Re: [PATCH 2/2] hpsa: export resettable host attribute

[Tomas Henzl <thenzl@redhat.com>]

>
> From: Stephen M. Cameron <scameron@beardog.cce.hp.com>
>
> 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>
>   
Thanks,looks good to me.
Tomas

> ---
>  Documentation/scsi/hpsa.txt |   12 ++++++++++++
>  drivers/scsi/hpsa.c         |   41 +++++++++++++++++++++++++++++++++++++++++
>  2 files changed, 53 insertions(+), 0 deletions(-)
>
> diff --git a/Documentation/scsi/hpsa.txt b/Documentation/scsi/hpsa.txt
> index dca6583..8b418b3 100644
> --- a/Documentation/scsi/hpsa.txt
> +++ b/Documentation/scsi/hpsa.txt
> @@ -39,6 +39,7 @@ HPSA specific entries in /sys
>  
>    /sys/class/scsi_host/host*/rescan
>    /sys/class/scsi_host/host*/firmware_revision
> +  /sys/class/scsi_host/host*/resettable
>  
>    the host "rescan" attribute is a write only attribute.  Writing to this
>    attribute will cause the driver to scan for new, changed, or removed devices
> @@ -55,6 +56,17 @@ HPSA specific entries in /sys
>  	root@host:/sys/class/scsi_host/host4# cat firmware_revision
>  	7.14
>  
> +  The "resettable" read-only attribute indicates whether a particular
> +  controller is able to honor the "reset_devices" kernel parameter.  If the
> +  device is resettable, this file will contain a "1", otherwise, a "0".  This
> +  parameter is used by kdump, for example, to reset the controller at driver
> +  load time to eliminate any outstanding commands on the controller and get the
> +  controller into a known state so that the kdump initiated i/o will work right
> +  and not be disrupted in any way by stale commands or other stale state
> +  remaining on the controller from the previous kernel.  This attribute enables
> +  kexec tools to warn the user if they attempt to designate a device which is
> +  unable to honor the reset_devices kernel parameter as a dump device.
> +
>    HPSA specific disk attributes:
>    ------------------------------
>  
> diff --git a/drivers/scsi/hpsa.c b/drivers/scsi/hpsa.c
> index dcabef4..415ad4f 100644
> --- a/drivers/scsi/hpsa.c
> +++ b/drivers/scsi/hpsa.c
> @@ -273,6 +273,44 @@ static ssize_t host_show_transport_mode(struct device *dev,
>  			"performant" : "simple");
>  }
>  
> +/* 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;
> +	struct Scsi_Host *shost = class_to_shost(dev);
> +
> +	h = shost_to_hba(shost);
> +	return snprintf(buf, 20, "%d\n", ctlr_is_resettable(h));
> +}
> +
>  static inline int is_logical_dev_addr_mode(unsigned char scsi3addr[])
>  {
>  	return (scsi3addr[3] & 0xC0) == 0x40;
> @@ -379,6 +417,8 @@ static DEVICE_ATTR(commands_outstanding, S_IRUGO,
>  	host_show_commands_outstanding, NULL);
>  static DEVICE_ATTR(transport_mode, S_IRUGO,
>  	host_show_transport_mode, NULL);
> +static DEVICE_ATTR(resettable, S_IRUGO,
> +	host_show_resettable, NULL);
>  
>  static struct device_attribute *hpsa_sdev_attrs[] = {
>  	&dev_attr_raid_level,
> @@ -392,6 +432,7 @@ static struct device_attribute *hpsa_shost_attrs[] = {
>  	&dev_attr_firmware_revision,
>  	&dev_attr_commands_outstanding,
>  	&dev_attr_transport_mode,
> +	&dev_attr_resettable,
>  	NULL,
>  };
>  
>
> --
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