diff options
| -rw-r--r-- | net/sunrpc/xprtmultipath.c | 67 |
1 files changed, 38 insertions, 29 deletions
diff --git a/net/sunrpc/xprtmultipath.c b/net/sunrpc/xprtmultipath.c index f3ecd0bee484..78c075a68c04 100644 --- a/net/sunrpc/xprtmultipath.c +++ b/net/sunrpc/xprtmultipath.c @@ -19,7 +19,7 @@ #include <linux/sunrpc/addr.h> #include <linux/sunrpc/xprtmultipath.h> -typedef struct rpc_xprt *(*xprt_switch_find_xprt_t)(struct list_head *head, +typedef struct rpc_xprt *(*xprt_switch_find_xprt_t)(struct rpc_xprt_switch *xps, const struct rpc_xprt *cur); static const struct rpc_xprt_iter_ops rpc_xprt_iter_singular; @@ -291,22 +291,15 @@ struct rpc_xprt *xprt_switch_find_next_entry(struct list_head *head, } static -struct rpc_xprt *xprt_switch_set_next_cursor(struct list_head *head, +struct rpc_xprt *xprt_switch_set_next_cursor(struct rpc_xprt_switch *xps, struct rpc_xprt **cursor, xprt_switch_find_xprt_t find_next) { - struct rpc_xprt *cur, *pos, *old; + struct rpc_xprt *pos, *old; - cur = READ_ONCE(*cursor); - for (;;) { - old = cur; - pos = find_next(head, old); - if (pos == NULL) - break; - cur = cmpxchg_relaxed(cursor, old, pos); - if (cur == old) - break; - } + old = smp_load_acquire(cursor); + pos = find_next(xps, old); + smp_store_release(cursor, pos); return pos; } @@ -318,13 +311,11 @@ struct rpc_xprt *xprt_iter_next_entry_multiple(struct rpc_xprt_iter *xpi, if (xps == NULL) return NULL; - return xprt_switch_set_next_cursor(&xps->xps_xprt_list, - &xpi->xpi_cursor, - find_next); + return xprt_switch_set_next_cursor(xps, &xpi->xpi_cursor, find_next); } static -struct rpc_xprt *xprt_switch_find_next_entry_roundrobin(struct list_head *head, +struct rpc_xprt *__xprt_switch_find_next_entry_roundrobin(struct list_head *head, const struct rpc_xprt *cur) { struct rpc_xprt *ret; @@ -336,31 +327,49 @@ struct rpc_xprt *xprt_switch_find_next_entry_roundrobin(struct list_head *head, } static -struct rpc_xprt *xprt_iter_next_entry_roundrobin(struct rpc_xprt_iter *xpi) +struct rpc_xprt *xprt_switch_find_next_entry_roundrobin(struct rpc_xprt_switch *xps, + const struct rpc_xprt *cur) { - struct rpc_xprt_switch *xps = rcu_dereference(xpi->xpi_xpswitch); + struct list_head *head = &xps->xps_xprt_list; struct rpc_xprt *xprt; - unsigned long xprt_queuelen; - unsigned long xps_queuelen; + unsigned int nactive; - do { - xprt = xprt_iter_next_entry_multiple(xpi, - xprt_switch_find_next_entry_roundrobin); - if (xprt == NULL) + for (;;) { + unsigned long xprt_queuelen, xps_queuelen; + + xprt = __xprt_switch_find_next_entry_roundrobin(head, cur); + if (!xprt) break; xprt_queuelen = atomic_long_read(&xprt->queuelen); - if (xprt_queuelen <= 2) - break; xps_queuelen = atomic_long_read(&xps->xps_queuelen); + nactive = READ_ONCE(xps->xps_nactive); /* Exit loop if xprt_queuelen <= average queue length */ - } while (xprt_queuelen * READ_ONCE(xps->xps_nactive) > xps_queuelen); + if (xprt_queuelen * nactive <= xps_queuelen) + break; + cur = xprt; + } return xprt; } static +struct rpc_xprt *xprt_iter_next_entry_roundrobin(struct rpc_xprt_iter *xpi) +{ + return xprt_iter_next_entry_multiple(xpi, + xprt_switch_find_next_entry_roundrobin); +} + +static +struct rpc_xprt *xprt_switch_find_next_entry_all(struct rpc_xprt_switch *xps, + const struct rpc_xprt *cur) +{ + return xprt_switch_find_next_entry(&xps->xps_xprt_list, cur); +} + +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); + return xprt_iter_next_entry_multiple(xpi, + xprt_switch_find_next_entry_all); } /* |