tty: Merge tty_buffer_find() into tty_buffer_alloc()

tty_buffer_find() implements a simple free list lookaside cache.
Merge this functionality into tty_buffer_alloc() to reflect the
more traditional alloc/free symmetry.

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/tty/tty_buffer.c b/drivers/tty/tty_buffer.c
index 56d4602..a428fa2 100644 (file)
--- a/drivers/tty/tty_buffer.c
+++ b/drivers/tty/tty_buffer.c
@@ -64,6 +64,8 @@ void tty_buffer_free_all(struct tty_port *port)
  *     @size: desired size (characters)
  *
  *     Allocate a new tty buffer to hold the desired number of characters.
+ *     We round our buffers off in 256 character chunks to get better
+ *     allocation behaviour.
  *     Return NULL if out of memory or the allocation would exceed the
  *     per device queue
  *
@@ -72,14 +74,29 @@ void tty_buffer_free_all(struct tty_port *port)
 
 static struct tty_buffer *tty_buffer_alloc(struct tty_port *port, size_t size)
 {
+       struct tty_buffer **tbh = &port->buf.free;
        struct tty_buffer *p;
 
+       /* Round the buffer size out */
+       size = __ALIGN_MASK(size, TTYB_ALIGN_MASK);
+
+       if (size <= MIN_TTYB_SIZE) {
+               if (*tbh) {
+                       p = *tbh;
+                       *tbh = p->next;
+                       goto found;
+               }
+       }
+
+       /* Should possibly check if this fails for the largest buffer we
+          have queued and recycle that ? */
        if (port->buf.memory_used + size > 65536)
                return NULL;
        p = kmalloc(sizeof(struct tty_buffer) + 2 * size, GFP_ATOMIC);
        if (p == NULL)
                return NULL;
 
+found:
        tty_buffer_reset(p, size);
        port->buf.memory_used += size;
        return p;
@@ -172,37 +189,6 @@ void tty_buffer_flush(struct tty_struct *tty)
 }
 
 /**
- *     tty_buffer_find         -       find a free tty buffer
- *     @tty: tty owning the buffer
- *     @size: characters wanted
- *
- *     Locate an existing suitable tty buffer or if we are lacking one then
- *     allocate a new one. We round our buffers off in 256 character chunks
- *     to get better allocation behaviour.
- *
- *     Locking: Caller must hold tty->buf.lock
- */
-
-static struct tty_buffer *tty_buffer_find(struct tty_port *port, size_t size)
-{
-       struct tty_buffer **tbh = &port->buf.free;
-       if (size <= MIN_TTYB_SIZE) {
-               if (*tbh) {
-                       struct tty_buffer *t = *tbh;
-
-                       *tbh = t->next;
-                       tty_buffer_reset(t, t->size);
-                       port->buf.memory_used += t->size;
-                       return t;
-               }
-       }
-       /* Round the buffer size out */
-       size = __ALIGN_MASK(size, TTYB_ALIGN_MASK);
-       return tty_buffer_alloc(port, size);
-       /* Should possibly check if this fails for the largest buffer we
-          have queued and recycle that ? */
-}
-/**
  *     tty_buffer_request_room         -       grow tty buffer if needed
  *     @tty: tty structure
  *     @size: size desired
@@ -230,7 +216,7 @@ int tty_buffer_request_room(struct tty_port *port, size_t size)
 
        if (left < size) {
                /* This is the slow path - looking for new buffers to use */
-               if ((n = tty_buffer_find(port, size)) != NULL) {
+               if ((n = tty_buffer_alloc(port, size)) != NULL) {
                        if (b != NULL) {
                                b->next = n;
                                b->commit = b->used;