On Wed, Sep 05, 2018 at 09:36:43PM +0000, Ruhl, Michael J wrote: > >From: linux-rdma-owner@xxxxxxxxxxxxxxx [mailto:linux-rdma- > >owner@xxxxxxxxxxxxxxx] On Behalf Of Leon Romanovsky > >Sent: Wednesday, September 5, 2018 5:54 AM > >To: Doug Ledford <dledford@xxxxxxxxxx>; Jason Gunthorpe > ><jgg@xxxxxxxxxxxx> > >Cc: Leon Romanovsky <leonro@xxxxxxxxxxxx>; RDMA mailing list <linux- > >rdma@xxxxxxxxxxxxxxx>; Daniel Jurgens <danielj@xxxxxxxxxxxx>; Parav > >Pandit <parav@xxxxxxxxxxxx>; Yuval Shaia <yuval.shaia@xxxxxxxxxx> > >Subject: [PATCH rdma-next 01/11] RDMA/core Introduce and use > >rdma_find_ndev_for_src_ip_rcu > > > >From: Parav Pandit <parav@xxxxxxxxxxxx> > > > >Commit in fixes tag introduced two issues. > >1. When address family is other than IPv4 or v6, rdma_translate_ip() > >returns success which is incorrect. > >2. When address familty is AF_INET6, and if the source address is not > >found, it returns success, which is also incorrect. > > > >Therefore, introduce and use rdma_find_ndev_for_src_ip_rcu() helper > >function which returns correct success or error status and is also > >useful for future code refactor in addr_resolve(). > > > >Fixes: e08ce2e82b2f ("RDMA/core: Make function rdma_copy_addr return > >void") > >Signed-off-by: Parav Pandit <parav@xxxxxxxxxxxx> > >Reviewed-by: Daniel Jurgens <danielj@xxxxxxxxxxxx> > >Signed-off-by: Leon Romanovsky <leonro@xxxxxxxxxxxx> > > drivers/infiniband/core/addr.c | 61 ++++++++++++++++++++++++------------- > > 1 file changed, 35 insertions(+), 26 deletions(-) > > > >diff --git a/drivers/infiniband/core/addr.c b/drivers/infiniband/core/addr.c > >index 94ff38731be8..50ab50f1908b 100644 > >+++ b/drivers/infiniband/core/addr.c > >@@ -232,6 +232,36 @@ void rdma_copy_addr(struct rdma_dev_addr > >*dev_addr, > > } > > EXPORT_SYMBOL(rdma_copy_addr); > > > >+static struct net_device * > >+rdma_find_ndev_for_src_ip_rcu(struct net *net, const struct sockaddr > >*src_in) > >+{ > >+ struct net_device *dev = NULL; > >+ int ret = -EADDRNOTAVAIL; > >+ > >+ switch (src_in->sa_family) { > >+ case AF_INET: > >+ dev = __ip_dev_find(net, > >+ ((const struct sockaddr_in *)src_in)- > >>sin_addr.s_addr, > >+ false); > > __ip_dev_find() does an rcu_read_lock()/rcu_read_unlock() sequence. > > Is taking it before calling rdma_find_ndev_for_src_ip_rcu() the right thing to do? rcu is safe to nest.. But I can't quite remember why we needed to hold the rcu there across rdma_copy_addr, as we do have the dev_hold at that point.. Maybe that use of RCU is overly pessimistic? Parav? Jason
