linux/drivers/scsi/isci/sata.c
Dan Williams 209fae14fa isci: atomic device lookup and reference counting
We have unsafe references to remote devices that are notified to
disappear at lldd_dev_gone.  In order to clean this up we need a single
canonical source for device lookups and stable references once a lookup
succeeds.  Towards that end guarantee that domain_device.lldd_dev is
NULL as soon as we start the process of stopping a device.  Any code
path that wants to safely lookup a remote device must do so through
task->dev->lldd_dev (isci_lookup_device()).

For in-flight references outside of scic_lock we need reference counting
to ensure that the device is not recycled before we are done with it.
Simplify device back references to just scic_sds_request.target_device
which is now the only permissible internal reference that is maintained
relative to the reference count.

There were two occasions where we wanted new i/o's to be treated as
SAS_TASK_UNDELIVERED but where the domain_dev->lldd_dev link is still
intact.  Introduce a 'gone' flag to prevent i/o while waiting for libsas
to take action on the port down event.

One 'core' leftover is that we currently call
scic_remote_device_destruct() from isci_remote_device_deconstruct()
which is called when the 'core' says the device is stopped.  It would be
more natural for the final put to trigger
isci_remote_device_deconstruct() but this implementation is deferred as
it requires other changes.

Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2011-07-03 04:04:51 -07:00

234 lines
7.3 KiB
C

/*
* This file is provided under a dual BSD/GPLv2 license. When using or
* redistributing this file, you may do so under either license.
*
* GPL LICENSE SUMMARY
*
* Copyright(c) 2008 - 2011 Intel Corporation. All rights reserved.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of version 2 of the GNU General Public License as
* published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
* The full GNU General Public License is included in this distribution
* in the file called LICENSE.GPL.
*
* BSD LICENSE
*
* Copyright(c) 2008 - 2011 Intel Corporation. All rights reserved.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
* * Neither the name of Intel Corporation nor the names of its
* contributors may be used to endorse or promote products derived
* from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include <scsi/sas.h>
#include "isci.h"
#include "remote_device.h"
#include "task.h"
#include "request.h"
#include "sata.h"
/**
* isci_sata_task_to_fis_copy() - This function gets the host_to_dev_fis from
* the core and copies the fis from the task into it.
* @task: This parameter is a pointer to the task struct from libsas.
*
* pointer to the host_to_dev_fis from the core request object.
*/
struct host_to_dev_fis *isci_sata_task_to_fis_copy(struct sas_task *task)
{
struct isci_request *ireq = task->lldd_task;
struct host_to_dev_fis *fis = &ireq->sci.stp.cmd;
memcpy(fis, &task->ata_task.fis, sizeof(struct host_to_dev_fis));
if (!task->ata_task.device_control_reg_update)
fis->flags |= 0x80;
fis->flags &= 0xF0;
return fis;
}
/**
* isci_sata_is_task_ncq() - This function determines if the given stp task is
* a ncq request.
* @task: This parameter is a pointer to the task struct from libsas.
*
* true if the task is ncq
*/
bool isci_sata_is_task_ncq(struct sas_task *task)
{
struct ata_queued_cmd *qc = task->uldd_task;
bool ret = (qc &&
(qc->tf.command == ATA_CMD_FPDMA_WRITE ||
qc->tf.command == ATA_CMD_FPDMA_READ));
return ret;
}
/**
* isci_sata_set_ncq_tag() - This function sets the ncq tag field in the
* host_to_dev_fis equal to the tag in the queue command in the task.
* @task: This parameter is a pointer to the task struct from libsas.
* @register_fis: This parameter is a pointer to the host_to_dev_fis from the
* core request object.
*
*/
void isci_sata_set_ncq_tag(
struct host_to_dev_fis *register_fis,
struct sas_task *task)
{
struct ata_queued_cmd *qc = task->uldd_task;
struct isci_request *request = task->lldd_task;
register_fis->sector_count = qc->tag << 3;
scic_stp_io_request_set_ncq_tag(&request->sci, qc->tag);
}
/**
* isci_request_process_stp_response() - This function sets the status and
* response, in the task struct, from the request object for the upper layer
* driver.
* @sas_task: This parameter is the task struct from the upper layer driver.
* @response_buffer: This parameter points to the response of the completed
* request.
*
* none.
*/
void isci_request_process_stp_response(struct sas_task *task,
void *response_buffer)
{
struct dev_to_host_fis *d2h_reg_fis = response_buffer;
struct task_status_struct *ts = &task->task_status;
struct ata_task_resp *resp = (void *)&ts->buf[0];
resp->frame_len = le16_to_cpu(*(__le16 *)(response_buffer + 6));
memcpy(&resp->ending_fis[0], response_buffer + 16, 24);
ts->buf_valid_size = sizeof(*resp);
/**
* If the device fault bit is set in the status register, then
* set the sense data and return.
*/
if (d2h_reg_fis->status & ATA_DF)
ts->stat = SAS_PROTO_RESPONSE;
else
ts->stat = SAM_STAT_GOOD;
ts->resp = SAS_TASK_COMPLETE;
}
enum sci_status isci_sata_management_task_request_build(struct isci_request *ireq)
{
struct scic_sds_request *sci_req = &ireq->sci;
struct isci_tmf *isci_tmf;
enum sci_status status;
if (tmf_task != ireq->ttype)
return SCI_FAILURE;
isci_tmf = isci_request_access_tmf(ireq);
switch (isci_tmf->tmf_code) {
case isci_tmf_sata_srst_high:
case isci_tmf_sata_srst_low: {
struct host_to_dev_fis *fis = &sci_req->stp.cmd;
memset(fis, 0, sizeof(*fis));
fis->fis_type = 0x27;
fis->flags &= ~0x80;
fis->flags &= 0xF0;
if (isci_tmf->tmf_code == isci_tmf_sata_srst_high)
fis->control |= ATA_SRST;
else
fis->control &= ~ATA_SRST;
break;
}
/* other management commnd go here... */
default:
return SCI_FAILURE;
}
/* core builds the protocol specific request
* based on the h2d fis.
*/
status = scic_task_request_construct_sata(&ireq->sci);
return status;
}
/**
* isci_task_send_lu_reset_sata() - This function is called by of the SAS
* Domain Template functions. This is one of the Task Management functoins
* called by libsas, to reset the given SAS lun. Note the assumption that
* while this call is executing, no I/O will be sent by the host to the
* device.
* @lun: This parameter specifies the lun to be reset.
*
* status, zero indicates success.
*/
int isci_task_send_lu_reset_sata(
struct isci_host *isci_host,
struct isci_remote_device *isci_device,
u8 *lun)
{
struct isci_tmf tmf;
int ret = TMF_RESP_FUNC_FAILED;
/* Send the soft reset to the target */
#define ISCI_SRST_TIMEOUT_MS 25000 /* 25 second timeout. */
isci_task_build_tmf(&tmf, isci_tmf_sata_srst_high, NULL, NULL);
ret = isci_task_execute_tmf(isci_host, isci_device, &tmf,
ISCI_SRST_TIMEOUT_MS);
if (ret != TMF_RESP_FUNC_COMPLETE) {
dev_warn(&isci_host->pdev->dev,
"%s: Assert SRST failed (%p) = %x",
__func__,
isci_device,
ret);
/* Return the failure so that the LUN reset is escalated
* to a target reset.
*/
}
return ret;
}