]> git.kernelconcepts.de Git - karo-tx-linux.git/blobdiff - drivers/tty/tty_buffer.c
TTY: move tty buffers to tty_port
[karo-tx-linux.git] / drivers / tty / tty_buffer.c
index 91e326ffe7db826054c2607c1ea2688ed047bb81..06725f5cc819aa98362ec87e41fa3c4c9418e9b6 100644 (file)
  *     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 +355,22 @@ 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);
+
+       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 +386,27 @@ 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 +424,27 @@ 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 +465,25 @@ 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"))
+               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 +492,14 @@ 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 +508,22 @@ 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 +538,8 @@ 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 +557,18 @@ 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 +582,15 @@ 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);
 }