From c46be11a683acc1ccf86883ea906f171b90ff29a Mon Sep 17 00:00:00 2001 From: Vasu Dev Date: Tue, 3 Nov 2009 11:48:00 -0800 Subject: [PATCH] [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: Vasu Dev Signed-off-by: Robert Love Signed-off-by: James Bottomley --- drivers/scsi/libfc/fc_fcp.c | 102 +++++++++++++++++++++--------------- 1 file changed, 59 insertions(+), 43 deletions(-) diff --git a/drivers/scsi/libfc/fc_fcp.c b/drivers/scsi/libfc/fc_fcp.c index 567eee7b8609..ac5c148d0182 100644 --- a/drivers/scsi/libfc/fc_fcp.c +++ b/drivers/scsi/libfc/fc_fcp.c @@ -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;