[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>

6 files changed, 112 insertions, 4 deletions

diff --git a/drivers/scsi/bfa/bfad.c b/drivers/scsi/bfa/bfad.c
index 66fb72531b34..404fd10ddb21 100644
--- a/drivers/scsi/bfa/bfad.c
+++ b/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)
diff --git a/drivers/scsi/bfa/bfad_attr.c b/drivers/scsi/bfa/bfad_attr.c
index 9d95844ab463..1938fe0473e9 100644
--- a/drivers/scsi/bfa/bfad_attr.c
+++ b/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;
diff --git a/drivers/scsi/bfa/bfad_bsg.c b/drivers/scsi/bfa/bfad_bsg.c
index 06fc00caeb41..530de2b1200a 100644
--- a/drivers/scsi/bfa/bfad_bsg.c
+++ b/drivers/scsi/bfa/bfad_bsg.c
@@ -2394,6 +2394,21 @@ out:
         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;
diff --git a/drivers/scsi/bfa/bfad_drv.h b/drivers/scsi/bfa/bfad_drv.h
index 5e19a5f820ec..dc5b9d99c450 100644
--- a/drivers/scsi/bfa/bfad_drv.h
+++ b/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 */
diff --git a/drivers/scsi/bfa/bfad_im.c b/drivers/scsi/bfa/bfad_im.c
index e5db649e8eb7..3153923f5b60 100644
--- a/drivers/scsi/bfa/bfad_im.c
+++ b/drivers/scsi/bfa/bfad_im.c
@@ -918,16 +918,70 @@ bfad_get_itnim(struct bfad_im_port_s *im_port, int id)
 }
 
 /*
+ * 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
  */
 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;
 }
 
diff --git a/drivers/scsi/bfa/bfad_im.h b/drivers/scsi/bfa/bfad_im.h
index 004b6cf848d9..0814367ef101 100644
--- a/drivers/scsi/bfa/bfad_im.h
+++ b/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