xfrm: state: use rcu_deref and assign_pointer helpers

Before xfrm_state_find() can use rcu_read_lock instead of xfrm_state_lock
we need to switch users of the hash table to assign/obtain the pointers
with the appropriate rcu helpers.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>

1 files changed, 10 insertions, 8 deletions

diff --git a/net/xfrm/xfrm_state.c b/net/xfrm/xfrm_state.c
index ac4037cf6a29..53e7867f9254 100644
--- a/net/xfrm/xfrm_state.c
+++ b/net/xfrm/xfrm_state.c
@@ -28,6 +28,9 @@
 
 #include "xfrm_hash.h"
 
+#define xfrm_state_deref_prot(table, net) \
+        rcu_dereference_protected((table), lockdep_is_held(&(net)->xfrm.xfrm_state_lock))
+
 /* Each xfrm_state may be linked to two tables:
 
    1. Hash table by (spi,daddr,ah/esp) to find SA by SPI. (input,ctl)
@@ -131,18 +134,17 @@ static void xfrm_hash_resize(struct work_struct *work)
         write_seqcount_begin(&xfrm_state_hash_generation);
 
         nhashmask = (nsize / sizeof(struct hlist_head)) - 1U;
+        odst = xfrm_state_deref_prot(net->xfrm.state_bydst, net);
         for (i = net->xfrm.state_hmask; i >= 0; i--)
-                xfrm_hash_transfer(net->xfrm.state_bydst+i, ndst, nsrc, nspi,
-                                   nhashmask);
+                xfrm_hash_transfer(odst + i, ndst, nsrc, nspi, nhashmask);
 
-        odst = net->xfrm.state_bydst;
-        osrc = net->xfrm.state_bysrc;
-        ospi = net->xfrm.state_byspi;
+        osrc = xfrm_state_deref_prot(net->xfrm.state_bysrc, net);
+        ospi = xfrm_state_deref_prot(net->xfrm.state_byspi, net);
         ohashmask = net->xfrm.state_hmask;
 
-        net->xfrm.state_bydst = ndst;
-        net->xfrm.state_bysrc = nsrc;
-        net->xfrm.state_byspi = nspi;
+        rcu_assign_pointer(net->xfrm.state_bydst, ndst);
+        rcu_assign_pointer(net->xfrm.state_bysrc, nsrc);
+        rcu_assign_pointer(net->xfrm.state_byspi, nspi);
         net->xfrm.state_hmask = nhashmask;
 
         write_seqcount_end(&xfrm_state_hash_generation);