[PATCH] Char: moxa, remove unused allocated page

moxaXmitBuff is almost unused -- only one byte from the whole PAGE_SIZE bytes
is used.  Do not alloc so much space for almost anything.  Also remove lock
protecting this page allocation.

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

diff --git a/drivers/char/moxa.c b/drivers/char/moxa.c
index f391a24..4db1dc4 100644 (file)
--- a/drivers/char/moxa.c
+++ b/drivers/char/moxa.c
@@ -212,12 +212,10 @@ module_param(verbose, bool, 0644);
 
 static struct tty_driver *moxaDriver;
 static struct moxa_str moxaChannels[MAX_PORTS];
-static unsigned char *moxaXmitBuff;
 static int moxaTimer_on;
 static struct timer_list moxaTimer;
 static int moxaEmptyTimer_on[MAX_PORTS];
 static struct timer_list moxaEmptyTimer[MAX_PORTS];
-static struct semaphore moxaBuffSem;
 
 /*
  * static functions:
@@ -343,7 +341,6 @@ static int __init moxa_init(void)
        if (!moxaDriver)
                return -ENOMEM;
 
-       init_MUTEX(&moxaBuffSem);
        moxaDriver->owner = THIS_MODULE;
        moxaDriver->name = "ttyMX";
        moxaDriver->major = ttymajor;
@@ -360,8 +357,6 @@ static int __init moxa_init(void)
        moxaDriver->flags = TTY_DRIVER_REAL_RAW;
        tty_set_operations(moxaDriver, &moxa_ops);
 
-       moxaXmitBuff = NULL;
-
        for (i = 0, ch = moxaChannels; i < MAX_PORTS; i++, ch++) {
                ch->type = PORT_16550A;
                ch->port = i;
@@ -533,7 +528,6 @@ static int moxa_open(struct tty_struct *tty, struct file *filp)
        struct moxa_str *ch;
        int port;
        int retval;
-       unsigned long page;
 
        port = PORTNO(tty);
        if (port == MAX_PORTS) {
@@ -543,21 +537,6 @@ static int moxa_open(struct tty_struct *tty, struct file *filp)
                tty->driver_data = NULL;
                return (-ENODEV);
        }
-       down(&moxaBuffSem);
-       if (!moxaXmitBuff) {
-               page = get_zeroed_page(GFP_KERNEL);
-               if (!page) {
-                       up(&moxaBuffSem);
-                       return (-ENOMEM);
-               }
-               /* This test is guarded by the BuffSem so no longer needed
-                  delete me in 2.5 */
-               if (moxaXmitBuff)
-                       free_page(page);
-               else
-                       moxaXmitBuff = (unsigned char *) page;
-       }
-       up(&moxaBuffSem);
 
        ch = &moxaChannels[port];
        ch->count++;
@@ -739,8 +718,7 @@ static void moxa_put_char(struct tty_struct *tty, unsigned char c)
                return;
        port = ch->port;
        spin_lock_irqsave(&moxa_lock, flags);
-       moxaXmitBuff[0] = c;
-       MoxaPortWriteData(port, moxaXmitBuff, 1);
+       MoxaPortWriteData(port, &c, 1);
        spin_unlock_irqrestore(&moxa_lock, flags);
        /************************************************
        if ( !(ch->statusflags & LOWWAIT) && (MoxaPortTxFree(port) <= 100) )