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authorNeilBrown <neilb@suse.de>2021-11-29 15:51:25 +1100
committerChuck Lever <chuck.lever@oracle.com>2021-12-13 13:42:51 -0500
commitec52361df99b490f6af412b046df9799b92c1050 (patch)
treee568a1248bfbbfc63a75f7368603be8a2b1dea5f /fs/nfs
parent8c62d12740a1450d2e8456d5747f440e10db281a (diff)
SUNRPC: stop using ->sv_nrthreads as a refcount
The use of sv_nrthreads as a general refcount results in clumsy code, as is seen by various comments needed to explain the situation. This patch introduces a 'struct kref' and uses that for reference counting, leaving sv_nrthreads to be a pure count of threads. The kref is managed particularly in svc_get() and svc_put(), and also nfsd_put(); svc_destroy() now takes a pointer to the embedded kref, rather than to the serv. nfsd allows the svc_serv to exist with ->sv_nrhtreads being zero. This happens when a transport is created before the first thread is started. To support this, a 'keep_active' flag is introduced which holds a ref on the svc_serv. This is set when any listening socket is successfully added (unless there are running threads), and cleared when the number of threads is set. So when the last thread exits, the nfs_serv will be destroyed. The use of 'keep_active' replaces previous code which checked if there were any permanent sockets. We no longer clear ->rq_server when nfsd() exits. This was done to prevent svc_exit_thread() from calling svc_destroy(). Instead we take an extra reference to the svc_serv to prevent svc_destroy() from being called. Signed-off-by: NeilBrown <neilb@suse.de> Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Diffstat (limited to 'fs/nfs')
-rw-r--r--fs/nfs/callback.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/fs/nfs/callback.c b/fs/nfs/callback.c
index edbc7579b4aa..d9d78ffd1d65 100644
--- a/fs/nfs/callback.c
+++ b/fs/nfs/callback.c
@@ -169,7 +169,7 @@ static int nfs_callback_start_svc(int minorversion, struct rpc_xprt *xprt,
if (nrservs < NFS4_MIN_NR_CALLBACK_THREADS)
nrservs = NFS4_MIN_NR_CALLBACK_THREADS;
- if (serv->sv_nrthreads-1 == nrservs)
+ if (serv->sv_nrthreads == nrservs)
return 0;
ret = serv->sv_ops->svo_setup(serv, NULL, nrservs);