fuse: add memory barrier to INIT
Theoretically we need to order setting of various fields in fc with
fc->initialized.
No known bug reports related to this yet.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
diff --git a/fs/fuse/dev.c b/fs/fuse/dev.c
index c847d6b..ed19a7d 100644
--- a/fs/fuse/dev.c
+++ b/fs/fuse/dev.c
@@ -131,6 +131,13 @@
req->in.h.pid = current->pid;
}
+void fuse_set_initialized(struct fuse_conn *fc)
+{
+ /* Make sure stores before this are seen on another CPU */
+ smp_wmb();
+ fc->initialized = 1;
+}
+
static bool fuse_block_alloc(struct fuse_conn *fc, bool for_background)
{
return !fc->initialized || (for_background && fc->blocked);
@@ -155,6 +162,8 @@
if (intr)
goto out;
}
+ /* Matches smp_wmb() in fuse_set_initialized() */
+ smp_rmb();
err = -ENOTCONN;
if (!fc->connected)
@@ -253,6 +262,8 @@
atomic_inc(&fc->num_waiting);
wait_event(fc->blocked_waitq, fc->initialized);
+ /* Matches smp_wmb() in fuse_set_initialized() */
+ smp_rmb();
req = fuse_request_alloc(0);
if (!req)
req = get_reserved_req(fc, file);
@@ -2163,7 +2174,7 @@
if (fc->connected) {
fc->connected = 0;
fc->blocked = 0;
- fc->initialized = 1;
+ fuse_set_initialized(fc);
end_io_requests(fc);
end_queued_requests(fc);
end_polls(fc);
@@ -2182,7 +2193,7 @@
spin_lock(&fc->lock);
fc->connected = 0;
fc->blocked = 0;
- fc->initialized = 1;
+ fuse_set_initialized(fc);
end_queued_requests(fc);
end_polls(fc);
wake_up_all(&fc->blocked_waitq);