[SCSI] libfc: fixes unnecessary seq id jump (a104c844) · Commits · 戴 / test

In some cases seq is incremented twice causing unnecessary seq jump, for instance fc_exch_recv_seq_resp increments seq id when fc_sof_is_init is true and that is true for each incoming xfer ready but then fc_fcp_send_data does another seq increment to send data for xfer ready. This patch removes all such seq id jumps, at least it eliminates few calls to fc_seq_start_next using ex_lock. Also removes seq id update with incoming frame's seq id as this is not needed since each end (I or T) just need to send incremented their own seq id on each TSI from other end & before sending new sequence within a exchange. Signed-off-by:

Vasu Dev <vasu.dev@intel.com> Signed-off-by:

Robert Love <robert.w.love@intel.com> Signed-off-by:

James Bottomley <James.Bottomley@suse.de>

drivers/scsi/libfc/fc_exch.c

+5 −14

Original line number	Diff line number	Diff line
		@@ -920,12 +920,7 @@ static enum fc_pf_rjt_reason fc_seq_lookup_recip(struct fc_lport *lport,
		* Find or create the sequence.
		*/
		if (fc_sof_is_init(fr_sof(fp))) {
		sp = fc_seq_start_next(&ep->seq);
		if (!sp) {
		reject = FC_RJT_SEQ_XS; /* exchange shortage */
		goto rel;
		}
		sp->id = fh->fh_seq_id;
		sp = &ep->seq;
		sp->ssb_stat \|= SSB_ST_RESP;
		} else {
		sp = &ep->seq;
		@@ -1336,17 +1331,14 @@ static void fc_exch_recv_seq_resp(struct fc_exch_mgr mp, struct fc_frame fp)
		goto rel;
		}
		sof = fr_sof(fp);
		if (fc_sof_is_init(sof)) {
		sp = fc_seq_start_next(&ep->seq);
		sp->id = fh->fh_seq_id;
		sp->ssb_stat \|= SSB_ST_RESP;
		} else {
		sp = &ep->seq;
		if (sp->id != fh->fh_seq_id) {
		if (fc_sof_is_init(sof))
		sp->ssb_stat \|= SSB_ST_RESP;
		else if (sp->id != fh->fh_seq_id) {
		atomic_inc(&mp->stats.seq_not_found);
		goto rel;
		}
		}

		f_ctl = ntoh24(fh->fh_f_ctl);
		fr_seq(fp) = sp;
		if (f_ctl & FC_FC_SEQ_INIT)
		@@ -1763,7 +1755,6 @@ static void fc_exch_els_rec(struct fc_seq sp, struct fc_frame rfp)
		fc_exch_done(sp);
		goto out;
		}
		sp = fc_seq_start_next(sp);
		acc = fc_frame_payload_get(fp, sizeof(*acc));
		memset(acc, 0, sizeof(*acc));
		acc->reca_cmd = ELS_LS_ACC;

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