[SCSI] bfa: Implement LUN Masking feature using the SCSI Slave Callouts.

This patch re-implements LUN Masking feature using SCSI Slave Callouts.  With
the new design in the slave_alloc entry point; for each new LUN discovered we
check with our internal LUN Masking config whether to expose or to mask this
particular LUN. We return -ENXIO (No such device or address) from slave_alloc
for the LUNs we don't want to be exposed.  We also notify the SCSI mid-layer
to do a sequential LUN scan rather than REPORT_LUNS based scan if LUN masking
is enabled on our HBA port, since a -ENXIO from any LUN in REPORT_LUNS based
scan translates to a scan abort.  This patch also handles the dynamic lun
masking config change from enable to disable or vice-versa by resetting
sdev_bflags of LUN 0 appropriately.
Signed-off-by: Krishna Gudipati <kgudipat@brocade.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>

drivers/scsi/bfa/bfad.c

@@ -674,6 +674,7 @@ bfad_vport_create(struct bfad_s *bfad, u16 vf_id,
 
 	spin_lock_irqsave(&bfad->bfad_lock, flags);
 	bfa_fcs_vport_start(&vport->fcs_vport);
+	list_add_tail(&vport->list_entry, &bfad->vport_list);
 	spin_unlock_irqrestore(&bfad->bfad_lock, flags);
 
 	return BFA_STATUS_OK;
@@ -1404,6 +1405,7 @@ bfad_pci_probe(struct pci_dev *pdev, const struct pci_device_id *pid)
 	bfad->ref_count = 0;
 	bfad->pport.bfad = bfad;
 	INIT_LIST_HEAD(&bfad->pbc_vport_list);
+	INIT_LIST_HEAD(&bfad->vport_list);
 
 	/* Setup the debugfs node for this bfad */
 	if (bfa_debugfs_enable)

drivers/scsi/bfa/bfad_attr.c

@@ -491,7 +491,7 @@ bfad_im_vport_delete(struct fc_vport *fc_vport)
 
 free_scsi_host:
 	bfad_scsi_host_free(bfad, im_port);
-
+	list_del(&vport->list_entry);
 	kfree(vport);
 
 	return 0;

drivers/scsi/bfa/bfad_bsg.c

@@ -2394,6 +2394,21 @@ bfad_iocmd_vf_clr_stats(struct bfad_s *bfad, void *cmd)
 	return 0;
 }
 
+/* Function to reset the LUN SCAN mode */
+static void
+bfad_iocmd_lunmask_reset_lunscan_mode(struct bfad_s *bfad, int lunmask_cfg)
+{
+	struct bfad_im_port_s *pport_im = bfad->pport.im_port;
+	struct bfad_vport_s *vport = NULL;
+
+	/* Set the scsi device LUN SCAN flags for base port */
+	bfad_reset_sdev_bflags(pport_im, lunmask_cfg);
+
+	/* Set the scsi device LUN SCAN flags for the vports */
+	list_for_each_entry(vport, &bfad->vport_list, list_entry)
+		bfad_reset_sdev_bflags(vport->drv_port.im_port, lunmask_cfg);
+}
+
 int
 bfad_iocmd_lunmask(struct bfad_s *bfad, void *pcmd, unsigned int v_cmd)
 {
@@ -2401,11 +2416,17 @@ bfad_iocmd_lunmask(struct bfad_s *bfad, void *pcmd, unsigned int v_cmd)
 	unsigned long	flags;
 
 	spin_lock_irqsave(&bfad->bfad_lock, flags);
-	if (v_cmd == IOCMD_FCPIM_LUNMASK_ENABLE)
+	if (v_cmd == IOCMD_FCPIM_LUNMASK_ENABLE) {
 		iocmd->status = bfa_fcpim_lunmask_update(&bfad->bfa, BFA_TRUE);
-	else if (v_cmd == IOCMD_FCPIM_LUNMASK_DISABLE)
+		/* Set the LUN Scanning mode to be Sequential scan */
+		if (iocmd->status == BFA_STATUS_OK)
+			bfad_iocmd_lunmask_reset_lunscan_mode(bfad, BFA_TRUE);
+	} else if (v_cmd == IOCMD_FCPIM_LUNMASK_DISABLE) {
 		iocmd->status = bfa_fcpim_lunmask_update(&bfad->bfa, BFA_FALSE);
-	else if (v_cmd == IOCMD_FCPIM_LUNMASK_CLEAR)
+		/* Set the LUN Scanning mode to default REPORT_LUNS scan */
+		if (iocmd->status == BFA_STATUS_OK)
+			bfad_iocmd_lunmask_reset_lunscan_mode(bfad, BFA_FALSE);
+	} else if (v_cmd == IOCMD_FCPIM_LUNMASK_CLEAR)
 		iocmd->status = bfa_fcpim_lunmask_clear(&bfad->bfa);
 	spin_unlock_irqrestore(&bfad->bfad_lock, flags);
 	return 0;

drivers/scsi/bfa/bfad_drv.h

@@ -43,6 +43,7 @@
 #include <scsi/scsi_transport_fc.h>
 #include <scsi/scsi_transport.h>
 #include <scsi/scsi_bsg_fc.h>
+#include <scsi/scsi_devinfo.h>
 
 #include "bfa_modules.h"
 #include "bfa_fcs.h"
@@ -227,6 +228,7 @@ struct bfad_s {
 	struct list_head	active_aen_q;
 	struct bfa_aen_entry_s	aen_list[BFA_AEN_MAX_ENTRY];
 	spinlock_t		bfad_aen_spinlock;
+	struct list_head	vport_list;
 };
 
 /* BFAD state machine events */

drivers/scsi/bfa/bfad_im.c

@@ -917,6 +917,37 @@ bfad_get_itnim(struct bfad_im_port_s *im_port, int id)
 	return NULL;
 }
 
+/*
+ * Function is invoked from the SCSI Host Template slave_alloc() entry point.
+ * Has the logic to query the LUN Mask database to check if this LUN needs to
+ * be made visible to the SCSI mid-layer or not.
+ *
+ * Returns BFA_STATUS_OK if this LUN needs to be added to the OS stack.
+ * Returns -ENXIO to notify SCSI mid-layer to not add this LUN to the OS stack.
+ */
+static int
+bfad_im_check_if_make_lun_visible(struct scsi_device *sdev,
+				  struct fc_rport *rport)
+{
+	struct bfad_itnim_data_s *itnim_data =
+				(struct bfad_itnim_data_s *) rport->dd_data;
+	struct bfa_s *bfa = itnim_data->itnim->bfa_itnim->bfa;
+	struct bfa_rport_s *bfa_rport = itnim_data->itnim->bfa_itnim->rport;
+	struct bfa_lun_mask_s *lun_list = bfa_get_lun_mask_list(bfa);
+	int i = 0, ret = -ENXIO;
+
+	for (i = 0; i < MAX_LUN_MASK_CFG; i++) {
+		if (lun_list[i].state == BFA_IOIM_LUN_MASK_ACTIVE &&
+		    scsilun_to_int(&lun_list[i].lun) == sdev->lun &&
+		    lun_list[i].rp_tag == bfa_rport->rport_tag &&
+		    lun_list[i].lp_tag == (u8)bfa_rport->rport_info.lp_tag) {
+			ret = BFA_STATUS_OK;
+			break;
+		}
+	}
+	return ret;
+}
+
 /*
  * Scsi_Host template entry slave_alloc
  */
@@ -924,10 +955,33 @@ static int
 bfad_im_slave_alloc(struct scsi_device *sdev)
 {
 	struct fc_rport *rport = starget_to_rport(scsi_target(sdev));
+	struct bfad_itnim_data_s *itnim_data =
+				(struct bfad_itnim_data_s *) rport->dd_data;
+	struct bfa_s *bfa = itnim_data->itnim->bfa_itnim->bfa;
 
 	if (!rport || fc_remote_port_chkready(rport))
 		return -ENXIO;
 
+	if (bfa_get_lun_mask_status(bfa) == BFA_LUNMASK_ENABLED) {
+		/*
+		 * We should not mask LUN 0 - since this will translate
+		 * to no LUN / TARGET for SCSI ml resulting no scan.
+		 */
+		if (sdev->lun == 0) {
+			sdev->sdev_bflags |= BLIST_NOREPORTLUN |
+					     BLIST_SPARSELUN;
+			goto done;
+		}
+
+		/*
+		 * Query LUN Mask configuration - to expose this LUN
+		 * to the SCSI mid-layer or to mask it.
+		 */
+		if (bfad_im_check_if_make_lun_visible(sdev, rport) !=
+							BFA_STATUS_OK)
+			return -ENXIO;
+	}
+done:
 	sdev->hostdata = rport->dd_data;
 
 	return 0;
@@ -1037,6 +1091,8 @@ bfad_im_fc_rport_add(struct bfad_im_port_s *im_port, struct bfad_itnim_s *itnim)
 	    && (fc_rport->scsi_target_id < MAX_FCP_TARGET))
 		itnim->scsi_tgt_id = fc_rport->scsi_target_id;
 
+	itnim->channel = fc_rport->channel;
+
 	return;
 }
 

drivers/scsi/bfa/bfad_im.h

@@ -91,6 +91,7 @@ struct bfad_itnim_s {
 	struct fc_rport *fc_rport;
 	struct bfa_itnim_s *bfa_itnim;
 	u16        scsi_tgt_id;
+	u16	   channel;
 	u16        queue_work;
 	unsigned long	last_ramp_up_time;
 	unsigned long	last_queue_full_time;
@@ -166,4 +167,30 @@ irqreturn_t bfad_intx(int irq, void *dev_id);
 int bfad_im_bsg_request(struct fc_bsg_job *job);
 int bfad_im_bsg_timeout(struct fc_bsg_job *job);
 
+/*
+ * Macro to set the SCSI device sdev_bflags - sdev_bflags are used by the
+ * SCSI mid-layer to choose LUN Scanning mode REPORT_LUNS vs. Sequential Scan
+ *
+ * Internally iterate's over all the ITNIM's part of the im_port & set's the
+ * sdev_bflags for the scsi_device associated with LUN #0.
+ */
+#define bfad_reset_sdev_bflags(__im_port, __lunmask_cfg) do {		\
+	struct scsi_device *__sdev = NULL;				\
+	struct bfad_itnim_s *__itnim = NULL;				\
+	u32 scan_flags = BLIST_NOREPORTLUN | BLIST_SPARSELUN;		\
+	list_for_each_entry(__itnim, &((__im_port)->itnim_mapped_list),	\
+			    list_entry) {				\
+		__sdev = scsi_device_lookup((__im_port)->shost,		\
+					    __itnim->channel,		\
+					    __itnim->scsi_tgt_id, 0);	\
+		if (__sdev) {						\
+			if ((__lunmask_cfg) == BFA_TRUE)		\
+				__sdev->sdev_bflags |= scan_flags;	\
+			else						\
+				__sdev->sdev_bflags &= ~scan_flags;	\
+			scsi_device_put(__sdev);			\
+		}							\
+	}								\
+} while (0)
+
 #endif