diff options
Diffstat (limited to 'drivers/tty/tty_buffer.c')
| -rw-r--r-- | drivers/tty/tty_buffer.c | 85 |
1 files changed, 65 insertions, 20 deletions
diff --git a/drivers/tty/tty_buffer.c b/drivers/tty/tty_buffer.c index 6c9b7cd6778..91e326ffe7d 100644 --- a/drivers/tty/tty_buffer.c +++ b/drivers/tty/tty_buffer.c @@ -185,25 +185,19 @@ static struct tty_buffer *tty_buffer_find(struct tty_struct *tty, size_t 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_buffer_request_room - grow tty buffer if needed * @tty: tty structure * @size: size desired * * 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: Caller must hold tty->buf.lock */ -int tty_buffer_request_room(struct tty_struct *tty, size_t size) +static int __tty_buffer_request_room(struct tty_struct *tty, size_t size) { struct tty_buffer *b, *n; int left; - unsigned long flags; - - spin_lock_irqsave(&tty->buf.lock, flags); - /* 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 */ @@ -225,9 +219,30 @@ int tty_buffer_request_room(struct tty_struct *tty, size_t size) size = left; } - spin_unlock_irqrestore(&tty->buf.lock, flags); return size; } + + +/** + * tty_buffer_request_room - grow tty buffer if needed + * @tty: tty structure + * @size: size desired + * + * 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 + */ +int tty_buffer_request_room(struct tty_struct *tty, size_t size) +{ + 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); + return length; +} EXPORT_SYMBOL_GPL(tty_buffer_request_room); /** @@ -249,14 +264,22 @@ int tty_insert_flip_string_fixed_flag(struct tty_struct *tty, int copied = 0; do { int goal = min_t(size_t, size - copied, TTY_BUFFER_PAGE); - int space = tty_buffer_request_room(tty, goal); - struct tty_buffer *tb = tty->buf.tail; + int space; + 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; /* If there is no space then tb may be NULL */ - if (unlikely(space == 0)) + if (unlikely(space == 0)) { + spin_unlock_irqrestore(&tty->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); copied += space; chars += space; /* There is a small chance that we need to split the data over @@ -286,14 +309,22 @@ int tty_insert_flip_string_flags(struct tty_struct *tty, int copied = 0; do { int goal = min_t(size_t, size - copied, TTY_BUFFER_PAGE); - int space = tty_buffer_request_room(tty, goal); - struct tty_buffer *tb = tty->buf.tail; + int space; + 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; /* If there is no space then tb may be NULL */ - if (unlikely(space == 0)) + if (unlikely(space == 0)) { + spin_unlock_irqrestore(&tty->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); copied += space; chars += space; flags += space; @@ -344,13 +375,20 @@ EXPORT_SYMBOL(tty_schedule_flip); int tty_prepare_flip_string(struct tty_struct *tty, unsigned char **chars, size_t size) { - int space = tty_buffer_request_room(tty, size); + int space; + unsigned long flags; + struct tty_buffer *tb; + + spin_lock_irqsave(&tty->buf.lock, flags); + space = __tty_buffer_request_room(tty, size); + + tb = tty->buf.tail; if (likely(space)) { - struct tty_buffer *tb = tty->buf.tail; *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); return space; } EXPORT_SYMBOL_GPL(tty_prepare_flip_string); @@ -374,13 +412,20 @@ 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) { - int space = tty_buffer_request_room(tty, size); + int space; + unsigned long __flags; + struct tty_buffer *tb; + + spin_lock_irqsave(&tty->buf.lock, __flags); + space = __tty_buffer_request_room(tty, size); + + tb = tty->buf.tail; if (likely(space)) { - struct tty_buffer *tb = tty->buf.tail; *chars = tb->char_buf_ptr + tb->used; *flags = tb->flag_buf_ptr + tb->used; tb->used += space; } + spin_unlock_irqrestore(&tty->buf.lock, __flags); return space; } EXPORT_SYMBOL_GPL(tty_prepare_flip_string_flags); |