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[68.40.189.247]) by smtp.gmail.com with ESMTPSA id i3sm18393763ion.9.2019.07.16.13.06.41 for (version=TLS1_3 cipher=AEAD-AES256-GCM-SHA384 bits=256/256); Tue, 16 Jul 2019 13:06:41 -0700 (PDT) From: Trond Myklebust X-Google-Original-From: Trond Myklebust To: linux-nfs@vger.kernel.org Subject: [PATCH 2/3] SUNRPC: Skip zero-refcount transports Date: Tue, 16 Jul 2019 16:04:32 -0400 Message-Id: <20190716200433.38758-2-trond.myklebust@hammerspace.com> X-Mailer: git-send-email 2.21.0 In-Reply-To: <20190716200433.38758-1-trond.myklebust@hammerspace.com> References: <20190716200433.38758-1-trond.myklebust@hammerspace.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-nfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-nfs@vger.kernel.org When looking for the next transport to use for an RPC call, skip those that are in the process of being destroyed and that have a zero refcount. Signed-off-by: Trond Myklebust --- net/sunrpc/xprtmultipath.c | 20 +++++++++++++++++++- 1 file changed, 19 insertions(+), 1 deletion(-) diff --git a/net/sunrpc/xprtmultipath.c b/net/sunrpc/xprtmultipath.c index 5df4e7adedf0..c12778e1235e 100644 --- a/net/sunrpc/xprtmultipath.c +++ b/net/sunrpc/xprtmultipath.c @@ -193,10 +193,22 @@ void xprt_iter_default_rewind(struct rpc_xprt_iter *xpi) WRITE_ONCE(xpi->xpi_cursor, NULL); } +static +bool xprt_is_active(const struct rpc_xprt *xprt) +{ + return kref_read(&xprt->kref) != 0; +} + static struct rpc_xprt *xprt_switch_find_first_entry(struct list_head *head) { - return list_first_or_null_rcu(head, struct rpc_xprt, xprt_switch); + struct rpc_xprt *pos; + + list_for_each_entry_rcu(pos, head, xprt_switch) { + if (xprt_is_active(pos)) + return pos; + } + return NULL; } static @@ -214,9 +226,12 @@ struct rpc_xprt *xprt_switch_find_current_entry(struct list_head *head, const struct rpc_xprt *cur) { struct rpc_xprt *pos; + bool found = false; list_for_each_entry_rcu(pos, head, xprt_switch) { if (cur == pos) + found = true; + if (found && xprt_is_active(pos)) return pos; } return NULL; @@ -261,9 +276,12 @@ struct rpc_xprt *xprt_switch_find_next_entry(struct list_head *head, const struct rpc_xprt *cur) { struct rpc_xprt *pos, *prev = NULL; + bool found = false; list_for_each_entry_rcu(pos, head, xprt_switch) { if (cur == prev) + found = true; + if (found && xprt_is_active(pos)) return pos; prev = pos; } -- 2.21.0