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![Bo Liu](/assets/img/avatar_default.png)
Use ida_alloc()/ida_free() instead of ida_simple_get()/ida_simple_remove(). The latter is deprecated and more verbose. Signed-off-by: Bo Liu <liubo03@inspur.com> Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
655 lines
16 KiB
C
655 lines
16 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Multipath support for RPC
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*
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* Copyright (c) 2015, 2016, Primary Data, Inc. All rights reserved.
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*
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* Trond Myklebust <trond.myklebust@primarydata.com>
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*
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*/
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#include <linux/atomic.h>
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#include <linux/types.h>
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#include <linux/kref.h>
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#include <linux/list.h>
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#include <linux/rcupdate.h>
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#include <linux/rculist.h>
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#include <linux/slab.h>
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#include <linux/spinlock.h>
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#include <linux/sunrpc/xprt.h>
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#include <linux/sunrpc/addr.h>
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#include <linux/sunrpc/xprtmultipath.h>
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#include "sysfs.h"
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typedef struct rpc_xprt *(*xprt_switch_find_xprt_t)(struct rpc_xprt_switch *xps,
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const struct rpc_xprt *cur);
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static const struct rpc_xprt_iter_ops rpc_xprt_iter_singular;
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static const struct rpc_xprt_iter_ops rpc_xprt_iter_roundrobin;
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static const struct rpc_xprt_iter_ops rpc_xprt_iter_listall;
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static const struct rpc_xprt_iter_ops rpc_xprt_iter_listoffline;
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static void xprt_switch_add_xprt_locked(struct rpc_xprt_switch *xps,
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struct rpc_xprt *xprt)
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{
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if (unlikely(xprt_get(xprt) == NULL))
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return;
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list_add_tail_rcu(&xprt->xprt_switch, &xps->xps_xprt_list);
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smp_wmb();
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if (xps->xps_nxprts == 0)
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xps->xps_net = xprt->xprt_net;
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xps->xps_nxprts++;
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xps->xps_nactive++;
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}
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/**
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* rpc_xprt_switch_add_xprt - Add a new rpc_xprt to an rpc_xprt_switch
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* @xps: pointer to struct rpc_xprt_switch
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* @xprt: pointer to struct rpc_xprt
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*
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* Adds xprt to the end of the list of struct rpc_xprt in xps.
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*/
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void rpc_xprt_switch_add_xprt(struct rpc_xprt_switch *xps,
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struct rpc_xprt *xprt)
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{
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if (xprt == NULL)
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return;
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spin_lock(&xps->xps_lock);
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if (xps->xps_net == xprt->xprt_net || xps->xps_net == NULL)
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xprt_switch_add_xprt_locked(xps, xprt);
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spin_unlock(&xps->xps_lock);
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rpc_sysfs_xprt_setup(xps, xprt, GFP_KERNEL);
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}
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static void xprt_switch_remove_xprt_locked(struct rpc_xprt_switch *xps,
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struct rpc_xprt *xprt, bool offline)
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{
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if (unlikely(xprt == NULL))
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return;
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if (!test_bit(XPRT_OFFLINE, &xprt->state) && offline)
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xps->xps_nactive--;
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xps->xps_nxprts--;
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if (xps->xps_nxprts == 0)
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xps->xps_net = NULL;
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smp_wmb();
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list_del_rcu(&xprt->xprt_switch);
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}
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/**
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* rpc_xprt_switch_remove_xprt - Removes an rpc_xprt from a rpc_xprt_switch
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* @xps: pointer to struct rpc_xprt_switch
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* @xprt: pointer to struct rpc_xprt
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* @offline: indicates if the xprt that's being removed is in an offline state
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*
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* Removes xprt from the list of struct rpc_xprt in xps.
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*/
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void rpc_xprt_switch_remove_xprt(struct rpc_xprt_switch *xps,
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struct rpc_xprt *xprt, bool offline)
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{
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spin_lock(&xps->xps_lock);
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xprt_switch_remove_xprt_locked(xps, xprt, offline);
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spin_unlock(&xps->xps_lock);
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xprt_put(xprt);
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}
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static DEFINE_IDA(rpc_xprtswitch_ids);
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void xprt_multipath_cleanup_ids(void)
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{
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ida_destroy(&rpc_xprtswitch_ids);
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}
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static int xprt_switch_alloc_id(struct rpc_xprt_switch *xps, gfp_t gfp_flags)
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{
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int id;
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id = ida_alloc(&rpc_xprtswitch_ids, gfp_flags);
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if (id < 0)
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return id;
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xps->xps_id = id;
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return 0;
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}
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static void xprt_switch_free_id(struct rpc_xprt_switch *xps)
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{
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ida_free(&rpc_xprtswitch_ids, xps->xps_id);
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}
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/**
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* xprt_switch_alloc - Allocate a new struct rpc_xprt_switch
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* @xprt: pointer to struct rpc_xprt
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* @gfp_flags: allocation flags
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*
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* On success, returns an initialised struct rpc_xprt_switch, containing
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* the entry xprt. Returns NULL on failure.
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*/
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struct rpc_xprt_switch *xprt_switch_alloc(struct rpc_xprt *xprt,
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gfp_t gfp_flags)
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{
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struct rpc_xprt_switch *xps;
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xps = kmalloc(sizeof(*xps), gfp_flags);
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if (xps != NULL) {
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spin_lock_init(&xps->xps_lock);
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kref_init(&xps->xps_kref);
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xprt_switch_alloc_id(xps, gfp_flags);
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xps->xps_nxprts = xps->xps_nactive = 0;
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atomic_long_set(&xps->xps_queuelen, 0);
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xps->xps_net = NULL;
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INIT_LIST_HEAD(&xps->xps_xprt_list);
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xps->xps_iter_ops = &rpc_xprt_iter_singular;
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rpc_sysfs_xprt_switch_setup(xps, xprt, gfp_flags);
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xprt_switch_add_xprt_locked(xps, xprt);
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xps->xps_nunique_destaddr_xprts = 1;
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rpc_sysfs_xprt_setup(xps, xprt, gfp_flags);
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}
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return xps;
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}
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static void xprt_switch_free_entries(struct rpc_xprt_switch *xps)
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{
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spin_lock(&xps->xps_lock);
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while (!list_empty(&xps->xps_xprt_list)) {
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struct rpc_xprt *xprt;
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xprt = list_first_entry(&xps->xps_xprt_list,
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struct rpc_xprt, xprt_switch);
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xprt_switch_remove_xprt_locked(xps, xprt, true);
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spin_unlock(&xps->xps_lock);
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xprt_put(xprt);
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spin_lock(&xps->xps_lock);
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}
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spin_unlock(&xps->xps_lock);
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}
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static void xprt_switch_free(struct kref *kref)
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{
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struct rpc_xprt_switch *xps = container_of(kref,
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struct rpc_xprt_switch, xps_kref);
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xprt_switch_free_entries(xps);
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rpc_sysfs_xprt_switch_destroy(xps);
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xprt_switch_free_id(xps);
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kfree_rcu(xps, xps_rcu);
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}
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/**
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* xprt_switch_get - Return a reference to a rpc_xprt_switch
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* @xps: pointer to struct rpc_xprt_switch
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*
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* Returns a reference to xps unless the refcount is already zero.
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*/
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struct rpc_xprt_switch *xprt_switch_get(struct rpc_xprt_switch *xps)
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{
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if (xps != NULL && kref_get_unless_zero(&xps->xps_kref))
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return xps;
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return NULL;
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}
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/**
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* xprt_switch_put - Release a reference to a rpc_xprt_switch
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* @xps: pointer to struct rpc_xprt_switch
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*
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* Release the reference to xps, and free it once the refcount is zero.
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*/
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void xprt_switch_put(struct rpc_xprt_switch *xps)
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{
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if (xps != NULL)
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kref_put(&xps->xps_kref, xprt_switch_free);
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}
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/**
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* rpc_xprt_switch_set_roundrobin - Set a round-robin policy on rpc_xprt_switch
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* @xps: pointer to struct rpc_xprt_switch
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*
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* Sets a round-robin default policy for iterators acting on xps.
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*/
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void rpc_xprt_switch_set_roundrobin(struct rpc_xprt_switch *xps)
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{
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if (READ_ONCE(xps->xps_iter_ops) != &rpc_xprt_iter_roundrobin)
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WRITE_ONCE(xps->xps_iter_ops, &rpc_xprt_iter_roundrobin);
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}
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static
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const struct rpc_xprt_iter_ops *xprt_iter_ops(const struct rpc_xprt_iter *xpi)
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{
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if (xpi->xpi_ops != NULL)
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return xpi->xpi_ops;
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return rcu_dereference(xpi->xpi_xpswitch)->xps_iter_ops;
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}
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static
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void xprt_iter_no_rewind(struct rpc_xprt_iter *xpi)
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{
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}
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static
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void xprt_iter_default_rewind(struct rpc_xprt_iter *xpi)
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{
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WRITE_ONCE(xpi->xpi_cursor, NULL);
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}
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static
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bool xprt_is_active(const struct rpc_xprt *xprt)
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{
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return (kref_read(&xprt->kref) != 0 &&
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!test_bit(XPRT_OFFLINE, &xprt->state));
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}
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static
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struct rpc_xprt *xprt_switch_find_first_entry(struct list_head *head)
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{
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struct rpc_xprt *pos;
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list_for_each_entry_rcu(pos, head, xprt_switch) {
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if (xprt_is_active(pos))
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return pos;
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}
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return NULL;
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}
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static
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struct rpc_xprt *xprt_switch_find_first_entry_offline(struct list_head *head)
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{
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struct rpc_xprt *pos;
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list_for_each_entry_rcu(pos, head, xprt_switch) {
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if (!xprt_is_active(pos))
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return pos;
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}
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return NULL;
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}
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static
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struct rpc_xprt *xprt_iter_first_entry(struct rpc_xprt_iter *xpi)
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{
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struct rpc_xprt_switch *xps = rcu_dereference(xpi->xpi_xpswitch);
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if (xps == NULL)
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return NULL;
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return xprt_switch_find_first_entry(&xps->xps_xprt_list);
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}
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static
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struct rpc_xprt *_xprt_switch_find_current_entry(struct list_head *head,
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const struct rpc_xprt *cur,
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bool find_active)
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{
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struct rpc_xprt *pos;
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bool found = false;
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list_for_each_entry_rcu(pos, head, xprt_switch) {
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if (cur == pos)
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found = true;
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if (found && ((find_active && xprt_is_active(pos)) ||
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(!find_active && xprt_is_active(pos))))
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return pos;
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}
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return NULL;
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}
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static
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struct rpc_xprt *xprt_switch_find_current_entry(struct list_head *head,
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const struct rpc_xprt *cur)
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{
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return _xprt_switch_find_current_entry(head, cur, true);
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}
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static
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struct rpc_xprt * _xprt_iter_current_entry(struct rpc_xprt_iter *xpi,
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struct rpc_xprt *first_entry(struct list_head *head),
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struct rpc_xprt *current_entry(struct list_head *head,
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const struct rpc_xprt *cur))
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{
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struct rpc_xprt_switch *xps = rcu_dereference(xpi->xpi_xpswitch);
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struct list_head *head;
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if (xps == NULL)
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return NULL;
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head = &xps->xps_xprt_list;
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if (xpi->xpi_cursor == NULL || xps->xps_nxprts < 2)
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return first_entry(head);
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return current_entry(head, xpi->xpi_cursor);
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}
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static
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struct rpc_xprt *xprt_iter_current_entry(struct rpc_xprt_iter *xpi)
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{
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return _xprt_iter_current_entry(xpi, xprt_switch_find_first_entry,
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xprt_switch_find_current_entry);
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}
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static
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struct rpc_xprt *xprt_switch_find_current_entry_offline(struct list_head *head,
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const struct rpc_xprt *cur)
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{
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return _xprt_switch_find_current_entry(head, cur, false);
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}
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static
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struct rpc_xprt *xprt_iter_current_entry_offline(struct rpc_xprt_iter *xpi)
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{
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return _xprt_iter_current_entry(xpi,
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xprt_switch_find_first_entry_offline,
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xprt_switch_find_current_entry_offline);
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}
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bool rpc_xprt_switch_has_addr(struct rpc_xprt_switch *xps,
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const struct sockaddr *sap)
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{
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struct list_head *head;
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struct rpc_xprt *pos;
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if (xps == NULL || sap == NULL)
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return false;
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head = &xps->xps_xprt_list;
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list_for_each_entry_rcu(pos, head, xprt_switch) {
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if (rpc_cmp_addr_port(sap, (struct sockaddr *)&pos->addr)) {
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pr_info("RPC: addr %s already in xprt switch\n",
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pos->address_strings[RPC_DISPLAY_ADDR]);
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return true;
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}
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}
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return false;
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}
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static
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struct rpc_xprt *xprt_switch_find_next_entry(struct list_head *head,
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const struct rpc_xprt *cur, bool check_active)
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{
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struct rpc_xprt *pos, *prev = NULL;
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bool found = false;
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list_for_each_entry_rcu(pos, head, xprt_switch) {
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if (cur == prev)
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found = true;
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/* for request to return active transports return only
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* active, for request to return offline transports
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* return only offline
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*/
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if (found && ((check_active && xprt_is_active(pos)) ||
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(!check_active && !xprt_is_active(pos))))
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return pos;
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prev = pos;
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}
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return NULL;
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}
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static
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struct rpc_xprt *xprt_switch_set_next_cursor(struct rpc_xprt_switch *xps,
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struct rpc_xprt **cursor,
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xprt_switch_find_xprt_t find_next)
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{
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struct rpc_xprt *pos, *old;
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old = smp_load_acquire(cursor);
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pos = find_next(xps, old);
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smp_store_release(cursor, pos);
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return pos;
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}
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static
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struct rpc_xprt *xprt_iter_next_entry_multiple(struct rpc_xprt_iter *xpi,
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xprt_switch_find_xprt_t find_next)
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{
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struct rpc_xprt_switch *xps = rcu_dereference(xpi->xpi_xpswitch);
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if (xps == NULL)
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return NULL;
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return xprt_switch_set_next_cursor(xps, &xpi->xpi_cursor, find_next);
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}
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static
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struct rpc_xprt *__xprt_switch_find_next_entry_roundrobin(struct list_head *head,
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const struct rpc_xprt *cur)
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{
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struct rpc_xprt *ret;
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ret = xprt_switch_find_next_entry(head, cur, true);
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if (ret != NULL)
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return ret;
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return xprt_switch_find_first_entry(head);
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}
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static
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struct rpc_xprt *xprt_switch_find_next_entry_roundrobin(struct rpc_xprt_switch *xps,
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const struct rpc_xprt *cur)
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{
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struct list_head *head = &xps->xps_xprt_list;
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struct rpc_xprt *xprt;
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unsigned int nactive;
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for (;;) {
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unsigned long xprt_queuelen, xps_queuelen;
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xprt = __xprt_switch_find_next_entry_roundrobin(head, cur);
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if (!xprt)
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break;
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xprt_queuelen = atomic_long_read(&xprt->queuelen);
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xps_queuelen = atomic_long_read(&xps->xps_queuelen);
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nactive = READ_ONCE(xps->xps_nactive);
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/* Exit loop if xprt_queuelen <= average queue length */
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if (xprt_queuelen * nactive <= xps_queuelen)
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break;
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cur = xprt;
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}
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return xprt;
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}
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static
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struct rpc_xprt *xprt_iter_next_entry_roundrobin(struct rpc_xprt_iter *xpi)
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{
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return xprt_iter_next_entry_multiple(xpi,
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xprt_switch_find_next_entry_roundrobin);
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}
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static
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struct rpc_xprt *xprt_switch_find_next_entry_all(struct rpc_xprt_switch *xps,
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const struct rpc_xprt *cur)
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{
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return xprt_switch_find_next_entry(&xps->xps_xprt_list, cur, true);
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}
|
|
|
|
static
|
|
struct rpc_xprt *xprt_switch_find_next_entry_offline(struct rpc_xprt_switch *xps,
|
|
const struct rpc_xprt *cur)
|
|
{
|
|
return xprt_switch_find_next_entry(&xps->xps_xprt_list, cur, false);
|
|
}
|
|
|
|
static
|
|
struct rpc_xprt *xprt_iter_next_entry_all(struct rpc_xprt_iter *xpi)
|
|
{
|
|
return xprt_iter_next_entry_multiple(xpi,
|
|
xprt_switch_find_next_entry_all);
|
|
}
|
|
|
|
static
|
|
struct rpc_xprt *xprt_iter_next_entry_offline(struct rpc_xprt_iter *xpi)
|
|
{
|
|
return xprt_iter_next_entry_multiple(xpi,
|
|
xprt_switch_find_next_entry_offline);
|
|
}
|
|
|
|
/*
|
|
* xprt_iter_rewind - Resets the xprt iterator
|
|
* @xpi: pointer to rpc_xprt_iter
|
|
*
|
|
* Resets xpi to ensure that it points to the first entry in the list
|
|
* of transports.
|
|
*/
|
|
void xprt_iter_rewind(struct rpc_xprt_iter *xpi)
|
|
{
|
|
rcu_read_lock();
|
|
xprt_iter_ops(xpi)->xpi_rewind(xpi);
|
|
rcu_read_unlock();
|
|
}
|
|
|
|
static void __xprt_iter_init(struct rpc_xprt_iter *xpi,
|
|
struct rpc_xprt_switch *xps,
|
|
const struct rpc_xprt_iter_ops *ops)
|
|
{
|
|
rcu_assign_pointer(xpi->xpi_xpswitch, xprt_switch_get(xps));
|
|
xpi->xpi_cursor = NULL;
|
|
xpi->xpi_ops = ops;
|
|
}
|
|
|
|
/**
|
|
* xprt_iter_init - Initialise an xprt iterator
|
|
* @xpi: pointer to rpc_xprt_iter
|
|
* @xps: pointer to rpc_xprt_switch
|
|
*
|
|
* Initialises the iterator to use the default iterator ops
|
|
* as set in xps. This function is mainly intended for internal
|
|
* use in the rpc_client.
|
|
*/
|
|
void xprt_iter_init(struct rpc_xprt_iter *xpi,
|
|
struct rpc_xprt_switch *xps)
|
|
{
|
|
__xprt_iter_init(xpi, xps, NULL);
|
|
}
|
|
|
|
/**
|
|
* xprt_iter_init_listall - Initialise an xprt iterator
|
|
* @xpi: pointer to rpc_xprt_iter
|
|
* @xps: pointer to rpc_xprt_switch
|
|
*
|
|
* Initialises the iterator to iterate once through the entire list
|
|
* of entries in xps.
|
|
*/
|
|
void xprt_iter_init_listall(struct rpc_xprt_iter *xpi,
|
|
struct rpc_xprt_switch *xps)
|
|
{
|
|
__xprt_iter_init(xpi, xps, &rpc_xprt_iter_listall);
|
|
}
|
|
|
|
void xprt_iter_init_listoffline(struct rpc_xprt_iter *xpi,
|
|
struct rpc_xprt_switch *xps)
|
|
{
|
|
__xprt_iter_init(xpi, xps, &rpc_xprt_iter_listoffline);
|
|
}
|
|
|
|
/**
|
|
* xprt_iter_xchg_switch - Atomically swap out the rpc_xprt_switch
|
|
* @xpi: pointer to rpc_xprt_iter
|
|
* @newswitch: pointer to a new rpc_xprt_switch or NULL
|
|
*
|
|
* Swaps out the existing xpi->xpi_xpswitch with a new value.
|
|
*/
|
|
struct rpc_xprt_switch *xprt_iter_xchg_switch(struct rpc_xprt_iter *xpi,
|
|
struct rpc_xprt_switch *newswitch)
|
|
{
|
|
struct rpc_xprt_switch __rcu *oldswitch;
|
|
|
|
/* Atomically swap out the old xpswitch */
|
|
oldswitch = xchg(&xpi->xpi_xpswitch, RCU_INITIALIZER(newswitch));
|
|
if (newswitch != NULL)
|
|
xprt_iter_rewind(xpi);
|
|
return rcu_dereference_protected(oldswitch, true);
|
|
}
|
|
|
|
/**
|
|
* xprt_iter_destroy - Destroys the xprt iterator
|
|
* @xpi: pointer to rpc_xprt_iter
|
|
*/
|
|
void xprt_iter_destroy(struct rpc_xprt_iter *xpi)
|
|
{
|
|
xprt_switch_put(xprt_iter_xchg_switch(xpi, NULL));
|
|
}
|
|
|
|
/**
|
|
* xprt_iter_xprt - Returns the rpc_xprt pointed to by the cursor
|
|
* @xpi: pointer to rpc_xprt_iter
|
|
*
|
|
* Returns a pointer to the struct rpc_xprt that is currently
|
|
* pointed to by the cursor.
|
|
* Caller must be holding rcu_read_lock().
|
|
*/
|
|
struct rpc_xprt *xprt_iter_xprt(struct rpc_xprt_iter *xpi)
|
|
{
|
|
WARN_ON_ONCE(!rcu_read_lock_held());
|
|
return xprt_iter_ops(xpi)->xpi_xprt(xpi);
|
|
}
|
|
|
|
static
|
|
struct rpc_xprt *xprt_iter_get_helper(struct rpc_xprt_iter *xpi,
|
|
struct rpc_xprt *(*fn)(struct rpc_xprt_iter *))
|
|
{
|
|
struct rpc_xprt *ret;
|
|
|
|
do {
|
|
ret = fn(xpi);
|
|
if (ret == NULL)
|
|
break;
|
|
ret = xprt_get(ret);
|
|
} while (ret == NULL);
|
|
return ret;
|
|
}
|
|
|
|
/**
|
|
* xprt_iter_get_xprt - Returns the rpc_xprt pointed to by the cursor
|
|
* @xpi: pointer to rpc_xprt_iter
|
|
*
|
|
* Returns a reference to the struct rpc_xprt that is currently
|
|
* pointed to by the cursor.
|
|
*/
|
|
struct rpc_xprt *xprt_iter_get_xprt(struct rpc_xprt_iter *xpi)
|
|
{
|
|
struct rpc_xprt *xprt;
|
|
|
|
rcu_read_lock();
|
|
xprt = xprt_iter_get_helper(xpi, xprt_iter_ops(xpi)->xpi_xprt);
|
|
rcu_read_unlock();
|
|
return xprt;
|
|
}
|
|
|
|
/**
|
|
* xprt_iter_get_next - Returns the next rpc_xprt following the cursor
|
|
* @xpi: pointer to rpc_xprt_iter
|
|
*
|
|
* Returns a reference to the struct rpc_xprt that immediately follows the
|
|
* entry pointed to by the cursor.
|
|
*/
|
|
struct rpc_xprt *xprt_iter_get_next(struct rpc_xprt_iter *xpi)
|
|
{
|
|
struct rpc_xprt *xprt;
|
|
|
|
rcu_read_lock();
|
|
xprt = xprt_iter_get_helper(xpi, xprt_iter_ops(xpi)->xpi_next);
|
|
rcu_read_unlock();
|
|
return xprt;
|
|
}
|
|
|
|
/* Policy for always returning the first entry in the rpc_xprt_switch */
|
|
static
|
|
const struct rpc_xprt_iter_ops rpc_xprt_iter_singular = {
|
|
.xpi_rewind = xprt_iter_no_rewind,
|
|
.xpi_xprt = xprt_iter_first_entry,
|
|
.xpi_next = xprt_iter_first_entry,
|
|
};
|
|
|
|
/* Policy for round-robin iteration of entries in the rpc_xprt_switch */
|
|
static
|
|
const struct rpc_xprt_iter_ops rpc_xprt_iter_roundrobin = {
|
|
.xpi_rewind = xprt_iter_default_rewind,
|
|
.xpi_xprt = xprt_iter_current_entry,
|
|
.xpi_next = xprt_iter_next_entry_roundrobin,
|
|
};
|
|
|
|
/* Policy for once-through iteration of entries in the rpc_xprt_switch */
|
|
static
|
|
const struct rpc_xprt_iter_ops rpc_xprt_iter_listall = {
|
|
.xpi_rewind = xprt_iter_default_rewind,
|
|
.xpi_xprt = xprt_iter_current_entry,
|
|
.xpi_next = xprt_iter_next_entry_all,
|
|
};
|
|
|
|
static
|
|
const struct rpc_xprt_iter_ops rpc_xprt_iter_listoffline = {
|
|
.xpi_rewind = xprt_iter_default_rewind,
|
|
.xpi_xprt = xprt_iter_current_entry_offline,
|
|
.xpi_next = xprt_iter_next_entry_offline,
|
|
};
|