[PATCH] ses: Handle non-unique element descriptors

[Ankit Jain <jankit@suse.de>]

Some SES devices give non-unique Element Descriptors as part of the
Element Descriptor diag page. Since we use these for creating sysfs
entries, they need to be unique.

Eg:
$ sg_ses -p 7 /dev/sg0
  FTS CORP  TXS6_SAS20BPX12   0500
    enclosure services device
Element descriptor In diagnostic page:
  generation code: 0x0
  element descriptor by type list
    Element type: Array device, subenclosure id: 0
      Overall descriptor: ArrayDevicesInSubEnclsr0
      Element 1 descriptor: ArrayDevice00
      Element 2 descriptor: ArrayDevice01
      Element 3 descriptor: ArrayDevice02
      Element 4 descriptor: ArrayDevice03
      Element 5 descriptor: ArrayDevice03
      Element 6 descriptor: ArrayDevice03
      Element 7 descriptor: ArrayDevice03
      Element 8 descriptor: ArrayDevice03
      Element 9 descriptor: ArrayDevice03
      Element 10 descriptor: ArrayDevice03
      Element 11 descriptor: ArrayDevice03
      Element 12 descriptor: ArrayDevice03

Based on scsi-misc

Signed-off-by: Ankit Jain <jankit@suse.de>

---
diff --git a/drivers/misc/enclosure.c b/drivers/misc/enclosure.c
index 00e5fca..8087055 100644
--- a/drivers/misc/enclosure.c
+++ b/drivers/misc/enclosure.c
@@ -239,6 +239,24 @@ static void enclosure_component_release(struct device *dev)
 	put_device(dev->parent);
 }
 
+struct enclosure_component *
+enclosure_component_find_by_name(struct enclosure_device *edev,
+				const char *name)
+{
+	int i;
+	if (!edev || !name || !name[0])
+		return NULL;
+
+	for (i=0; i<edev->components; i++) {
+		struct enclosure_component *ecomp = &edev->component[i];
+		if (ecomp->number != -1 && !strcmp(dev_name(&ecomp->cdev), name))
+			return ecomp;
+	}
+
+	return NULL;
+}
+EXPORT_SYMBOL_GPL(enclosure_component_find_by_name);
+
 static const struct attribute_group *enclosure_groups[];
 
 /**
diff --git a/drivers/scsi/ses.c b/drivers/scsi/ses.c
index eba183c..abfd962 100644
--- a/drivers/scsi/ses.c
+++ b/drivers/scsi/ses.c
@@ -421,12 +421,17 @@ static void ses_enclosure_data_process(struct enclosure_device *edev,
 			if (type_ptr[0] == ENCLOSURE_COMPONENT_DEVICE ||
 			    type_ptr[0] == ENCLOSURE_COMPONENT_ARRAY_DEVICE) {
 
-				if (create)
+				if (create) {
+					if (enclosure_component_find_by_name(edev, name))
+						/* name is not unique, already used
+						 * set to NULL, so that enclosure_component_register
+						 * will assign us a new one */
+						name = NULL;
 					ecomp =	enclosure_component_register(edev,
 									     components++,
 									     type_ptr[0],
 									     name);
-				else
+				} else
 					ecomp = &edev->component[components++];
 
 				if (!IS_ERR(ecomp) && addl_desc_ptr)
diff --git a/include/linux/enclosure.h b/include/linux/enclosure.h
index 9a33c5f..7e48ba9 100644
--- a/include/linux/enclosure.h
+++ b/include/linux/enclosure.h
@@ -122,6 +122,8 @@ void enclosure_unregister(struct enclosure_device *);
 struct enclosure_component *
 enclosure_component_register(struct enclosure_device *, unsigned int,
 				 enum enclosure_component_type, const char *);
+struct enclosure_component *
+enclosure_component_find_by_name(struct enclosure_device *, const char *);
 int enclosure_add_device(struct enclosure_device *enclosure, int component,
 			 struct device *dev);
 int enclosure_remove_device(struct enclosure_device *, struct device *);
-- 
Ankit Jain
SUSE Labs