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Commit 832b4c5e authored by Stephen Hemminger's avatar Stephen Hemminger Committed by David S. Miller
Browse files

[IPV4] fib: convert reader/writer to spinlock 



Ther is no point in using a more expensive reader/writer lock
for a low contention lock like the fib_info_lock. The only
reader case is in handling route redirects.

Signed-off-by: default avatarStephen Hemminger <shemminger@osdl.org>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent b1429553

net/ipv4/fib_semantics.c

+10 −10
Original line number Diff line number Diff line
@@ -49,7 +49,7 @@ 


#define FSprintk(a...)



static DEFINE_RWLOCK(fib_info_lock);

static DEFINE_SPINLOCK(fib_info_lock);

static struct hlist_head *fib_info_hash;

static struct hlist_head *fib_info_laddrhash;

static unsigned int fib_hash_size;
@@ -159,7 +159,7 @@ void free_fib_info(struct fib_info *fi) 


void fib_release_info(struct fib_info *fi)

{

	write_lock_bh(&fib_info_lock);

	spin_lock_bh(&fib_info_lock);

	if (fi && --fi->fib_treeref == 0) {

		hlist_del(&fi->fib_hash);

		if (fi->fib_prefsrc)
@@ -172,7 +172,7 @@ void fib_release_info(struct fib_info *fi) 
		fi->fib_dead = 1;

		fib_info_put(fi);

	}

	write_unlock_bh(&fib_info_lock);

	spin_unlock_bh(&fib_info_lock);

}



static __inline__ int nh_comp(const struct fib_info *fi, const struct fib_info *ofi)
@@ -254,7 +254,7 @@ int ip_fib_check_default(u32 gw, struct net_device *dev) 
	struct fib_nh *nh;

	unsigned int hash;



	read_lock(&fib_info_lock);

	spin_lock(&fib_info_lock);



	hash = fib_devindex_hashfn(dev->ifindex);

	head = &fib_info_devhash[hash];
@@ -262,12 +262,12 @@ int ip_fib_check_default(u32 gw, struct net_device *dev) 
		if (nh->nh_dev == dev &&

		    nh->nh_gw == gw &&

		    !(nh->nh_flags&RTNH_F_DEAD)) {

			read_unlock(&fib_info_lock);

			spin_unlock(&fib_info_lock);

			return 0;

		}

	}



	read_unlock(&fib_info_lock);

	spin_unlock(&fib_info_lock);



	return -1;

}
@@ -598,7 +598,7 @@ static void fib_hash_move(struct hlist_head *new_info_hash, 
	unsigned int old_size = fib_hash_size;

	unsigned int i, bytes;



	write_lock_bh(&fib_info_lock);

	spin_lock_bh(&fib_info_lock);

	old_info_hash = fib_info_hash;

	old_laddrhash = fib_info_laddrhash;

	fib_hash_size = new_size;
@@ -639,7 +639,7 @@ static void fib_hash_move(struct hlist_head *new_info_hash, 
	}

	fib_info_laddrhash = new_laddrhash;



	write_unlock_bh(&fib_info_lock);

	spin_unlock_bh(&fib_info_lock);



	bytes = old_size * sizeof(struct hlist_head *);

	fib_hash_free(old_info_hash, bytes);
@@ -820,7 +820,7 @@ fib_create_info(const struct rtmsg *r, struct kern_rta *rta, 


	fi->fib_treeref++;

	atomic_inc(&fi->fib_clntref);

	write_lock_bh(&fib_info_lock);

	spin_lock_bh(&fib_info_lock);

	hlist_add_head(&fi->fib_hash,

		       &fib_info_hash[fib_info_hashfn(fi)]);

	if (fi->fib_prefsrc) {
@@ -839,7 +839,7 @@ fib_create_info(const struct rtmsg *r, struct kern_rta *rta, 
		head = &fib_info_devhash[hash];

		hlist_add_head(&nh->nh_hash, head);

	} endfor_nexthops(fi)

	write_unlock_bh(&fib_info_lock);

	spin_unlock_bh(&fib_info_lock);

	return fi;



err_inval: