Re: [PATCH 8/9] libceph: protect ceph_con_open() with mutex

[Alex Elder <elder@inktank.com>]

On 07/20/2012 07:41 PM, Sage Weil wrote:
> Take the con mutex while we are initiating a ceph open.  This is necessary
> because the may have previously been in use and then closed, which could
> result in a racing workqueue running con_work().
> 
> Signed-off-by: Sage Weil <sage@inktank.com>

Well there you go, another place where a state bit is
changed without holding the mutex.

Looks good.

Reviewed-by: Alex Elder <elder@inktank.com>

> ---
>  net/ceph/messenger.c |    2 ++
>  1 files changed, 2 insertions(+), 0 deletions(-)
> 
> diff --git a/net/ceph/messenger.c b/net/ceph/messenger.c
> index efa369f..65964c2 100644
> --- a/net/ceph/messenger.c
> +++ b/net/ceph/messenger.c
> @@ -537,6 +537,7 @@ void ceph_con_open(struct ceph_connection *con,
>  		   __u8 entity_type, __u64 entity_num,
>  		   struct ceph_entity_addr *addr)
>  {
> +	mutex_lock(&con->mutex);
>  	dout("con_open %p %s\n", con, ceph_pr_addr(&addr->in_addr));
>  	set_bit(OPENING, &con->state);
>  	WARN_ON(!test_and_clear_bit(CLOSED, &con->state));
> @@ -546,6 +547,7 @@ void ceph_con_open(struct ceph_connection *con,
>  
>  	memcpy(&con->peer_addr, addr, sizeof(*addr));
>  	con->delay = 0;      /* reset backoff memory */
> +	mutex_unlock(&con->mutex);
>  	queue_con(con);
>  }
>  EXPORT_SYMBOL(ceph_con_open);
>