cciss: export resettable host attribute

This attribute, requested by Redhat, allows kexec-tools to know
whether the controller can honor the reset_devices kernel parameter
and actually reset the controller.  For kdump to work properly it
is necessary that the reset_devices parameter be honored.  This
attribute enables kexec-tools to warn the user if they attempt to
designate a non-resettable controller as the dump device.

Signed-off-by: Stephen M. Cameron <scameron@beardog.cce.hp.com>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>

diff --git a/Documentation/ABI/testing/sysfs-bus-pci-devices-cciss b/Documentation/ABI/testing/sysfs-bus-pci-devices-cciss
index 4f29e5f..f5bb0a3 100644 (file)
--- a/Documentation/ABI/testing/sysfs-bus-pci-devices-cciss
+++ b/Documentation/ABI/testing/sysfs-bus-pci-devices-cciss
@@ -59,3 +59,15 @@ Kernel Version: 2.6.31
 Contact:       iss_storagedev@hp.com
 Description:   Displays the usage count (number of opens) of logical drive Y
                of controller X.
+
+Where:         /sys/bus/pci/devices/<dev>/ccissX/resettable
+Date:          February 2011
+Kernel Version:        2.6.38
+Contact:       iss_storagedev@hp.com
+Description:   Value of 1 indicates the controller can honor the reset_devices
+               kernel parameter.  Value of 0 indicates reset_devices cannot be
+               honored.  This is to allow, for example, kexec tools to be able
+               to warn the user if they designate an unresettable device as
+               a dump device, as kdump requires resetting the device in order
+               to work reliably.
+

diff --git a/drivers/block/cciss.c b/drivers/block/cciss.c
index 35658f4..eeed7ae 100644 (file)
--- a/drivers/block/cciss.c
+++ b/drivers/block/cciss.c
@@ -556,6 +556,44 @@ static void __devinit cciss_procinit(ctlr_info_t *h)
 #define to_hba(n) container_of(n, struct ctlr_info, dev)
 #define to_drv(n) container_of(n, drive_info_struct, dev)
 
+/* List of controllers which cannot be reset on kexec with reset_devices */
+static u32 unresettable_controller[] = {
+       0x324a103C, /* Smart Array P712m */
+       0x324b103C, /* SmartArray P711m */
+       0x3223103C, /* Smart Array P800 */
+       0x3234103C, /* Smart Array P400 */
+       0x3235103C, /* Smart Array P400i */
+       0x3211103C, /* Smart Array E200i */
+       0x3212103C, /* Smart Array E200 */
+       0x3213103C, /* Smart Array E200i */
+       0x3214103C, /* Smart Array E200i */
+       0x3215103C, /* Smart Array E200i */
+       0x3237103C, /* Smart Array E500 */
+       0x323D103C, /* Smart Array P700m */
+       0x409C0E11, /* Smart Array 6400 */
+       0x409D0E11, /* Smart Array 6400 EM */
+};
+
+static int ctlr_is_resettable(struct ctlr_info *h)
+{
+       int i;
+
+       for (i = 0; i < ARRAY_SIZE(unresettable_controller); i++)
+               if (unresettable_controller[i] == h->board_id)
+                       return 0;
+       return 1;
+}
+
+static ssize_t host_show_resettable(struct device *dev,
+                                   struct device_attribute *attr,
+                                   char *buf)
+{
+       struct ctlr_info *h = to_hba(dev);
+
+       return snprintf(buf, 20, "%d\n", ctlr_is_resettable(h));
+}
+static DEVICE_ATTR(resettable, S_IRUGO, host_show_resettable, NULL);
+
 static ssize_t host_store_rescan(struct device *dev,
                                 struct device_attribute *attr,
                                 const char *buf, size_t count)
@@ -741,6 +779,7 @@ static DEVICE_ATTR(usage_count, S_IRUGO, cciss_show_usage_count, NULL);
 
 static struct attribute *cciss_host_attrs[] = {
        &dev_attr_rescan.attr,
+       &dev_attr_resettable.attr,
        NULL
 };