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path: root/drivers/tty/tty_buffer.c
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Diffstat (limited to 'drivers/tty/tty_buffer.c')
-rw-r--r--drivers/tty/tty_buffer.c228
1 files changed, 129 insertions, 99 deletions
diff --git a/drivers/tty/tty_buffer.c b/drivers/tty/tty_buffer.c
index 91e326ffe7db..45d916198f78 100644
--- a/drivers/tty/tty_buffer.c
+++ b/drivers/tty/tty_buffer.c
@@ -27,19 +27,21 @@
* Locking: none
*/
-void tty_buffer_free_all(struct tty_struct *tty)
+void tty_buffer_free_all(struct tty_port *port)
{
+ struct tty_bufhead *buf = &port->buf;
struct tty_buffer *thead;
- while ((thead = tty->buf.head) != NULL) {
- tty->buf.head = thead->next;
+
+ while ((thead = buf->head) != NULL) {
+ buf->head = thead->next;
kfree(thead);
}
- while ((thead = tty->buf.free) != NULL) {
- tty->buf.free = thead->next;
+ while ((thead = buf->free) != NULL) {
+ buf->free = thead->next;
kfree(thead);
}
- tty->buf.tail = NULL;
- tty->buf.memory_used = 0;
+ buf->tail = NULL;
+ buf->memory_used = 0;
}
/**
@@ -54,11 +56,11 @@ void tty_buffer_free_all(struct tty_struct *tty)
* Locking: Caller must hold tty->buf.lock
*/
-static struct tty_buffer *tty_buffer_alloc(struct tty_struct *tty, size_t size)
+static struct tty_buffer *tty_buffer_alloc(struct tty_port *port, size_t size)
{
struct tty_buffer *p;
- if (tty->buf.memory_used + size > 65536)
+ if (port->buf.memory_used + size > 65536)
return NULL;
p = kmalloc(sizeof(struct tty_buffer) + 2 * size, GFP_ATOMIC);
if (p == NULL)
@@ -70,7 +72,7 @@ static struct tty_buffer *tty_buffer_alloc(struct tty_struct *tty, size_t size)
p->read = 0;
p->char_buf_ptr = (char *)(p->data);
p->flag_buf_ptr = (unsigned char *)p->char_buf_ptr + size;
- tty->buf.memory_used += size;
+ port->buf.memory_used += size;
return p;
}
@@ -85,17 +87,19 @@ static struct tty_buffer *tty_buffer_alloc(struct tty_struct *tty, size_t size)
* Locking: Caller must hold tty->buf.lock
*/
-static void tty_buffer_free(struct tty_struct *tty, struct tty_buffer *b)
+static void tty_buffer_free(struct tty_port *port, struct tty_buffer *b)
{
+ struct tty_bufhead *buf = &port->buf;
+
/* Dumb strategy for now - should keep some stats */
- tty->buf.memory_used -= b->size;
- WARN_ON(tty->buf.memory_used < 0);
+ buf->memory_used -= b->size;
+ WARN_ON(buf->memory_used < 0);
if (b->size >= 512)
kfree(b);
else {
- b->next = tty->buf.free;
- tty->buf.free = b;
+ b->next = buf->free;
+ buf->free = b;
}
}
@@ -110,15 +114,16 @@ static void tty_buffer_free(struct tty_struct *tty, struct tty_buffer *b)
* Locking: Caller must hold tty->buf.lock
*/
-static void __tty_buffer_flush(struct tty_struct *tty)
+static void __tty_buffer_flush(struct tty_port *port)
{
+ struct tty_bufhead *buf = &port->buf;
struct tty_buffer *thead;
- while ((thead = tty->buf.head) != NULL) {
- tty->buf.head = thead->next;
- tty_buffer_free(tty, thead);
+ while ((thead = buf->head) != NULL) {
+ buf->head = thead->next;
+ tty_buffer_free(port, thead);
}
- tty->buf.tail = NULL;
+ buf->tail = NULL;
}
/**
@@ -134,21 +139,24 @@ static void __tty_buffer_flush(struct tty_struct *tty)
void tty_buffer_flush(struct tty_struct *tty)
{
+ struct tty_port *port = tty->port;
+ struct tty_bufhead *buf = &port->buf;
unsigned long flags;
- spin_lock_irqsave(&tty->buf.lock, flags);
+
+ spin_lock_irqsave(&buf->lock, flags);
/* If the data is being pushed to the tty layer then we can't
process it here. Instead set a flag and the flush_to_ldisc
path will process the flush request before it exits */
- if (test_bit(TTY_FLUSHING, &tty->flags)) {
- set_bit(TTY_FLUSHPENDING, &tty->flags);
- spin_unlock_irqrestore(&tty->buf.lock, flags);
+ if (test_bit(TTYP_FLUSHING, &port->iflags)) {
+ set_bit(TTYP_FLUSHPENDING, &port->iflags);
+ spin_unlock_irqrestore(&buf->lock, flags);
wait_event(tty->read_wait,
- test_bit(TTY_FLUSHPENDING, &tty->flags) == 0);
+ test_bit(TTYP_FLUSHPENDING, &port->iflags) == 0);
return;
} else
- __tty_buffer_flush(tty);
- spin_unlock_irqrestore(&tty->buf.lock, flags);
+ __tty_buffer_flush(port);
+ spin_unlock_irqrestore(&buf->lock, flags);
}
/**
@@ -163,9 +171,9 @@ void tty_buffer_flush(struct tty_struct *tty)
* Locking: Caller must hold tty->buf.lock
*/
-static struct tty_buffer *tty_buffer_find(struct tty_struct *tty, size_t size)
+static struct tty_buffer *tty_buffer_find(struct tty_port *port, size_t size)
{
- struct tty_buffer **tbh = &tty->buf.free;
+ struct tty_buffer **tbh = &port->buf.free;
while ((*tbh) != NULL) {
struct tty_buffer *t = *tbh;
if (t->size >= size) {
@@ -174,14 +182,14 @@ static struct tty_buffer *tty_buffer_find(struct tty_struct *tty, size_t size)
t->used = 0;
t->commit = 0;
t->read = 0;
- tty->buf.memory_used += t->size;
+ port->buf.memory_used += t->size;
return t;
}
tbh = &((*tbh)->next);
}
/* Round the buffer size out */
size = (size + 0xFF) & ~0xFF;
- return tty_buffer_alloc(tty, size);
+ return tty_buffer_alloc(port, size);
/* Should possibly check if this fails for the largest buffer we
have queued and recycle that ? */
}
@@ -192,29 +200,31 @@ static struct tty_buffer *tty_buffer_find(struct tty_struct *tty, size_t size)
*
* Make at least size bytes of linear space available for the tty
* buffer. If we fail return the size we managed to find.
- * Locking: Caller must hold tty->buf.lock
+ * Locking: Caller must hold port->buf.lock
*/
-static int __tty_buffer_request_room(struct tty_struct *tty, size_t size)
+static int __tty_buffer_request_room(struct tty_port *port, size_t size)
{
+ struct tty_bufhead *buf = &port->buf;
struct tty_buffer *b, *n;
int left;
/* OPTIMISATION: We could keep a per tty "zero" sized buffer to
remove this conditional if its worth it. This would be invisible
to the callers */
- if ((b = tty->buf.tail) != NULL)
+ b = buf->tail;
+ if (b != NULL)
left = b->size - b->used;
else
left = 0;
if (left < size) {
/* This is the slow path - looking for new buffers to use */
- if ((n = tty_buffer_find(tty, size)) != NULL) {
+ if ((n = tty_buffer_find(port, size)) != NULL) {
if (b != NULL) {
b->next = n;
b->commit = b->used;
} else
- tty->buf.head = n;
- tty->buf.tail = n;
+ buf->head = n;
+ buf->tail = n;
} else
size = left;
}
@@ -231,16 +241,17 @@ static int __tty_buffer_request_room(struct tty_struct *tty, size_t size)
* Make at least size bytes of linear space available for the tty
* buffer. If we fail return the size we managed to find.
*
- * Locking: Takes tty->buf.lock
+ * Locking: Takes port->buf.lock
*/
int tty_buffer_request_room(struct tty_struct *tty, size_t size)
{
+ struct tty_port *port = tty->port;
unsigned long flags;
int length;
- spin_lock_irqsave(&tty->buf.lock, flags);
- length = __tty_buffer_request_room(tty, size);
- spin_unlock_irqrestore(&tty->buf.lock, flags);
+ spin_lock_irqsave(&port->buf.lock, flags);
+ length = __tty_buffer_request_room(port, size);
+ spin_unlock_irqrestore(&port->buf.lock, flags);
return length;
}
EXPORT_SYMBOL_GPL(tty_buffer_request_room);
@@ -255,12 +266,13 @@ EXPORT_SYMBOL_GPL(tty_buffer_request_room);
* Queue a series of bytes to the tty buffering. All the characters
* passed are marked with the supplied flag. Returns the number added.
*
- * Locking: Called functions may take tty->buf.lock
+ * Locking: Called functions may take port->buf.lock
*/
int tty_insert_flip_string_fixed_flag(struct tty_struct *tty,
const unsigned char *chars, char flag, size_t size)
{
+ struct tty_bufhead *buf = &tty->port->buf;
int copied = 0;
do {
int goal = min_t(size_t, size - copied, TTY_BUFFER_PAGE);
@@ -268,18 +280,18 @@ int tty_insert_flip_string_fixed_flag(struct tty_struct *tty,
unsigned long flags;
struct tty_buffer *tb;
- spin_lock_irqsave(&tty->buf.lock, flags);
- space = __tty_buffer_request_room(tty, goal);
- tb = tty->buf.tail;
+ spin_lock_irqsave(&buf->lock, flags);
+ space = __tty_buffer_request_room(tty->port, goal);
+ tb = buf->tail;
/* If there is no space then tb may be NULL */
if (unlikely(space == 0)) {
- spin_unlock_irqrestore(&tty->buf.lock, flags);
+ spin_unlock_irqrestore(&buf->lock, flags);
break;
}
memcpy(tb->char_buf_ptr + tb->used, chars, space);
memset(tb->flag_buf_ptr + tb->used, flag, space);
tb->used += space;
- spin_unlock_irqrestore(&tty->buf.lock, flags);
+ spin_unlock_irqrestore(&buf->lock, flags);
copied += space;
chars += space;
/* There is a small chance that we need to split the data over
@@ -300,12 +312,13 @@ EXPORT_SYMBOL(tty_insert_flip_string_fixed_flag);
* the flags array indicates the status of the character. Returns the
* number added.
*
- * Locking: Called functions may take tty->buf.lock
+ * Locking: Called functions may take port->buf.lock
*/
int tty_insert_flip_string_flags(struct tty_struct *tty,
const unsigned char *chars, const char *flags, size_t size)
{
+ struct tty_bufhead *buf = &tty->port->buf;
int copied = 0;
do {
int goal = min_t(size_t, size - copied, TTY_BUFFER_PAGE);
@@ -313,18 +326,18 @@ int tty_insert_flip_string_flags(struct tty_struct *tty,
unsigned long __flags;
struct tty_buffer *tb;
- spin_lock_irqsave(&tty->buf.lock, __flags);
- space = __tty_buffer_request_room(tty, goal);
- tb = tty->buf.tail;
+ spin_lock_irqsave(&buf->lock, __flags);
+ space = __tty_buffer_request_room(tty->port, goal);
+ tb = buf->tail;
/* If there is no space then tb may be NULL */
if (unlikely(space == 0)) {
- spin_unlock_irqrestore(&tty->buf.lock, __flags);
+ spin_unlock_irqrestore(&buf->lock, __flags);
break;
}
memcpy(tb->char_buf_ptr + tb->used, chars, space);
memcpy(tb->flag_buf_ptr + tb->used, flags, space);
tb->used += space;
- spin_unlock_irqrestore(&tty->buf.lock, __flags);
+ spin_unlock_irqrestore(&buf->lock, __flags);
copied += space;
chars += space;
flags += space;
@@ -342,18 +355,23 @@ EXPORT_SYMBOL(tty_insert_flip_string_flags);
* Takes any pending buffers and transfers their ownership to the
* ldisc side of the queue. It then schedules those characters for
* processing by the line discipline.
+ * Note that this function can only be used when the low_latency flag
+ * is unset. Otherwise the workqueue won't be flushed.
*
- * Locking: Takes tty->buf.lock
+ * Locking: Takes port->buf.lock
*/
void tty_schedule_flip(struct tty_struct *tty)
{
+ struct tty_bufhead *buf = &tty->port->buf;
unsigned long flags;
- spin_lock_irqsave(&tty->buf.lock, flags);
- if (tty->buf.tail != NULL)
- tty->buf.tail->commit = tty->buf.tail->used;
- spin_unlock_irqrestore(&tty->buf.lock, flags);
- schedule_work(&tty->buf.work);
+ WARN_ON(tty->low_latency);
+
+ spin_lock_irqsave(&buf->lock, flags);
+ if (buf->tail != NULL)
+ buf->tail->commit = buf->tail->used;
+ spin_unlock_irqrestore(&buf->lock, flags);
+ schedule_work(&buf->work);
}
EXPORT_SYMBOL(tty_schedule_flip);
@@ -369,26 +387,27 @@ EXPORT_SYMBOL(tty_schedule_flip);
* that need their own block copy routines into the buffer. There is no
* guarantee the buffer is a DMA target!
*
- * Locking: May call functions taking tty->buf.lock
+ * Locking: May call functions taking port->buf.lock
*/
int tty_prepare_flip_string(struct tty_struct *tty, unsigned char **chars,
- size_t size)
+ size_t size)
{
+ struct tty_bufhead *buf = &tty->port->buf;
int space;
unsigned long flags;
struct tty_buffer *tb;
- spin_lock_irqsave(&tty->buf.lock, flags);
- space = __tty_buffer_request_room(tty, size);
+ spin_lock_irqsave(&buf->lock, flags);
+ space = __tty_buffer_request_room(tty->port, size);
- tb = tty->buf.tail;
+ tb = buf->tail;
if (likely(space)) {
*chars = tb->char_buf_ptr + tb->used;
memset(tb->flag_buf_ptr + tb->used, TTY_NORMAL, space);
tb->used += space;
}
- spin_unlock_irqrestore(&tty->buf.lock, flags);
+ spin_unlock_irqrestore(&buf->lock, flags);
return space;
}
EXPORT_SYMBOL_GPL(tty_prepare_flip_string);
@@ -406,26 +425,27 @@ EXPORT_SYMBOL_GPL(tty_prepare_flip_string);
* that need their own block copy routines into the buffer. There is no
* guarantee the buffer is a DMA target!
*
- * Locking: May call functions taking tty->buf.lock
+ * Locking: May call functions taking port->buf.lock
*/
int tty_prepare_flip_string_flags(struct tty_struct *tty,
unsigned char **chars, char **flags, size_t size)
{
+ struct tty_bufhead *buf = &tty->port->buf;
int space;
unsigned long __flags;
struct tty_buffer *tb;
- spin_lock_irqsave(&tty->buf.lock, __flags);
- space = __tty_buffer_request_room(tty, size);
+ spin_lock_irqsave(&buf->lock, __flags);
+ space = __tty_buffer_request_room(tty->port, size);
- tb = tty->buf.tail;
+ tb = buf->tail;
if (likely(space)) {
*chars = tb->char_buf_ptr + tb->used;
*flags = tb->flag_buf_ptr + tb->used;
tb->used += space;
}
- spin_unlock_irqrestore(&tty->buf.lock, __flags);
+ spin_unlock_irqrestore(&buf->lock, __flags);
return space;
}
EXPORT_SYMBOL_GPL(tty_prepare_flip_string_flags);
@@ -446,20 +466,25 @@ EXPORT_SYMBOL_GPL(tty_prepare_flip_string_flags);
static void flush_to_ldisc(struct work_struct *work)
{
- struct tty_struct *tty =
- container_of(work, struct tty_struct, buf.work);
+ struct tty_port *port = container_of(work, struct tty_port, buf.work);
+ struct tty_bufhead *buf = &port->buf;
+ struct tty_struct *tty;
unsigned long flags;
struct tty_ldisc *disc;
+ tty = port->itty;
+ if (WARN_RATELIMIT(tty == NULL, "tty is NULL\n"))
+ return;
+
disc = tty_ldisc_ref(tty);
if (disc == NULL) /* !TTY_LDISC */
return;
- spin_lock_irqsave(&tty->buf.lock, flags);
+ spin_lock_irqsave(&buf->lock, flags);
- if (!test_and_set_bit(TTY_FLUSHING, &tty->flags)) {
+ if (!test_and_set_bit(TTYP_FLUSHING, &port->iflags)) {
struct tty_buffer *head;
- while ((head = tty->buf.head) != NULL) {
+ while ((head = buf->head) != NULL) {
int count;
char *char_buf;
unsigned char *flag_buf;
@@ -468,14 +493,14 @@ static void flush_to_ldisc(struct work_struct *work)
if (!count) {
if (head->next == NULL)
break;
- tty->buf.head = head->next;
- tty_buffer_free(tty, head);
+ buf->head = head->next;
+ tty_buffer_free(port, head);
continue;
}
/* Ldisc or user is trying to flush the buffers
we are feeding to the ldisc, stop feeding the
line discipline as we want to empty the queue */
- if (test_bit(TTY_FLUSHPENDING, &tty->flags))
+ if (test_bit(TTYP_FLUSHPENDING, &port->iflags))
break;
if (!tty->receive_room)
break;
@@ -484,22 +509,22 @@ static void flush_to_ldisc(struct work_struct *work)
char_buf = head->char_buf_ptr + head->read;
flag_buf = head->flag_buf_ptr + head->read;
head->read += count;
- spin_unlock_irqrestore(&tty->buf.lock, flags);
+ spin_unlock_irqrestore(&buf->lock, flags);
disc->ops->receive_buf(tty, char_buf,
flag_buf, count);
- spin_lock_irqsave(&tty->buf.lock, flags);
+ spin_lock_irqsave(&buf->lock, flags);
}
- clear_bit(TTY_FLUSHING, &tty->flags);
+ clear_bit(TTYP_FLUSHING, &port->iflags);
}
/* We may have a deferred request to flush the input buffer,
if so pull the chain under the lock and empty the queue */
- if (test_bit(TTY_FLUSHPENDING, &tty->flags)) {
- __tty_buffer_flush(tty);
- clear_bit(TTY_FLUSHPENDING, &tty->flags);
+ if (test_bit(TTYP_FLUSHPENDING, &port->iflags)) {
+ __tty_buffer_flush(port);
+ clear_bit(TTYP_FLUSHPENDING, &port->iflags);
wake_up(&tty->read_wait);
}
- spin_unlock_irqrestore(&tty->buf.lock, flags);
+ spin_unlock_irqrestore(&buf->lock, flags);
tty_ldisc_deref(disc);
}
@@ -514,7 +539,8 @@ static void flush_to_ldisc(struct work_struct *work)
*/
void tty_flush_to_ldisc(struct tty_struct *tty)
{
- flush_work(&tty->buf.work);
+ if (!tty->low_latency)
+ flush_work(&tty->port->buf.work);
}
/**
@@ -532,16 +558,18 @@ void tty_flush_to_ldisc(struct tty_struct *tty)
void tty_flip_buffer_push(struct tty_struct *tty)
{
+ struct tty_bufhead *buf = &tty->port->buf;
unsigned long flags;
- spin_lock_irqsave(&tty->buf.lock, flags);
- if (tty->buf.tail != NULL)
- tty->buf.tail->commit = tty->buf.tail->used;
- spin_unlock_irqrestore(&tty->buf.lock, flags);
+
+ spin_lock_irqsave(&buf->lock, flags);
+ if (buf->tail != NULL)
+ buf->tail->commit = buf->tail->used;
+ spin_unlock_irqrestore(&buf->lock, flags);
if (tty->low_latency)
- flush_to_ldisc(&tty->buf.work);
+ flush_to_ldisc(&buf->work);
else
- schedule_work(&tty->buf.work);
+ schedule_work(&buf->work);
}
EXPORT_SYMBOL(tty_flip_buffer_push);
@@ -555,13 +583,15 @@ EXPORT_SYMBOL(tty_flip_buffer_push);
* Locking: none
*/
-void tty_buffer_init(struct tty_struct *tty)
+void tty_buffer_init(struct tty_port *port)
{
- spin_lock_init(&tty->buf.lock);
- tty->buf.head = NULL;
- tty->buf.tail = NULL;
- tty->buf.free = NULL;
- tty->buf.memory_used = 0;
- INIT_WORK(&tty->buf.work, flush_to_ldisc);
+ struct tty_bufhead *buf = &port->buf;
+
+ spin_lock_init(&buf->lock);
+ buf->head = NULL;
+ buf->tail = NULL;
+ buf->free = NULL;
+ buf->memory_used = 0;
+ INIT_WORK(&buf->work, flush_to_ldisc);
}
Copyright © 1996 – 2023 Jason A. Donenfeld. All Rights Reverse Engineered.