From f95b35cfcacadac16dbc5477fd22b0786256a3d1 Mon Sep 17 00:00:00 2001 From: Bart Van Assche Date: Wed, 14 Aug 2013 15:38:24 +0000 Subject: [PATCH] libfc: Reduce exchange lock contention in fc_exch_recv_abts() Reduce the time during which the exchange lock is held by allocating a frame before obtaining the exchange lock. Signed-off-by: Bart Van Assche Cc: Neil Horman Signed-off-by: Robert Love --- drivers/scsi/libfc/fc_exch.c | 18 ++++++++++-------- 1 file changed, 10 insertions(+), 8 deletions(-) diff --git a/drivers/scsi/libfc/fc_exch.c b/drivers/scsi/libfc/fc_exch.c index 2a7fd5a..47ebc7b1 100644 --- a/drivers/scsi/libfc/fc_exch.c +++ b/drivers/scsi/libfc/fc_exch.c @@ -1307,9 +1307,16 @@ static void fc_exch_recv_abts(struct fc_exch *ep, struct fc_frame *rx_fp) if (!ep) goto reject; + + fp = fc_frame_alloc(ep->lp, sizeof(*ap)); + if (!fp) + goto free; + spin_lock_bh(&ep->ex_lock); if (ep->esb_stat & ESB_ST_COMPLETE) { spin_unlock_bh(&ep->ex_lock); + + fc_frame_free(fp); goto reject; } if (!(ep->esb_stat & ESB_ST_REC_QUAL)) { @@ -1317,12 +1324,6 @@ static void fc_exch_recv_abts(struct fc_exch *ep, struct fc_frame *rx_fp) fc_exch_hold(ep); /* hold for REC_QUAL */ } fc_exch_timer_set_locked(ep, ep->r_a_tov); - - fp = fc_frame_alloc(ep->lp, sizeof(*ap)); - if (!fp) { - spin_unlock_bh(&ep->ex_lock); - goto free; - } fh = fc_frame_header_get(fp); ap = fc_frame_payload_get(fp, sizeof(*ap)); memset(ap, 0, sizeof(*ap)); @@ -1338,13 +1339,14 @@ static void fc_exch_recv_abts(struct fc_exch *ep, struct fc_frame *rx_fp) fc_seq_send_last(sp, fp, FC_RCTL_BA_ACC, FC_TYPE_BLS); ep->esb_stat |= ESB_ST_ABNORMAL; spin_unlock_bh(&ep->ex_lock); + +free: fc_frame_free(rx_fp); return; reject: fc_exch_send_ba_rjt(rx_fp, FC_BA_RJT_UNABLE, FC_BA_RJT_INV_XID); -free: - fc_frame_free(rx_fp); + goto free; } /** -- 2.7.4