Author: ken
Date: Thu Jan  8 17:51:12 2015
New Revision: 276842
URL: https://svnweb.freebsd.org/changeset/base/276842

Log:
  Close a race in the isp(4) driver that caused devices to disappear
  and not automatically come back if they were gone for a short
  period of time.
  
  The isp(4) driver has a 30 second gone device timer that gets
  activated whenever a device goes away.  If the device comes back
  before the timer expires, we don't send a notification to CAM that
  it has gone away.  If, however, there is a command sent to the
  device while it is gone and before it comes back, the isp(4) driver
  sends the command back with CAM_SEL_TIMEOUT status.
  
  CAM responds to the CAM_SEL_TIMEOUT status by removing the device.
  In the case where a device comes back within the 30 second gone
  device timer window, though, we weren't telling CAM the device
  came back.
  
  So, fix this by tracking whether we have told CAM the device is
  gone, and if we have, send a rescan if it comes back within the 30
  second window.
  
  ispvar.h:
        In the fcportdb_t structure, add a new bitfield,
        reported_gone.  This gets set whenever we return a command
        with CAM_SEL_TIMEOUT status on a Fibre Channel device.
  
  isp_freebsd.c:
        In isp_done(), if we're sending CAM_SEL_TIMEOUT for for a
        command sent to a FC device, set the reported_gone bit.
  
        In isp_async(), in the ISPASYNC_DEV_STAYED case, rescan the
        device in question if it is mapped to a target ID and has
        been reported gone.
  
        In isp_make_here(), take a port database entry argument,
        and clear the reported_gone bit when we send a rescan to
        CAM.
  
        In isp_make_gone(), take a port database entry as an
        argument, and set the reported_gone bit when we send an
        async event telling CAM consumers that the device is gone.
  
  Sponsored by: Spectra Logic
  MFC after:    1 week

Modified:
  head/sys/dev/isp/isp_freebsd.c
  head/sys/dev/isp/ispvar.h

Modified: head/sys/dev/isp/isp_freebsd.c
==============================================================================
--- head/sys/dev/isp/isp_freebsd.c      Thu Jan  8 17:49:07 2015        
(r276841)
+++ head/sys/dev/isp/isp_freebsd.c      Thu Jan  8 17:51:12 2015        
(r276842)
@@ -4565,7 +4565,7 @@ isp_watchdog(void *arg)
 }
 
 static void
-isp_make_here(ispsoftc_t *isp, int chan, int tgt)
+isp_make_here(ispsoftc_t *isp, fcportdb_t *fcp, int chan, int tgt)
 {
        union ccb *ccb;
        struct isp_fc *fc = ISP_FC_PC(isp, chan);
@@ -4588,11 +4588,18 @@ isp_make_here(ispsoftc_t *isp, int chan,
                xpt_free_ccb(ccb);
                return;
        }
+
+       /*
+        * Since we're about to issue a rescan, mark this device as not
+        * reported gone.
+        */
+       fcp->reported_gone = 0;
+
        xpt_rescan(ccb);
 }
 
 static void
-isp_make_gone(ispsoftc_t *isp, int chan, int tgt)
+isp_make_gone(ispsoftc_t *isp, fcportdb_t *fcp, int chan, int tgt)
 {
        struct cam_path *tp;
        struct isp_fc *fc = ISP_FC_PC(isp, chan);
@@ -4601,6 +4608,11 @@ isp_make_gone(ispsoftc_t *isp, int chan,
                return;
        }
        if (xpt_create_path(&tp, NULL, cam_sim_path(fc->sim), tgt, 
CAM_LUN_WILDCARD) == CAM_REQ_CMP) {
+               /*
+                * We're about to send out the lost device async
+                * notification, so indicate that we have reported it gone.
+                */
+               fcp->reported_gone = 1;
                xpt_async(AC_LOST_DEVICE, tp, NULL);
                xpt_free_path(tp);
        }
@@ -4654,7 +4666,7 @@ isp_gdt_task(void *arg, int pending)
                lp->dev_map_idx = 0;
                lp->state = FC_PORTDB_STATE_NIL;
                isp_prt(isp, ISP_LOGCONFIG, prom3, chan, lp->portid, tgt, "Gone 
Device Timeout");
-               isp_make_gone(isp, chan, tgt);
+               isp_make_gone(isp, lp, chan, tgt);
        }
        if (fc->ready) {
                if (more_to_do) {
@@ -4747,7 +4759,7 @@ isp_ldt_task(void *arg, int pending)
                lp->dev_map_idx = 0;
                lp->state = FC_PORTDB_STATE_NIL;
                isp_prt(isp, ISP_LOGCONFIG, prom3, chan, lp->portid, tgt, "Loop 
Down Timeout");
-               isp_make_gone(isp, chan, tgt);
+               isp_make_gone(isp, lp, chan, tgt);
        }
 
        if (FCPARAM(isp, chan)->role & ISP_ROLE_INITIATOR) {
@@ -5561,6 +5573,21 @@ isp_done(XS_T *sccb)
        if (status != CAM_REQ_CMP) {
                if (status != CAM_SEL_TIMEOUT)
                        isp_prt(isp, ISP_LOGDEBUG0, "target %d lun %d CAM 
status 0x%x SCSI status 0x%x", XS_TGT(sccb), XS_LUN(sccb), sccb->ccb_h.status, 
sccb->scsi_status);
+               else if ((IS_FC(isp))
+                     && (XS_TGT(sccb) < MAX_FC_TARG)) {
+                       fcparam *fcp;
+                       int hdlidx;
+
+                       fcp = FCPARAM(isp, XS_CHANNEL(sccb));
+                       hdlidx = fcp->isp_dev_map[XS_TGT(sccb)] - 1;
+                       /*
+                        * Note that we have reported that this device is
+                        * gone.  If it reappears, we'll need to issue a
+                        * rescan.
+                        */
+                       if (hdlidx > 0 && hdlidx < MAX_FC_TARG)
+                               fcp->portdb[hdlidx].reported_gone = 1;
+               }
                if ((sccb->ccb_h.status & CAM_DEV_QFRZN) == 0) {
                        sccb->ccb_h.status |= CAM_DEV_QFRZN;
                        xpt_freeze_devq(sccb->ccb_h.path, 1);
@@ -5750,7 +5777,7 @@ isp_async(ispsoftc_t *isp, ispasync_t cm
                        tgt = lp->dev_map_idx - 1;
                        isp_prt(isp, ISP_LOGCONFIG, prom2, bus, lp->portid, 
lp->handle, buf, "arrived at", tgt, (uint32_t) (lp->port_wwn >> 32), (uint32_t) 
lp->port_wwn);
                        isp_fcp_reset_crn(fc, tgt, /*tgt_set*/ 1);
-                       isp_make_here(isp, bus, tgt);
+                       isp_make_here(isp, lp, bus, tgt);
                } else {
                        isp_prt(isp, ISP_LOGCONFIG, prom0, bus, lp->portid, 
lp->handle, buf, "arrived", (uint32_t) (lp->port_wwn >> 32), (uint32_t) 
lp->port_wwn);
                }
@@ -5770,7 +5797,7 @@ isp_async(ispsoftc_t *isp, ispasync_t cm
                                FCPARAM(isp, bus)->isp_dev_map[tgt] = 0;
                                lp->dev_map_idx = 0;
                                isp_prt(isp, ISP_LOGCONFIG, prom3, bus, 
lp->portid, tgt, "change is bad");
-                               isp_make_gone(isp, bus, tgt);
+                               isp_make_gone(isp, lp, bus, tgt);
                        } else {
                                isp_gen_role_str(buf, sizeof (buf), 
lp->prli_word3);
                                isp_prt(isp, ISP_LOGCONFIG, prom0, bus, 
lp->portid, lp->handle, buf, "changed and departed",
@@ -5803,6 +5830,15 @@ isp_async(ispsoftc_t *isp, ispasync_t cm
                        tgt = lp->dev_map_idx - 1;
                        isp_prt(isp, ISP_LOGCONFIG, prom2, bus, lp->portid, 
lp->handle, buf, "stayed at", tgt,
                            (uint32_t) (lp->port_wwn >> 32), (uint32_t) 
lp->port_wwn);
+                       /*
+                        * Only issue a rescan if we've actually reported
+                        * that this device is gone.
+                        */
+                       if (lp->reported_gone != 0) {
+                               isp_prt(isp, ISP_LOGCONFIG, prom2, bus, 
lp->portid, lp->handle, buf, "rescanned at", tgt, 
+                                   (uint32_t) (lp->port_wwn >> 32), (uint32_t) 
lp->port_wwn);
+                               isp_make_here(isp, lp, bus, tgt);
+                       }
                } else {
                        isp_prt(isp, ISP_LOGCONFIG, prom0, bus, lp->portid, 
lp->handle, buf, "stayed",
                            (uint32_t) (lp->port_wwn >> 32), (uint32_t) 
lp->port_wwn);

Modified: head/sys/dev/isp/ispvar.h
==============================================================================
--- head/sys/dev/isp/ispvar.h   Thu Jan  8 17:49:07 2015        (r276841)
+++ head/sys/dev/isp/ispvar.h   Thu Jan  8 17:51:12 2015        (r276842)
@@ -421,7 +421,8 @@ typedef struct {
                        target_mode     : 1,
                        portid          : 24;
        uint32_t
-                                       : 6,
+                                       : 5,
+                       reported_gone   : 1,
                        announced       : 1,
                        dirty           : 1,    /* commands have been run */
                        new_portid      : 24;
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