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Message-Id: <1366039567-8620-5-git-send-email-peter@hurleysoftware.com>
Date: Mon, 15 Apr 2013 11:25:55 -0400
From: Peter Hurley <peter@...leysoftware.com>
To: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Cc: Jiri Slaby <jslaby@...e.cz>, linux-serial@...r.kernel.org,
linux-kernel@...r.kernel.org,
Peter Hurley <peter@...leysoftware.com>
Subject: [PATCH 04/16] 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@...leysoftware.com>
---
drivers/tty/tty_buffer.c | 50 +++++++++++++++++-------------------------------
1 file changed, 18 insertions(+), 32 deletions(-)
diff --git a/drivers/tty/tty_buffer.c b/drivers/tty/tty_buffer.c
index 56d4602..a428fa2 100644
--- 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;
--
1.8.1.2
--
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