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Commit c46be11a authored by Vasu Dev's avatar Vasu Dev Committed by James Bottomley
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[SCSI] libfc: reduce can_queue for all FCP frame allocation failures 



Currently can_queue is reduced only if frame alloc fails
during fc_fcp_send_data but frame alloc can fail at several
other places in FCP data path and can_queue needs to be
reduced for any FCP frame alloc failure.

This patch adds fc_fcp_frame_alloc for all FCP frame allocations
and if fc_frame_alloc fails in fc_fcp_frame_alloc then reduce
can_queue in fc_fcp_frame_alloc, this will reduce can_queue for
all FCP frame alloc failures.

This required moving fc_fcp_reduce_can_queue up, to build without
adding its prototype. Also renamed fc_fcp_reduce_can_queue to
fc_fcp_can_queue_ramp_down.

Removes fc_fcp_reduce_can_queue calling from fc_fcp_recv since
not needed with added fc_fcp_frame_alloc reducing can_queue.

Signed-off-by: default avatarVasu Dev <vasu.dev@intel.com>
Signed-off-by: default avatarRobert Love <robert.w.love@intel.com>
Signed-off-by: default avatarJames Bottomley <James.Bottomley@suse.de>
parent a7bbc7f4

drivers/scsi/libfc/fc_fcp.c

+59 −43
Original line number Diff line number Diff line
@@ -326,6 +326,57 @@ static void fc_fcp_ddp_done(struct fc_fcp_pkt *fsp) 
	}

}



/**

 * fc_fcp_can_queue_ramp_down() - reduces can_queue

 * @lport: lport to reduce can_queue

 *

 * If we are getting memory allocation failures, then we may

 * be trying to execute too many commands. We let the running

 * commands complete or timeout, then try again with a reduced

 * can_queue. Eventually we will hit the point where we run

 * on all reserved structs.

 */

static void fc_fcp_can_queue_ramp_down(struct fc_lport *lport)

{

	struct fc_fcp_internal *si = fc_get_scsi_internal(lport);

	unsigned long flags;

	int can_queue;



	spin_lock_irqsave(lport->host->host_lock, flags);

	if (si->throttled)

		goto done;

	si->throttled = 1;



	can_queue = lport->host->can_queue;

	can_queue >>= 1;

	if (!can_queue)

		can_queue = 1;

	lport->host->can_queue = can_queue;

	shost_printk(KERN_ERR, lport->host, "libfc: Could not allocate frame.\n"

		     "Reducing can_queue to %d.\n", can_queue);

done:

	spin_unlock_irqrestore(lport->host->host_lock, flags);

}



/*

 * fc_fcp_frame_alloc() -  Allocates fc_frame structure and buffer.

 * @lport:	fc lport struct

 * @len:	payload length

 *

 * Allocates fc_frame structure and buffer but if fails to allocate

 * then reduce can_queue.

 */

static inline struct fc_frame *fc_fcp_frame_alloc(struct fc_lport *lport,

						  size_t len)

{

	struct fc_frame *fp;



	fp = fc_frame_alloc(lport, len);

	if (!fp)

		fc_fcp_can_queue_ramp_down(lport);

	return fp;

}



/**

 * fc_fcp_recv_data() - Handler for receiving SCSI-FCP data from a target

 * @fsp: The FCP packet the data is on
@@ -615,38 +666,6 @@ static void fc_fcp_abts_resp(struct fc_fcp_pkt *fsp, struct fc_frame *fp) 
	}

}



/**

 * fc_fcp_reduce_can_queue() - Reduce the can_queue value for a local port

 * @lport: The local port to reduce can_queue on

 *

 * If we are getting memory allocation failures, then we may

 * be trying to execute too many commands. We let the running

 * commands complete or timeout, then try again with a reduced

 * can_queue. Eventually we will hit the point where we run

 * on all reserved structs.

 */

static void fc_fcp_reduce_can_queue(struct fc_lport *lport)

{

	struct fc_fcp_internal *si = fc_get_scsi_internal(lport);

	unsigned long flags;

	int can_queue;



	spin_lock_irqsave(lport->host->host_lock, flags);

	if (si->throttled)

		goto done;

	si->throttled = 1;



	can_queue = lport->host->can_queue;

	can_queue >>= 1;

	if (!can_queue)

		can_queue = 1;

	lport->host->can_queue = can_queue;

	shost_printk(KERN_ERR, lport->host, "libfc: Could not allocate frame.\n"

		     "Reducing can_queue to %d.\n", can_queue);

done:

	spin_unlock_irqrestore(lport->host->host_lock, flags);

}



/**

 * fc_fcp_recv() - Reveive an FCP frame

 * @seq: The sequence the frame is on
@@ -665,8 +684,10 @@ static void fc_fcp_recv(struct fc_seq *seq, struct fc_frame *fp, void *arg) 
	u8 r_ctl;

	int rc = 0;



	if (IS_ERR(fp))

		goto errout;

	if (IS_ERR(fp)) {

		fc_fcp_error(fsp, fp);

		return;

	}



	fh = fc_frame_header_get(fp);

	r_ctl = fh->fh_r_ctl;
@@ -720,11 +741,6 @@ static void fc_fcp_recv(struct fc_seq *seq, struct fc_frame *fp, void *arg) 
	fc_fcp_unlock_pkt(fsp);

out:

	fc_frame_free(fp);

errout:

	if (IS_ERR(fp))

		fc_fcp_error(fsp, fp);

	else if (rc == -ENOMEM)

		fc_fcp_reduce_can_queue(lport);

}



/**
@@ -886,7 +902,7 @@ static void fc_fcp_complete_locked(struct fc_fcp_pkt *fsp) 
			struct fc_seq *csp;



			csp = lport->tt.seq_start_next(seq);

			conf_frame = fc_frame_alloc(fsp->lp, 0);

			conf_frame = fc_fcp_frame_alloc(fsp->lp, 0);

			if (conf_frame) {

				f_ctl = FC_FC_SEQ_INIT;

				f_ctl |= FC_FC_LAST_SEQ | FC_FC_END_SEQ;
@@ -1026,7 +1042,7 @@ static int fc_fcp_cmd_send(struct fc_lport *lport, struct fc_fcp_pkt *fsp, 
	if (fc_fcp_lock_pkt(fsp))

		return 0;



	fp = fc_frame_alloc(lport, sizeof(fsp->cdb_cmd));

	fp = fc_fcp_frame_alloc(lport, sizeof(fsp->cdb_cmd));

	if (!fp) {

		rc = -1;

		goto unlock;
@@ -1306,7 +1322,7 @@ static void fc_fcp_rec(struct fc_fcp_pkt *fsp) 
		fc_fcp_complete_locked(fsp);

		return;

	}

	fp = fc_frame_alloc(lport, sizeof(struct fc_els_rec));

	fp = fc_fcp_frame_alloc(lport, sizeof(struct fc_els_rec));

	if (!fp)

		goto retry;
@@ -1557,7 +1573,7 @@ static void fc_fcp_srr(struct fc_fcp_pkt *fsp, enum fc_rctl r_ctl, u32 offset) 
	if (!(rpriv->flags & FC_RP_FLAGS_RETRY) ||

	    rpriv->rp_state != RPORT_ST_READY)

		goto retry;			/* shouldn't happen */

	fp = fc_frame_alloc(lport, sizeof(*srr));

	fp = fc_fcp_frame_alloc(lport, sizeof(*srr));

	if (!fp)

		goto retry;