From 9ca1e182b9d1ef3f97718c4072a18a23dc47d4f9 Mon Sep 17 00:00:00 2001 From: Hannes Reinecke Date: Thu, 13 Oct 2016 15:10:50 +0200 Subject: [PATCH] scsi: libfc: quarantine timed out xids When a sequence times out we have no idea what happened to the frame. And we do not know if we will ever receive the frame. Hence we cannot re-use the xid as we would risk data corruption if the xid had been re-used and the timed out frame would be received after that. So we need to quarantine the xid until the lport is reset. Yes, I know this will (eventually) deplete the xid pool. But for now it's the safest method. Signed-off-by: Hannes Reinecke Reviewed-by: Bart Van Assche Signed-off-by: Martin K. Petersen --- drivers/scsi/libfc/fc_exch.c | 33 ++++++++++++++++++++++----------- drivers/scsi/libfc/fc_fcp.c | 13 +++++++------ include/scsi/libfc.h | 1 + 3 files changed, 30 insertions(+), 17 deletions(-) diff --git a/drivers/scsi/libfc/fc_exch.c b/drivers/scsi/libfc/fc_exch.c index 7b47ab1389ca..ca7d947dc427 100644 --- a/drivers/scsi/libfc/fc_exch.c +++ b/drivers/scsi/libfc/fc_exch.c @@ -94,6 +94,7 @@ struct fc_exch_pool { struct fc_exch_mgr { struct fc_exch_pool __percpu *pool; mempool_t *ep_pool; + struct fc_lport *lport; enum fc_class class; struct kref kref; u16 min_xid; @@ -408,6 +409,8 @@ static int fc_exch_done_locked(struct fc_exch *ep) return rc; } +static struct fc_exch fc_quarantine_exch; + /** * fc_exch_ptr_get() - Return an exchange from an exchange pool * @pool: Exchange Pool to get an exchange from @@ -452,14 +455,17 @@ static void fc_exch_delete(struct fc_exch *ep) /* update cache of free slot */ index = (ep->xid - ep->em->min_xid) >> fc_cpu_order; - if (pool->left == FC_XID_UNKNOWN) - pool->left = index; - else if (pool->right == FC_XID_UNKNOWN) - pool->right = index; - else - pool->next_index = index; - - fc_exch_ptr_set(pool, index, NULL); + if (!(ep->state & FC_EX_QUARANTINE)) { + if (pool->left == FC_XID_UNKNOWN) + pool->left = index; + else if (pool->right == FC_XID_UNKNOWN) + pool->right = index; + else + pool->next_index = index; + fc_exch_ptr_set(pool, index, NULL); + } else { + fc_exch_ptr_set(pool, index, &fc_quarantine_exch); + } list_del(&ep->ex_list); spin_unlock_bh(&pool->lock); fc_exch_release(ep); /* drop hold for exch in mp */ @@ -921,14 +927,14 @@ static struct fc_exch *fc_exch_alloc(struct fc_lport *lport, */ static struct fc_exch *fc_exch_find(struct fc_exch_mgr *mp, u16 xid) { + struct fc_lport *lport = mp->lport; struct fc_exch_pool *pool; struct fc_exch *ep = NULL; u16 cpu = xid & fc_cpu_mask; if (cpu >= nr_cpu_ids || !cpu_possible(cpu)) { - printk_ratelimited(KERN_ERR - "libfc: lookup request for XID = %d, " - "indicates invalid CPU %d\n", xid, cpu); + pr_err("host%u: lport %6.6x: xid %d invalid CPU %d\n:", + lport->host->host_no, lport->port_id, xid, cpu); return NULL; } @@ -936,6 +942,10 @@ static struct fc_exch *fc_exch_find(struct fc_exch_mgr *mp, u16 xid) pool = per_cpu_ptr(mp->pool, cpu); spin_lock_bh(&pool->lock); ep = fc_exch_ptr_get(pool, (xid - mp->min_xid) >> fc_cpu_order); + if (ep == &fc_quarantine_exch) { + FC_LPORT_DBG(lport, "xid %x quarantined\n", xid); + ep = NULL; + } if (ep) { WARN_ON(ep->xid != xid); fc_exch_hold(ep); @@ -2434,6 +2444,7 @@ struct fc_exch_mgr *fc_exch_mgr_alloc(struct fc_lport *lport, return NULL; mp->class = class; + mp->lport = lport; /* adjust em exch xid range for offload */ mp->min_xid = min_xid; diff --git a/drivers/scsi/libfc/fc_fcp.c b/drivers/scsi/libfc/fc_fcp.c index f7700cccf793..780d9f09a267 100644 --- a/drivers/scsi/libfc/fc_fcp.c +++ b/drivers/scsi/libfc/fc_fcp.c @@ -1529,13 +1529,14 @@ static void fc_fcp_rec_resp(struct fc_seq *seq, struct fc_frame *fp, void *arg) fsp->rport->port_id, rjt->er_reason, rjt->er_explan); /* - * If no data transfer, the command frame got dropped - * so we just retry. If data was transferred, we - * lost the response but the target has no record, - * so we abort and retry. + * If response got lost or is stuck in the + * queue somewhere we have no idea if and when + * the response will be received. So quarantine + * the xid and retry the command. */ - if (rjt->er_explan == ELS_EXPL_OXID_RXID && - fsp->xfer_len == 0) { + if (rjt->er_explan == ELS_EXPL_OXID_RXID) { + struct fc_exch *ep = fc_seq_exch(fsp->seq_ptr); + ep->state |= FC_EX_QUARANTINE; fsp->state |= FC_SRB_ABORTED; fc_fcp_retry_cmd(fsp, FC_TRANS_RESET); break; diff --git a/include/scsi/libfc.h b/include/scsi/libfc.h index dc42d8070f6f..8cb752f8d12b 100644 --- a/include/scsi/libfc.h +++ b/include/scsi/libfc.h @@ -390,6 +390,7 @@ struct fc_seq { #define FC_EX_DONE (1 << 0) /* ep is completed */ #define FC_EX_RST_CLEANUP (1 << 1) /* reset is forcing completion */ +#define FC_EX_QUARANTINE (1 << 2) /* exch is quarantined */ /** * struct fc_exch - Fibre Channel Exchange -- 2.30.2