[PATCH] sbp2: add ability to override hardwired blacklist

In case the blacklist with workarounds for device bugs yields a false
positive, the module load parameter can now also be used as an override
instead of an addition to the blacklist.

Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

2 files changed, 19 insertions, 11 deletions

diff --git a/drivers/ieee1394/sbp2.c b/drivers/ieee1394/sbp2.c
index 09e9291f1848..73555806c483 100644
--- a/drivers/ieee1394/sbp2.c
+++ b/drivers/ieee1394/sbp2.c
@@ -156,6 +156,11 @@ MODULE_PARM_DESC(exclusive_login, "Exclusive login to sbp2 device (default = 1)"
  *   Tell sd_mod to correct the last sector number reported by read_capacity.
  *   Avoids access beyond actual disk limits on devices with an off-by-one bug.
  *   Don't use this with devices which don't have this bug.
+ *
+ * - override internal blacklist
+ *   Instead of adding to the built-in blacklist, use only the workarounds
+ *   specified in the module load parameter.
+ *   Useful if a blacklist entry interfered with a non-broken device.
  */
 static int sbp2_default_workarounds;
 module_param_named(workarounds, sbp2_default_workarounds, int, 0644);
@@ -164,6 +169,7 @@ MODULE_PARM_DESC(workarounds, "Work around device bugs (default = 0"
         ", 36 byte inquiry = "    __stringify(SBP2_WORKAROUND_INQUIRY_36)
         ", skip mode page 8 = "   __stringify(SBP2_WORKAROUND_MODE_SENSE_8)
         ", fix capacity = "       __stringify(SBP2_WORKAROUND_FIX_CAPACITY)
+        ", override internal blacklist = " __stringify(SBP2_WORKAROUND_OVERRIDE)
         ", or a combination)");
 
 /* legacy parameter */
@@ -1587,17 +1593,18 @@ static void sbp2_parse_unit_directory(struct scsi_id_instance_data *scsi_id,
                 workarounds |= SBP2_WORKAROUND_INQUIRY_36;
         }
 
-        for (i = 0; i < ARRAY_SIZE(sbp2_workarounds_table); i++) {
-                if (sbp2_workarounds_table[i].firmware_revision &&
-                    sbp2_workarounds_table[i].firmware_revision !=
-                    (firmware_revision & 0xffff00))
-                        continue;
-                if (sbp2_workarounds_table[i].model_id &&
-                    sbp2_workarounds_table[i].model_id != ud->model_id)
-                        continue;
-                workarounds |= sbp2_workarounds_table[i].workarounds;
-                break;
-        }
+        if (!(workarounds & SBP2_WORKAROUND_OVERRIDE))
+                for (i = 0; i < ARRAY_SIZE(sbp2_workarounds_table); i++) {
+                        if (sbp2_workarounds_table[i].firmware_revision &&
+                            sbp2_workarounds_table[i].firmware_revision !=
+                            (firmware_revision & 0xffff00))
+                                continue;
+                        if (sbp2_workarounds_table[i].model_id &&
+                            sbp2_workarounds_table[i].model_id != ud->model_id)
+                                continue;
+                        workarounds |= sbp2_workarounds_table[i].workarounds;
+                        break;
+                }
 
         if (workarounds)
                 SBP2_INFO("Workarounds for node " NODE_BUS_FMT ": 0x%x "
diff --git a/drivers/ieee1394/sbp2.h b/drivers/ieee1394/sbp2.h
index 3af2710f1858..f4ccc9d0fba4 100644
--- a/drivers/ieee1394/sbp2.h
+++ b/drivers/ieee1394/sbp2.h
@@ -239,6 +239,7 @@ struct sbp2_status_block {
 #define SBP2_WORKAROUND_INQUIRY_36      0x2
 #define SBP2_WORKAROUND_MODE_SENSE_8    0x4
 #define SBP2_WORKAROUND_FIX_CAPACITY    0x8
+#define SBP2_WORKAROUND_OVERRIDE        0x100
 
 /* This is the two dma types we use for cmd_dma below */
 enum cmd_dma_types {