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, 29 insertions, 16 deletions

diff --git a/fs/nfsd/nfssvc.c b/fs/nfsd/nfssvc.c
index 6339cb70a08d..9e2156813710 100644
--- a/fs/nfsd/nfssvc.c
+++ b/fs/nfsd/nfssvc.c
@@ -21,6 +21,7 @@
 #include <linux/smp_lock.h>
 #include <linux/freezer.h>
 #include <linux/fs_struct.h>
+#include <linux/kthread.h>
 
 #include <linux/sunrpc/types.h>
 #include <linux/sunrpc/stats.h>
@@ -46,7 +47,7 @@
 #define SHUTDOWN_SIGS   (sigmask(SIGKILL) | sigmask(SIGHUP) | sigmask(SIGINT) | sigmask(SIGQUIT))
 
 extern struct svc_program       nfsd_program;
-static void                     nfsd(struct svc_rqst *rqstp);
+static int                      nfsd(void *vrqstp);
 struct timeval                  nfssvc_boot;
 static atomic_t                 nfsd_busy;
 static unsigned long            nfsd_last_call;
@@ -407,18 +408,19 @@ update_thread_usage(int busy_threads)
 /*
  * This is the NFS server kernel thread
  */
-static void
-nfsd(struct svc_rqst *rqstp)
+static int
+nfsd(void *vrqstp)
 {
+        struct svc_rqst *rqstp = (struct svc_rqst *) vrqstp;
         struct fs_struct *fsp;
-        int             err;
         sigset_t shutdown_mask, allowed_mask;
+        int err, preverr = 0;
+        unsigned int signo;
 
         /* Lock module and set up kernel thread */
         mutex_lock(&nfsd_mutex);
-        daemonize("nfsd");
 
-        /* After daemonize() this kernel thread shares current->fs
+        /* At this point, the thread shares current->fs
          * with the init process. We need to create files with a
          * umask of 0 instead of init's umask. */
         fsp = copy_fs_struct(current->fs);
@@ -433,14 +435,18 @@ nfsd(struct svc_rqst *rqstp)
         siginitsetinv(&shutdown_mask, SHUTDOWN_SIGS);
         siginitsetinv(&allowed_mask, ALLOWED_SIGS);
 
+        /*
+         * thread is spawned with all signals set to SIG_IGN, re-enable
+         * the ones that matter
+         */
+        for (signo = 1; signo <= _NSIG; signo++) {
+                if (!sigismember(&shutdown_mask, signo))
+                        allow_signal(signo);
+        }
 
         nfsdstats.th_cnt++;
-
-        rqstp->rq_task = current;
-
         mutex_unlock(&nfsd_mutex);
 
-
         /*
          * We want less throttling in balance_dirty_pages() so that nfs to
          * localhost doesn't cause nfsd to lock up due to all the client's
@@ -462,15 +468,25 @@ nfsd(struct svc_rqst *rqstp)
                  */
                 while ((err = svc_recv(rqstp, 60*60*HZ)) == -EAGAIN)
                         ;
-                if (err < 0)
+                if (err == -EINTR)
                         break;
+                else if (err < 0) {
+                        if (err != preverr) {
+                                printk(KERN_WARNING "%s: unexpected error "
+                                        "from svc_recv (%d)\n", __func__, -err);
+                                preverr = err;
+                        }
+                        schedule_timeout_uninterruptible(HZ);
+                        continue;
+                }
+
                 update_thread_usage(atomic_read(&nfsd_busy));
                 atomic_inc(&nfsd_busy);
 
                 /* Lock the export hash tables for reading. */
                 exp_readlock();
 
-                /* Process request with signals blocked.  */
+                /* Process request with signals blocked. */
                 sigprocmask(SIG_SETMASK, &allowed_mask, NULL);
 
                 svc_process(rqstp);
@@ -481,14 +497,10 @@ nfsd(struct svc_rqst *rqstp)
                 atomic_dec(&nfsd_busy);
         }
 
-        if (err != -EINTR)
-                printk(KERN_WARNING "nfsd: terminating on error %d\n", -err);
-
         /* Clear signals before calling svc_exit_thread() */
         flush_signals(current);
 
         mutex_lock(&nfsd_mutex);
-
         nfsdstats.th_cnt --;
 
 out:
@@ -498,6 +510,7 @@ out:
         /* Release module */
         mutex_unlock(&nfsd_mutex);
         module_put_and_exit(0);
+        return 0;
 }
 
 static __be32 map_new_errors(u32 vers, __be32 nfserr)