diff options
| author | Toke Høiland-Jørgensen <toke@redhat.com> | 2021-06-24 19:06:01 +0300 |
|---|---|---|
| committer | Daniel Borkmann <daniel@iogearbox.net> | 2021-06-24 20:44:34 +0300 |
| commit | 49589b23d5a92dff4a7cb705608dff7dd13ef709 (patch) | |
| tree | 83b9f210e32623ee94a0aeff93fa8708d485df59 /drivers/net/ethernet/intel/i40e/i40e_xsk.c | |
| parent | 547aabcac3251c40e4cd09d79dba70f7eab8cca2 (diff) | |
| download | linux-49589b23d5a92dff4a7cb705608dff7dd13ef709.tar.xz | |
intel: Remove rcu_read_lock() around XDP program invocation
The Intel drivers all have 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>
Tested-by: Jesper Dangaard Brouer <brouer@redhat.com> # i40e
Cc: Jesse Brandeburg <jesse.brandeburg@intel.com>
Cc: Tony Nguyen <anthony.l.nguyen@intel.com>
Cc: intel-wired-lan@lists.osuosl.org
Link: https://lore.kernel.org/bpf/20210624160609.292325-12-toke@redhat.com
Diffstat (limited to 'drivers/net/ethernet/intel/i40e/i40e_xsk.c')
| -rw-r--r-- | drivers/net/ethernet/intel/i40e/i40e_xsk.c | 3 |
1 files changed, 0 insertions, 3 deletions
diff --git a/drivers/net/ethernet/intel/i40e/i40e_xsk.c b/drivers/net/ethernet/intel/i40e/i40e_xsk.c index 68f177a86403..e7e778ca074c 100644 --- a/drivers/net/ethernet/intel/i40e/i40e_xsk.c +++ b/drivers/net/ethernet/intel/i40e/i40e_xsk.c @@ -153,7 +153,6 @@ static int i40e_run_xdp_zc(struct i40e_ring *rx_ring, struct xdp_buff *xdp) struct bpf_prog *xdp_prog; u32 act; - rcu_read_lock(); /* NB! xdp_prog will always be !NULL, due to the fact that * this path is enabled by setting an XDP program. */ @@ -164,7 +163,6 @@ static int i40e_run_xdp_zc(struct i40e_ring *rx_ring, struct xdp_buff *xdp) err = xdp_do_redirect(rx_ring->netdev, xdp, xdp_prog); if (err) goto out_failure; - rcu_read_unlock(); return I40E_XDP_REDIR; } @@ -188,7 +186,6 @@ out_failure: result = I40E_XDP_CONSUMED; break; } - rcu_read_unlock(); return result; } |