[for-6.13 PATCH v2 13/15] nfs/localio: remove redundant code and simplify LOCALIO enablement

Mike Snitzer
2024-11-14T04:00:11Z

Remove nfs_local_enable and nfs_local_disable, instead use
nfs_localio_enable_client and nfs_localio_disable_client.

Discontinue use of the NFS_CS_LOCAL_IO bit in the nfs_client struct's
cl_flags to reflect that LOCALIO is enabled; instead just test if the
net member of the nfs_uuid_t struct is set.

Also remove trace_nfs_local_enable and trace_nfs_local_disable,
comparable traces are available from nfs_localio.ko.

Suggested-by: NeilBrown <neilb@suse.de>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
---
fs/nfs/client.c | 2 +-
fs/nfs/internal.h | 2 --
fs/nfs/localio.c | 28 +++++-----------------------
fs/nfs/nfstrace.h | 32 --------------------------------
fs/nfs_common/nfslocalio.c | 34 +++++++++++-----------------------
5 files changed, 17 insertions(+), 81 deletions(-)

diff --git a/fs/nfs/client.c b/fs/nfs/client.c
index e83e1ce046130..a657318fede46 100644
--- a/fs/nfs/client.c
+++ b/fs/nfs/client.c
@@ -243,7 +243,7 @@ static void pnfs_init_server(struct nfs_server *server)
*/
void nfs_free_client(struct nfs_client *clp)
{
- nfs_local_disable(clp);
+ nfs_localio_disable_client(clp);

/* -EIO all pending I/O */
if (!IS_ERR(clp->cl_rpcclient))
diff --git a/fs/nfs/internal.h b/fs/nfs/internal.h
index 57af3ab3adbe5..a252191b9335c 100644
--- a/fs/nfs/internal.h
+++ b/fs/nfs/internal.h
@@ -454,7 +454,6 @@ extern int nfs_wait_bit_killable(struct wait_bit_key *key, int mode);

#if IS_ENABLED(CONFIG_NFS_LOCALIO)
/* localio.c */
-extern void nfs_local_disable(struct nfs_client *);
extern void nfs_local_probe(struct nfs_client *);
extern struct nfsd_file *nfs_local_open_fh(struct nfs_client *,
const struct cred *,
@@ -471,7 +470,6 @@ extern int nfs_local_commit(struct nfsd_file *,
extern bool nfs_server_is_local(const struct nfs_client *clp);

#else /* CONFIG_NFS_LOCALIO */
-static inline void nfs_local_disable(struct nfs_client *clp) {}
static inline void nfs_local_probe(struct nfs_client *clp) {}
static inline struct nfsd_file *
nfs_local_open_fh(struct nfs_client *clp, const struct cred *cred,
diff --git a/fs/nfs/localio.c b/fs/nfs/localio.c
index 7e432057c3a1f..4b6bf4ea7d7fc 100644
--- a/fs/nfs/localio.c
+++ b/fs/nfs/localio.c
@@ -56,7 +56,7 @@ MODULE_PARM_DESC(localio_O_DIRECT_semantics,

static inline bool nfs_client_is_local(const struct nfs_client *clp)
{
- return !!test_bit(NFS_CS_LOCAL_IO, &clp->cl_flags);
+ return !!rcu_access_pointer(clp->cl_uuid.net);
}

bool nfs_server_is_local(const struct nfs_client *clp)
@@ -121,24 +121,6 @@ const struct rpc_program nfslocalio_program = {
.stats = &nfslocalio_rpcstat,
};

-/*
- * nfs_local_enable - enable local i/o for an nfs_client
- */
-static void nfs_local_enable(struct nfs_client *clp)
-{
- trace_nfs_local_enable(clp);
- nfs_localio_enable_client(clp);
-}
-
-/*
- * nfs_local_disable - disable local i/o for an nfs_client
- */
-void nfs_local_disable(struct nfs_client *clp)
-{
- trace_nfs_local_disable(clp);
- nfs_localio_disable_client(clp);
-}
-
/*
* nfs_init_localioclient - Initialise an NFS localio client connection
*/
@@ -194,19 +176,19 @@ void nfs_local_probe(struct nfs_client *clp)
/* Disallow localio if disabled via sysfs or AUTH_SYS isn't used */
if (!localio_enabled ||
clp->cl_rpcclient->cl_auth->au_flavor != RPC_AUTH_UNIX) {
- nfs_local_disable(clp);
+ nfs_localio_disable_client(clp);
return;
}

if (nfs_client_is_local(clp)) {
/* If already enabled, disable and re-enable */
- nfs_local_disable(clp);
+ nfs_localio_disable_client(clp);
}

if (!nfs_uuid_begin(&clp->cl_uuid))
return;
if (nfs_server_uuid_is_local(clp))
- nfs_local_enable(clp);
+ nfs_localio_enable_client(clp);
nfs_uuid_end(&clp->cl_uuid);
}
EXPORT_SYMBOL_GPL(nfs_local_probe);
@@ -748,7 +730,7 @@ int nfs_local_doio(struct nfs_client *clp, struct nfsd_file *localio,

if (status != 0) {
if (status == -EAGAIN)
- nfs_local_disable(clp);
+ nfs_localio_disable_client(clp);
nfs_local_file_put(localio);
hdr->task.tk_status = status;
nfs_local_hdr_release(hdr, call_ops);
diff --git a/fs/nfs/nfstrace.h b/fs/nfs/nfstrace.h
index 1eab98c277fab..7a058bd8c566e 100644
--- a/fs/nfs/nfstrace.h
+++ b/fs/nfs/nfstrace.h
@@ -1714,38 +1714,6 @@ TRACE_EVENT(nfs_local_open_fh,
)
);

-DECLARE_EVENT_CLASS(nfs_local_client_event,
- TP_PROTO(
- const struct nfs_client *clp
- ),
-
- TP_ARGS(clp),
-
- TP_STRUCT__entry(
- __field(unsigned int, protocol)
- __string(server, clp->cl_hostname)
- ),
-
- TP_fast_assign(
- __entry->protocol = clp->rpc_ops->version;
- __assign_str(server);
- ),
-
- TP_printk(
- "server=%s NFSv%u", __get_str(server), __entry->protocol
- )
-);
-
-#define DEFINE_NFS_LOCAL_CLIENT_EVENT(name) \
- DEFINE_EVENT(nfs_local_client_event, name, \
- TP_PROTO( \
- const struct nfs_client *clp \
- ), \
- TP_ARGS(clp))
-
-DEFINE_NFS_LOCAL_CLIENT_EVENT(nfs_local_enable);
-DEFINE_NFS_LOCAL_CLIENT_EVENT(nfs_local_disable);
-
DECLARE_EVENT_CLASS(nfs_xdr_event,
TP_PROTO(
const struct xdr_stream *xdr,
diff --git a/fs/nfs_common/nfslocalio.c b/fs/nfs_common/nfslocalio.c
index 4e4991e059413..0a26c0ca99c21 100644
--- a/fs/nfs_common/nfslocalio.c
+++ b/fs/nfs_common/nfslocalio.c
@@ -37,7 +37,7 @@ static LIST_HEAD(nfs_uuids);

void nfs_uuid_init(nfs_uuid_t *nfs_uuid)
{
- nfs_uuid->net = NULL;
+ RCU_INIT_POINTER(nfs_uuid->net, NULL);
nfs_uuid->dom = NULL;
nfs_uuid->list_lock = NULL;
INIT_LIST_HEAD(&nfs_uuid->list);
@@ -49,7 +49,7 @@ EXPORT_SYMBOL_GPL(nfs_uuid_init);
bool nfs_uuid_begin(nfs_uuid_t *nfs_uuid)
{
spin_lock(&nfs_uuid->lock);
- if (nfs_uuid->net) {
+ if (rcu_access_pointer(nfs_uuid->net)) {
/* This nfs_uuid is already in use */
spin_unlock(&nfs_uuid->lock);
return false;
@@ -74,9 +74,9 @@ EXPORT_SYMBOL_GPL(nfs_uuid_begin);

void nfs_uuid_end(nfs_uuid_t *nfs_uuid)
{
- if (nfs_uuid->net == NULL) {
+ if (!rcu_access_pointer(nfs_uuid->net)) {
spin_lock(&nfs_uuid->lock);
- if (nfs_uuid->net == NULL) {
+ if (!rcu_access_pointer(nfs_uuid->net)) {
/* Not local, remove from nfs_uuids */
spin_lock(&nfs_uuids_lock);
list_del_init(&nfs_uuid->list);
@@ -139,12 +139,8 @@ EXPORT_SYMBOL_GPL(nfs_uuid_is_local);

void nfs_localio_enable_client(struct nfs_client *clp)
{
- nfs_uuid_t *nfs_uuid = &clp->cl_uuid;
-
- spin_lock(&nfs_uuid->lock);
- set_bit(NFS_CS_LOCAL_IO, &clp->cl_flags);
+ /* nfs_uuid_is_local() does the actual enablement */
trace_nfs_localio_enable_client(clp);
- spin_unlock(&nfs_uuid->lock);
}
EXPORT_SYMBOL_GPL(nfs_localio_enable_client);

@@ -152,15 +148,15 @@ EXPORT_SYMBOL_GPL(nfs_localio_enable_client);
* Cleanup the nfs_uuid_t embedded in an nfs_client.
* This is the long-form of nfs_uuid_init().
*/
-static void nfs_uuid_put(nfs_uuid_t *nfs_uuid)
+static bool nfs_uuid_put(nfs_uuid_t *nfs_uuid)
{
LIST_HEAD(local_files);
struct nfs_file_localio *nfl, *tmp;

spin_lock(&nfs_uuid->lock);
- if (unlikely(!nfs_uuid->net)) {
+ if (unlikely(!rcu_access_pointer(nfs_uuid->net))) {
spin_unlock(&nfs_uuid->lock);
- return;
+ return false;
}
RCU_INIT_POINTER(nfs_uuid->net, NULL);

@@ -192,22 +188,14 @@ static void nfs_uuid_put(nfs_uuid_t *nfs_uuid)

module_put(nfsd_mod);
spin_unlock(&nfs_uuid->lock);
+
+ return true;
}

void nfs_localio_disable_client(struct nfs_client *clp)
{
- nfs_uuid_t *nfs_uuid = NULL;
-
- spin_lock(&clp->cl_uuid.lock); /* aka &nfs_uuid->lock */
- if (test_and_clear_bit(NFS_CS_LOCAL_IO, &clp->cl_flags)) {
- /* &clp->cl_uuid is always not NULL, using as bool here */
- nfs_uuid = &clp->cl_uuid;
+ if (nfs_uuid_put(&clp->cl_uuid))
trace_nfs_localio_disable_client(clp);
- }
- spin_unlock(&clp->cl_uuid.lock);
-
- if (nfs_uuid)
- nfs_uuid_put(nfs_uuid);
}
EXPORT_SYMBOL_GPL(nfs_localio_disable_client);

--
2.44.0