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Commit da0697bd authored by Scott Teel's avatar Scott Teel Committed by James Bottomley
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[SCSI] hpsa: allow user to disable accelerated i/o path 



Allow SSD Smart Path for a controller to be disabled by
the user, regardless of settings in controller firmware
or array configuration.

To disable:     echo 0 > /sys/class/scsi_host/host<id>/acciopath_status
To re-enable:   echo 1 > /sys/class/scsi_host/host<id>/acciopath_status
To check state: cat /sys/class/scsi_host/host<id>/acciopath_status

Signed-off-by: default avatarScott Teel <scott.teel@hp.com>
Signed-off-by: default avatarStephen M. Cameron <scameron@beardog.cce.hp.com>
Signed-off-by: default avatarJames Bottomley <JBottomley@Parallels.com>
parent 6b80b18f

Documentation/ABI/testing/sysfs-class-scsi_host

+16 −0
Original line number Diff line number Diff line
@@ -11,3 +11,19 @@ Description: 
		guaranteed.  The 'isci_id' attribute unambiguously identifies

		the controller index: '0' for the first controller,

		'1' for the second.



What:		/sys/class/scsi_host/hostX/acciopath_status

Date:		November 2013

Contact:	Stephen M. Cameron <scameron@beardog.cce.hp.com>

Description:	This file contains the current status of the "SSD Smart Path"

		feature of HP Smart Array RAID controllers using the hpsa

		driver.  SSD Smart Path, when enabled permits the driver to

		send i/o requests directly to physical devices that are part

		of a logical drive, bypassing the controllers firmware RAID

		stack for a performance advantage when possible.  A value of

		'1' indicates the feature is enabled, and the controller may

		use the direct i/o path to physical devices.  A value of zero

		means the feature is disabled and the controller may not use

		the direct i/o path to physical devices.  This setting is

		controller wide, affecting all configured logical drives on the

		controller.  This file is readable and writable.

drivers/scsi/hpsa.c

+44 −1
Original line number Diff line number Diff line
@@ -287,6 +287,30 @@ static int check_for_busy(struct ctlr_info *h, struct CommandList *c) 
	return 1;

}



static ssize_t host_store_hp_ssd_smart_path_status(struct device *dev,

					 struct device_attribute *attr,

					 const char *buf, size_t count)

{

	int status, len;

	struct ctlr_info *h;

	struct Scsi_Host *shost = class_to_shost(dev);

	char tmpbuf[10];



	if (!capable(CAP_SYS_ADMIN) || !capable(CAP_SYS_RAWIO))

		return -EACCES;

	len = count > sizeof(tmpbuf) - 1 ? sizeof(tmpbuf) - 1 : count;

	strncpy(tmpbuf, buf, len);

	tmpbuf[len] = '\0';

	if (sscanf(tmpbuf, "%d", &status) != 1)

		return -EINVAL;

	h = shost_to_hba(shost);

	h->acciopath_status = !!status;

	dev_warn(&h->pdev->dev,

		"hpsa: HP SSD Smart Path %s via sysfs update.\n",

		h->acciopath_status ? "enabled" : "disabled");

	return count;

}



static ssize_t host_store_rescan(struct device *dev,

				 struct device_attribute *attr,

				 const char *buf, size_t count)
@@ -334,6 +358,17 @@ static ssize_t host_show_transport_mode(struct device *dev, 
			"performant" : "simple");

}



static ssize_t host_show_hp_ssd_smart_path_status(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, 30, "HP SSD Smart Path %s\n",

		(h->acciopath_status == 1) ?  "enabled" : "disabled");

}



/* List of controllers which cannot be hard reset on kexec with reset_devices */

static u32 unresettable_controller[] = {

	0x324a103C, /* Smart Array P712m */
@@ -546,6 +581,9 @@ static DEVICE_ATTR(unique_id, S_IRUGO, unique_id_show, NULL); 
static DEVICE_ATTR(rescan, S_IWUSR, NULL, host_store_rescan);

static DEVICE_ATTR(hp_ssd_smart_path_enabled, S_IRUGO,

			host_show_hp_ssd_smart_path_enabled, NULL);

static DEVICE_ATTR(hp_ssd_smart_path_status, S_IWUSR|S_IRUGO|S_IROTH,

		host_show_hp_ssd_smart_path_status,

		host_store_hp_ssd_smart_path_status);

static DEVICE_ATTR(firmware_revision, S_IRUGO,

	host_show_firmware_revision, NULL);

static DEVICE_ATTR(commands_outstanding, S_IRUGO,
@@ -569,6 +607,7 @@ static struct device_attribute *hpsa_shost_attrs[] = { 
	&dev_attr_commands_outstanding,

	&dev_attr_transport_mode,

	&dev_attr_resettable,

	&dev_attr_hp_ssd_smart_path_status,

	NULL,

};
@@ -3341,7 +3380,8 @@ static int hpsa_scsi_queue_command_lck(struct scsi_cmnd *cmd, 
	 * Retries always go down the normal I/O path.

	 */

	if (likely(cmd->retries == 0 &&

		cmd->request->cmd_type == REQ_TYPE_FS)) {

		cmd->request->cmd_type == REQ_TYPE_FS &&

		h->acciopath_status)) {

		if (dev->offload_enabled) {

			rc = hpsa_scsi_ioaccel_raid_map(h, c);

			if (rc == 0)
@@ -6326,6 +6366,9 @@ static int hpsa_init_one(struct pci_dev *pdev, const struct pci_device_id *ent) 
		goto reinit_after_soft_reset;

	}



	/* Enable Accelerated IO path at driver layer */

	h->acciopath_status = 1;



	/* Turn the interrupts on so we can service requests */

	h->access.set_intr_mask(h, HPSA_INTR_ON);

drivers/scsi/hpsa.h

+1 −0
Original line number Diff line number Diff line
@@ -181,6 +181,7 @@ struct ctlr_info { 
#define HPSATMF_LOG_QRY_TSET    (1 << 24)

#define HPSATMF_LOG_QRY_ASYNC   (1 << 25)

	u32 events;

	int	acciopath_status;

};

#define HPSA_ABORT_MSG 0

#define HPSA_DEVICE_RESET_MSG 1