diff options
| author | Eric Dumazet <edumazet@google.com> | 2022-06-23 04:34:48 +0000 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2022-06-24 11:34:38 +0100 |
| commit | 3f55211ecf6a8fb271565adcb704cd57a8e4547c (patch) | |
| tree | 6779414584f1dd5651d0c3a4b596a163aae3595f | |
| parent | b96ef16d2f837870daaea51c38cd50458b95ad5c (diff) | |
ipmr: convert mrt_lock to a spinlock
mrt_lock is only held in write mode, from process context only.
We can switch to a mere spinlock, and avoid blocking BH.
Also, vif_dev_read() is always called under standard rcu_read_lock().
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
| -rw-r--r-- | net/ipv4/ipmr.c | 19 |
1 files changed, 9 insertions, 10 deletions
diff --git a/net/ipv4/ipmr.c b/net/ipv4/ipmr.c index 2e39f73fe81a..f095b6c8100b 100644 --- a/net/ipv4/ipmr.c +++ b/net/ipv4/ipmr.c @@ -77,12 +77,11 @@ struct ipmr_result { * Note that the changes are semaphored via rtnl_lock. */ -static DEFINE_RWLOCK(mrt_lock); +static DEFINE_SPINLOCK(mrt_lock); static struct net_device *vif_dev_read(const struct vif_device *vif) { - return rcu_dereference_check(vif->dev, - lockdep_is_held(&mrt_lock)); + return rcu_dereference(vif->dev); } /* Multicast router control variables */ @@ -664,7 +663,7 @@ static int vif_delete(struct mr_table *mrt, int vifi, int notify, if (!dev) return -EADDRNOTAVAIL; - write_lock_bh(&mrt_lock); + spin_lock(&mrt_lock); call_ipmr_vif_entry_notifiers(net, FIB_EVENT_VIF_DEL, v, dev, vifi, mrt->id); RCU_INIT_POINTER(v->dev, NULL); @@ -683,7 +682,7 @@ static int vif_delete(struct mr_table *mrt, int vifi, int notify, WRITE_ONCE(mrt->maxvif, tmp + 1); } - write_unlock_bh(&mrt_lock); + spin_unlock(&mrt_lock); dev_set_allmulti(dev, -1); @@ -785,7 +784,7 @@ out: spin_unlock(&mfc_unres_lock); } -/* Fill oifs list. It is called under write locked mrt_lock. */ +/* Fill oifs list. It is called under locked mrt_lock. */ static void ipmr_update_thresholds(struct mr_table *mrt, struct mr_mfc *cache, unsigned char *ttls) { @@ -897,7 +896,7 @@ static int vif_add(struct net *net, struct mr_table *mrt, v->remote = vifc->vifc_rmt_addr.s_addr; /* And finish update writing critical data */ - write_lock_bh(&mrt_lock); + spin_lock(&mrt_lock); rcu_assign_pointer(v->dev, dev); netdev_tracker_alloc(dev, &v->dev_tracker, GFP_ATOMIC); if (v->flags & VIFF_REGISTER) { @@ -906,7 +905,7 @@ static int vif_add(struct net *net, struct mr_table *mrt, } if (vifi+1 > mrt->maxvif) WRITE_ONCE(mrt->maxvif, vifi + 1); - write_unlock_bh(&mrt_lock); + spin_unlock(&mrt_lock); call_ipmr_vif_entry_notifiers(net, FIB_EVENT_VIF_ADD, v, dev, vifi, mrt->id); return 0; @@ -1211,12 +1210,12 @@ static int ipmr_mfc_add(struct net *net, struct mr_table *mrt, mfc->mfcc_mcastgrp.s_addr, parent); rcu_read_unlock(); if (c) { - write_lock_bh(&mrt_lock); + spin_lock(&mrt_lock); c->_c.mfc_parent = mfc->mfcc_parent; ipmr_update_thresholds(mrt, &c->_c, mfc->mfcc_ttls); if (!mrtsock) c->_c.mfc_flags |= MFC_STATIC; - write_unlock_bh(&mrt_lock); + spin_unlock(&mrt_lock); call_ipmr_mfc_entry_notifiers(net, FIB_EVENT_ENTRY_REPLACE, c, mrt->id); mroute_netlink_event(mrt, c, RTM_NEWROUTE); |