1 files changed, 139 insertions, 60 deletions

diff --git a/drivers/scsi/xen-scsifront.c b/drivers/scsi/xen-scsifront.c
index 12109e4c73d4..51afc66e839d 100644
--- a/drivers/scsi/xen-scsifront.c
+++ b/drivers/scsi/xen-scsifront.c
@@ -58,9 +58,6 @@
 
 #include <asm/xen/hypervisor.h>
 
-
-#define GRANT_INVALID_REF	0
-
 #define VSCSIFRONT_OP_ADD_LUN	1
 #define VSCSIFRONT_OP_DEL_LUN	2
 #define VSCSIFRONT_OP_READD_LUN	3
@@ -83,6 +80,8 @@ struct vscsifrnt_shadow {
 	uint16_t rqid;
 	uint16_t ref_rqid;
 
+	bool inflight;
+
 	unsigned int nr_grants;		/* number of grants in gref[] */
 	struct scsiif_request_segment *sg;	/* scatter/gather elements */
 	struct scsiif_request_segment seg[VSCSIIF_SG_TABLESIZE];
@@ -104,7 +103,11 @@ struct vscsifrnt_info {
 	struct xenbus_device *dev;
 
 	struct Scsi_Host *host;
-	int host_active;
+	enum {
+		STATE_INACTIVE,
+		STATE_ACTIVE,
+		STATE_ERROR
+	}  host_active;
 
 	unsigned int evtchn;
 	unsigned int irq;
@@ -217,6 +220,8 @@ static int scsifront_do_request(struct vscsifrnt_info *info,
 	for (i = 0; i < (shadow->nr_segments & ~VSCSIIF_SG_GRANT); i++)
 		ring_req->seg[i] = shadow->seg[i];
 
+	shadow->inflight = true;
+
 	RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(ring, notify);
 	if (notify)
 		notify_remote_via_irq(info->irq);
@@ -224,6 +229,13 @@ static int scsifront_do_request(struct vscsifrnt_info *info,
 	return 0;
 }
 
+static void scsifront_set_error(struct vscsifrnt_info *info, const char *msg)
+{
+	shost_printk(KERN_ERR, info->host, KBUILD_MODNAME "%s\n"
+		     "Disabling device for further use\n", msg);
+	info->host_active = STATE_ERROR;
+}
+
 static void scsifront_gnttab_done(struct vscsifrnt_info *info,
 				  struct vscsifrnt_shadow *shadow)
 {
@@ -234,15 +246,64 @@ static void scsifront_gnttab_done(struct vscsifrnt_info *info,
 
 	for (i = 0; i < shadow->nr_grants; i++) {
 		if (unlikely(!gnttab_try_end_foreign_access(shadow->gref[i]))) {
-			shost_printk(KERN_ALERT, info->host, KBUILD_MODNAME
-				     "grant still in use by backend\n");
-			BUG();
+			scsifront_set_error(info, "grant still in use by backend");
+			return;
 		}
 	}
 
 	kfree(shadow->sg);
 }
 
+static unsigned int scsifront_host_byte(int32_t rslt)
+{
+	switch (XEN_VSCSIIF_RSLT_HOST(rslt)) {
+	case XEN_VSCSIIF_RSLT_HOST_OK:
+		return DID_OK;
+	case XEN_VSCSIIF_RSLT_HOST_NO_CONNECT:
+		return DID_NO_CONNECT;
+	case XEN_VSCSIIF_RSLT_HOST_BUS_BUSY:
+		return DID_BUS_BUSY;
+	case XEN_VSCSIIF_RSLT_HOST_TIME_OUT:
+		return DID_TIME_OUT;
+	case XEN_VSCSIIF_RSLT_HOST_BAD_TARGET:
+		return DID_BAD_TARGET;
+	case XEN_VSCSIIF_RSLT_HOST_ABORT:
+		return DID_ABORT;
+	case XEN_VSCSIIF_RSLT_HOST_PARITY:
+		return DID_PARITY;
+	case XEN_VSCSIIF_RSLT_HOST_ERROR:
+		return DID_ERROR;
+	case XEN_VSCSIIF_RSLT_HOST_RESET:
+		return DID_RESET;
+	case XEN_VSCSIIF_RSLT_HOST_BAD_INTR:
+		return DID_BAD_INTR;
+	case XEN_VSCSIIF_RSLT_HOST_PASSTHROUGH:
+		return DID_PASSTHROUGH;
+	case XEN_VSCSIIF_RSLT_HOST_SOFT_ERROR:
+		return DID_SOFT_ERROR;
+	case XEN_VSCSIIF_RSLT_HOST_IMM_RETRY:
+		return DID_IMM_RETRY;
+	case XEN_VSCSIIF_RSLT_HOST_REQUEUE:
+		return DID_REQUEUE;
+	case XEN_VSCSIIF_RSLT_HOST_TRANSPORT_DISRUPTED:
+		return DID_TRANSPORT_DISRUPTED;
+	case XEN_VSCSIIF_RSLT_HOST_TRANSPORT_FAILFAST:
+		return DID_TRANSPORT_FAILFAST;
+	case XEN_VSCSIIF_RSLT_HOST_TARGET_FAILURE:
+		return DID_TARGET_FAILURE;
+	case XEN_VSCSIIF_RSLT_HOST_NEXUS_FAILURE:
+		return DID_NEXUS_FAILURE;
+	case XEN_VSCSIIF_RSLT_HOST_ALLOC_FAILURE:
+		return DID_ALLOC_FAILURE;
+	case XEN_VSCSIIF_RSLT_HOST_MEDIUM_ERROR:
+		return DID_MEDIUM_ERROR;
+	case XEN_VSCSIIF_RSLT_HOST_TRANSPORT_MARGINAL:
+		return DID_TRANSPORT_MARGINAL;
+	default:
+		return DID_ERROR;
+	}
+}
+
 static void scsifront_cdb_cmd_done(struct vscsifrnt_info *info,
 				   struct vscsiif_response *ring_rsp)
 {
@@ -250,7 +311,6 @@ static void scsifront_cdb_cmd_done(struct vscsifrnt_info *info,
 	struct scsi_cmnd *sc;
 	uint32_t id;
 	uint8_t sense_len;
-	int result;
 
 	id = ring_rsp->rqid;
 	shadow = info->shadow[id];
@@ -259,14 +319,12 @@ static void scsifront_cdb_cmd_done(struct vscsifrnt_info *info,
 	BUG_ON(sc == NULL);
 
 	scsifront_gnttab_done(info, shadow);
+	if (info->host_active == STATE_ERROR)
+		return;
 	scsifront_put_rqid(info, id);
 
-	result = ring_rsp->rslt;
-	if (result >> 24)
-		set_host_byte(sc, DID_ERROR);
-	else
-		set_host_byte(sc, host_byte(result));
-	set_status_byte(sc, result & 0xff);
+	set_host_byte(sc, scsifront_host_byte(ring_rsp->rslt));
+	set_status_byte(sc, XEN_VSCSIIF_RSLT_STATUS(ring_rsp->rslt));
 	scsi_set_resid(sc, ring_rsp->residual_len);
 
 	sense_len = min_t(uint8_t, VSCSIIF_SENSE_BUFFERSIZE,
@@ -290,7 +348,10 @@ static void scsifront_sync_cmd_done(struct vscsifrnt_info *info,
 	shadow->wait_reset = 1;
 	switch (shadow->rslt_reset) {
 	case RSLT_RESET_WAITING:
-		shadow->rslt_reset = ring_rsp->rslt;
+		if (ring_rsp->rslt == XEN_VSCSIIF_RSLT_RESET_SUCCESS)
+			shadow->rslt_reset = SUCCESS;
+		else
+			shadow->rslt_reset = FAILED;
 		break;
 	case RSLT_RESET_ERR:
 		kick = _scsifront_put_rqid(info, id);
@@ -300,9 +361,7 @@ static void scsifront_sync_cmd_done(struct vscsifrnt_info *info,
 			scsifront_wake_up(info);
 		return;
 	default:
-		shost_printk(KERN_ERR, info->host, KBUILD_MODNAME
-			     "bad reset state %d, possibly leaking %u\n",
-			     shadow->rslt_reset, id);
+		scsifront_set_error(info, "bad reset state");
 		break;
 	}
 	spin_unlock_irqrestore(&info->shadow_lock, flags);
@@ -313,28 +372,41 @@ static void scsifront_sync_cmd_done(struct vscsifrnt_info *info,
 static void scsifront_do_response(struct vscsifrnt_info *info,
 				  struct vscsiif_response *ring_rsp)
 {
-	if (WARN(ring_rsp->rqid >= VSCSIIF_MAX_REQS ||
-		 test_bit(ring_rsp->rqid, info->shadow_free_bitmap),
-		 "illegal rqid %u returned by backend!\n", ring_rsp->rqid))
+	struct vscsifrnt_shadow *shadow;
+
+	if (ring_rsp->rqid >= VSCSIIF_MAX_REQS ||
+	    !info->shadow[ring_rsp->rqid]->inflight) {
+		scsifront_set_error(info, "illegal rqid returned by backend!");
 		return;
+	}
+	shadow = info->shadow[ring_rsp->rqid];
+	shadow->inflight = false;
 
-	if (info->shadow[ring_rsp->rqid]->act == VSCSIIF_ACT_SCSI_CDB)
+	if (shadow->act == VSCSIIF_ACT_SCSI_CDB)
 		scsifront_cdb_cmd_done(info, ring_rsp);
 	else
 		scsifront_sync_cmd_done(info, ring_rsp);
 }
 
-static int scsifront_ring_drain(struct vscsifrnt_info *info)
+static int scsifront_ring_drain(struct vscsifrnt_info *info,
+				unsigned int *eoiflag)
 {
-	struct vscsiif_response *ring_rsp;
+	struct vscsiif_response ring_rsp;
 	RING_IDX i, rp;
 	int more_to_do = 0;
 
-	rp = info->ring.sring->rsp_prod;
-	rmb();	/* ordering required respective to dom0 */
+	rp = READ_ONCE(info->ring.sring->rsp_prod);
+	virt_rmb();	/* ordering required respective to backend */
+	if (RING_RESPONSE_PROD_OVERFLOW(&info->ring, rp)) {
+		scsifront_set_error(info, "illegal number of responses");
+		return 0;
+	}
 	for (i = info->ring.rsp_cons; i != rp; i++) {
-		ring_rsp = RING_GET_RESPONSE(&info->ring, i);
-		scsifront_do_response(info, ring_rsp);
+		RING_COPY_RESPONSE(&info->ring, i, &ring_rsp);
+		scsifront_do_response(info, &ring_rsp);
+		if (info->host_active == STATE_ERROR)
+			return 0;
+		*eoiflag &= ~XEN_EOI_FLAG_SPURIOUS;
 	}
 
 	info->ring.rsp_cons = i;
@@ -347,14 +419,15 @@ static int scsifront_ring_drain(struct vscsifrnt_info *info)
 	return more_to_do;
 }
 
-static int scsifront_cmd_done(struct vscsifrnt_info *info)
+static int scsifront_cmd_done(struct vscsifrnt_info *info,
+			      unsigned int *eoiflag)
 {
 	int more_to_do;
 	unsigned long flags;
 
 	spin_lock_irqsave(info->host->host_lock, flags);
 
-	more_to_do = scsifront_ring_drain(info);
+	more_to_do = scsifront_ring_drain(info, eoiflag);
 
 	info->wait_ring_available = 0;
 
@@ -368,20 +441,28 @@ static int scsifront_cmd_done(struct vscsifrnt_info *info)
 static irqreturn_t scsifront_irq_fn(int irq, void *dev_id)
 {
 	struct vscsifrnt_info *info = dev_id;
+	unsigned int eoiflag = XEN_EOI_FLAG_SPURIOUS;
 
-	while (scsifront_cmd_done(info))
+	if (info->host_active == STATE_ERROR) {
+		xen_irq_lateeoi(irq, XEN_EOI_FLAG_SPURIOUS);
+		return IRQ_HANDLED;
+	}
+
+	while (scsifront_cmd_done(info, &eoiflag))
 		/* Yield point for this unbounded loop. */
 		cond_resched();
 
+	xen_irq_lateeoi(irq, eoiflag);
+
 	return IRQ_HANDLED;
 }
 
 static void scsifront_finish_all(struct vscsifrnt_info *info)
 {
-	unsigned i;
+	unsigned int i, dummy;
 	struct vscsiif_response resp;
 
-	scsifront_ring_drain(info);
+	scsifront_ring_drain(info, &dummy);
 
 	for (i = 0; i < VSCSIIF_MAX_REQS; i++) {
 		if (test_bit(i, info->shadow_free_bitmap))
@@ -538,6 +619,9 @@ static int scsifront_queuecommand(struct Scsi_Host *shost,
 	unsigned long flags;
 	int err;
 
+	if (info->host_active == STATE_ERROR)
+		return SCSI_MLQUEUE_HOST_BUSY;
+
 	sc->result = 0;
 
 	shadow->sc  = sc;
@@ -590,6 +674,9 @@ static int scsifront_action_handler(struct scsi_cmnd *sc, uint8_t act)
 	struct vscsifrnt_shadow *shadow, *s = scsi_cmd_priv(sc);
 	int err = 0;
 
+	if (info->host_active == STATE_ERROR)
+		return FAILED;
+
 	shadow = kzalloc(sizeof(*shadow), GFP_NOIO);
 	if (!shadow)
 		return FAILED;
@@ -661,6 +748,9 @@ static int scsifront_sdev_configure(struct scsi_device *sdev)
 	struct vscsifrnt_info *info = shost_priv(sdev->host);
 	int err;
 
+	if (info->host_active == STATE_ERROR)
+		return -EIO;
+
 	if (info && current == info->curr) {
 		err = xenbus_printf(XBT_NIL, info->dev->nodename,
 			      info->dev_state_path, "%d", XenbusStateConnected);
@@ -708,27 +798,15 @@ static int scsifront_alloc_ring(struct vscsifrnt_info *info)
 {
 	struct xenbus_device *dev = info->dev;
 	struct vscsiif_sring *sring;
-	grant_ref_t gref;
-	int err = -ENOMEM;
+	int err;
 
 	/***** Frontend to Backend ring start *****/
-	sring = (struct vscsiif_sring *)__get_free_page(GFP_KERNEL);
-	if (!sring) {
-		xenbus_dev_fatal(dev, err,
-			"fail to allocate shared ring (Front to Back)");
+	err = xenbus_setup_ring(dev, GFP_KERNEL, (void **)&sring, 1,
+				&info->ring_ref);
+	if (err)
 		return err;
-	}
-	SHARED_RING_INIT(sring);
-	FRONT_RING_INIT(&info->ring, sring, PAGE_SIZE);
 
-	err = xenbus_grant_ring(dev, sring, 1, &gref);
-	if (err < 0) {
-		free_page((unsigned long)sring);
-		xenbus_dev_fatal(dev, err,
-			"fail to grant shared ring (Front to Back)");
-		return err;
-	}
-	info->ring_ref = gref;
+	XEN_FRONT_RING_INIT(&info->ring, sring, PAGE_SIZE);
 
 	err = xenbus_alloc_evtchn(dev, &info->evtchn);
 	if (err) {
@@ -736,7 +814,7 @@ static int scsifront_alloc_ring(struct vscsifrnt_info *info)
 		goto free_gnttab;
 	}
 
-	err = bind_evtchn_to_irq(info->evtchn);
+	err = bind_evtchn_to_irq_lateeoi(info->evtchn);
 	if (err <= 0) {
 		xenbus_dev_fatal(dev, err, "bind_evtchn_to_irq");
 		goto free_gnttab;
@@ -757,8 +835,7 @@ static int scsifront_alloc_ring(struct vscsifrnt_info *info)
 free_irq:
 	unbind_from_irqhandler(info->irq, info);
 free_gnttab:
-	gnttab_end_foreign_access(info->ring_ref,
-				  (unsigned long)info->ring.sring);
+	xenbus_teardown_ring((void **)&sring, 1, &info->ring_ref);
 
 	return err;
 }
@@ -766,8 +843,7 @@ free_gnttab:
 static void scsifront_free_ring(struct vscsifrnt_info *info)
 {
 	unbind_from_irqhandler(info->irq, info);
-	gnttab_end_foreign_access(info->ring_ref,
-				  (unsigned long)info->ring.sring);
+	xenbus_teardown_ring((void **)&info->ring.sring, 1, &info->ring_ref);
 }
 
 static int scsifront_init_ring(struct vscsifrnt_info *info)
@@ -866,7 +942,7 @@ static int scsifront_probe(struct xenbus_device *dev,
 		goto free_sring;
 	}
 	info->host = host;
-	info->host_active = 1;
+	info->host_active = STATE_ACTIVE;
 
 	xenbus_switch_state(dev, XenbusStateInitialised);
 
@@ -934,10 +1010,10 @@ static int scsifront_remove(struct xenbus_device *dev)
 	pr_debug("%s: %s removed\n", __func__, dev->nodename);
 
 	mutex_lock(&scsifront_mutex);
-	if (info->host_active) {
+	if (info->host_active != STATE_INACTIVE) {
 		/* Scsi_host not yet removed */
 		scsi_remove_host(info->host);
-		info->host_active = 0;
+		info->host_active = STATE_INACTIVE;
 	}
 	mutex_unlock(&scsifront_mutex);
 
@@ -961,9 +1037,9 @@ static void scsifront_disconnect(struct vscsifrnt_info *info)
 	 */
 
 	mutex_lock(&scsifront_mutex);
-	if (info->host_active) {
+	if (info->host_active != STATE_INACTIVE) {
 		scsi_remove_host(host);
-		info->host_active = 0;
+		info->host_active = STATE_INACTIVE;
 	}
 	mutex_unlock(&scsifront_mutex);
 
@@ -981,6 +1057,9 @@ static void scsifront_do_lun_hotplug(struct vscsifrnt_info *info, int op)
 	unsigned int hst, chn, tgt, lun;
 	struct scsi_device *sdev;
 
+	if (info->host_active == STATE_ERROR)
+		return;
+
 	dir = xenbus_directory(XBT_NIL, dev->otherend, "vscsi-devs", &dir_n);
 	if (IS_ERR(dir))
 		return;