[PATCH v2 12/16] nfsd: add support for workqueue based service processing

From: Jeff Layton
Date: Wed Dec 10 2014 - 14:09:45 EST


Allow nfsd to create a workqueue based nfsd service if the sunrpc
pool_mode is set to "workqueue".

The first iteration here is fairly simple. The xprt work simply
allocates a svc_rqst object, and then queues that work.

Signed-off-by: Jeff Layton <jlayton@xxxxxxxxxxxxxxx>
---
fs/fs_struct.c | 3 ++-
fs/nfsd/nfssvc.c | 69 +++++++++++++++++++++++++++++++++++++++++++++--
include/linux/fs_struct.h | 1 +
3 files changed, 70 insertions(+), 3 deletions(-)

diff --git a/fs/fs_struct.c b/fs/fs_struct.c
index 9bc08ea2f433..68985c76cd75 100644
--- a/fs/fs_struct.c
+++ b/fs/fs_struct.c
@@ -130,7 +130,7 @@ struct fs_struct *copy_fs_struct(struct fs_struct *old)
EXPORT_SYMBOL_GPL(copy_fs_struct);

/* Replace current fs struct with one given. Return a pointer to old one. */
-static struct fs_struct *
+struct fs_struct *
swap_fs_struct(struct fs_struct *new_fs)
{
struct fs_struct *old_fs;
@@ -142,6 +142,7 @@ swap_fs_struct(struct fs_struct *new_fs)

return old_fs;
}
+EXPORT_SYMBOL_GPL(swap_fs_struct);

/* Put a reference to a fs_struct. */
void put_fs_struct(struct fs_struct *fs)
diff --git a/fs/nfsd/nfssvc.c b/fs/nfsd/nfssvc.c
index f37bd7db2176..7e22068bdad4 100644
--- a/fs/nfsd/nfssvc.c
+++ b/fs/nfsd/nfssvc.c
@@ -28,6 +28,8 @@
extern struct svc_program nfsd_program;
static int nfsd(void *vrqstp);

+static struct svc_serv_ops nfsd_wq_sv_ops;
+
/*
* nfsd_mutex protects nn->nfsd_serv -- both the pointer itself and the members
* of the svc_serv struct. In particular, ->sv_nrthreads but also to some
@@ -398,10 +400,19 @@ static struct svc_serv_ops nfsd_thread_sv_ops = {
.svo_module = THIS_MODULE,
};

+static struct svc_serv_ops *
+select_svc_serv_ops(void)
+{
+ if (svc_pool_map.mode == SVC_POOL_WORKQUEUE)
+ return &nfsd_wq_sv_ops;
+ return &nfsd_thread_sv_ops;
+}
+
int nfsd_create_serv(struct net *net)
{
int error;
struct nfsd_net *nn = net_generic(net, nfsd_net_id);
+ struct svc_serv_ops *ops;

WARN_ON(!mutex_is_locked(&nfsd_mutex));
if (nn->nfsd_serv) {
@@ -411,8 +422,11 @@ int nfsd_create_serv(struct net *net)
if (nfsd_max_blksize == 0)
nfsd_max_blksize = nfsd_get_default_max_blksize();
nfsd_reset_versions();
- nn->nfsd_serv = svc_create_pooled(&nfsd_program, nfsd_max_blksize,
- &nfsd_thread_sv_ops);
+
+ svc_pool_map_get();
+ ops = select_svc_serv_ops();
+ nn->nfsd_serv = svc_create_pooled(&nfsd_program, nfsd_max_blksize, ops);
+ svc_pool_map_put();
if (nn->nfsd_serv == NULL)
return -ENOMEM;

@@ -643,6 +657,57 @@ nfsd(void *vrqstp)
return 0;
}

+static void
+nfsd_rqst_work(struct work_struct *work)
+{
+ struct svc_rqst *rqstp = container_of(work, struct svc_rqst, rq_work);
+ struct svc_xprt *xprt = rqstp->rq_xprt;
+ struct net *net = xprt->xpt_net;
+ struct nfsd_net *nn = net_generic(net, nfsd_net_id);
+ struct fs_struct *saved_fs;
+
+ rqstp->rq_server->sv_maxconn = nn->max_connections;
+
+ if (svc_wq_recv(rqstp) < 0) {
+ svc_rqst_free(rqstp);
+ return;
+ }
+
+ saved_fs = swap_fs_struct(rqstp->rq_fs);
+ svc_process(rqstp);
+ saved_fs = swap_fs_struct(saved_fs);
+ svc_rqst_free(rqstp);
+}
+
+/* work function for workqueue-based nfsd */
+static void
+nfsd_xprt_work(struct work_struct *work)
+{
+ int node = numa_node_id();
+ struct svc_xprt *xprt = container_of(work, struct svc_xprt, xpt_work);
+ struct svc_rqst *rqstp;
+ struct svc_serv *serv = xprt->xpt_server;
+
+ rqstp = svc_rqst_alloc(serv, &serv->sv_pools[node], node);
+ if (!rqstp) {
+ /* Alloc failure. Give up for now, and requeue the work */
+ queue_work(serv->sv_wq, &xprt->xpt_work);
+ return;
+ }
+
+ rqstp->rq_xprt = xprt;
+ queue_work(serv->sv_wq, &rqstp->rq_work);
+}
+
+static struct svc_serv_ops nfsd_wq_sv_ops = {
+ .svo_shutdown = nfsd_last_thread,
+ .svo_enqueue_xprt = svc_wq_enqueue_xprt,
+ .svo_xprt_work = nfsd_xprt_work,
+ .svo_rqst_work = nfsd_rqst_work,
+ .svo_setup = svc_wq_setup,
+ .svo_module = THIS_MODULE,
+};
+
static __be32 map_new_errors(u32 vers, __be32 nfserr)
{
if (nfserr == nfserr_jukebox && vers == 2)
diff --git a/include/linux/fs_struct.h b/include/linux/fs_struct.h
index d2b7a1942790..671c49f13396 100644
--- a/include/linux/fs_struct.h
+++ b/include/linux/fs_struct.h
@@ -20,6 +20,7 @@ extern void exit_fs(struct task_struct *);
extern void set_fs_root(struct fs_struct *, const struct path *);
extern void set_fs_pwd(struct fs_struct *, const struct path *);
extern struct fs_struct *copy_fs_struct(struct fs_struct *);
+extern struct fs_struct *swap_fs_struct(struct fs_struct *);
extern void free_fs_struct(struct fs_struct *);
extern void replace_fs_struct(struct fs_struct *);
extern int unshare_fs_struct(void);
--
2.1.0

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