5.10-stable review patch. If anyone has any objections, please let me know.
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From: NeilBrown neilb@suse.de
[ Upstream commit 93aa619eb0b42eec2f3a9b4d9db41f5095390aec ]
Currently 'pooled' services hold a reference on the pool_map, and 'unpooled' services do not. svc_destroy() uses the presence of ->svo_function (via svc_serv_is_pooled()) to determine if the reference should be dropped. There is no direct correlation between being pooled and the use of svo_function, though in practice, lockd is the only non-pooled service, and the only one not to use svo_function.
This is untidy and would cause problems if we changed lockd to use svc_set_num_threads(), which requires the use of ->svo_function.
So change the test for "is the service pooled" to "is sv_nrpools > 1".
This means that when svc_pool_map_get() returns 1, it must NOT take a reference to the pool.
We discard svc_serv_is_pooled(), and test sv_nrpools directly.
Signed-off-by: NeilBrown neilb@suse.de Signed-off-by: Chuck Lever chuck.lever@oracle.com Signed-off-by: Sasha Levin sashal@kernel.org --- net/sunrpc/svc.c | 54 ++++++++++++++++++++++++++---------------------- 1 file changed, 29 insertions(+), 25 deletions(-)
diff --git a/net/sunrpc/svc.c b/net/sunrpc/svc.c index c681ac1c9d569..ceccd4ae5f797 100644 --- a/net/sunrpc/svc.c +++ b/net/sunrpc/svc.c @@ -35,8 +35,6 @@
static void svc_unregister(const struct svc_serv *serv, struct net *net);
-#define svc_serv_is_pooled(serv) ((serv)->sv_ops->svo_function) - #define SVC_POOL_DEFAULT SVC_POOL_GLOBAL
/* @@ -238,8 +236,10 @@ svc_pool_map_init_pernode(struct svc_pool_map *m)
/* * Add a reference to the global map of cpus to pools (and - * vice versa). Initialise the map if we're the first user. - * Returns the number of pools. + * vice versa) if pools are in use. + * Initialise the map if we're the first user. + * Returns the number of pools. If this is '1', no reference + * was taken. */ static unsigned int svc_pool_map_get(void) @@ -251,6 +251,7 @@ svc_pool_map_get(void)
if (m->count++) { mutex_unlock(&svc_pool_map_mutex); + WARN_ON_ONCE(m->npools <= 1); return m->npools; }
@@ -266,29 +267,36 @@ svc_pool_map_get(void) break; }
- if (npools < 0) { + if (npools <= 0) { /* default, or memory allocation failure */ npools = 1; m->mode = SVC_POOL_GLOBAL; } m->npools = npools;
+ if (npools == 1) + /* service is unpooled, so doesn't hold a reference */ + m->count--; + mutex_unlock(&svc_pool_map_mutex); - return m->npools; + return npools; }
/* - * Drop a reference to the global map of cpus to pools. + * Drop a reference to the global map of cpus to pools, if + * pools were in use, i.e. if npools > 1. * When the last reference is dropped, the map data is * freed; this allows the sysadmin to change the pool * mode using the pool_mode module option without * rebooting or re-loading sunrpc.ko. */ static void -svc_pool_map_put(void) +svc_pool_map_put(int npools) { struct svc_pool_map *m = &svc_pool_map;
+ if (npools <= 1) + return; mutex_lock(&svc_pool_map_mutex);
if (!--m->count) { @@ -357,21 +365,18 @@ svc_pool_for_cpu(struct svc_serv *serv, int cpu) struct svc_pool_map *m = &svc_pool_map; unsigned int pidx = 0;
- /* - * An uninitialised map happens in a pure client when - * lockd is brought up, so silently treat it the - * same as SVC_POOL_GLOBAL. - */ - if (svc_serv_is_pooled(serv)) { - switch (m->mode) { - case SVC_POOL_PERCPU: - pidx = m->to_pool[cpu]; - break; - case SVC_POOL_PERNODE: - pidx = m->to_pool[cpu_to_node(cpu)]; - break; - } + if (serv->sv_nrpools <= 1) + return serv->sv_pools; + + switch (m->mode) { + case SVC_POOL_PERCPU: + pidx = m->to_pool[cpu]; + break; + case SVC_POOL_PERNODE: + pidx = m->to_pool[cpu_to_node(cpu)]; + break; } + return &serv->sv_pools[pidx % serv->sv_nrpools]; }
@@ -524,7 +529,7 @@ svc_create_pooled(struct svc_program *prog, unsigned int bufsize, goto out_err; return serv; out_err: - svc_pool_map_put(); + svc_pool_map_put(npools); return NULL; } EXPORT_SYMBOL_GPL(svc_create_pooled); @@ -559,8 +564,7 @@ svc_destroy(struct kref *ref)
cache_clean_deferred(serv);
- if (svc_serv_is_pooled(serv)) - svc_pool_map_put(); + svc_pool_map_put(serv->sv_nrpools);
kfree(serv->sv_pools); kfree(serv);