SUNRPC: Convert gss_ctx_lock to an RCU lock
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
diff --git a/net/sunrpc/auth_gss/auth_gss.c b/net/sunrpc/auth_gss/auth_gss.c
index 8653a92..15da6f8 100644
--- a/net/sunrpc/auth_gss/auth_gss.c
+++ b/net/sunrpc/auth_gss/auth_gss.c
@@ -78,8 +78,6 @@
/* dump the buffer in `emacs-hexl' style */
#define isprint(c) ((c > 0x1f) && (c < 0x7f))
-static DEFINE_RWLOCK(gss_ctx_lock);
-
struct gss_auth {
struct rpc_auth rpc_auth;
struct gss_api_mech *mech;
@@ -88,7 +86,7 @@
struct dentry *dentry;
};
-static void gss_destroy_ctx(struct gss_cl_ctx *);
+static void gss_free_ctx(struct gss_cl_ctx *);
static struct rpc_pipe_ops gss_upcall_ops;
static inline struct gss_cl_ctx *
@@ -102,20 +100,24 @@
gss_put_ctx(struct gss_cl_ctx *ctx)
{
if (atomic_dec_and_test(&ctx->count))
- gss_destroy_ctx(ctx);
+ gss_free_ctx(ctx);
}
+/* gss_cred_set_ctx:
+ * called by gss_upcall_callback and gss_create_upcall in order
+ * to set the gss context. The actual exchange of an old context
+ * and a new one is protected by the inode->i_lock.
+ */
static void
gss_cred_set_ctx(struct rpc_cred *cred, struct gss_cl_ctx *ctx)
{
struct gss_cred *gss_cred = container_of(cred, struct gss_cred, gc_base);
struct gss_cl_ctx *old;
- write_lock(&gss_ctx_lock);
+
old = gss_cred->gc_ctx;
- gss_cred->gc_ctx = ctx;
+ rcu_assign_pointer(gss_cred->gc_ctx, ctx);
set_bit(RPCAUTH_CRED_UPTODATE, &cred->cr_flags);
clear_bit(RPCAUTH_CRED_NEW, &cred->cr_flags);
- write_unlock(&gss_ctx_lock);
if (old)
gss_put_ctx(old);
}
@@ -126,10 +128,10 @@
struct gss_cred *gss_cred = container_of(cred, struct gss_cred, gc_base);
int res = 0;
- read_lock(&gss_ctx_lock);
+ rcu_read_lock();
if (test_bit(RPCAUTH_CRED_UPTODATE, &cred->cr_flags) && gss_cred->gc_ctx)
res = 1;
- read_unlock(&gss_ctx_lock);
+ rcu_read_unlock();
return res;
}
@@ -168,10 +170,10 @@
struct gss_cred *gss_cred = container_of(cred, struct gss_cred, gc_base);
struct gss_cl_ctx *ctx = NULL;
- read_lock(&gss_ctx_lock);
+ rcu_read_lock();
if (gss_cred->gc_ctx)
ctx = gss_get_ctx(gss_cred->gc_ctx);
- read_unlock(&gss_ctx_lock);
+ rcu_read_unlock();
return ctx;
}
@@ -333,11 +335,11 @@
struct gss_upcall_msg *gss_msg = gss_cred->gc_upcall;
struct inode *inode = gss_msg->auth->dentry->d_inode;
+ spin_lock(&inode->i_lock);
if (gss_msg->ctx)
gss_cred_set_ctx(task->tk_msg.rpc_cred, gss_get_ctx(gss_msg->ctx));
else
task->tk_status = gss_msg->msg.errno;
- spin_lock(&inode->i_lock);
gss_cred->gc_upcall = NULL;
rpc_wake_up_status(&gss_msg->rpc_waitqueue, gss_msg->msg.errno);
spin_unlock(&inode->i_lock);
@@ -440,7 +442,6 @@
prepare_to_wait(&gss_msg->waitqueue, &wait, TASK_INTERRUPTIBLE);
spin_lock(&inode->i_lock);
if (gss_msg->ctx != NULL || gss_msg->msg.errno < 0) {
- spin_unlock(&inode->i_lock);
break;
}
spin_unlock(&inode->i_lock);
@@ -454,6 +455,7 @@
gss_cred_set_ctx(cred, gss_get_ctx(gss_msg->ctx));
else
err = gss_msg->msg.errno;
+ spin_unlock(&inode->i_lock);
out_intr:
finish_wait(&gss_msg->waitqueue, &wait);
gss_release_msg(gss_msg);
@@ -681,9 +683,9 @@
* to create a new cred or context, so they check that things have been
* allocated before freeing them. */
static void
-gss_destroy_ctx(struct gss_cl_ctx *ctx)
+gss_do_free_ctx(struct gss_cl_ctx *ctx)
{
- dprintk("RPC: gss_destroy_ctx\n");
+ dprintk("RPC: gss_free_ctx\n");
if (ctx->gc_gss_ctx)
gss_delete_sec_context(&ctx->gc_gss_ctx);
@@ -693,11 +695,22 @@
}
static void
+gss_free_ctx_callback(struct rcu_head *head)
+{
+ struct gss_cl_ctx *ctx = container_of(head, struct gss_cl_ctx, gc_rcu);
+ gss_do_free_ctx(ctx);
+}
+
+static void
+gss_free_ctx(struct gss_cl_ctx *ctx)
+{
+ call_rcu(&ctx->gc_rcu, gss_free_ctx_callback);
+}
+
+static void
gss_free_cred(struct gss_cred *gss_cred)
{
dprintk("RPC: gss_free_cred %p\n", gss_cred);
- if (gss_cred->gc_ctx)
- gss_put_ctx(gss_cred->gc_ctx);
kfree(gss_cred);
}
@@ -711,7 +724,13 @@
static void
gss_destroy_cred(struct rpc_cred *cred)
{
+ struct gss_cred *gss_cred = container_of(cred, struct gss_cred, gc_base);
+ struct gss_cl_ctx *ctx = gss_cred->gc_ctx;
+
+ rcu_assign_pointer(gss_cred->gc_ctx, NULL);
call_rcu(&cred->cr_rcu, gss_free_cred_callback);
+ if (ctx)
+ gss_put_ctx(ctx);
}
/*