scsi_scan: Restrict sequential scan to 256 LUNs
authorHannes Reinecke <hare@suse.de>
Tue, 3 Jun 2014 08:58:53 +0000 (10:58 +0200)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Wed, 17 Sep 2014 16:19:13 +0000 (09:19 -0700)
commit 22ffeb48b7584d6cd50f2a595ed6065d86a87459 upstream.

Sequential scan for more than 256 LUNs is very fragile as
LUNs might not be numbered sequentially after that point.

SAM revisions later than SCSI-3 impose a structure on
LUNs larger than 256, making LUN numbers between 256
and 16384 illegal.
SCSI-3, however allows for plain 64-bit numbers with
no internal structure.

So restrict sequential LUN scan to 256 LUNs and add a
new blacklist flag 'BLIST_SCSI3LUN' to scan up to
max_lun devices.

Signed-off-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Ewan Milne <emilne@redhat.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
drivers/scsi/scsi_scan.c
include/scsi/scsi_devinfo.h

index 4109530..bfad358 100644 (file)
@@ -1236,6 +1236,12 @@ static void scsi_sequential_lun_scan(struct scsi_target *starget,
                max_dev_lun = min(8U, max_dev_lun);
 
        /*
+        * Stop scanning at 255 unless BLIST_SCSI3LUN
+        */
+       if (!(bflags & BLIST_SCSI3LUN))
+               max_dev_lun = min(256U, max_dev_lun);
+
+       /*
         * We have already scanned LUN 0, so start at LUN 1. Keep scanning
         * until we reach the max, or no LUN is found and we are not
         * sparse_lun.
index 447d2d7..8670c04 100644 (file)
@@ -32,4 +32,6 @@
 #define BLIST_ATTACH_PQ3       0x1000000 /* Scan: Attach to PQ3 devices */
 #define BLIST_NO_DIF           0x2000000 /* Disable T10 PI (DIF) */
 #define BLIST_SKIP_VPD_PAGES   0x4000000 /* Ignore SBC-3 VPD pages */
+#define BLIST_SCSI3LUN         0x8000000 /* Scan more than 256 LUNs
+                                            for sequential scan */
 #endif