From 3a2886cca703fde5ee21baea9fedf8b1389c59d7 Mon Sep 17 00:00:00 2001 From: Gerd Rausch Date: Tue, 16 Jul 2019 15:29:17 -0700 Subject: [PATCH] net/rds: Keep track of and wait for FRWR segments in use upon shutdown Since "rds_ib_free_frmr" and "rds_ib_free_frmr_list" simply put the FRMR memory segments on the "drop_list" or "free_list", and it is the job of "rds_ib_flush_mr_pool" to reap those entries by ultimately issuing a "IB_WR_LOCAL_INV" work-request, we need to trigger and then wait for all those memory segments attached to a particular connection to be fully released before we can move on to release the QP, CQ, etc. So we make "rds_ib_conn_path_shutdown" wait for one more atomic_t called "i_fastreg_inuse_count" that keeps track of how many FRWR memory segments are out there marked "FRMR_IS_INUSE" (and also wake_up rds_ib_ring_empty_wait, as they go away). Signed-off-by: Gerd Rausch Acked-by: Santosh Shilimkar Signed-off-by: David S. Miller --- net/rds/ib.h | 1 + net/rds/ib_cm.c | 7 +++++++ net/rds/ib_frmr.c | 43 +++++++++++++++++++++++++++++++++++++------ 3 files changed, 45 insertions(+), 6 deletions(-) diff --git a/net/rds/ib.h b/net/rds/ib.h index 66c03c7665b2..303c6ee8bdb7 100644 --- a/net/rds/ib.h +++ b/net/rds/ib.h @@ -156,6 +156,7 @@ struct rds_ib_connection { /* To control the number of wrs from fastreg */ atomic_t i_fastreg_wrs; + atomic_t i_fastreg_inuse_count; /* interrupt handling */ struct tasklet_struct i_send_tasklet; diff --git a/net/rds/ib_cm.c b/net/rds/ib_cm.c index 8891822eba4f..1b6fd6c8b12b 100644 --- a/net/rds/ib_cm.c +++ b/net/rds/ib_cm.c @@ -40,6 +40,7 @@ #include "rds_single_path.h" #include "rds.h" #include "ib.h" +#include "ib_mr.h" /* * Set the selected protocol version @@ -993,6 +994,11 @@ void rds_ib_conn_path_shutdown(struct rds_conn_path *cp) ic->i_cm_id, err); } + /* kick off "flush_worker" for all pools in order to reap + * all FRMR registrations that are still marked "FRMR_IS_INUSE" + */ + rds_ib_flush_mrs(); + /* * We want to wait for tx and rx completion to finish * before we tear down the connection, but we have to be @@ -1005,6 +1011,7 @@ void rds_ib_conn_path_shutdown(struct rds_conn_path *cp) wait_event(rds_ib_ring_empty_wait, rds_ib_ring_empty(&ic->i_recv_ring) && (atomic_read(&ic->i_signaled_sends) == 0) && + (atomic_read(&ic->i_fastreg_inuse_count) == 0) && (atomic_read(&ic->i_fastreg_wrs) == RDS_IB_DEFAULT_FR_WR)); tasklet_kill(&ic->i_send_tasklet); tasklet_kill(&ic->i_recv_tasklet); diff --git a/net/rds/ib_frmr.c b/net/rds/ib_frmr.c index adaa8e99e5a9..06ecf9d2d4bf 100644 --- a/net/rds/ib_frmr.c +++ b/net/rds/ib_frmr.c @@ -32,6 +32,24 @@ #include "ib_mr.h" +static inline void +rds_transition_frwr_state(struct rds_ib_mr *ibmr, + enum rds_ib_fr_state old_state, + enum rds_ib_fr_state new_state) +{ + if (cmpxchg(&ibmr->u.frmr.fr_state, + old_state, new_state) == old_state && + old_state == FRMR_IS_INUSE) { + /* enforce order of ibmr->u.frmr.fr_state update + * before decrementing i_fastreg_inuse_count + */ + smp_mb__before_atomic(); + atomic_dec(&ibmr->ic->i_fastreg_inuse_count); + if (waitqueue_active(&rds_ib_ring_empty_wait)) + wake_up(&rds_ib_ring_empty_wait); + } +} + static struct rds_ib_mr *rds_ib_alloc_frmr(struct rds_ib_device *rds_ibdev, int npages) { @@ -118,13 +136,18 @@ static int rds_ib_post_reg_frmr(struct rds_ib_mr *ibmr) if (unlikely(ret != ibmr->sg_len)) return ret < 0 ? ret : -EINVAL; + if (cmpxchg(&frmr->fr_state, + FRMR_IS_FREE, FRMR_IS_INUSE) != FRMR_IS_FREE) + return -EBUSY; + + atomic_inc(&ibmr->ic->i_fastreg_inuse_count); + /* Perform a WR for the fast_reg_mr. Each individual page * in the sg list is added to the fast reg page list and placed * inside the fast_reg_mr WR. The key used is a rolling 8bit * counter, which should guarantee uniqueness. */ ib_update_fast_reg_key(frmr->mr, ibmr->remap_count++); - frmr->fr_state = FRMR_IS_INUSE; frmr->fr_reg = true; memset(®_wr, 0, sizeof(reg_wr)); @@ -141,7 +164,8 @@ static int rds_ib_post_reg_frmr(struct rds_ib_mr *ibmr) ret = ib_post_send(ibmr->ic->i_cm_id->qp, ®_wr.wr, NULL); if (unlikely(ret)) { /* Failure here can be because of -ENOMEM as well */ - frmr->fr_state = FRMR_IS_STALE; + rds_transition_frwr_state(ibmr, FRMR_IS_INUSE, FRMR_IS_STALE); + atomic_inc(&ibmr->ic->i_fastreg_wrs); if (printk_ratelimit()) pr_warn("RDS/IB: %s returned error(%d)\n", @@ -268,8 +292,12 @@ static int rds_ib_post_inv(struct rds_ib_mr *ibmr) ret = ib_post_send(i_cm_id->qp, s_wr, NULL); if (unlikely(ret)) { - frmr->fr_state = FRMR_IS_STALE; + rds_transition_frwr_state(ibmr, FRMR_IS_INUSE, FRMR_IS_STALE); frmr->fr_inv = false; + /* enforce order of frmr->fr_inv update + * before incrementing i_fastreg_wrs + */ + smp_mb__before_atomic(); atomic_inc(&ibmr->ic->i_fastreg_wrs); pr_err("RDS/IB: %s returned error(%d)\n", __func__, ret); goto out; @@ -297,7 +325,7 @@ void rds_ib_mr_cqe_handler(struct rds_ib_connection *ic, struct ib_wc *wc) struct rds_ib_frmr *frmr = &ibmr->u.frmr; if (wc->status != IB_WC_SUCCESS) { - frmr->fr_state = FRMR_IS_STALE; + rds_transition_frwr_state(ibmr, FRMR_IS_INUSE, FRMR_IS_STALE); if (rds_conn_up(ic->conn)) rds_ib_conn_error(ic->conn, "frmr completion <%pI4,%pI4> status %u(%s), vendor_err 0x%x, disconnecting and reconnecting\n", @@ -309,8 +337,7 @@ void rds_ib_mr_cqe_handler(struct rds_ib_connection *ic, struct ib_wc *wc) } if (frmr->fr_inv) { - if (frmr->fr_state == FRMR_IS_INUSE) - frmr->fr_state = FRMR_IS_FREE; + rds_transition_frwr_state(ibmr, FRMR_IS_INUSE, FRMR_IS_FREE); frmr->fr_inv = false; wake_up(&frmr->fr_inv_done); } @@ -320,6 +347,10 @@ void rds_ib_mr_cqe_handler(struct rds_ib_connection *ic, struct ib_wc *wc) wake_up(&frmr->fr_reg_done); } + /* enforce order of frmr->{fr_reg,fr_inv} update + * before incrementing i_fastreg_wrs + */ + smp_mb__before_atomic(); atomic_inc(&ic->i_fastreg_wrs); }