afs: Push the net ns pointer to more places

Push the network namespace pointer to more places in AFS, including the
afs_server structure (which doesn't hold a ref on the netns).

In particular, afs_put_cell() now takes requires a net ns parameter so that
it can safely alter the netns after decrementing the cell usage count - the
cell will be deallocated by a background thread after being cached for a
period, which means that it's not safe to access it after reducing its
usage count.

Signed-off-by: David Howells <dhowells@redhat.com>

1 files changed, 3 insertions, 4 deletions

diff --git a/fs/afs/server.c b/fs/afs/server.c
index 33aeb527ac7e..d8044be913f0 100644
--- a/fs/afs/server.c
+++ b/fs/afs/server.c
@@ -85,6 +85,7 @@ static struct afs_server *afs_alloc_server(struct afs_cell *cell,
 	server = kzalloc(sizeof(struct afs_server), GFP_KERNEL);
 	if (server) {
 		atomic_set(&server->usage, 1);
+		server->net = cell->net;
 		server->cell = cell;
 
 		INIT_LIST_HEAD(&server->link);
@@ -245,10 +246,8 @@ static void afs_set_server_timer(struct afs_net *net, time64_t delay)
  * destroy a server record
  * - removes from the cell list
  */
-void afs_put_server(struct afs_server *server)
+void afs_put_server(struct afs_net *net, struct afs_server *server)
 {
-	struct afs_net *net = server->cell->net;
-
 	if (!server)
 		return;
 
@@ -290,7 +289,7 @@ static void afs_destroy_server(struct afs_net *net, struct afs_server *server)
 	ASSERTCMP(server->cb_break_head, ==, server->cb_break_tail);
 	ASSERTCMP(atomic_read(&server->cb_break_n), ==, 0);
 
-	afs_put_cell(server->cell);
+	afs_put_cell(server->net, server->cell);
 	kfree(server);
 	afs_dec_servers_outstanding(net);
 }