knfsd: convert knfsd to kthread API

This patch is rather large, but I couldn't figure out a way to break it
up that would remain bisectable. It does several things:

- change svc_thread_fn typedef to better match what kthread_create expects
- change svc_pool_map_set_cpumask to be more kthread friendly. Make it
  take a task arg and and get rid of the "oldmask"
- have svc_set_num_threads call kthread_create directly
- eliminate __svc_create_thread

Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>

1 files changed, 34 insertions, 66 deletions

diff --git a/net/sunrpc/svc.c b/net/sunrpc/svc.c
index 7bffaff2a3ab..03a9f1a9e75c 100644
--- a/net/sunrpc/svc.c
+++ b/net/sunrpc/svc.c
@@ -18,6 +18,7 @@
 #include <linux/mm.h>
 #include <linux/interrupt.h>
 #include <linux/module.h>
+#include <linux/kthread.h>
 
 #include <linux/sunrpc/types.h>
 #include <linux/sunrpc/xdr.h>
@@ -291,15 +292,14 @@ svc_pool_map_put(void)
 
 
 /*
- * Set the current thread's cpus_allowed mask so that it
+ * Set the given thread's cpus_allowed mask so that it
  * will only run on cpus in the given pool.
- *
- * Returns 1 and fills in oldmask iff a cpumask was applied.
  */
-static inline int
-svc_pool_map_set_cpumask(unsigned int pidx, cpumask_t *oldmask)
+static inline void
+svc_pool_map_set_cpumask(struct task_struct *task, unsigned int pidx)
 {
         struct svc_pool_map *m = &svc_pool_map;
+        unsigned int node = m->pool_to[pidx];
 
         /*
          * The caller checks for sv_nrpools > 1, which
@@ -307,26 +307,17 @@ svc_pool_map_set_cpumask(unsigned int pidx, cpumask_t *oldmask)
          */
         BUG_ON(m->count == 0);
 
-        switch (m->mode)
-        {
-        default:
-                return 0;
+        switch (m->mode) {
         case SVC_POOL_PERCPU:
         {
-                unsigned int cpu = m->pool_to[pidx];
-
-                *oldmask = current->cpus_allowed;
-                set_cpus_allowed_ptr(current, &cpumask_of_cpu(cpu));
-                return 1;
+                set_cpus_allowed_ptr(task, &cpumask_of_cpu(node));
+                break;
         }
         case SVC_POOL_PERNODE:
         {
-                unsigned int node = m->pool_to[pidx];
                 node_to_cpumask_ptr(nodecpumask, node);
-
-                *oldmask = current->cpus_allowed;
-                set_cpus_allowed_ptr(current, nodecpumask);
-                return 1;
+                set_cpus_allowed_ptr(task, nodecpumask);
+                break;
         }
         }
 }
@@ -579,47 +570,6 @@ out_enomem:
 EXPORT_SYMBOL(svc_prepare_thread);
 
 /*
- * Create a thread in the given pool.  Caller must hold BKL or another lock to
- * serialize access to the svc_serv struct. On a NUMA or SMP machine, with a
- * multi-pool serv, the thread will be restricted to run on the cpus belonging
- * to the pool.
- */
-static int
-__svc_create_thread(svc_thread_fn func, struct svc_serv *serv,
-                    struct svc_pool *pool)
-{
-        struct svc_rqst *rqstp;
-        int             error = -ENOMEM;
-        int             have_oldmask = 0;
-        cpumask_t       uninitialized_var(oldmask);
-
-        rqstp = svc_prepare_thread(serv, pool);
-        if (IS_ERR(rqstp)) {
-                error = PTR_ERR(rqstp);
-                goto out;
-        }
-
-        if (serv->sv_nrpools > 1)
-                have_oldmask = svc_pool_map_set_cpumask(pool->sp_id, &oldmask);
-
-        error = kernel_thread((int (*)(void *)) func, rqstp, 0);
-
-        if (have_oldmask)
-                set_cpus_allowed(current, oldmask);
-
-        if (error < 0)
-                goto out_thread;
-        svc_sock_update_bufs(serv);
-        error = 0;
-out:
-        return error;
-
-out_thread:
-        svc_exit_thread(rqstp);
-        goto out;
-}
-
-/*
  * Choose a pool in which to create a new thread, for svc_set_num_threads
  */
 static inline struct svc_pool *
@@ -688,7 +638,9 @@ found_pool:
 int
 svc_set_num_threads(struct svc_serv *serv, struct svc_pool *pool, int nrservs)
 {
-        struct task_struct *victim;
+        struct svc_rqst *rqstp;
+        struct task_struct *task;
+        struct svc_pool *chosen_pool;
         int error = 0;
         unsigned int state = serv->sv_nrthreads-1;
 
@@ -704,18 +656,34 @@ svc_set_num_threads(struct svc_serv *serv, struct svc_pool *pool, int nrservs)
         /* create new threads */
         while (nrservs > 0) {
                 nrservs--;
+                chosen_pool = choose_pool(serv, pool, &state);
+
+                rqstp = svc_prepare_thread(serv, chosen_pool);
+                if (IS_ERR(rqstp)) {
+                        error = PTR_ERR(rqstp);
+                        break;
+                }
+
                 __module_get(serv->sv_module);
-                error = __svc_create_thread(serv->sv_function, serv,
-                                            choose_pool(serv, pool, &state));
-                if (error < 0) {
+                task = kthread_create(serv->sv_function, rqstp, serv->sv_name);
+                if (IS_ERR(task)) {
+                        error = PTR_ERR(task);
                         module_put(serv->sv_module);
+                        svc_exit_thread(rqstp);
                         break;
                 }
+
+                rqstp->rq_task = task;
+                if (serv->sv_nrpools > 1)
+                        svc_pool_map_set_cpumask(task, chosen_pool->sp_id);
+
+                svc_sock_update_bufs(serv);
+                wake_up_process(task);
         }
         /* destroy old threads */
         while (nrservs < 0 &&
-               (victim = choose_victim(serv, pool, &state)) != NULL) {
-                send_sig(serv->sv_kill_signal, victim, 1);
+               (task = choose_victim(serv, pool, &state)) != NULL) {
+                send_sig(serv->sv_kill_signal, task, 1);
                 nrservs++;
         }