mirrors
/
linux-stable
mirror of https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
1
0
Fork 0
Code Issues Releases Wiki Activity

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>
This commit is contained in:
Peter Hurley 2013-06-15 09:36:04 -04:00 committed by Greg Kroah-Hartman
parent 9dd5139f97
commit 11b9faa44d
1 changed files with 18 additions and 32 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

50
drivers/tty/tty_buffer.c
View File

@ -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;
@ -171,37 +188,6 @@ void tty_buffer_flush(struct tty_struct *tty)
spin_unlock_irqrestore(&buf->lock, flags);
}
/**
* 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
@ -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;