155 lines
4.5 KiB
Diff
155 lines
4.5 KiB
Diff
From: Trond Myklebust <trond.myklebust@primarydata.com>
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Date: Wed, 26 Apr 2017 11:55:26 -0400
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Subject: [1/2] SUNRPC: Refactor svc_set_num_threads()
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Origin: https://git.kernel.org/linus/9e0d87680d689f1758185851c3da6eafb16e71e1
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Bug-Debian-Security: https://security-tracker.debian.org/tracker/CVE-2017-9059
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Refactor to separate out the functions of starting and stopping threads
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so that they can be used in other helpers.
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Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
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Tested-and-reviewed-by: Kinglong Mee <kinglongmee@gmail.com>
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Signed-off-by: J. Bruce Fields <bfields@redhat.com>
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---
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net/sunrpc/svc.c | 96 ++++++++++++++++++++++++++++++++++----------------------
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1 file changed, 58 insertions(+), 38 deletions(-)
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diff --git a/net/sunrpc/svc.c b/net/sunrpc/svc.c
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index a08aeb56b8e4..98dc33ae738b 100644
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--- a/net/sunrpc/svc.c
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+++ b/net/sunrpc/svc.c
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@@ -702,59 +702,32 @@ choose_victim(struct svc_serv *serv, struct svc_pool *pool, unsigned int *state)
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return task;
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}
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-/*
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- * Create or destroy enough new threads to make the number
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- * of threads the given number. If `pool' is non-NULL, applies
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- * only to threads in that pool, otherwise round-robins between
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- * all pools. Caller must ensure that mutual exclusion between this and
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- * server startup or shutdown.
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- *
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- * Destroying threads relies on the service threads filling in
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- * rqstp->rq_task, which only the nfs ones do. Assumes the serv
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- * has been created using svc_create_pooled().
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- *
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- * Based on code that used to be in nfsd_svc() but tweaked
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- * to be pool-aware.
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- */
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-int
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-svc_set_num_threads(struct svc_serv *serv, struct svc_pool *pool, int nrservs)
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+/* create new threads */
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+static int
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+svc_start_kthreads(struct svc_serv *serv, struct svc_pool *pool, int nrservs)
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{
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struct svc_rqst *rqstp;
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struct task_struct *task;
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struct svc_pool *chosen_pool;
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- int error = 0;
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unsigned int state = serv->sv_nrthreads-1;
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int node;
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- if (pool == NULL) {
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- /* The -1 assumes caller has done a svc_get() */
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- nrservs -= (serv->sv_nrthreads-1);
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- } else {
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- spin_lock_bh(&pool->sp_lock);
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- nrservs -= pool->sp_nrthreads;
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- spin_unlock_bh(&pool->sp_lock);
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- }
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-
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- /* create new threads */
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- while (nrservs > 0) {
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+ do {
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nrservs--;
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chosen_pool = choose_pool(serv, pool, &state);
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node = svc_pool_map_get_node(chosen_pool->sp_id);
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rqstp = svc_prepare_thread(serv, chosen_pool, node);
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- if (IS_ERR(rqstp)) {
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- error = PTR_ERR(rqstp);
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- break;
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- }
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+ if (IS_ERR(rqstp))
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+ return PTR_ERR(rqstp);
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__module_get(serv->sv_ops->svo_module);
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task = kthread_create_on_node(serv->sv_ops->svo_function, rqstp,
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node, "%s", serv->sv_name);
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if (IS_ERR(task)) {
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- error = PTR_ERR(task);
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module_put(serv->sv_ops->svo_module);
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svc_exit_thread(rqstp);
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- break;
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+ return PTR_ERR(task);
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}
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rqstp->rq_task = task;
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@@ -763,15 +736,62 @@ svc_set_num_threads(struct svc_serv *serv, struct svc_pool *pool, int nrservs)
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svc_sock_update_bufs(serv);
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wake_up_process(task);
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- }
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+ } while (nrservs > 0);
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+
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+ return 0;
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+}
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+
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+
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+/* destroy old threads */
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+static int
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+svc_signal_kthreads(struct svc_serv *serv, struct svc_pool *pool, int nrservs)
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+{
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+ struct task_struct *task;
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+ unsigned int state = serv->sv_nrthreads-1;
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+
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/* destroy old threads */
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- while (nrservs < 0 &&
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- (task = choose_victim(serv, pool, &state)) != NULL) {
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+ do {
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+ task = choose_victim(serv, pool, &state);
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+ if (task == NULL)
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+ break;
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send_sig(SIGINT, task, 1);
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nrservs++;
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+ } while (nrservs < 0);
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+
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+ return 0;
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+}
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+
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+/*
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+ * Create or destroy enough new threads to make the number
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+ * of threads the given number. If `pool' is non-NULL, applies
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+ * only to threads in that pool, otherwise round-robins between
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+ * all pools. Caller must ensure that mutual exclusion between this and
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+ * server startup or shutdown.
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+ *
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+ * Destroying threads relies on the service threads filling in
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+ * rqstp->rq_task, which only the nfs ones do. Assumes the serv
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+ * has been created using svc_create_pooled().
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+ *
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+ * Based on code that used to be in nfsd_svc() but tweaked
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+ * to be pool-aware.
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+ */
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+int
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+svc_set_num_threads(struct svc_serv *serv, struct svc_pool *pool, int nrservs)
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+{
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+ if (pool == NULL) {
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+ /* The -1 assumes caller has done a svc_get() */
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+ nrservs -= (serv->sv_nrthreads-1);
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+ } else {
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+ spin_lock_bh(&pool->sp_lock);
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+ nrservs -= pool->sp_nrthreads;
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+ spin_unlock_bh(&pool->sp_lock);
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}
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- return error;
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+ if (nrservs > 0)
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+ return svc_start_kthreads(serv, pool, nrservs);
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+ if (nrservs < 0)
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+ return svc_signal_kthreads(serv, pool, nrservs);
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+ return 0;
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}
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EXPORT_SYMBOL_GPL(svc_set_num_threads);
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