From 5a081caa0414b9bbb82c17ffab9d6fe66edbb72f Mon Sep 17 00:00:00 2001 From: Ohad Ben-Cohen Date: Wed, 6 Jun 2012 10:09:25 +0300 Subject: rpmsg: avoid premature deallocation of endpoints When an inbound message arrives, the rpmsg core looks up its associated endpoint and invokes the registered callback. If a message arrives while its endpoint is being removed (because the rpmsg driver was removed, or a recovery of a remote processor has kicked in) we must ensure atomicity, i.e.: - Either the ept is removed before it is found or - The ept is found but will not be freed until the callback returns This is achieved by maintaining a per-ept reference count, which, when drops to zero, will trigger deallocation of the ept. With this in hand, it is now forbidden to directly deallocate epts once they have been added to the endpoints idr. Cc: stable Reported-by: Fernando Guzman Lugo Signed-off-by: Ohad Ben-Cohen --- include/linux/rpmsg.h | 3 +++ 1 file changed, 3 insertions(+) (limited to 'include') diff --git a/include/linux/rpmsg.h b/include/linux/rpmsg.h index a8e50e44203c..195f373590b8 100644 --- a/include/linux/rpmsg.h +++ b/include/linux/rpmsg.h @@ -38,6 +38,7 @@ #include #include #include +#include /* The feature bitmap for virtio rpmsg */ #define VIRTIO_RPMSG_F_NS 0 /* RP supports name service notifications */ @@ -120,6 +121,7 @@ typedef void (*rpmsg_rx_cb_t)(struct rpmsg_channel *, void *, int, void *, u32); /** * struct rpmsg_endpoint - binds a local rpmsg address to its user * @rpdev: rpmsg channel device + * @refcount: when this drops to zero, the ept is deallocated * @cb: rx callback handler * @addr: local rpmsg address * @priv: private data for the driver's use @@ -140,6 +142,7 @@ typedef void (*rpmsg_rx_cb_t)(struct rpmsg_channel *, void *, int, void *, u32); */ struct rpmsg_endpoint { struct rpmsg_channel *rpdev; + struct kref refcount; rpmsg_rx_cb_t cb; u32 addr; void *priv; -- cgit v1.2.3