SCSI & usb-storage: add flags for VPD pages and REPORT LUNS

This patch (as1507) adds a skip_vpd_pages flag to struct scsi_device
and a no_report_luns flag to struct scsi_target.  The first is used to
control whether sd will look at VPD pages for information on block
provisioning, limits, and characteristics.  The second prevents
scsi_report_lun_scan() from issuing a REPORT LUNS command.

The patch also modifies usb-storage to set the new flag bits for all
USB devices and targets, and to stop adjusting the scsi_level value.

Historically we have seen that USB mass-storage devices often don't
support VPD pages or REPORT LUNS properly.  Until now we have avoided
these things by setting the scsi_level to SCSI_2 for all USB devices.
But this has the side effect of storing the LUN bits into the second
byte of each CDB, and now we have a report of a device which doesn't
like that.  The best solution is to stop abusing scsi_level and
instead have separate flags for VPD pages and REPORT LUNS.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Reported-by: Perry Wagle <wagle@mac.com>
CC: Matthew Dharm <mdharm-usb@one-eyed-alien.net>
Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

4 files changed, 24 insertions, 11 deletions

diff --git a/drivers/scsi/scsi_scan.c b/drivers/scsi/scsi_scan.c
index 89da43f73c00..fd37bfbfbcdb 100644
--- a/drivers/scsi/scsi_scan.c
+++ b/drivers/scsi/scsi_scan.c
@@ -1295,6 +1295,7 @@ EXPORT_SYMBOL(int_to_scsilun);
  *   LUNs even if it's older than SCSI-3.
  *   If BLIST_NOREPORTLUN is set, return 1 always.
  *   If BLIST_NOLUN is set, return 0 always.
+ *   If starget->no_report_luns is set, return 1 always.
  *
  * Return:
  *     0: scan completed (or no memory, so further scanning is futile)
@@ -1321,6 +1322,7 @@ static int scsi_report_lun_scan(struct scsi_target *starget, int bflags,
          * Only support SCSI-3 and up devices if BLIST_NOREPORTLUN is not set.
          * Also allow SCSI-2 if BLIST_REPORTLUN2 is set and host adapter does
          * support more than 8 LUNs.
+         * Don't attempt if the target doesn't support REPORT LUNS.
          */
         if (bflags & BLIST_NOREPORTLUN)
                 return 1;
@@ -1332,6 +1334,8 @@ static int scsi_report_lun_scan(struct scsi_target *starget, int bflags,
                 return 1;
         if (bflags & BLIST_NOLUN)
                 return 0;
+        if (starget->no_report_luns)
+                return 1;
 
         if (!(sdev = scsi_device_lookup_by_target(starget, 0))) {
                 sdev = scsi_alloc_sdev(starget, 0, NULL);
diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
index c691fb50e6cb..d173b90b25e9 100644
--- a/drivers/scsi/sd.c
+++ b/drivers/scsi/sd.c
@@ -2349,7 +2349,7 @@ static int sd_try_extended_inquiry(struct scsi_device *sdp)
          * some USB ones crash on receiving them, and the pages
          * we currently ask for are for SPC-3 and beyond
          */
-        if (sdp->scsi_level > SCSI_SPC_2)
+        if (sdp->scsi_level > SCSI_SPC_2 && !sdp->skip_vpd_pages)
                 return 1;
         return 0;
 }
diff --git a/drivers/usb/storage/scsiglue.c b/drivers/usb/storage/scsiglue.c
index 13b8bcdf3dba..dc68cc9fef5d 100644
--- a/drivers/usb/storage/scsiglue.c
+++ b/drivers/usb/storage/scsiglue.c
@@ -197,6 +197,9 @@ static int slave_configure(struct scsi_device *sdev)
                  * page x08, so we will skip it. */
                 sdev->skip_ms_page_8 = 1;
 
+                /* Some devices don't handle VPD pages correctly */
+                sdev->skip_vpd_pages = 1;
+
                 /* Some disks return the total number of blocks in response
                  * to READ CAPACITY rather than the highest block number.
                  * If this device makes that mistake, tell the sd driver. */
@@ -217,16 +220,6 @@ static int slave_configure(struct scsi_device *sdev)
                 if (sdev->scsi_level > SCSI_SPC_2)
                         us->fflags |= US_FL_SANE_SENSE;
 
-                /* Some devices report a SCSI revision level above 2 but are
-                 * unable to handle the REPORT LUNS command (for which
-                 * support is mandatory at level 3).  Since we already have
-                 * a Get-Max-LUN request, we won't lose much by setting the
-                 * revision level down to 2.  The only devices that would be
-                 * affected are those with sparse LUNs. */
-                if (sdev->scsi_level > SCSI_2)
-                        sdev->sdev_target->scsi_level =
-                                        sdev->scsi_level = SCSI_2;
-
                 /* USB-IDE bridges tend to report SK = 0x04 (Non-recoverable
                  * Hardware Error) when any low-level error occurs,
                  * recoverable or not.  Setting this flag tells the SCSI
@@ -283,6 +276,18 @@ static int slave_configure(struct scsi_device *sdev)
         return 0;
 }
 
+static int target_alloc(struct scsi_target *starget)
+{
+        /*
+         * Some USB drives don't support REPORT LUNS, even though they
+         * report a SCSI revision level above 2.  Tell the SCSI layer
+         * not to issue that command; it will perform a normal sequential
+         * scan instead.
+         */
+        starget->no_report_luns = 1;
+        return 0;
+}
+
 /* queue a command */
 /* This is always called with scsi_lock(host) held */
 static int queuecommand_lck(struct scsi_cmnd *srb,
@@ -546,6 +551,7 @@ struct scsi_host_template usb_stor_host_template = {
 
         .slave_alloc =                  slave_alloc,
         .slave_configure =              slave_configure,
+        .target_alloc =                 target_alloc,
 
         /* lots of sg segments can be handled */
         .sg_tablesize =                 SCSI_MAX_SG_CHAIN_SEGMENTS,
diff --git a/include/scsi/scsi_device.h b/include/scsi/scsi_device.h
index 01cb3c4cb74d..b3a1c2daf6cc 100644
--- a/include/scsi/scsi_device.h
+++ b/include/scsi/scsi_device.h
@@ -136,6 +136,7 @@ struct scsi_device {
         unsigned use_10_for_ms:1; /* first try 10-byte mode sense/select */
         unsigned skip_ms_page_8:1;      /* do not use MODE SENSE page 0x08 */
         unsigned skip_ms_page_3f:1;     /* do not use MODE SENSE page 0x3f */
+        unsigned skip_vpd_pages:1;      /* do not read VPD pages */
         unsigned use_192_bytes_for_3f:1; /* ask for 192 bytes from page 0x3f */
         unsigned no_start_on_add:1;     /* do not issue start on add */
         unsigned allow_restart:1; /* issue START_UNIT in error handler */
@@ -248,6 +249,8 @@ struct scsi_target {
                                                  * for the device at a time. */
         unsigned int            pdt_1f_for_no_lun:1;    /* PDT = 0x1f
                                                  * means no lun present. */
+        unsigned int            no_report_luns:1;       /* Don't use
+                                                 * REPORT LUNS for scanning. */
         /* commands actually active on LLD. protected by host lock. */
         unsigned int            target_busy;
         /*