Merge tag 'pinctrl-v3.15-3' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw...

[mirror_ubuntu-bionic-kernel.git] / drivers / tty / tty_buffer.c

diff --git a/drivers/tty/tty_buffer.c b/drivers/tty/tty_buffer.c
index 8ebd9f88a6f69ff85f63139944fad2542c789483..f1d30f6945af2cf8fece1a5a1b40d59aa46cd5e0 100644 (file)
--- a/drivers/tty/tty_buffer.c
+++ b/drivers/tty/tty_buffer.c
@@ -255,11 +255,16 @@ static int __tty_buffer_request_room(struct tty_port *port, size_t size,
        if (change || left < size) {
                /* This is the slow path - looking for new buffers to use */
                if ((n = tty_buffer_alloc(port, size)) != NULL) {
+                       unsigned long iflags;
+
                        n->flags = flags;
                        buf->tail = n;
+
+                       spin_lock_irqsave(&buf->flush_lock, iflags);
                        b->commit = b->used;
-                       smp_mb();
                        b->next = n;
+                       spin_unlock_irqrestore(&buf->flush_lock, iflags);
+
                } else if (change)
                        size = 0;
                else
@@ -443,6 +448,7 @@ static void flush_to_ldisc(struct work_struct *work)
        mutex_lock(&buf->lock);
 
        while (1) {
+               unsigned long flags;
                struct tty_buffer *head = buf->head;
                int count;
 
@@ -450,14 +456,19 @@ static void flush_to_ldisc(struct work_struct *work)
                if (atomic_read(&buf->priority))
                        break;
 
+               spin_lock_irqsave(&buf->flush_lock, flags);
                count = head->commit - head->read;
                if (!count) {
-                       if (head->next == NULL)
+                       if (head->next == NULL) {
+                               spin_unlock_irqrestore(&buf->flush_lock, flags);
                                break;
+                       }
                        buf->head = head->next;
+                       spin_unlock_irqrestore(&buf->flush_lock, flags);
                        tty_buffer_free(port, head);
                        continue;
                }
+               spin_unlock_irqrestore(&buf->flush_lock, flags);
 
                count = receive_buf(tty, head, count);
                if (!count)
@@ -512,6 +523,7 @@ void tty_buffer_init(struct tty_port *port)
        struct tty_bufhead *buf = &port->buf;
 
        mutex_init(&buf->lock);
+       spin_lock_init(&buf->flush_lock);
        tty_buffer_reset(&buf->sentinel, 0);
        buf->head = &buf->sentinel;
        buf->tail = &buf->sentinel;