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-rw-r--r--drivers/tty/tty_buffer.c45
-rw-r--r--include/linux/tty.h4
-rw-r--r--include/linux/tty_flip.h8
3 files changed, 45 insertions, 12 deletions
diff --git a/drivers/tty/tty_buffer.c b/drivers/tty/tty_buffer.c
index 08835a6dd022..3002e20e10d7 100644
--- a/drivers/tty/tty_buffer.c
+++ b/drivers/tty/tty_buffer.c
@@ -101,6 +101,7 @@ static void tty_buffer_reset(struct tty_buffer *p, size_t size)
p->next = NULL;
p->commit = 0;
p->read = 0;
+ p->flags = 0;
}
/**
@@ -229,31 +230,49 @@ void tty_buffer_flush(struct tty_struct *tty)
* tty_buffer_request_room - grow tty buffer if needed
* @tty: tty structure
* @size: size desired
+ * @flags: buffer flags if new buffer allocated (default = 0)
*
* Make at least size bytes of linear space available for the tty
* buffer. If we fail return the size we managed to find.
+ *
+ * Will change over to a new buffer if the current buffer is encoded as
+ * TTY_NORMAL (so has no flags buffer) and the new buffer requires
+ * a flags buffer.
*/
-int tty_buffer_request_room(struct tty_port *port, size_t size)
+static int __tty_buffer_request_room(struct tty_port *port, size_t size,
+ int flags)
{
struct tty_bufhead *buf = &port->buf;
struct tty_buffer *b, *n;
- int left;
+ int left, change;
b = buf->tail;
- left = b->size - b->used;
+ if (b->flags & TTYB_NORMAL)
+ left = 2 * b->size - b->used;
+ else
+ left = b->size - b->used;
- if (left < size) {
+ change = (b->flags & TTYB_NORMAL) && (~flags & TTYB_NORMAL);
+ if (change || left < size) {
/* This is the slow path - looking for new buffers to use */
if ((n = tty_buffer_alloc(port, size)) != NULL) {
+ n->flags = flags;
buf->tail = n;
b->commit = b->used;
smp_mb();
b->next = n;
- } else
+ } else if (change)
+ size = 0;
+ else
size = left;
}
return size;
}
+
+int tty_buffer_request_room(struct tty_port *port, size_t size)
+{
+ return __tty_buffer_request_room(port, size, 0);
+}
EXPORT_SYMBOL_GPL(tty_buffer_request_room);
/**
@@ -273,12 +292,14 @@ int tty_insert_flip_string_fixed_flag(struct tty_port *port,
int copied = 0;
do {
int goal = min_t(size_t, size - copied, TTY_BUFFER_PAGE);
- int space = tty_buffer_request_room(port, goal);
+ int flags = (flag == TTY_NORMAL) ? TTYB_NORMAL : 0;
+ int space = __tty_buffer_request_room(port, goal, flags);
struct tty_buffer *tb = port->buf.tail;
if (unlikely(space == 0))
break;
memcpy(char_buf_ptr(tb, tb->used), chars, space);
- memset(flag_buf_ptr(tb, tb->used), flag, space);
+ if (~tb->flags & TTYB_NORMAL)
+ memset(flag_buf_ptr(tb, tb->used), flag, space);
tb->used += space;
copied += space;
chars += space;
@@ -361,11 +382,12 @@ EXPORT_SYMBOL(tty_schedule_flip);
int tty_prepare_flip_string(struct tty_port *port, unsigned char **chars,
size_t size)
{
- int space = tty_buffer_request_room(port, size);
+ int space = __tty_buffer_request_room(port, size, TTYB_NORMAL);
if (likely(space)) {
struct tty_buffer *tb = port->buf.tail;
*chars = char_buf_ptr(tb, tb->used);
- memset(flag_buf_ptr(tb, tb->used), TTY_NORMAL, space);
+ if (~tb->flags & TTYB_NORMAL)
+ memset(flag_buf_ptr(tb, tb->used), TTY_NORMAL, space);
tb->used += space;
}
return space;
@@ -378,7 +400,10 @@ receive_buf(struct tty_struct *tty, struct tty_buffer *head, int count)
{
struct tty_ldisc *disc = tty->ldisc;
unsigned char *p = char_buf_ptr(head, head->read);
- char *f = flag_buf_ptr(head, head->read);
+ char *f = NULL;
+
+ if (~head->flags & TTYB_NORMAL)
+ f = flag_buf_ptr(head, head->read);
if (disc->ops->receive_buf2)
count = disc->ops->receive_buf2(tty, p, f, count);
diff --git a/include/linux/tty.h b/include/linux/tty.h
index 38fcc0574ba9..ad98b4376968 100644
--- a/include/linux/tty.h
+++ b/include/linux/tty.h
@@ -39,10 +39,14 @@ struct tty_buffer {
int size;
int commit;
int read;
+ int flags;
/* Data points here */
unsigned long data[0];
};
+/* Values for .flags field of tty_buffer */
+#define TTYB_NORMAL 1 /* buffer has no flags buffer */
+
static inline unsigned char *char_buf_ptr(struct tty_buffer *b, int ofs)
{
return ((unsigned char *)b->data) + ofs;
diff --git a/include/linux/tty_flip.h b/include/linux/tty_flip.h
index 3f821e98af0f..c28dd523f96e 100644
--- a/include/linux/tty_flip.h
+++ b/include/linux/tty_flip.h
@@ -17,8 +17,12 @@ static inline int tty_insert_flip_char(struct tty_port *port,
unsigned char ch, char flag)
{
struct tty_buffer *tb = port->buf.tail;
- if (tb && tb->used < tb->size) {
- *flag_buf_ptr(tb, tb->used) = flag;
+ int change;
+
+ change = (tb->flags & TTYB_NORMAL) && (flag != TTY_NORMAL);
+ if (!change && tb->used < tb->size) {
+ if (~tb->flags & TTYB_NORMAL)
+ *flag_buf_ptr(tb, tb->used) = flag;
*char_buf_ptr(tb, tb->used++) = ch;
return 1;
}