diff options
Diffstat (limited to 'drivers/tty/tty_buffer.c')
| -rw-r--r-- | drivers/tty/tty_buffer.c | 28 |
1 files changed, 19 insertions, 9 deletions
diff --git a/drivers/tty/tty_buffer.c b/drivers/tty/tty_buffer.c index 9733469a14b2..635d0af229b7 100644 --- a/drivers/tty/tty_buffer.c +++ b/drivers/tty/tty_buffer.c @@ -32,8 +32,8 @@ * We default to dicing tty buffer allocations to this many characters * in order to avoid multiple page allocations. We know the size of * tty_buffer itself but it must also be taken into account that the - * the buffer is 256 byte aligned. See tty_buffer_find for the allocation - * logic this must match + * buffer is 256 byte aligned. See tty_buffer_find for the allocation + * logic this must match. */ #define TTY_BUFFER_PAGE (((PAGE_SIZE - sizeof(struct tty_buffer)) / 2) & ~0xFF) @@ -88,9 +88,10 @@ EXPORT_SYMBOL_GPL(tty_buffer_unlock_exclusive); * pre-allocate if memory guarantee is required). */ -int tty_buffer_space_avail(struct tty_port *port) +unsigned int tty_buffer_space_avail(struct tty_port *port) { int space = port->buf.mem_limit - atomic_read(&port->buf.mem_used); + return max(space, 0); } EXPORT_SYMBOL_GPL(tty_buffer_space_avail); @@ -169,7 +170,8 @@ static struct tty_buffer *tty_buffer_alloc(struct tty_port *port, size_t size) } /* Should possibly check if this fails for the largest buffer we - have queued and recycle that ? */ + * have queued and recycle that ? + */ if (atomic_read(&port->buf.mem_used) > port->buf.mem_limit) return NULL; p = kmalloc(sizeof(struct tty_buffer) + 2 * size, GFP_ATOMIC); @@ -242,7 +244,7 @@ void tty_buffer_flush(struct tty_struct *tty, struct tty_ldisc *ld) } /** - * tty_buffer_request_room - grow tty buffer if needed + * __tty_buffer_request_room - grow tty buffer if needed * @port: tty port * @size: size desired * @flags: buffer flags if new buffer allocated (default = 0) @@ -312,11 +314,13 @@ int tty_insert_flip_string_fixed_flag(struct tty_port *port, const unsigned char *chars, char flag, size_t size) { int copied = 0; + do { int goal = min_t(size_t, size - copied, TTY_BUFFER_PAGE); 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); @@ -326,7 +330,8 @@ int tty_insert_flip_string_fixed_flag(struct tty_port *port, copied += space; chars += space; /* There is a small chance that we need to split the data over - several buffers. If this is the case we must loop */ + * several buffers. If this is the case we must loop. + */ } while (unlikely(size > copied)); return copied; } @@ -348,10 +353,12 @@ int tty_insert_flip_string_flags(struct tty_port *port, const unsigned char *chars, const char *flags, size_t size) { int copied = 0; + do { int goal = min_t(size_t, size - copied, TTY_BUFFER_PAGE); int space = tty_buffer_request_room(port, goal); struct tty_buffer *tb = port->buf.tail; + if (unlikely(space == 0)) break; memcpy(char_buf_ptr(tb, tb->used), chars, space); @@ -361,7 +368,8 @@ int tty_insert_flip_string_flags(struct tty_port *port, chars += space; flags += space; /* There is a small chance that we need to split the data over - several buffers. If this is the case we must loop */ + * several buffers. If this is the case we must loop. + */ } while (unlikely(size > copied)); return copied; } @@ -431,8 +439,10 @@ int tty_prepare_flip_string(struct tty_port *port, unsigned char **chars, size_t 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); if (~tb->flags & TTYB_NORMAL) memset(flag_buf_ptr(tb, tb->used), TTY_NORMAL, space); @@ -455,7 +465,7 @@ EXPORT_SYMBOL_GPL(tty_prepare_flip_string); * Returns the number of bytes processed */ int tty_ldisc_receive_buf(struct tty_ldisc *ld, const unsigned char *p, - char *f, int count) + const char *f, int count) { if (ld->ops->receive_buf2) count = ld->ops->receive_buf2(ld->tty, p, f, count); @@ -472,7 +482,7 @@ static int receive_buf(struct tty_port *port, struct tty_buffer *head, int count) { unsigned char *p = char_buf_ptr(head, head->read); - char *f = NULL; + const char *f = NULL; int n; if (~head->flags & TTYB_NORMAL) |