net: convert TCP/DCCP ehash rwlocks to spinlocks

Now TCP & DCCP use RCU lookups, we can convert ehash rwlocks to spinlocks.

/proc/net/tcp and other seq_file 'readers' can safely be converted to 'writers'.

This should speedup writers, since spin_lock()/spin_unlock()
only use one atomic operation instead of two for write_lock()/write_unlock()

Signed-off-by: Eric Dumazet <dada1@cosmosbay.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 7 insertions, 7 deletions

diff --git a/include/net/inet_hashtables.h b/include/net/inet_hashtables.h
index 62d2dd0d7860..28b3ee3e8d6d 100644
--- a/include/net/inet_hashtables.h
+++ b/include/net/inet_hashtables.h
@@ -116,7 +116,7 @@ struct inet_hashinfo {
          * TIME_WAIT sockets use a separate chain (twchain).
          */
         struct inet_ehash_bucket        *ehash;
-        rwlock_t                        *ehash_locks;
+        spinlock_t                      *ehash_locks;
         unsigned int                    ehash_size;
         unsigned int                    ehash_locks_mask;
 
@@ -152,7 +152,7 @@ static inline struct inet_ehash_bucket *inet_ehash_bucket(
         return &hashinfo->ehash[hash & (hashinfo->ehash_size - 1)];
 }
 
-static inline rwlock_t *inet_ehash_lockp(
+static inline spinlock_t *inet_ehash_lockp(
         struct inet_hashinfo *hashinfo,
         unsigned int hash)
 {
@@ -177,16 +177,16 @@ static inline int inet_ehash_locks_alloc(struct inet_hashinfo *hashinfo)
                 size = 4096;
         if (sizeof(rwlock_t) != 0) {
 #ifdef CONFIG_NUMA
-                if (size * sizeof(rwlock_t) > PAGE_SIZE)
-                        hashinfo->ehash_locks = vmalloc(size * sizeof(rwlock_t));
+                if (size * sizeof(spinlock_t) > PAGE_SIZE)
+                        hashinfo->ehash_locks = vmalloc(size * sizeof(spinlock_t));
                 else
 #endif
-                hashinfo->ehash_locks = kmalloc(size * sizeof(rwlock_t),
+                hashinfo->ehash_locks = kmalloc(size * sizeof(spinlock_t),
                                                 GFP_KERNEL);
                 if (!hashinfo->ehash_locks)
                         return ENOMEM;
                 for (i = 0; i < size; i++)
-                        rwlock_init(&hashinfo->ehash_locks[i]);
+                        spin_lock_init(&hashinfo->ehash_locks[i]);
         }
         hashinfo->ehash_locks_mask = size - 1;
         return 0;
@@ -197,7 +197,7 @@ static inline void inet_ehash_locks_free(struct inet_hashinfo *hashinfo)
         if (hashinfo->ehash_locks) {
 #ifdef CONFIG_NUMA
                 unsigned int size = (hashinfo->ehash_locks_mask + 1) *
-                                                        sizeof(rwlock_t);
+                                                        sizeof(spinlock_t);
                 if (size > PAGE_SIZE)
                         vfree(hashinfo->ehash_locks);
                 else