On 11/11/2013 03:05 PM, Jiri Slaby wrote:
When we leak something, warn about that. For that we need to account
the memory used also in the free_all method. It is handled elsewhere
correctly.

Hi Jiri,

Good idea.

Signed-off-by: Jiri Slaby <[email protected]>
---
  drivers/tty/tty_buffer.c | 10 ++++++++--
  1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/drivers/tty/tty_buffer.c b/drivers/tty/tty_buffer.c
index 5f08c39e76ab..20cb9492dbf8 100644
--- a/drivers/tty/tty_buffer.c
+++ b/drivers/tty/tty_buffer.c
@@ -115,21 +115,27 @@ void tty_buffer_free_all(struct tty_port *port)
        struct tty_bufhead *buf = &port->buf;
        struct tty_buffer *p, *next;
        struct llist_node *llist;
+       int zero = 0;

        while ((p = buf->head) != NULL) {
                buf->head = p->next;
+               atomic_sub(p->size, &buf->memory_used);

buf->memory_used doesn't need to be treated atomically here,
and doing so implies that it's necessary.

Accumulating p->size in a non-atomic local is probably better.

                if (p->size > 0)
                        kfree(p);
        }
        llist = llist_del_all(&buf->free);
-       llist_for_each_entry_safe(p, next, llist, free)
+       llist_for_each_entry_safe(p, next, llist, free) {
+               atomic_sub(p->size, &buf->memory_used);

Same here.

                kfree(p);
+       }
+

        tty_buffer_reset(&buf->sentinel, 0);
        buf->head = &buf->sentinel;
        buf->tail = &buf->sentinel;

-       atomic_set(&buf->memory_used, 0);
+       atomic_xchg(&buf->memory_used, zero);
+       WARN_ON(zero != 0);

Then,

WARN_ON(atomic_read(&buf->memory_used) != <local accum>);
atomic_set(&buf->memory_used, 0);

?

Regards,
Peter Hurley

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