xfrm: state: simplify rcu_read_unlock handling in two spots

[mirror_ubuntu-artful-kernel.git] / net / xfrm / xfrm_state.c

diff --git a/net/xfrm/xfrm_state.c b/net/xfrm/xfrm_state.c
index 45cb7c699b65ba4e1c928e94c1a65d8ee7a8ef96..a62097e640b5690edc4d6f9bf794d1a2c80725f7 100644 (file)
--- a/net/xfrm/xfrm_state.c
+++ b/net/xfrm/xfrm_state.c
@@ -20,7 +20,7 @@
 #include <linux/module.h>
 #include <linux/cache.h>
 #include <linux/audit.h>
-#include <asm/uaccess.h>
+#include <linux/uaccess.h>
 #include <linux/ktime.h>
 #include <linux/slab.h>
 #include <linux/interrupt.h>
@@ -192,7 +192,7 @@ int xfrm_register_type(const struct xfrm_type *type, unsigned short family)
        else
                err = -EEXIST;
        spin_unlock_bh(&xfrm_type_lock);
-       xfrm_state_put_afinfo(afinfo);
+       rcu_read_unlock();
        return err;
 }
 EXPORT_SYMBOL(xfrm_register_type);
@@ -213,7 +213,7 @@ int xfrm_unregister_type(const struct xfrm_type *type, unsigned short family)
        else
                typemap[type->proto] = NULL;
        spin_unlock_bh(&xfrm_type_lock);
-       xfrm_state_put_afinfo(afinfo);
+       rcu_read_unlock();
        return err;
 }
 EXPORT_SYMBOL(xfrm_unregister_type);
@@ -231,17 +231,18 @@ retry:
                return NULL;
        typemap = afinfo->type_map;
 
-       type = typemap[proto];
+       type = READ_ONCE(typemap[proto]);
        if (unlikely(type && !try_module_get(type->owner)))
                type = NULL;
+
+       rcu_read_unlock();
+
        if (!type && !modload_attempted) {
-               xfrm_state_put_afinfo(afinfo);
                request_module("xfrm-type-%d-%d", family, proto);
                modload_attempted = 1;
                goto retry;
        }
 
-       xfrm_state_put_afinfo(afinfo);
        return type;
 }
 
@@ -280,7 +281,7 @@ int xfrm_register_mode(struct xfrm_mode *mode, int family)
 
 out:
        spin_unlock_bh(&xfrm_mode_lock);
-       xfrm_state_put_afinfo(afinfo);
+       rcu_read_unlock();
        return err;
 }
 EXPORT_SYMBOL(xfrm_register_mode);
@@ -308,7 +309,7 @@ int xfrm_unregister_mode(struct xfrm_mode *mode, int family)
        }
 
        spin_unlock_bh(&xfrm_mode_lock);
-       xfrm_state_put_afinfo(afinfo);
+       rcu_read_unlock();
        return err;
 }
 EXPORT_SYMBOL(xfrm_unregister_mode);
@@ -327,17 +328,17 @@ retry:
        if (unlikely(afinfo == NULL))
                return NULL;
 
-       mode = afinfo->mode_map[encap];
+       mode = READ_ONCE(afinfo->mode_map[encap]);
        if (unlikely(mode && !try_module_get(mode->owner)))
                mode = NULL;
+
+       rcu_read_unlock();
        if (!mode && !modload_attempted) {
-               xfrm_state_put_afinfo(afinfo);
                request_module("xfrm-mode-%d-%d", family, encap);
                modload_attempted = 1;
                goto retry;
        }
 
-       xfrm_state_put_afinfo(afinfo);
        return mode;
 }
 
@@ -409,7 +410,7 @@ static enum hrtimer_restart xfrm_timer_handler(struct hrtimer *me)
                        if (x->xflags & XFRM_SOFT_EXPIRE) {
                                /* enter hard expire without soft expire first?!
                                 * setting a new date could trigger this.
-                                * workarbound: fix x->curflt.add_time by below:
+                                * workaround: fix x->curflt.add_time by below:
                                 */
                                x->curlft.add_time = now - x->saved_tmo - 1;
                                tmo = x->lft.hard_add_expires_seconds - x->saved_tmo;
@@ -639,26 +640,23 @@ void xfrm_sad_getinfo(struct net *net, struct xfrmk_sadinfo *si)
 }
 EXPORT_SYMBOL(xfrm_sad_getinfo);
 
-static int
+static void
 xfrm_init_tempstate(struct xfrm_state *x, const struct flowi *fl,
                    const struct xfrm_tmpl *tmpl,
                    const xfrm_address_t *daddr, const xfrm_address_t *saddr,
                    unsigned short family)
 {
-       struct xfrm_state_afinfo *afinfo = xfrm_state_get_afinfo(family);
-       if (!afinfo)
-               return -1;
-       afinfo->init_tempsel(&x->sel, fl);
+       struct xfrm_state_afinfo *afinfo = xfrm_state_afinfo_get_rcu(family);
+
+       if (afinfo)
+               afinfo->init_tempsel(&x->sel, fl);
 
        if (family != tmpl->encap_family) {
-               xfrm_state_put_afinfo(afinfo);
-               afinfo = xfrm_state_get_afinfo(tmpl->encap_family);
+               afinfo = xfrm_state_afinfo_get_rcu(tmpl->encap_family);
                if (!afinfo)
-                       return -1;
+                       return;
        }
        afinfo->init_temprop(x, tmpl, daddr, saddr);
-       xfrm_state_put_afinfo(afinfo);
-       return 0;
 }
 
 static struct xfrm_state *__xfrm_state_lookup(struct net *net, u32 mark,
@@ -1404,7 +1402,7 @@ int xfrm_state_check_expire(struct xfrm_state *x)
        if (x->curlft.bytes >= x->lft.hard_byte_limit ||
            x->curlft.packets >= x->lft.hard_packet_limit) {
                x->km.state = XFRM_STATE_EXPIRED;
-               tasklet_hrtimer_start(&x->mtimer, ktime_set(0, 0), HRTIMER_MODE_REL);
+               tasklet_hrtimer_start(&x->mtimer, 0, HRTIMER_MODE_REL);
                return -EINVAL;
        }
 
@@ -1474,7 +1472,7 @@ xfrm_tmpl_sort(struct xfrm_tmpl **dst, struct xfrm_tmpl **src, int n,
        if (afinfo->tmpl_sort)
                err = afinfo->tmpl_sort(dst, src, n);
        spin_unlock_bh(&net->xfrm.xfrm_state_lock);
-       xfrm_state_put_afinfo(afinfo);
+       rcu_read_unlock();
        return err;
 }
 EXPORT_SYMBOL(xfrm_tmpl_sort);
@@ -1494,7 +1492,7 @@ xfrm_state_sort(struct xfrm_state **dst, struct xfrm_state **src, int n,
        if (afinfo->state_sort)
                err = afinfo->state_sort(dst, src, n);
        spin_unlock_bh(&net->xfrm.xfrm_state_lock);
-       xfrm_state_put_afinfo(afinfo);
+       rcu_read_unlock();
        return err;
 }
 EXPORT_SYMBOL(xfrm_state_sort);
@@ -1932,10 +1930,10 @@ EXPORT_SYMBOL(xfrm_unregister_km);
 int xfrm_state_register_afinfo(struct xfrm_state_afinfo *afinfo)
 {
        int err = 0;
-       if (unlikely(afinfo == NULL))
-               return -EINVAL;
-       if (unlikely(afinfo->family >= NPROTO))
+
+       if (WARN_ON(afinfo->family >= NPROTO))
                return -EAFNOSUPPORT;
+
        spin_lock_bh(&xfrm_state_afinfo_lock);
        if (unlikely(xfrm_state_afinfo[afinfo->family] != NULL))
                err = -EEXIST;
@@ -1948,14 +1946,14 @@ EXPORT_SYMBOL(xfrm_state_register_afinfo);
 
 int xfrm_state_unregister_afinfo(struct xfrm_state_afinfo *afinfo)
 {
-       int err = 0;
-       if (unlikely(afinfo == NULL))
-               return -EINVAL;
-       if (unlikely(afinfo->family >= NPROTO))
+       int err = 0, family = afinfo->family;
+
+       if (WARN_ON(family >= NPROTO))
                return -EAFNOSUPPORT;
+
        spin_lock_bh(&xfrm_state_afinfo_lock);
        if (likely(xfrm_state_afinfo[afinfo->family] != NULL)) {
-               if (unlikely(xfrm_state_afinfo[afinfo->family] != afinfo))
+               if (rcu_access_pointer(xfrm_state_afinfo[family]) != afinfo)
                        err = -EINVAL;
                else
                        RCU_INIT_POINTER(xfrm_state_afinfo[afinfo->family], NULL);
@@ -1966,6 +1964,14 @@ int xfrm_state_unregister_afinfo(struct xfrm_state_afinfo *afinfo)
 }
 EXPORT_SYMBOL(xfrm_state_unregister_afinfo);
 
+struct xfrm_state_afinfo *xfrm_state_afinfo_get_rcu(unsigned int family)
+{
+       if (unlikely(family >= NPROTO))
+               return NULL;
+
+       return rcu_dereference(xfrm_state_afinfo[family]);
+}
+
 struct xfrm_state_afinfo *xfrm_state_get_afinfo(unsigned int family)
 {
        struct xfrm_state_afinfo *afinfo;
@@ -1978,11 +1984,6 @@ struct xfrm_state_afinfo *xfrm_state_get_afinfo(unsigned int family)
        return afinfo;
 }
 
-void xfrm_state_put_afinfo(struct xfrm_state_afinfo *afinfo)
-{
-       rcu_read_unlock();
-}
-
 /* Temporarily located here until net/xfrm/xfrm_tunnel.c is created */
 void xfrm_state_delete_tunnel(struct xfrm_state *x)
 {
@@ -2000,16 +2001,13 @@ EXPORT_SYMBOL(xfrm_state_delete_tunnel);
 
 int xfrm_state_mtu(struct xfrm_state *x, int mtu)
 {
-       int res;
+       const struct xfrm_type *type = READ_ONCE(x->type);
 
-       spin_lock_bh(&x->lock);
        if (x->km.state == XFRM_STATE_VALID &&
-           x->type && x->type->get_mtu)
-               res = x->type->get_mtu(x, mtu);
-       else
-               res = mtu - x->props.header_len;
-       spin_unlock_bh(&x->lock);
-       return res;
+           type && type->get_mtu)
+               return type->get_mtu(x, mtu);
+
+       return mtu - x->props.header_len;
 }
 
 int __xfrm_init_state(struct xfrm_state *x, bool init_replay)
@@ -2028,7 +2026,7 @@ int __xfrm_init_state(struct xfrm_state *x, bool init_replay)
        if (afinfo->init_flags)
                err = afinfo->init_flags(x);
 
-       xfrm_state_put_afinfo(afinfo);
+       rcu_read_unlock();
 
        if (err)
                goto error;