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path: root/drivers/tty/tty_buffer.c
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Diffstat (limited to 'drivers/tty/tty_buffer.c')
-rw-r--r--drivers/tty/tty_buffer.c12
1 files changed, 5 insertions, 7 deletions
diff --git a/drivers/tty/tty_buffer.c b/drivers/tty/tty_buffer.c
index 4cf263d7dffc..5a3fa8913880 100644
--- a/drivers/tty/tty_buffer.c
+++ b/drivers/tty/tty_buffer.c
@@ -291,12 +291,11 @@ static int __tty_buffer_request_room(struct tty_port *port, size_t size,
n->flags = flags;
buf->tail = n;
b->commit = b->used;
- /* paired w/ barrier in flush_to_ldisc(); ensures the
+ /* paired w/ acquire in flush_to_ldisc(); ensures the
* latest commit value can be read before the head is
* advanced to the next buffer
*/
- smp_wmb();
- b->next = n;
+ smp_store_release(&b->next, n);
} else if (change)
size = 0;
else
@@ -445,7 +444,6 @@ receive_buf(struct tty_struct *tty, struct tty_buffer *head, int count)
if (count)
disc->ops->receive_buf(tty, p, f, count);
}
- head->read += count;
return count;
}
@@ -488,12 +486,11 @@ static void flush_to_ldisc(struct work_struct *work)
if (atomic_read(&buf->priority))
break;
- next = head->next;
- /* paired w/ barrier in __tty_buffer_request_room();
+ /* paired w/ release in __tty_buffer_request_room();
* ensures commit value read is not stale if the head
* is advancing to the next buffer
*/
- smp_rmb();
+ next = smp_load_acquire(&head->next);
count = head->commit - head->read;
if (!count) {
if (next == NULL) {
@@ -508,6 +505,7 @@ static void flush_to_ldisc(struct work_struct *work)
count = receive_buf(tty, head, count);
if (!count)
break;
+ head->read += count;
}
mutex_unlock(&buf->lock);