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authorToke Høiland-Jørgensen <toke@redhat.com>2021-06-24 18:05:59 +0200
committerDaniel Borkmann <daniel@iogearbox.net>2021-06-24 19:44:02 +0200
commit36baafe347a85a9d85f61aac0a9b53c53635829e (patch)
treeedcad54526c97cfef56d152c7512ddf4bebfa822 /drivers/net
parent158c1399fc45c5178a3f2b8b68ff2faa2e36a52d (diff)
thunderx: Remove rcu_read_lock() around XDP program invocation
The thunderx driver has rcu_read_lock()/rcu_read_unlock() pairs around XDP program invocations. However, the actual lifetime of the objects referred by the XDP program invocation is longer, all the way through to the call to xdp_do_flush(), making the scope of the rcu_read_lock() too small. This turns out to be harmless because it all happens in a single NAPI poll cycle (and thus under local_bh_disable()), but it makes the rcu_read_lock() misleading. Rather than extend the scope of the rcu_read_lock(), just get rid of it entirely. With the addition of RCU annotations to the XDP_REDIRECT map types that take bh execution into account, lockdep even understands this to be safe, so there's really no reason to keep it around. Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Cc: Sunil Goutham <sgoutham@marvell.com> Cc: linux-arm-kernel@lists.infradead.org Link: https://lore.kernel.org/bpf/20210624160609.292325-10-toke@redhat.com
Diffstat (limited to 'drivers/net')
-rw-r--r--drivers/net/ethernet/cavium/thunder/nicvf_main.c2
1 files changed, 0 insertions, 2 deletions
diff --git a/drivers/net/ethernet/cavium/thunder/nicvf_main.c b/drivers/net/ethernet/cavium/thunder/nicvf_main.c
index c33b4e837515..e2b290135fd9 100644
--- a/drivers/net/ethernet/cavium/thunder/nicvf_main.c
+++ b/drivers/net/ethernet/cavium/thunder/nicvf_main.c
@@ -555,9 +555,7 @@ static inline bool nicvf_xdp_rx(struct nicvf *nic, struct bpf_prog *prog,
xdp_prepare_buff(&xdp, hard_start, data - hard_start, len, false);
orig_data = xdp.data;
- rcu_read_lock();
action = bpf_prog_run_xdp(prog, &xdp);
- rcu_read_unlock();
len = xdp.data_end - xdp.data;
/* Check if XDP program has changed headers */