[PATCH] char: kill unneeded memsets

char, another tmp_buf cleanup

No need to allocate one page as a side buffer.  It's no more used.  Clean this
(de)allocs of this useless memory pages in char subtree.

Signed-off-by: Jiri Slaby <jirislaby@gmail.com>
Acked-by: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 1 insertions, 27 deletions

diff --git a/drivers/char/cyclades.c b/drivers/char/cyclades.c
index f85b4eb16618..87b2fb510871 100644
--- a/drivers/char/cyclades.c
+++ b/drivers/char/cyclades.c
@@ -748,18 +748,6 @@ static struct cyclades_port cy_port[NR_PORTS];
 static int cy_next_channel; /* next minor available */
 
 /*
- * tmp_buf is used as a temporary buffer by serial_write.  We need to
- * lock it in case the copy_from_user blocks while swapping in a page,
- * and some other program tries to do a serial write at the same time.
- * Since the lock will only come under contention when the system is
- * swapping and available memory is low, it makes sense to share one
- * buffer across all the serial ports, since it significantly saves
- * memory if large numbers of serial ports are open.  This buffer is
- * allocated when the first cy_open occurs.
- */
-static unsigned char *tmp_buf;
-
-/*
  * This is used to look up the divisor speeds and the timeouts
  * We're normally limited to 15 distinct baud rates.  The extra
  * are accessed via settings in info->flags.
@@ -2466,7 +2454,6 @@ cy_open(struct tty_struct *tty, struct file * filp)
 {
   struct cyclades_port  *info;
   int retval, line;
-  unsigned long page;
 
     line = tty->index;
     if ((line < 0) || (NR_PORTS <= line)){
@@ -2545,15 +2532,6 @@ cy_open(struct tty_struct *tty, struct file * filp)
     printk("cyc:cy_open (%d): incrementing count to %d\n",
         current->pid, info->count);
 #endif
-    if (!tmp_buf) {
-        page = get_zeroed_page(GFP_KERNEL);
-        if (!page)
-            return -ENOMEM;
-        if (tmp_buf)
-            free_page(page);
-        else
-            tmp_buf = (unsigned char *) page;
-    }
 
     /*
      * If the port is the middle of closing, bail out now
@@ -2832,7 +2810,7 @@ cy_write(struct tty_struct * tty, const unsigned char *buf, int count)
         return 0;
     }
         
-    if (!info->xmit_buf || !tmp_buf)
+    if (!info->xmit_buf)
         return 0;
 
     CY_LOCK(info, flags);
@@ -5490,10 +5468,6 @@ cy_cleanup_module(void)
 #endif
         }
     }
-    if (tmp_buf) {
-        free_page((unsigned long) tmp_buf);
-        tmp_buf = NULL;
-    }
 } /* cy_cleanup_module */
 
 module_init(cy_init);