tty_wakeup(tty);
+        tty_kref_put(tty);
 ztxdone:
-                /* Update tx_put */
-                cy_writel(&buf_ctrl->tx_put, tx_put);
-        }
+        /* Update tx_put */
+        cy_writel(&buf_ctrl->tx_put, tx_put);
 }
 
 static void cyz_handle_cmd(struct cyclades_card *cinfo)
 {
         struct BOARD_CTRL __iomem *board_ctrl = cinfo->board_ctrl;
-        struct tty_struct *tty;
         struct cyclades_port *info;
         __u32 channel, param, fw_ver;
         __u8 cmd;
@@ -1102,9 +1099,6 @@ static void cyz_handle_cmd(struct cyclades_card *cinfo)
                 special_count = 0;
                 delta_count = 0;
                 info = &cinfo->ports[channel];
-                tty = tty_port_tty_get(&info->port);
-                if (tty == NULL)
-                        continue;
 
                 switch (cmd) {
                 case C_CM_PR_ERROR:
@@ -1130,8 +1124,14 @@ static void cyz_handle_cmd(struct cyclades_card *cinfo)
                                         readl(&info->u.cyz.ch_ctrl->rs_status);
                                 if (dcd & C_RS_DCD)
                                         wake_up_interruptible(&info->port.open_wait);
-                                else
-                                        tty_hangup(tty);
+                                else {
+                                        struct tty_struct *tty;
+                                        tty = tty_port_tty_get(&info->port);
+                                        if (tty) {
+                                                tty_hangup(tty);
+                                                tty_kref_put(tty);
+                                        }
+                                }
                         }
                         break;
                 case C_CM_MCTS:
@@ -1160,7 +1160,7 @@ static void cyz_handle_cmd(struct cyclades_card *cinfo)
                         printk(KERN_DEBUG "cyz_interrupt: rcvd intr, card %d, "
                                         "port %ld\n", info->card, channel);
 #endif
-                        cyz_handle_rx(info, tty);
+                        cyz_handle_rx(info);
                         break;
                 case C_CM_TXBEMPTY:
                 case C_CM_TXLOWWM:
@@ -1170,7 +1170,7 @@ static void cyz_handle_cmd(struct cyclades_card *cinfo)
                         printk(KERN_DEBUG "cyz_interrupt: xmit intr, card %d, "
                                         "port %ld\n", info->card, channel);
 #endif
-                        cyz_handle_tx(info, tty);
+                        cyz_handle_tx(info);
                         break;
 #endif                          /* CONFIG_CYZ_INTR */
                 case C_CM_FATAL:
@@ -1183,7 +1183,6 @@ static void cyz_handle_cmd(struct cyclades_card *cinfo)
                         wake_up_interruptible(&info->port.delta_msr_wait);
                 if (special_count)
                         tty_schedule_flip(&info->port);
-                tty_kref_put(tty);
         }
 }
 
@@ -1249,17 +1248,11 @@ static void cyz_poll(unsigned long arg)
                 cyz_handle_cmd(cinfo);
 
                 for (port = 0; port < cinfo->nports; port++) {
-                        struct tty_struct *tty;
-
                         info = &cinfo->ports[port];
-                        tty = tty_port_tty_get(&info->port);
-                        /* OK to pass NULL to the handle functions below.
-                           They need to drop the data in that case. */
 
                         if (!info->throttle)
-                                cyz_handle_rx(info, tty);
-                        cyz_handle_tx(info, tty);
-                        tty_kref_put(tty);
+                                cyz_handle_rx(info);
+                        cyz_handle_tx(info);
                 }
                 /* poll every 'cyz_polling_cycle' period */
                 expires = jiffies + cyz_polling_cycle;