[SCSI] make some sas class properties optional

aic94xx doesn't have a use for the bay or enclosure identifiers.
Also, I think it's not going to need a get_linkerrors(), so wire up
all of these exported properties as conditional on the underlying
function support.

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

1 files changed, 31 insertions, 5 deletions

diff --git a/drivers/scsi/scsi_transport_sas.c b/drivers/scsi/scsi_transport_sas.c
index fed39abeff86..434f3954aa87 100644
--- a/drivers/scsi/scsi_transport_sas.c
+++ b/drivers/scsi/scsi_transport_sas.c
@@ -273,7 +273,7 @@ show_sas_phy_##field(struct class_device *cdev, char *buf)		\
         if (!phy->local_attached)                                       \
                 return -EINVAL;                                         \
                                                                         \
-        error = i->f->get_linkerrors(phy);                              \
+        error = i->f->get_linkerrors ? i->f->get_linkerrors(phy) : 0;   \
         if (error)                                                      \
                 return error;                                           \
         return snprintf(buf, 20, "%u\n", phy->field);                   \
@@ -814,6 +814,14 @@ static int sas_user_scan(struct Scsi_Host *shost, uint channel,
         i->rphy_attrs[count] = &i->private_rphy_attrs[count];   \
         count++
 
+#define SETUP_OPTIONAL_RPORT_ATTRIBUTE(field, func)                     \
+        i->private_rphy_attrs[count] = class_device_attr_##field;       \
+        i->private_rphy_attrs[count].attr.mode = S_IRUGO;               \
+        i->private_rphy_attrs[count].store = NULL;                      \
+        i->rphy_attrs[count] = &i->private_rphy_attrs[count];           \
+        if (i->f->func)                                                 \
+                count++
+
 #define SETUP_PORT_ATTRIBUTE(field)                                     \
         i->private_phy_attrs[count] = class_device_attr_##field;        \
         i->private_phy_attrs[count].attr.mode = S_IRUGO;                \
@@ -821,6 +829,14 @@ static int sas_user_scan(struct Scsi_Host *shost, uint channel,
         i->phy_attrs[count] = &i->private_phy_attrs[count];             \
         count++
 
+#define SETUP_OPTIONAL_PORT_ATTRIBUTE(field, func)                      \
+        i->private_phy_attrs[count] = class_device_attr_##field;        \
+        i->private_phy_attrs[count].attr.mode = S_IRUGO;                \
+        i->private_phy_attrs[count].store = NULL;                       \
+        i->phy_attrs[count] = &i->private_phy_attrs[count];             \
+        if (i->f->func)                                                 \
+                count++
+
 #define SETUP_PORT_ATTRIBUTE_WRONLY(field)                              \
         i->private_phy_attrs[count] = class_device_attr_##field;        \
         i->private_phy_attrs[count].attr.mode = S_IWUGO;                \
@@ -828,6 +844,14 @@ static int sas_user_scan(struct Scsi_Host *shost, uint channel,
         i->phy_attrs[count] = &i->private_phy_attrs[count];             \
         count++
 
+#define SETUP_OPTIONAL_PORT_ATTRIBUTE_WRONLY(field, func)               \
+        i->private_phy_attrs[count] = class_device_attr_##field;        \
+        i->private_phy_attrs[count].attr.mode = S_IWUGO;                \
+        i->private_phy_attrs[count].show = NULL;                        \
+        i->phy_attrs[count] = &i->private_phy_attrs[count];             \
+        if (i->f->func)                                                 \
+                count++
+
 
 /**
  * sas_attach_transport  --  instantiate SAS transport template
@@ -883,8 +907,8 @@ sas_attach_transport(struct sas_function_template *ft)
         SETUP_PORT_ATTRIBUTE(running_disparity_error_count);
         SETUP_PORT_ATTRIBUTE(loss_of_dword_sync_count);
         SETUP_PORT_ATTRIBUTE(phy_reset_problem_count);
-        SETUP_PORT_ATTRIBUTE_WRONLY(link_reset);
-        SETUP_PORT_ATTRIBUTE_WRONLY(hard_reset);
+        SETUP_OPTIONAL_PORT_ATTRIBUTE_WRONLY(link_reset, phy_reset);
+        SETUP_OPTIONAL_PORT_ATTRIBUTE_WRONLY(hard_reset, phy_reset);
         i->phy_attrs[count] = NULL;
 
         count = 0;
@@ -893,8 +917,10 @@ sas_attach_transport(struct sas_function_template *ft)
         SETUP_RPORT_ATTRIBUTE(rphy_device_type);
         SETUP_RPORT_ATTRIBUTE(rphy_sas_address);
         SETUP_RPORT_ATTRIBUTE(rphy_phy_identifier);
-        SETUP_RPORT_ATTRIBUTE(rphy_enclosure_identifier);
-        SETUP_RPORT_ATTRIBUTE(rphy_bay_identifier);
+        SETUP_OPTIONAL_RPORT_ATTRIBUTE(rphy_enclosure_identifier,
+                                       get_enclosure_identifier);
+        SETUP_OPTIONAL_RPORT_ATTRIBUTE(rphy_bay_identifier,
+                                       get_bay_identifier);
         i->rphy_attrs[count] = NULL;
 
         return &i->t;