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tty: Fix flip buffer free list

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Since flip buffers are size-aligned to 256 bytes and all flip
buffers 512-bytes or larger are not added to the free list, the
free list only contains 256-byte flip buffers.

Remove the list search when allocating a new flip buffer.

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Peter Hurley 2013-06-15 09:36:02 -04:00 committed by Greg Kroah-Hartman
parent 1fc359fc3e
commit 1cef50e317
1 changed files with 10 additions and 6 deletions
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14
drivers/tty/tty_buffer.c
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@ -18,6 +18,10 @@
#include <linux/module.h>
#include <linux/ratelimit.h>
#define MIN_TTYB_SIZE 256
#define TTYB_ALIGN_MASK 255
/**
* tty_buffer_free_all - free buffers used by a tty
* @tty: tty to free from
@ -94,7 +98,7 @@ static void tty_buffer_free(struct tty_port *port, struct tty_buffer *b)
buf->memory_used -= b->size;
WARN_ON(buf->memory_used < 0);
if (b->size >= 512)
if (b->size > MIN_TTYB_SIZE)
kfree(b);
else {
b->next = buf->free;
@ -176,9 +180,10 @@ void tty_buffer_flush(struct tty_struct *tty)
static struct tty_buffer *tty_buffer_find(struct tty_port *port, size_t size)
{
struct tty_buffer **tbh = &port->buf.free;
while ((*tbh) != NULL) {
if (size <= MIN_TTYB_SIZE) {
if (*tbh) {
struct tty_buffer *t = *tbh;
if (t->size >= size) {
*tbh = t->next;
t->next = NULL;
t->used = 0;
@ -187,10 +192,9 @@ static struct tty_buffer *tty_buffer_find(struct tty_port *port, size_t size)
port->buf.memory_used += t->size;
return t;
}
tbh = &((*tbh)->next);
}
/* Round the buffer size out */
size = (size + 0xFF) & ~0xFF;
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 ? */