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authorJakub Kicinski <kuba@kernel.org>2020-09-09 10:37:51 -0700
committerDavid S. Miller <davem@davemloft.net>2020-09-10 13:08:46 -0700
commit5198d545dba8ad893f5e5a029ca8d43ee7bcf011 (patch)
treec06ec2bb85e93be90c7d71026c0d2affb984fcd6 /drivers/net/ethernet
parent8b40f21b699df25dcc8b98d0de7774a1e45fca4f (diff)
net: remove napi_hash_del() from driver-facing API
We allow drivers to call napi_hash_del() before calling netif_napi_del() to batch RCU grace periods. This makes the API asymmetric and leaks internal implementation details. Soon we will want the grace period to protect more than just the NAPI hash table. Restructure the API and have drivers call a new function - __netif_napi_del() if they want to take care of RCU waits. Note that only core was checking the return status from napi_hash_del() so the new helper does not report if the NAPI was actually deleted. Some notes on driver oddness: - veth observed the grace period before calling netif_napi_del() but that should not matter - myri10ge observed normal RCU flavor - bnx2x and enic did not actually observe the grace period (unless they did so implicitly) - virtio_net and enic only unhashed Rx NAPIs The last two points seem to indicate that the calls to napi_hash_del() were a left over rather than an optimization. Regardless, it's easy enough to correct them. This patch may introduce extra synchronize_net() calls for interfaces which set NAPI_STATE_NO_BUSY_POLL and depend on free_netdev() to call netif_napi_del(). This seems inevitable since we want to use RCU for netpoll dev->napi_list traversal, and almost no drivers set IFF_DISABLE_NETPOLL. Signed-off-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'drivers/net/ethernet')
-rw-r--r--drivers/net/ethernet/broadcom/bnx2x/bnx2x_cmn.h8
-rw-r--r--drivers/net/ethernet/broadcom/bnxt/bnxt.c5
-rw-r--r--drivers/net/ethernet/cisco/enic/enic_main.c12
-rw-r--r--drivers/net/ethernet/intel/ixgbe/ixgbe_lib.c4
-rw-r--r--drivers/net/ethernet/myricom/myri10ge/myri10ge.c5
5 files changed, 17 insertions, 17 deletions
diff --git a/drivers/net/ethernet/broadcom/bnx2x/bnx2x_cmn.h b/drivers/net/ethernet/broadcom/bnx2x/bnx2x_cmn.h
index 7e4c93be4451..d8b1824c334d 100644
--- a/drivers/net/ethernet/broadcom/bnx2x/bnx2x_cmn.h
+++ b/drivers/net/ethernet/broadcom/bnx2x/bnx2x_cmn.h
@@ -825,9 +825,9 @@ static inline void bnx2x_del_all_napi_cnic(struct bnx2x *bp)
int i;
for_each_rx_queue_cnic(bp, i) {
- napi_hash_del(&bnx2x_fp(bp, i, napi));
- netif_napi_del(&bnx2x_fp(bp, i, napi));
+ __netif_napi_del(&bnx2x_fp(bp, i, napi));
}
+ synchronize_net();
}
static inline void bnx2x_del_all_napi(struct bnx2x *bp)
@@ -835,9 +835,9 @@ static inline void bnx2x_del_all_napi(struct bnx2x *bp)
int i;
for_each_eth_queue(bp, i) {
- napi_hash_del(&bnx2x_fp(bp, i, napi));
- netif_napi_del(&bnx2x_fp(bp, i, napi));
+ __netif_napi_del(&bnx2x_fp(bp, i, napi));
}
+ synchronize_net();
}
int bnx2x_set_int_mode(struct bnx2x *bp);
diff --git a/drivers/net/ethernet/broadcom/bnxt/bnxt.c b/drivers/net/ethernet/broadcom/bnxt/bnxt.c
index b167066af450..53f64ca673c3 100644
--- a/drivers/net/ethernet/broadcom/bnxt/bnxt.c
+++ b/drivers/net/ethernet/broadcom/bnxt/bnxt.c
@@ -8634,10 +8634,9 @@ static void bnxt_del_napi(struct bnxt *bp)
for (i = 0; i < bp->cp_nr_rings; i++) {
struct bnxt_napi *bnapi = bp->bnapi[i];
- napi_hash_del(&bnapi->napi);
- netif_napi_del(&bnapi->napi);
+ __netif_napi_del(&bnapi->napi);
}
- /* We called napi_hash_del() before netif_napi_del(), we need
+ /* We called __netif_napi_del(), we need
* to respect an RCU grace period before freeing napi structures.
*/
synchronize_net();
diff --git a/drivers/net/ethernet/cisco/enic/enic_main.c b/drivers/net/ethernet/cisco/enic/enic_main.c
index a4e307636f5a..4f0329d8778f 100644
--- a/drivers/net/ethernet/cisco/enic/enic_main.c
+++ b/drivers/net/ethernet/cisco/enic/enic_main.c
@@ -2529,13 +2529,15 @@ static void enic_dev_deinit(struct enic *enic)
{
unsigned int i;
- for (i = 0; i < enic->rq_count; i++) {
- napi_hash_del(&enic->napi[i]);
- netif_napi_del(&enic->napi[i]);
- }
+ for (i = 0; i < enic->rq_count; i++)
+ __netif_napi_del(&enic->napi[i]);
+
if (vnic_dev_get_intr_mode(enic->vdev) == VNIC_DEV_INTR_MODE_MSIX)
for (i = 0; i < enic->wq_count; i++)
- netif_napi_del(&enic->napi[enic_cq_wq(enic, i)]);
+ __netif_napi_del(&enic->napi[enic_cq_wq(enic, i)]);
+
+ /* observe RCU grace period after __netif_napi_del() calls */
+ synchronize_net();
enic_free_vnic_resources(enic);
enic_clear_intr_mode(enic);
diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_lib.c b/drivers/net/ethernet/intel/ixgbe/ixgbe_lib.c
index 2e35c5706cf1..df389a11d3af 100644
--- a/drivers/net/ethernet/intel/ixgbe/ixgbe_lib.c
+++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_lib.c
@@ -1029,10 +1029,10 @@ static void ixgbe_free_q_vector(struct ixgbe_adapter *adapter, int v_idx)
WRITE_ONCE(adapter->rx_ring[ring->queue_index], NULL);
adapter->q_vector[v_idx] = NULL;
- napi_hash_del(&q_vector->napi);
- netif_napi_del(&q_vector->napi);
+ __netif_napi_del(&q_vector->napi);
/*
+ * after a call to __netif_napi_del() napi may still be used and
* ixgbe_get_stats64() might access the rings on this vector,
* we must wait a grace period before freeing it.
*/
diff --git a/drivers/net/ethernet/myricom/myri10ge/myri10ge.c b/drivers/net/ethernet/myricom/myri10ge/myri10ge.c
index 4a5beafa0493..1634ca6d4a8f 100644
--- a/drivers/net/ethernet/myricom/myri10ge/myri10ge.c
+++ b/drivers/net/ethernet/myricom/myri10ge/myri10ge.c
@@ -3543,11 +3543,10 @@ static void myri10ge_free_slices(struct myri10ge_priv *mgp)
ss->fw_stats, ss->fw_stats_bus);
ss->fw_stats = NULL;
}
- napi_hash_del(&ss->napi);
- netif_napi_del(&ss->napi);
+ __netif_napi_del(&ss->napi);
}
/* Wait till napi structs are no longer used, and then free ss. */
- synchronize_rcu();
+ synchronize_net();
kfree(mgp->ss);
mgp->ss = NULL;
}