From 5b7eb78486cd9ac58bfbd6d84ea0fe2d9fead03b Mon Sep 17 00:00:00 2001 From: Olga Kornievskaia Date: Wed, 23 Jun 2021 23:28:50 -0400 Subject: [PATCH] SUNRPC: take a xprt offline using sysfs Using sysfs's xprt_state attribute, mark a particular transport offline. It will not be picked during the round-robin selection. It's not allowed to take the main (1st created transport associated with the rpc_client) offline. Also bring a transport back online via sysfs by writing "online" and that would allow for this transport to be picked during the round- robin selection. Signed-off-by: Olga Kornievskaia Signed-off-by: Trond Myklebust --- include/linux/sunrpc/xprt.h | 1 + net/sunrpc/sysfs.c | 66 ++++++++++++++++++++++++++++++++++++++++++--- net/sunrpc/sysfs.h | 1 + net/sunrpc/xprtmultipath.c | 6 +++-- 4 files changed, 68 insertions(+), 6 deletions(-) diff --git a/include/linux/sunrpc/xprt.h b/include/linux/sunrpc/xprt.h index 692e594..b8ed7fa 100644 --- a/include/linux/sunrpc/xprt.h +++ b/include/linux/sunrpc/xprt.h @@ -427,6 +427,7 @@ void xprt_release_write(struct rpc_xprt *, struct rpc_task *); #define XPRT_BOUND (4) #define XPRT_BINDING (5) #define XPRT_CLOSING (6) +#define XPRT_OFFLINE (7) #define XPRT_CONGESTED (9) #define XPRT_CWND_WAIT (10) #define XPRT_WRITE_SPACE (11) diff --git a/net/sunrpc/sysfs.c b/net/sunrpc/sysfs.c index 08aa503..a30ad18 100644 --- a/net/sunrpc/sysfs.c +++ b/net/sunrpc/sysfs.c @@ -69,6 +69,15 @@ rpc_sysfs_xprt_kobj_get_xprt(struct kobject *kobj) } static inline struct rpc_xprt_switch * +rpc_sysfs_xprt_kobj_get_xprt_switch(struct kobject *kobj) +{ + struct rpc_sysfs_xprt *x = container_of(kobj, + struct rpc_sysfs_xprt, kobject); + + return xprt_switch_get(x->xprt_switch); +} + +static inline struct rpc_xprt_switch * rpc_sysfs_xprt_switch_kobj_get_xprt(struct kobject *kobj) { struct rpc_sysfs_xprt_switch *x = container_of(kobj, @@ -122,7 +131,7 @@ static ssize_t rpc_sysfs_xprt_state_show(struct kobject *kobj, struct rpc_xprt *xprt = rpc_sysfs_xprt_kobj_get_xprt(kobj); ssize_t ret; int locked, connected, connecting, close_wait, bound, binding, - closing, congested, cwnd_wait, write_space; + closing, congested, cwnd_wait, write_space, offline; if (!xprt) return 0; @@ -140,8 +149,9 @@ static ssize_t rpc_sysfs_xprt_state_show(struct kobject *kobj, congested = test_bit(XPRT_CONGESTED, &xprt->state); cwnd_wait = test_bit(XPRT_CWND_WAIT, &xprt->state); write_space = test_bit(XPRT_WRITE_SPACE, &xprt->state); + offline = test_bit(XPRT_OFFLINE, &xprt->state); - ret = sprintf(buf, "state=%s %s %s %s %s %s %s %s %s %s\n", + ret = sprintf(buf, "state=%s %s %s %s %s %s %s %s %s %s %s\n", locked ? "LOCKED" : "", connected ? "CONNECTED" : "", connecting ? "CONNECTING" : "", @@ -151,7 +161,8 @@ static ssize_t rpc_sysfs_xprt_state_show(struct kobject *kobj, closing ? "CLOSING" : "", congested ? "CONGESTED" : "", cwnd_wait ? "CWND_WAIT" : "", - write_space ? "WRITE_SPACE" : ""); + write_space ? "WRITE_SPACE" : "", + offline ? "OFFLINE" : ""); } xprt_put(xprt); @@ -233,6 +244,52 @@ out_err: goto out; } +static ssize_t rpc_sysfs_xprt_state_change(struct kobject *kobj, + struct kobj_attribute *attr, + const char *buf, size_t count) +{ + struct rpc_xprt *xprt = rpc_sysfs_xprt_kobj_get_xprt(kobj); + int offline = 0, online = 0; + struct rpc_xprt_switch *xps = rpc_sysfs_xprt_kobj_get_xprt_switch(kobj); + + if (!xprt) + return 0; + + if (!strncmp(buf, "offline", 7)) + offline = 1; + else if (!strncmp(buf, "online", 6)) + online = 1; + else + return -EINVAL; + + if (wait_on_bit_lock(&xprt->state, XPRT_LOCKED, TASK_KILLABLE)) { + count = -EINTR; + goto out_put; + } + if (xprt->main) { + count = -EINVAL; + goto release_tasks; + } + if (offline) { + set_bit(XPRT_OFFLINE, &xprt->state); + spin_lock(&xps->xps_lock); + xps->xps_nactive--; + spin_unlock(&xps->xps_lock); + } else if (online) { + clear_bit(XPRT_OFFLINE, &xprt->state); + spin_lock(&xps->xps_lock); + xps->xps_nactive++; + spin_unlock(&xps->xps_lock); + } + +release_tasks: + xprt_release_write(xprt, NULL); +out_put: + xprt_put(xprt); + xprt_switch_put(xps); + return count; +} + int rpc_sysfs_init(void) { rpc_sunrpc_kset = kset_create_and_add("sunrpc", NULL, kernel_kobj); @@ -303,7 +360,7 @@ static struct kobj_attribute rpc_sysfs_xprt_info = __ATTR(xprt_info, 0444, rpc_sysfs_xprt_info_show, NULL); static struct kobj_attribute rpc_sysfs_xprt_change_state = __ATTR(xprt_state, - 0644, rpc_sysfs_xprt_state_show, NULL); + 0644, rpc_sysfs_xprt_state_show, rpc_sysfs_xprt_state_change); static struct attribute *rpc_sysfs_xprt_attrs[] = { &rpc_sysfs_xprt_dstaddr.attr, @@ -466,6 +523,7 @@ void rpc_sysfs_xprt_setup(struct rpc_xprt_switch *xprt_switch, if (rpc_xprt) { xprt->xprt_sysfs = rpc_xprt; rpc_xprt->xprt = xprt; + rpc_xprt->xprt_switch = xprt_switch; kobject_uevent(&rpc_xprt->kobject, KOBJ_ADD); } } diff --git a/net/sunrpc/sysfs.h b/net/sunrpc/sysfs.h index ff10451..6620ceb 100644 --- a/net/sunrpc/sysfs.h +++ b/net/sunrpc/sysfs.h @@ -22,6 +22,7 @@ struct rpc_sysfs_xprt_switch { struct rpc_sysfs_xprt { struct kobject kobject; struct rpc_xprt *xprt; + struct rpc_xprt_switch *xprt_switch; }; int rpc_sysfs_init(void); diff --git a/net/sunrpc/xprtmultipath.c b/net/sunrpc/xprtmultipath.c index 07e76ae..5f4845d 100644 --- a/net/sunrpc/xprtmultipath.c +++ b/net/sunrpc/xprtmultipath.c @@ -65,7 +65,8 @@ static void xprt_switch_remove_xprt_locked(struct rpc_xprt_switch *xps, { if (unlikely(xprt == NULL)) return; - xps->xps_nactive--; + if (!test_bit(XPRT_OFFLINE, &xprt->state)) + xps->xps_nactive--; xps->xps_nxprts--; if (xps->xps_nxprts == 0) xps->xps_net = NULL; @@ -230,7 +231,8 @@ void xprt_iter_default_rewind(struct rpc_xprt_iter *xpi) static bool xprt_is_active(const struct rpc_xprt *xprt) { - return kref_read(&xprt->kref) != 0; + return (kref_read(&xprt->kref) != 0 && + !test_bit(XPRT_OFFLINE, &xprt->state)); } static -- 2.7.4