[SCSI] Update the SCSI state model to allow blocking in the created state

Brian King <brking@linux.vnet.ibm.com> reported that fibre channel
devices can oops during scanning if their ports block (because the
device goes from CREATED -> BLOCK -> RUNNING rather than CREATED ->
BLOCK -> CREATED).

Fix this by adding a new state: CREATED_BLOCK which can only transition
back to CREATED and disallow the CREATED -> BLOCK transition.  Now both
the created and blocked states that the mid-layer recognises can include
CREATED_BLOCK.

Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>

1 files changed, 14 insertions, 2 deletions

diff --git a/drivers/scsi/scsi_scan.c b/drivers/scsi/scsi_scan.c
index 2926baaac31e..334862e26a1b 100644
--- a/drivers/scsi/scsi_scan.c
+++ b/drivers/scsi/scsi_scan.c
@@ -730,6 +730,8 @@ static int scsi_probe_lun(struct scsi_device *sdev, unsigned char *inq_result,
 static int scsi_add_lun(struct scsi_device *sdev, unsigned char *inq_result,
                 int *bflags, int async)
 {
+        int ret;
+
         /*
          * XXX do not save the inquiry, since it can change underneath us,
          * save just vendor/model/rev.
@@ -885,7 +887,17 @@ static int scsi_add_lun(struct scsi_device *sdev, unsigned char *inq_result,
 
         /* set the device running here so that slave configure
          * may do I/O */
-        scsi_device_set_state(sdev, SDEV_RUNNING);
+        ret = scsi_device_set_state(sdev, SDEV_RUNNING);
+        if (ret) {
+                ret = scsi_device_set_state(sdev, SDEV_BLOCK);
+
+                if (ret) {
+                        sdev_printk(KERN_ERR, sdev,
+                                    "in wrong state %s to complete scan\n",
+                                    scsi_device_state_name(sdev->sdev_state));
+                        return SCSI_SCAN_NO_RESPONSE;
+                }
+        }
 
         if (*bflags & BLIST_MS_192_BYTES_FOR_3F)
                 sdev->use_192_bytes_for_3f = 1;
@@ -899,7 +911,7 @@ static int scsi_add_lun(struct scsi_device *sdev, unsigned char *inq_result,
         transport_configure_device(&sdev->sdev_gendev);
 
         if (sdev->host->hostt->slave_configure) {
-                int ret = sdev->host->hostt->slave_configure(sdev);
+                ret = sdev->host->hostt->slave_configure(sdev);
                 if (ret) {
                         /*
                          * if LLDD reports slave not present, don't clutter