| Message ID | 20210623110727.221922-16-toke@redhat.com (mailing list archive) |
|---|---|
| State | Superseded |
| Delegated to: | BPF |
| Headers | show |
| Series | Clean up and document RCU-based object protection for XDP and TC BPF | expand |
| Context | Check | Description |
|---|---|---|
| netdev/apply | fail | Patch does not apply to bpf-next |
| netdev/tree_selection | success | Clearly marked for bpf-next |
diff --git a/drivers/net/ethernet/qlogic/qede/qede_fp.c b/drivers/net/ethernet/qlogic/qede/qede_fp.c index 8e150dd4f899..065e9004598e 100644 --- a/drivers/net/ethernet/qlogic/qede/qede_fp.c +++ b/drivers/net/ethernet/qlogic/qede/qede_fp.c @@ -1089,13 +1089,7 @@ static bool qede_rx_xdp(struct qede_dev *edev, xdp_prepare_buff(&xdp, page_address(bd->data), *data_offset, *len, false); - /* Queues always have a full reset currently, so for the time - * being until there's atomic program replace just mark read - * side for map helpers. - */ - rcu_read_lock(); act = bpf_prog_run_xdp(prog, &xdp); - rcu_read_unlock(); /* Recalculate, as XDP might have changed the headers */ *data_offset = xdp.data - xdp.data_hard_start;
The qede 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. Cc: Ariel Elior <aelior@marvell.com> Cc: GR-everest-linux-l2@marvell.com Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com> --- drivers/net/ethernet/qlogic/qede/qede_fp.c | 6 ------ 1 file changed, 6 deletions(-)