tty/serial: lay the foundations for the next set of reworks

- Stop drivers calling their own flush method indirectly, it obfuscates code
  and it will change soon anyway

- A few more lock_kernel paths temporarily needed in some driver internal
  waiting code

- Remove private put_char method that does a write call for one char - we
  have that anyway

- Most but not yet all of the termios copy under lock fixing (some has other
  dependencies to follow)

- Note a few locking bugs in drivers found in the process

- Kill remaining [ab]users of TIOCG/SSOFTCAR in the driver, these must go to
  fix the termios locking

Signed-off-by: Alan Cox <alan@redhat.com>
Cc: Jiri Slaby <jirislaby@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 40 insertions, 36 deletions

diff --git a/drivers/char/cyclades.c b/drivers/char/cyclades.c
index e61939d3331..571e4fab5bf 100644
--- a/drivers/char/cyclades.c
+++ b/drivers/char/cyclades.c
@@ -2522,6 +2522,7 @@ static void cy_wait_until_sent(struct tty_struct *tty, int timeout)
                 return;         /* Just in case.... */
 
         orig_jiffies = jiffies;
+        lock_kernel();
         /*
          * Set the check interval to be 1/5 of the estimated time to
          * send a single character, and make it at least 1.  The check
@@ -2573,11 +2574,47 @@ static void cy_wait_until_sent(struct tty_struct *tty, int timeout)
         }
         /* Run one more char cycle */
         msleep_interruptible(jiffies_to_msecs(char_time * 5));
+        unlock_kernel();
 #ifdef CY_DEBUG_WAIT_UNTIL_SENT
         printk(KERN_DEBUG "Clean (jiff=%lu)...done\n", jiffies);
 #endif
 }
 
+static void cy_flush_buffer(struct tty_struct *tty)
+{
+        struct cyclades_port *info = tty->driver_data;
+        struct cyclades_card *card;
+        int channel, retval;
+        unsigned long flags;
+
+#ifdef CY_DEBUG_IO
+        printk(KERN_DEBUG "cyc:cy_flush_buffer ttyC%d\n", info->line);
+#endif
+
+        if (serial_paranoia_check(info, tty->name, "cy_flush_buffer"))
+                return;
+
+        card = info->card;
+        channel = info->line - card->first_line;
+
+        spin_lock_irqsave(&card->card_lock, flags);
+        info->xmit_cnt = info->xmit_head = info->xmit_tail = 0;
+        spin_unlock_irqrestore(&card->card_lock, flags);
+
+        if (IS_CYC_Z(*card)) {  /* If it is a Z card, flush the on-board
+                                           buffers as well */
+                spin_lock_irqsave(&card->card_lock, flags);
+                retval = cyz_issue_cmd(card, channel, C_CM_FLUSH_TX, 0L);
+                if (retval != 0) {
+                        printk(KERN_ERR "cyc: flush_buffer retval on ttyC%d "
+                                "was %x\n", info->line, retval);
+                }
+                spin_unlock_irqrestore(&card->card_lock, flags);
+        }
+        tty_wakeup(tty);
+}                               /* cy_flush_buffer */
+
+
 /*
  * This routine is called when a particular tty device is closed.
  */
@@ -2689,8 +2726,7 @@ static void cy_close(struct tty_struct *tty, struct file *filp)
 
         spin_unlock_irqrestore(&card->card_lock, flags);
         shutdown(info);
-        if (tty->driver->flush_buffer)
-                tty->driver->flush_buffer(tty);
+        cy_flush_buffer(tty);
         tty_ldisc_flush(tty);
         spin_lock_irqsave(&card->card_lock, flags);
 
@@ -2881,6 +2917,7 @@ static int cy_chars_in_buffer(struct tty_struct *tty)
                 int char_count;
                 __u32 tx_put, tx_get, tx_bufsize;
 
+                lock_kernel();
                 firm_id = card->base_addr + ID_ADDRESS;
                 zfw_ctrl = card->base_addr +
                         (readl(&firm_id->zfwctrl_addr) & 0xfffff);
@@ -2898,6 +2935,7 @@ static int cy_chars_in_buffer(struct tty_struct *tty)
                 printk(KERN_DEBUG "cyc:cy_chars_in_buffer ttyC%d %d\n",
                         info->line, info->xmit_cnt + char_count);
 #endif
+                unlock_kernel();
                 return info->xmit_cnt + char_count;
         }
 #endif                          /* Z_EXT_CHARS_IN_BUFFER */
@@ -4271,40 +4309,6 @@ static void cy_start(struct tty_struct *tty)
         }
 }                               /* cy_start */
 
-static void cy_flush_buffer(struct tty_struct *tty)
-{
-        struct cyclades_port *info = tty->driver_data;
-        struct cyclades_card *card;
-        int channel, retval;
-        unsigned long flags;
-
-#ifdef CY_DEBUG_IO
-        printk(KERN_DEBUG "cyc:cy_flush_buffer ttyC%d\n", info->line);
-#endif
-
-        if (serial_paranoia_check(info, tty->name, "cy_flush_buffer"))
-                return;
-
-        card = info->card;
-        channel = info->line - card->first_line;
-
-        spin_lock_irqsave(&card->card_lock, flags);
-        info->xmit_cnt = info->xmit_head = info->xmit_tail = 0;
-        spin_unlock_irqrestore(&card->card_lock, flags);
-
-        if (IS_CYC_Z(*card)) {  /* If it is a Z card, flush the on-board
-                                           buffers as well */
-                spin_lock_irqsave(&card->card_lock, flags);
-                retval = cyz_issue_cmd(card, channel, C_CM_FLUSH_TX, 0L);
-                if (retval != 0) {
-                        printk(KERN_ERR "cyc: flush_buffer retval on ttyC%d "
-                                "was %x\n", info->line, retval);
-                }
-                spin_unlock_irqrestore(&card->card_lock, flags);
-        }
-        tty_wakeup(tty);
-}                               /* cy_flush_buffer */
-
 /*
  * cy_hangup() --- called by tty_hangup() when a hangup is signaled.
  */