This commit was manufactured by cvs2svn to create tag

[linux-2.6.git] / net / irda / ircomm / ircomm_tty.c

diff --git a/net/irda/ircomm/ircomm_tty.c b/net/irda/ircomm/ircomm_tty.c
index eb430e8..f0c93ca 100644 (file)
--- a/net/irda/ircomm/ircomm_tty.c
+++ b/net/irda/ircomm/ircomm_tty.c
@@ -52,7 +52,7 @@
 
 static int  ircomm_tty_open(struct tty_struct *tty, struct file *filp);
 static void ircomm_tty_close(struct tty_struct * tty, struct file *filp);
-static int  ircomm_tty_write(struct tty_struct * tty,
+static int  ircomm_tty_write(struct tty_struct * tty, int from_user,
                             const unsigned char *buf, int count);
 static int  ircomm_tty_write_room(struct tty_struct *tty);
 static void ircomm_tty_throttle(struct tty_struct *tty);
@@ -662,14 +662,14 @@ static void ircomm_tty_do_softint(void *private_)
 }
 
 /*
- * Function ircomm_tty_write (tty, buf, count)
+ * Function ircomm_tty_write (tty, from_user, buf, count)
  *
  *    This routine is called by the kernel to write a series of characters
  *    to the tty device. The characters may come from user space or kernel
  *    space. This routine will return the number of characters actually
  *    accepted for writing. This routine is mandatory.
  */
-static int ircomm_tty_write(struct tty_struct *tty,
+static int ircomm_tty_write(struct tty_struct *tty, int from_user,
                            const unsigned char *ubuf, int count)
 {
        struct ircomm_tty_cb *self = (struct ircomm_tty_cb *) tty->driver_data;
@@ -713,8 +713,21 @@ static int ircomm_tty_write(struct tty_struct *tty,
        if (count < 1)
                return 0;
 
-       /* The buffer is already in kernel space */
-       kbuf = (unsigned char *) ubuf;
+       /* Additional copy to avoid copy_from_user() under spinlock.
+        * We tradeoff this extra copy to allow to pack more the
+        * IrCOMM frames. This is advantageous because the IrDA link
+        * is the bottleneck. */
+       if (from_user) {
+               kbuf = kmalloc(count, GFP_KERNEL);
+               if (kbuf == NULL)
+                       return -ENOMEM;
+               if (copy_from_user(kbuf, ubuf, count)) {
+                       kfree(kbuf);
+                       return -EFAULT;
+               }
+       } else
+               /* The buffer is already in kernel space */
+               kbuf = (unsigned char *) ubuf;
 
        /* Protect our manipulation of self->tx_skb and related */
        spin_lock_irqsave(&self->spinlock, flags);
@@ -768,6 +781,8 @@ static int ircomm_tty_write(struct tty_struct *tty,
                                            self->max_header_size);
                        if (!skb) {
                                spin_unlock_irqrestore(&self->spinlock, flags);
+                               if (from_user)
+                                       kfree(kbuf);
                                return -ENOBUFS;
                        }
                        skb_reserve(skb, self->max_header_size);
@@ -786,6 +801,9 @@ static int ircomm_tty_write(struct tty_struct *tty,
 
        spin_unlock_irqrestore(&self->spinlock, flags);
 
+       if (from_user)
+               kfree(kbuf);
+
        /*     
         * Schedule a new thread which will transmit the frame as soon
         * as possible, but at a safe point in time. We do this so the