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yaml
---
r: 338351
b: refs/heads/master
c: 5cff39c
h: refs/heads/master
i:
  338349: 5a3f448
  338347: 1ed57a0
  338343: a9e18ba
  338335: 4ba2bf5
v: v3
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Jiri Slaby authored and Greg Kroah-Hartman committed Oct 22, 2012
1 parent bc224e5 commit f0a7c0f
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Showing 2 changed files with 77 additions and 57 deletions.
2 changes: 1 addition & 1 deletion [refs]
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Original file line number Diff line number Diff line change
@@ -1,2 +1,2 @@
---
refs/heads/master: 2fc20661e3171d45e8e58a61eb5c6b7d8d614fde
refs/heads/master: 5cff39c69b57df6d7bf4e87f2963571aa4ea6336
132 changes: 76 additions & 56 deletions trunk/drivers/tty/tty_buffer.c
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Original file line number Diff line number Diff line change
Expand Up @@ -29,17 +29,19 @@

void tty_buffer_free_all(struct tty_struct *tty)
{
struct tty_bufhead *buf = &tty->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;
}

/**
Expand Down Expand Up @@ -87,15 +89,17 @@ static struct tty_buffer *tty_buffer_alloc(struct tty_struct *tty, size_t size)

static void tty_buffer_free(struct tty_struct *tty, struct tty_buffer *b)
{
struct tty_bufhead *buf = &tty->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;
}
}

Expand All @@ -112,13 +116,14 @@ static void tty_buffer_free(struct tty_struct *tty, struct tty_buffer *b)

static void __tty_buffer_flush(struct tty_struct *tty)
{
struct tty_bufhead *buf = &tty->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;
tty_buffer_free(tty, thead);
}
tty->buf.tail = NULL;
buf->tail = NULL;
}

/**
Expand All @@ -135,21 +140,23 @@ 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 = &tty->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(TTYP_FLUSHING, &port->iflags)) {
set_bit(TTYP_FLUSHPENDING, &port->iflags);
spin_unlock_irqrestore(&tty->buf.lock, flags);
spin_unlock_irqrestore(&buf->lock, flags);
wait_event(tty->read_wait,
test_bit(TTYP_FLUSHPENDING, &port->iflags) == 0);
return;
} else
__tty_buffer_flush(tty);
spin_unlock_irqrestore(&tty->buf.lock, flags);
spin_unlock_irqrestore(&buf->lock, flags);
}

/**
Expand Down Expand Up @@ -197,12 +204,14 @@ static struct tty_buffer *tty_buffer_find(struct tty_struct *tty, size_t size)
*/
static int __tty_buffer_request_room(struct tty_struct *tty, size_t size)
{
struct tty_bufhead *buf = &tty->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;
Expand All @@ -214,8 +223,8 @@ static int __tty_buffer_request_room(struct tty_struct *tty, size_t size)
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;
}
Expand Down Expand Up @@ -262,25 +271,26 @@ EXPORT_SYMBOL_GPL(tty_buffer_request_room);
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->buf;
int copied = 0;
do {
int goal = min_t(size_t, size - copied, TTY_BUFFER_PAGE);
int space;
unsigned long flags;
struct tty_buffer *tb;

spin_lock_irqsave(&tty->buf.lock, flags);
spin_lock_irqsave(&buf->lock, flags);
space = __tty_buffer_request_room(tty, goal);
tb = tty->buf.tail;
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
Expand All @@ -307,25 +317,26 @@ EXPORT_SYMBOL(tty_insert_flip_string_fixed_flag);
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->buf;
int copied = 0;
do {
int goal = min_t(size_t, size - copied, TTY_BUFFER_PAGE);
int space;
unsigned long __flags;
struct tty_buffer *tb;

spin_lock_irqsave(&tty->buf.lock, __flags);
spin_lock_irqsave(&buf->lock, __flags);
space = __tty_buffer_request_room(tty, goal);
tb = tty->buf.tail;
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;
Expand All @@ -351,12 +362,14 @@ EXPORT_SYMBOL(tty_insert_flip_string_flags);

void tty_schedule_flip(struct tty_struct *tty)
{
struct tty_bufhead *buf = &tty->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);

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);

Expand All @@ -378,20 +391,21 @@ EXPORT_SYMBOL(tty_schedule_flip);
int tty_prepare_flip_string(struct tty_struct *tty, unsigned char **chars,
size_t size)
{
struct tty_bufhead *buf = &tty->buf;
int space;
unsigned long flags;
struct tty_buffer *tb;

spin_lock_irqsave(&tty->buf.lock, flags);
spin_lock_irqsave(&buf->lock, flags);
space = __tty_buffer_request_room(tty, 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);
Expand All @@ -415,20 +429,21 @@ EXPORT_SYMBOL_GPL(tty_prepare_flip_string);
int tty_prepare_flip_string_flags(struct tty_struct *tty,
unsigned char **chars, char **flags, size_t size)
{
struct tty_bufhead *buf = &tty->buf;
int space;
unsigned long __flags;
struct tty_buffer *tb;

spin_lock_irqsave(&tty->buf.lock, __flags);
spin_lock_irqsave(&buf->lock, __flags);
space = __tty_buffer_request_room(tty, 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);
Expand All @@ -452,18 +467,19 @@ 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 = tty->port;
struct tty_bufhead *buf = &tty->buf;
unsigned long flags;
struct tty_ldisc *disc;

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(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;
Expand All @@ -472,7 +488,7 @@ static void flush_to_ldisc(struct work_struct *work)
if (!count) {
if (head->next == NULL)
break;
tty->buf.head = head->next;
buf->head = head->next;
tty_buffer_free(tty, head);
continue;
}
Expand All @@ -488,10 +504,10 @@ 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(TTYP_FLUSHING, &port->iflags);
}
Expand All @@ -503,7 +519,7 @@ static void flush_to_ldisc(struct work_struct *work)
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);
}
Expand Down Expand Up @@ -537,16 +553,18 @@ void tty_flush_to_ldisc(struct tty_struct *tty)

void tty_flip_buffer_push(struct tty_struct *tty)
{
struct tty_bufhead *buf = &tty->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);

Expand All @@ -562,11 +580,13 @@ EXPORT_SYMBOL(tty_flip_buffer_push);

void tty_buffer_init(struct tty_struct *tty)
{
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 = &tty->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);
}

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