/*
* scsi_error.c Copyright (C) 1997 Eric Youngdale
*
* SCSI error/timeout handling
* Initial versions: Eric Youngdale. Based upon conversations with
* Leonard Zubkoff and David Miller at Linux Expo,
* ideas originating from all over the place.
*
* Restructured scsi_unjam_host and associated functions.
* September 04, 2002 Mike Anderson (andmike@us.ibm.com)
*
* Forward port of Russell King's (rmk@arm.linux.org.uk) changes and
* minor cleanups.
* September 30, 2002 Mike Anderson (andmike@us.ibm.com)
*/
#include <linux/module.h>
#include <linux/sched.h>
#include <linux/timer.h>
#include <linux/string.h>
#include <linux/slab.h>
#include <linux/kernel.h>
#include <linux/interrupt.h>
#include <linux/blkdev.h>
#include <linux/delay.h>
#include <scsi/scsi.h>
#include <scsi/scsi_dbg.h>
#include <scsi/scsi_device.h>
#include <scsi/scsi_eh.h>
#include <scsi/scsi_host.h>
#include <scsi/scsi_ioctl.h>
#include <scsi/scsi_request.h>
#include "scsi_priv.h"
#include "scsi_logging.h"
#define SENSE_TIMEOUT (10*HZ)
#define START_UNIT_TIMEOUT (30*HZ)
/*
* These should *probably* be handled by the host itself.
* Since it is allowed to sleep, it probably should.
*/
#define BUS_RESET_SETTLE_TIME (10)
#define HOST_RESET_SETTLE_TIME (10)
/* called with shost->host_lock held */
void scsi_eh_wakeup(struct Scsi_Host *shost)
{
if (shost->host_busy == shost->host_failed) {
up(shost->eh_wait);
SCSI_LOG_ERROR_RECOVERY(5,
printk("Waking error handler thread\n"));
}
}
/**
* scsi_eh_scmd_add - add scsi cmd to error handling.
* @scmd: scmd to run eh on.
* @eh_flag: optional SCSI_EH flag.
*
* Return value:
* 0 on failure.
**/
int scsi_eh_scmd_add(struct scsi_cmnd *scmd, int eh_flag)
{
struct Scsi_Host *shost = scmd->device->host;
unsigned long flags;
if (shost->eh_wait == NULL)
return 0;
spin_lock_irqsave(shost->host_lock, flags);
scsi_eh_eflags_set(scmd, eh_flag);
list_add_tail(&scmd->eh_entry, &shost->eh_cmd_q);
set_bit(SHOST_RECOVERY, &shost->shost_state);
shost->host_failed++;
scsi_eh_wakeup(shost);
spin_unlock_irqrestore(shost->host_lock, flags);
return 1;
}
/**
* scsi_add_timer - Start timeout timer for a single scsi command.
* @scmd: scsi command that is about to start running.
* @timeout: amount of time to allow this command to run.
* @complete: timeout function to call if timer isn't canceled.
*
* Notes:
* This should be turned into an inline function. Each scsi command
* has its own timer, and as it is added to the queue, we set up the
* timer. When the command completes, we cancel the timer.
**/
void scsi_add_timer(struct scsi_cmnd *scmd, int timeout,
void (*complete)(struct scsi_cmnd *))
{
/*
* If the clock was already running for this command, then
* first delete the timer. The timer handling code gets rather
* confused if we don't do this.
*/
if (scmd->eh_timeout.function)
del_timer(&scmd->eh_timeout);
scmd->eh_timeout.data = (unsigned long)scmd;
scmd->eh_timeout.expires = jiffies + timeout;
scmd->eh_timeout.function = (void (*)(unsigned long)) complete;
SCSI_LOG_ERROR_RECOVERY(5, printk("%s: scmd: %p, time:"
" %d, (%p)\n", __FUNCTION__,
scmd, timeout, complete));
add_timer(&scmd->eh_timeout);
}
EXPORT_SYMBOL(scsi_add_timer);
/**
* scsi_delete_timer - Delete/cancel timer for a given function.
* @scmd: Cmd that we are canceling timer for
*
* Notes:
* This should be turned into an inline function.
*
* Return value:
* 1 if we were able to detach the timer. 0 if we blew it, and the
* timer function has already started to run.
**/
int scsi_delete_timer(struct scsi_cmnd *scmd)
{
int rtn;
rtn = del_timer(&scmd->eh_timeout);
SCSI_LOG_ERROR_RECOVERY(5, printk("%s: scmd: %p,"
" rtn: %d\n", __FUNCTION__,
scmd, rtn));
scmd->eh_timeout.data = (unsigned long)NULL;
scmd->eh_timeout.function = NULL;
return rtn;
}
EXPORT_SYMBOL(scsi_delete_timer);
/**
* scsi_times_out - Timeout function for normal scsi commands.
* @scmd: Cmd that is timing out.
*
* Notes:
* We do not need to lock this. There is the potential for a race
* only in that the normal completion handling might run, but if the
* normal completion function determines that the timer has already
* fired, then it mustn't do anything.
**/
void scsi_times_out(struct scsi_cmnd *scmd)
{
scsi_log_completion(scmd, TIMEOUT_ERROR);
if (scmd->device->host->hostt->eh_timed_out)
switch (scmd->device->host->hostt->eh_timed_out(scmd)) {
case EH_HANDLED:
__scsi_done(scmd);
return;
case EH_RESET_TIMER:
/* This allows a single retry even of a command
* with allowed == 0 */
if (scmd->retries++ > scmd->allowed)
break;
scsi_add_timer(scmd, scmd->timeout_per_command,
scsi_times_out);
return;
case EH_NOT_HANDLED:
break;
}
if (unlikely(!scsi_eh_scmd_add(scmd, SCSI_EH_CANCEL_CMD))) {
panic("Error handler thread not present at %p %p %s %d",
scmd, scmd->device->host, __FILE__, __LINE__);
}
}
/**
* scsi_block_when_processing_errors - Prevent cmds from being queued.
* @sdev: Device on which we are performing recovery.
*
* Description:
* We block until the host is out of error recovery, and then check to
* see whether the host or the device is offline.
*
* Return value:
* 0 when dev was taken offline by error recovery. 1 OK to proceed.
**/
int scsi_block_when_processing_errors(struct scsi_device *sdev)
{
int online;
wait_event(sdev->host->host_wait, (!test_bit(SHOST_RECOVERY, &sdev->host->shost_state)));
online = scsi_device_online(sdev);
SCSI_LOG_ERROR_RECOVERY(5, printk("%s: rtn: %d\n", __FUNCTION__,
online));
return online;
}
EXPORT_SYMBOL(scsi_block_when_processing_errors);
#ifdef CONFIG_SCSI_LOGGING
/**
* scsi_eh_prt_fail_stats - Log info on failures.
* @shost: scsi host being recovered.
* @work_q: Queue of scsi cmds to process.
**/
static inline void scsi_eh_prt_fail_stats(struct Scsi_Host *shost,
struct list_head *work_q)
{
struct scsi_cmnd *scmd;
struct scsi_device *sdev;
int total_failures = 0;
int cmd_failed = 0;
int cmd_cancel = 0;
int devices_failed = 0;
shost_for_each_device(sdev, shost) {
list_for_each_entry(scmd, work_q, eh_entry) {
if (scmd->device == sdev) {
++total_failures;
if (scsi_eh_eflags_chk(scmd,
SCSI_EH_CANCEL_CMD))
++cmd_cancel;
else
++cmd_failed;
}
}
if (cmd_cancel || cmd_failed) {
SCSI_LOG_ERROR_RECOVERY(3,
printk("%s: %d:%d:%d:%d cmds failed: %d,"
" cancel: %d\n",
__FUNCTION__, shost->host_no,
sdev->channel, sdev->id, sdev->lun,
cmd_failed, cmd_cancel));
cmd_cancel = 0;
cmd_failed = 0;
++devices_failed;
}
}
SCSI_LOG_ERROR_RECOVERY(2, printk("Total of %d commands on %d"
" devices require eh work\n",
total_failures, devices_failed));
}
#endif
/**
* scsi_check_sense - Examine scsi cmd sense
* @scmd: Cmd to have sense checked.
*
* Return value:
* SUCCESS or FAILED or NEEDS_RETRY
*
* Notes:
* When a deferred error is detected the current command has
* not been executed and needs retrying.
**/
static int scsi_check_sense(struct scsi_cmnd *scmd)
{
struct scsi_sense_hdr sshdr;
if (! scsi_command_normalize_sense(scmd, &sshdr))
return FAILED; /* no valid sense data */
if (scsi_sense_is_deferred(&sshdr))
return NEEDS_RETRY;
/*
* Previous logic looked for FILEMARK, EOM or ILI which are
* mainly associated with tapes and returned SUCCESS.
*/
if (sshdr.response_code == 0x70) {
/* fixed format */
if (scmd->sense_buffer[2] & 0xe0)
return SUCCESS;
} else {
/*
* descriptor format: look for "stream commands sense data
* descriptor" (see SSC-3). Assume single sense data
* descriptor. Ignore ILI from SBC-2 READ LONG and WRITE LONG.
*/
if ((sshdr.additional_length > 3) &&
(scmd->sense_buffer[8] == 0x4) &&
(scmd->sense_buffer[11] & 0xe0))
return SUCCESS;
}
switch (sshdr.sense_key) {
case NO_SENSE:
return SUCCESS;
case RECOVERED_ERROR:
return /* soft_error */ SUCCESS;
case ABORTED_COMMAND:
return NEEDS_RETRY;
case NOT_READY:
case UNIT_ATTENTION:
/*
* if we are expecting a cc/ua because of a bus reset that we
* performed, treat this just as a retry. otherwise this is
* information that we should pass up to the upper-level driver
* so that we can deal with it there.
*/
if (scmd->device->expecting_cc_ua) {
scmd->device->expecting_cc_ua = 0;
return NEEDS_RETRY;
}
/*
* if the device is in the process of becoming ready, we
* should retry.
*/
if ((sshdr.asc == 0x04) && (sshdr.ascq == 0x01))
return NEEDS_RETRY;
/*
* if the device is not started, we need to wake
* the error handler to start the motor
*/
if (scmd->device->allow_restart &&
(sshdr.asc == 0x04) && (sshdr.ascq == 0x02))
return FAILED;
return SUCCESS;
/* these three are not supported */
case COPY_ABORTED:
case VOLUME_OVERFLOW:
case MISCOMPARE:
return SUCCESS;
case MEDIUM_ERROR:
return NEEDS_RETRY;
case HARDWARE_ERROR:
if (scmd->device->retry_hwerror)
return NEEDS_RETRY;
else
return SUCCESS;
case ILLEGAL_REQUEST:
case BLANK_CHECK:
case DATA_PROTECT:
default:
return SUCCESS;
}
}
/**
* scsi_eh_completed_normally - Disposition a eh cmd on return from LLD.
* @scmd: SCSI cmd to examine.
*
* Notes:
* This is *only* called when we are examining the status of commands
* queued during error recovery. the main difference here is that we
* don't allow for the possibility of retries here, and we are a lot
* more restrictive about what we consider acceptable.
**/
static int scsi_eh_completed_normally(struct scsi_cmnd *scmd)
{
/*
* first check the host byte, to see if there is anything in there
* that would indicate what we need to do.
*/
if (host_byte(scmd->result) == DID_RESET) {
/*
* rats. we are already in the error handler, so we now
* get to try and figure out what to do next. if the sense
* is valid, we have a pretty good idea of what to do.
* if not, we mark it as FAILED.
*/
return scsi_check_sense(scmd);
}
if (host_byte(scmd->result) != DID_OK)
return FAILED;
/*
* next, check the message byte.
*/
if (msg_byte(scmd->result) != COMMAND_COMPLETE)
return FAILED;
/*
* now, check the status byte to see if this indicates
* anything special.
*/
switch (status_byte(scmd->result)) {
case GOOD:
case COMMAND_TERMINATED:
return SUCCESS;
case CHECK_CONDITION:
return scsi_check_sense(scmd);
case CONDITION_GOOD:
case INTERMEDIATE_GOOD:
case INTERMEDIATE_C_GOOD:
/*
* who knows? FIXME(eric)
*/
return SUCCESS;
case BUSY:
case QUEUE_FULL:
case RESERVATION_CONFLICT:
default:
return FAILED;
}
return FAILED;
}
/**
* scsi_eh_times_out - timeout function for error handling.
* @scmd: Cmd that is timing out.
*
* Notes:
* During error handling, the kernel thread will be sleeping waiting
* for some action to complete on the device. our only job is to
* record that it timed out, and to wake up the thread.
**/
static void scsi_eh_times_out(struct scsi_cmnd *scmd)
{
scsi_eh_eflags_set(scmd, SCSI_EH_REC_TIMEOUT);
SCSI_LOG_ERROR_RECOVERY(3, printk("%s: scmd:%p\n", __FUNCTION__,
scmd));
up(scmd->device->host->eh_action);
}
/**
* scsi_eh_done - Completion function for error handling.
* @scmd: Cmd that is done.
**/
static void scsi_eh_done(struct scsi_cmnd *scmd)
{
/*
* if the timeout handler is already running, then just set the
* flag which says we finished late, and return. we have no
* way of stopping the timeout handler from running, so we must
* always defer to it.
*/
if (del_timer(&scmd->eh_timeout)) {
scmd->request->rq_status = RQ_SCSI_DONE;
SCSI_LOG_ERROR_RECOVERY(3, printk("%s scmd: %p result: %x\n",
__FUNCTION__, scmd, scmd->result));
up(scmd->device->host->eh_action);
}
}
/**
* scsi_send_eh_cmnd - send a cmd to a device as part of error recovery.
* @scmd: SCSI Cmd to send.
* @timeout: Timeout for cmd.
*
* Notes:
* The initialization of the structures is quite a bit different in
* this case, and furthermore, there is a different completion handler
* vs scsi_dispatch_cmd.
* Return value:
* SUCCESS or FAILED or NEEDS_RETRY
**/
static int scsi_send_eh_cmnd(struct scsi_cmnd *scmd, int timeout)
{
struct scsi_device *sdev = scmd->device;
struct Scsi_Host *shost = sdev->host;
DECLARE_MUTEX_LOCKED(sem);
unsigned long flags;
int rtn = SUCCESS;
/*
* we will use a queued command if possible, otherwise we will
* emulate the queuing and calling of completion function ourselves.
*/
if (sdev->scsi_level <= SCSI_2)
scmd->cmnd[1] = (scmd->cmnd[1] & 0x1f) |
(sdev->lun << 5 & 0xe0);
scsi_add_timer(scmd, timeout, scsi_eh_times_out);
/*
* set up the semaphore so we wait for the command to complete.
*/
shost->eh_action = &sem;
scmd->request->rq_status = RQ_SCSI_BUSY;
spin_lock_irqsave(shost->host_lock, flags);
scsi_log_send(scmd);
shost->hostt->queuecommand(scmd, scsi_eh_done);
spin_unlock_irqrestore(shost->host_lock, flags);
down(&sem);
scsi_log_completion(scmd, SUCCESS);
shost->eh_action = NULL;
/*
* see if timeout. if so, tell the host to forget about it.
* in other words, we don't want a callback any more.
*/
if (scsi_eh_eflags_chk(scmd, SCSI_EH_REC_TIMEOUT)) {
scsi_eh_eflags_clr(scmd, SCSI_EH_REC_TIMEOUT);
/*
* as far as the low level driver is
* concerned, this command is still active, so
* we must give the low level driver a chance
* to abort it. (db)
*
* FIXME(eric) - we are not tracking whether we could
* abort a timed out command or not. not sure how
* we should treat them differently anyways.
*/
if (shost->hostt->eh_abort_handler)
shost->hostt->eh_abort_handler(scmd);
scmd->request->rq_status = RQ_SCSI_DONE;
rtn = FAILED;
}
SCSI_LOG_ERROR_RECOVERY(3, printk("%s: scmd: %p, rtn:%x\n",
__FUNCTION__, scmd, rtn));
/*
* now examine the actual status codes to see whether the command
* actually did complete normally.
*/
if (rtn == SUCCESS) {
rtn = scsi_eh_completed_normally(scmd);
SCSI_LOG_ERROR_RECOVERY(3,
printk("%s: scsi_eh_completed_normally %x\n",
__FUNCTION__, rtn));
switch (rtn) {
case SUCCESS:
case NEEDS_RETRY:
case FAILED:
break;
default:
rtn = FAILED;
break;
}
}
return rtn;
}
/**
* scsi_request_sense - Request sense data from a particular target.
* @scmd: SCSI cmd for request sense.
*
* Notes:
* Some hosts automatically obtain this information, others require
* that we obtain it on our own. This function will *not* return until
* the command either times out, or it completes.
**/
static int scsi_request_sense(struct scsi_cmnd *scmd)
{
static unsigned char generic_sense[6] =
{REQUEST_SENSE, 0, 0, 0, 252, 0};
unsigned char *scsi_result;
int saved_result;
int rtn;
memcpy(scmd->cmnd, generic_sense, sizeof(generic_sense));
scsi_result = kmalloc(252, GFP_ATOMIC | ((scmd->device->host->hostt->unchecked_isa_dma) ? __GFP_DMA : 0));
if (unlikely(!scsi_result)) {
printk(KERN_ERR "%s: cannot allocate scsi_result.\n",
__FUNCTION__);
return FAILED;
}
/*
* zero the sense buffer. some host adapters automatically always
* request sense, so it is not a good idea that
* scmd->request_buffer and scmd->sense_buffer point to the same
* address (db). 0 is not a valid sense code.
*/
memset(scmd->sense_buffer, 0, sizeof(scmd->sense_buffer));
memset(scsi_result, 0, 252);
saved_result = scmd->result;
scmd->request_buffer = scsi_result;
scmd->request_bufflen = 252;
scmd->use_sg = 0;
scmd->cmd_len = COMMAND_SIZE(scmd->cmnd[0]);
scmd->sc_data_direction = DMA_FROM_DEVICE;
scmd->underflow = 0;
rtn = scsi_send_eh_cmnd(scmd, SENSE_TIMEOUT);
/* last chance to have valid sense data */
if(!SCSI_SENSE_VALID(scmd)) {
memcpy(scmd->sense_buffer, scmd->request_buffer,
sizeof(scmd->sense_buffer));
}
kfree(scsi_result);
/*
* when we eventually call scsi_finish, we really wish to complete
* the original request, so let's restore the original data. (db)
*/
scsi_setup_cmd_retry(scmd);
scmd->result = saved_result;
return rtn;
}
/**
* scsi_eh_finish_cmd - Handle a cmd that eh is finished with.
* @scmd: Original SCSI cmd that eh has finished.
* @done_q: Queue for processed commands.
*
* Notes:
* We don't want to use the normal command completion while we are are
* still handling errors - it may cause other commands to be queued,
* and that would disturb what we are doing. thus we really want to
* keep a list of pending commands for final completion, and once we
* are ready to leave error handling we handle completion for real.
**/
static void scsi_eh_finish_cmd(struct scsi_cmnd *scmd,
struct list_head *done_q)
{
scmd->device->host->host_failed--;
scsi_eh_eflags_clr_all(scmd);
/*
* set this back so that the upper level can correctly free up
* things.
*/
scsi_setup_cmd_retry(scmd);
list_move_tail(&scmd->eh_entry, done_q);
}
/**
* scsi_eh_get_sense - Get device sense data.
* @work_q: Queue of commands to process.
* @done_q: Queue of proccessed commands..
*
* Description:
* See if we need to request sense information. if so, then get it
* now, so we have a better idea of what to do.
*
* Notes:
* This has the unfortunate side effect that if a shost adapter does
* not automatically request sense information, that we end up shutting
* it down before we request it.
*
* All drivers should request sense information internally these days,
* so for now all I have to say is tough noogies if you end up in here.
*
* XXX: Long term this code should go away, but that needs an audit of
* all LLDDs first.
**/
static int scsi_eh_get_sense(struct list_head *work_q,
struct list_head *done_q)
{
struct list_head *lh, *lh_sf;
struct scsi_cmnd *scmd;
int rtn;
list_for_each_safe(lh, lh_sf, work_q) {
scmd = list_entry(lh, struct scsi_cmnd, eh_entry);
if (scsi_eh_eflags_chk(scmd, SCSI_EH_CANCEL_CMD) ||
SCSI_SENSE_VALID(scmd))
continue;
SCSI_LOG_ERROR_RECOVERY(2, printk("%s: requesting sense"
" for id: %d\n",
current->comm,
scmd->device->id));
rtn = scsi_request_sense(scmd);
if (rtn != SUCCESS)
continue;
SCSI_LOG_ERROR_RECOVERY(3, printk("sense requested for %p"
" result %x\n", scmd,
scmd->result));
SCSI_LOG_ERROR_RECOVERY(3, scsi_print_sense("bh", scmd));
rtn = scsi_decide_disposition(scmd);
/*
* if the result was normal, then just pass it along to the
* upper level.
*/
if (rtn == SUCCESS)
/* we don't want this command reissued, just
* finished with the sense data, so set
* retries to the max allowed to ensure it
* won't get reissued */
scmd->retries = scmd->allowed;
else if (rtn != NEEDS_RETRY)
continue;
scsi_eh_finish_cmd(scmd, done_q);
}
return list_empty(work_q);
}
/**
* scsi_try_to_abort_cmd - Ask host to abort a running command.
* @scmd: SCSI cmd to abort from Lower Level.
*
* Notes:
* This function will not return until the user's completion function
* has been called. there is no timeout on this operation. if the
* author of the low-level driver wishes this operation to be timed,
* they can provide this facility themselves. helper functions in
* scsi_error.c can be supplied to make this easier to do.
**/
static int scsi_try_to_abort_cmd(struct scsi_cmnd *scmd)
{
if (!scmd->device->host->hostt->eh_abort_handler)
return FAILED;
/*
* scsi_done was called just after the command timed out and before
* we had a chance to process it. (db)
*/
if (scmd->serial_number == 0)
return SUCCESS;
return scmd->device->host->hostt->eh_abort_handler(scmd);
}
/**
* scsi_eh_tur - Send TUR to device.
* @scmd: Scsi cmd to send TUR
*
* Return value:
* 0 - Device is ready. 1 - Device NOT ready.
**/
static int scsi_eh_tur(struct scsi_cmnd *scmd)
{
static unsigned char tur_command[6] = {TEST_UNIT_READY, 0, 0, 0, 0, 0};
int retry_cnt = 1, rtn;
int saved_result;
retry_tur:
memcpy(scmd->cmnd, tur_command, sizeof(tur_command));
/*
* zero the sense buffer. the scsi spec mandates that any
* untransferred sense data should be interpreted as being zero.
*/
memset(scmd->sense_buffer, 0, sizeof(scmd->sense_buffer));
saved_result = scmd->result;
scmd->request_buffer = NULL;
scmd->request_bufflen = 0;
scmd->use_sg = 0;
scmd->cmd_len = COMMAND_SIZE(scmd->cmnd[0]);
scmd->underflow = 0;
scmd->sc_data_direction = DMA_NONE;
rtn = scsi_send_eh_cmnd(scmd, SENSE_TIMEOUT);
/*
* when we eventually call scsi_finish, we really wish to complete
* the original request, so let's restore the original data. (db)
*/
scsi_setup_cmd_retry(scmd);
scmd->result = saved_result;
/*
* hey, we are done. let's look to see what happened.
*/
SCSI_LOG_ERROR_RECOVERY(3, printk("%s: scmd %p rtn %x\n",
__FUNCTION__, scmd, rtn));
if (rtn == SUCCESS)
return 0;
else if (rtn == NEEDS_RETRY)
if (retry_cnt--)
goto retry_tur;
return 1;
}
/**
* scsi_eh_abort_cmds - abort canceled commands.
* @shost: scsi host being recovered.
* @eh_done_q: list_head for processed commands.
*
* Decription:
* Try and see whether or not it makes sense to try and abort the
* running command. this only works out to be the case if we have one
* command that has timed out. if the command simply failed, it makes
* no sense to try and abort the command, since as far as the shost
* adapter is concerned, it isn't running.
**/
static int scsi_eh_abort_cmds(struct list_head *work_q,
struct list_head *done_q)
{
struct list_head *lh, *lh_sf;
struct scsi_cmnd *scmd;
int rtn;
list_for_each_safe(lh, lh_sf, work_q) {
scmd = list_entry(lh, struct scsi_cmnd, eh_entry);
if (!scsi_eh_eflags_chk(scmd, SCSI_EH_CANCEL_CMD))
continue;
SCSI_LOG_ERROR_RECOVERY(3, printk("%s: aborting cmd:"
"0x%p\n", current->comm,
scmd));
rtn = scsi_try_to_abort_cmd(scmd);
if (rtn == SUCCESS) {
scsi_eh_eflags_clr(scmd, SCSI_EH_CANCEL_CMD);
if (!scsi_device_online(scmd->device) ||
!scsi_eh_tur(scmd)) {
scsi_eh_finish_cmd(scmd, done_q);
}
} else
SCSI_LOG_ERROR_RECOVERY(3, printk("%s: aborting"
" cmd failed:"
"0x%p\n",
current->comm,
scmd));
}
return list_empty(work_q);
}
/**
* scsi_try_bus_device_reset - Ask host to perform a BDR on a dev
* @scmd: SCSI cmd used to send BDR
*
* Notes:
* There is no timeout for this operation. if this operation is
* unreliable for a given host, then the host itself needs to put a
* timer on it, and set the host back to a consistent state prior to
* returning.
**/
static int scsi_try_bus_device_reset(struct scsi_cmnd *scmd)
{
int rtn;
if (!scmd->device->host->hostt->eh_device_reset_handler)
return FAILED;
rtn = scmd->device->host->hostt->eh_device_reset_handler(scmd);
if (rtn == SUCCESS) {
scmd->device->was_reset = 1;
scmd->device->expecting_cc_ua = 1;
}
return rtn;
}
/**
* scsi_eh_try_stu - Send START_UNIT to device.
* @scmd: Scsi cmd to send START_UNIT
*
* Return value:
* 0 - Device is ready. 1 - Device NOT ready.
**/
static int scsi_eh_try_stu(struct scsi_cmnd *scmd)
{
static unsigned char stu_command[6] = {START_STOP, 0, 0, 0, 1, 0};
int rtn;
int saved_result;
if (!scmd->device->allow_restart)
return 1;
memcpy(scmd->cmnd, stu_command, sizeof(stu_command));
/*
* zero the sense buffer. the scsi spec mandates that any
* untransferred sense data should be interpreted as being zero.
*/
memset(scmd->sense_buffer, 0, sizeof(scmd->sense_buffer));
saved_result = scmd->result;
scmd->request_buffer = NULL;
scmd->request_bufflen = 0;
scmd->use_sg = 0;
scmd->cmd_len = COMMAND_SIZE(scmd->cmnd[0]);
scmd->underflow = 0;
scmd->sc_data_direction = DMA_NONE;
rtn = scsi_send_eh_cmnd(scmd, START_UNIT_TIMEOUT);
/*
* when we eventually call scsi_finish, we really wish to complete
* the original request, so let's restore the original data. (db)
*/
scsi_setup_cmd_retry(scmd);
scmd->result = saved_result;
/*
* hey, we are done. let's look to see what happened.
*/
SCSI_LOG_ERROR_RECOVERY(3, printk("%s: scmd %p rtn %x\n",
__FUNCTION__, scmd, rtn));
if (rtn == SUCCESS)
return 0;
return 1;
}
/**
* scsi_eh_stu - send START_UNIT if needed
* @shost: scsi host being recovered.
* @eh_done_q: list_head for processed commands.
*
* Notes:
* If commands are failing due to not ready, initializing command required,
* try revalidating the device, which will end up sending a start unit.
**/
static int scsi_eh_stu(struct Scsi_Host *shost,
struct list_head *work_q,
struct list_head *done_q)
{
struct list_head *lh, *lh_sf;
struct scsi_cmnd *scmd, *stu_scmd;
struct scsi_device *sdev;
shost_for_each_device(sdev, shost) {
stu_scmd = NULL;
list_for_each_entry(scmd, work_q, eh_entry)
if (scmd->device == sdev && SCSI_SENSE_VALID(scmd) &&
scsi_check_sense(scmd) == FAILED ) {
stu_scmd = scmd;
break;
}
if (!stu_scmd)
continue;
SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Sending START_UNIT to sdev:"
" 0x%p\n", current->comm, sdev));
if (!scsi_eh_try_stu(stu_scmd)) {
if (!scsi_device_online(sdev) ||
!scsi_eh_tur(stu_scmd)) {
list_for_each_safe(lh, lh_sf, work_q) {
scmd = list_entry(lh, struct scsi_cmnd, eh_entry);
if (scmd->device == sdev)
scsi_eh_finish_cmd(scmd, done_q);
}
}
} else {
SCSI_LOG_ERROR_RECOVERY(3,
printk("%s: START_UNIT failed to sdev:"
" 0x%p\n", current->comm, sdev));
}
}
return list_empty(work_q);
}
/**
* scsi_eh_bus_device_reset - send bdr if needed
* @shost: scsi host being recovered.
* @eh_done_q: list_head for processed commands.
*
* Notes:
* Try a bus device reset. still, look to see whether we have multiple
* devices that are jammed or not - if we have multiple devices, it
* makes no sense to try bus_device_reset - we really would need to try
* a bus_reset instead.
**/
static int scsi_eh_bus_device_reset(struct Scsi_Host *shost,
struct list_head *work_q,
struct list_head *done_q)
{
struct list_head *lh, *lh_sf;
struct scsi_cmnd *scmd, *bdr_scmd;
struct scsi_device *sdev;
int rtn;
shost_for_each_device(sdev, shost) {
bdr_scmd = NULL;
list_for_each_entry(scmd, work_q, eh_entry)
if (scmd->device == sdev) {
bdr_scmd = scmd;
break;
}
if (!bdr_scmd)
continue;
SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Sending BDR sdev:"
" 0x%p\n", current->comm,
sdev));
rtn = scsi_try_bus_device_reset(bdr_scmd);
if (rtn == SUCCESS) {
if (!scsi_device_online(sdev) ||
!scsi_eh_tur(bdr_scmd)) {
list_for_each_safe(lh, lh_sf,
work_q) {
scmd = list_entry(lh, struct
scsi_cmnd,
eh_entry);
if (scmd->device == sdev)
scsi_eh_finish_cmd(scmd,
done_q);
}
}
} else {
SCSI_LOG_ERROR_RECOVERY(3, printk("%s: BDR"
" failed sdev:"
"0x%p\n",
current->comm,
sdev));
}
}
return list_empty(work_q);
}
/**
* scsi_try_bus_reset - ask host to perform a bus reset
* @scmd: SCSI cmd to send bus reset.
**/
static int scsi_try_bus_reset(struct scsi_cmnd *scmd)
{
unsigned long flags;
int rtn;
SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Snd Bus RST\n",
__FUNCTION__));
if (!scmd->device->host->hostt->eh_bus_reset_handler)
return FAILED;
rtn = scmd->device->host->hostt->eh_bus_reset_handler(scmd);
if (rtn == SUCCESS) {
if (!scmd->device->host->hostt->skip_settle_delay)
ssleep(BUS_RESET_SETTLE_TIME);
spin_lock_irqsave(scmd->device->host->host_lock, flags);
scsi_report_bus_reset(scmd->device->host, scmd->device->channel);
spin_unlock_irqrestore(scmd->device->host->host_lock, flags);
}
return rtn;
}
/**
* scsi_try_host_reset - ask host adapter to reset itself
* @scmd: SCSI cmd to send hsot reset.
**/
static int scsi_try_host_reset(struct scsi_cmnd *scmd)
{
unsigned long flags;
int rtn;
SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Snd Host RST\n",
__FUNCTION__));
if (!scmd->device->host->hostt->eh_host_reset_handler)
return FAILED;
rtn = scmd->device->host->hostt->eh_host_reset_handler(scmd);
if (rtn == SUCCESS) {
if (!scmd->device->host->hostt->skip_settle_delay)
ssleep(HOST_RESET_SETTLE_TIME);
spin_lock_irqsave(scmd->device->host->host_lock, flags);
scsi_report_bus_reset(scmd->device->host, scmd->device->channel);
spin_unlock_irqrestore(scmd->device->host->host_lock, flags);
}
return rtn;
}
/**
* scsi_eh_bus_reset - send a bus reset
* @shost: scsi host being recovered.
* @eh_done_q: list_head for processed commands.
**/
static int scsi_eh_bus_reset(struct Scsi_Host *shost,
struct list_head *work_q,
struct list_head *done_q)
{
struct list_head *lh, *lh_sf;
struct scsi_cmnd *scmd;
struct scsi_cmnd *chan_scmd;
unsigned int channel;
int rtn;
/*
* we really want to loop over the various channels, and do this on
* a channel by channel basis. we should also check to see if any
* of the failed commands are on soft_reset devices, and if so, skip
* the reset.
*/
for (channel = 0; channel <= shost->max_channel; channel++) {
chan_scmd = NULL;
list_for_each_entry(scmd, work_q, eh_entry) {
if (channel == scmd->device->channel) {
chan_scmd = scmd;
break;
/*
* FIXME add back in some support for
* soft_reset devices.
*/
}
}
if (!chan_scmd)
continue;
SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Sending BRST chan:"
" %d\n", current->comm,
channel));
rtn = scsi_try_bus_reset(chan_scmd);
if (rtn == SUCCESS) {
list_for_each_safe(lh, lh_sf, work_q) {
scmd = list_entry(lh, struct scsi_cmnd,
eh_entry);
if (channel == scmd->device->channel)
if (!scsi_device_online(scmd->device) ||
!scsi_eh_tur(scmd))
scsi_eh_finish_cmd(scmd,
done_q);
}
} else {
SCSI_LOG_ERROR_RECOVERY(3, printk("%s: BRST"
" failed chan: %d\n",
current->comm,
channel));
}
}
return list_empty(work_q);
}
/**
* scsi_eh_host_reset - send a host reset
* @work_q: list_head for processed commands.
* @done_q: list_head for processed commands.
**/
static int scsi_eh_host_reset(struct list_head *work_q,
struct list_head *done_q)
{
int rtn;
struct list_head *lh, *lh_sf;
struct scsi_cmnd *scmd;
if (!list_empty(work_q)) {
scmd = list_entry(work_q->next,
struct scsi_cmnd, eh_entry);
SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Sending HRST\n"
, current->comm));
rtn = scsi_try_host_reset(scmd);
if (rtn == SUCCESS) {
list_for_each_safe(lh, lh_sf, work_q) {
scmd = list_entry(lh, struct scsi_cmnd, eh_entry);
if (!scsi_device_online(scmd->device) ||
(!scsi_eh_try_stu(scmd) && !scsi_eh_tur(scmd)) ||
!scsi_eh_tur(scmd))
scsi_eh_finish_cmd(scmd, done_q);
}
} else {
SCSI_LOG_ERROR_RECOVERY(3, printk("%s: HRST"
" failed\n",
current->comm));
}
}
return list_empty(work_q);
}
/**
* scsi_eh_offline_sdevs - offline scsi devices that fail to recover
* @work_q: list_head for processed commands.
* @done_q: list_head for processed commands.
*
**/
static void scsi_eh_offline_sdevs(struct list_head *work_q,
struct list_head *done_q)
{
struct list_head *lh, *lh_sf;
struct scsi_cmnd *scmd;
list_for_each_safe(lh, lh_sf, work_q) {
scmd = list_entry(lh, struct scsi_cmnd, eh_entry);
printk(KERN_INFO "scsi: Device offlined - not"
" ready after error recovery: host"
" %d channel %d id %d lun %d\n",
scmd->device->host->host_no,
scmd->device->channel,
scmd->device->id,
scmd->device->lun);
scsi_device_set_state(scmd->device, SDEV_OFFLINE);
if (scsi_eh_eflags_chk(scmd, SCSI_EH_CANCEL_CMD)) {
/*
* FIXME: Handle lost cmds.
*/
}
scsi_eh_finish_cmd(scmd, done_q);
}
return;
}
/**
* scsi_decide_disposition - Disposition a cmd on return from LLD.
* @scmd: SCSI cmd to examine.
*
* Notes:
* This is *only* called when we are examining the status after sending
* out the actual data command. any commands that are queued for error
* recovery (e.g. test_unit_ready) do *not* come through here.
*
* When this routine returns failed, it means the error handler thread
* is woken. In cases where the error code indicates an error that
* doesn't require the error handler read (i.e. we don't need to
* abort/reset), this function should return SUCCESS.
**/
int scsi_decide_disposition(struct scsi_cmnd *scmd)
{
int rtn;
/*
* if the device is offline, then we clearly just pass the result back
* up to the top level.
*/
if (!scsi_device_online(scmd->device)) {
SCSI_LOG_ERROR_RECOVERY(5, printk("%s: device offline - report"
" as SUCCESS\n",
__FUNCTION__));
return SUCCESS;
}
/*
* first check the host byte, to see if there is anything in there
* that would indicate what we need to do.
*/
switch (host_byte(scmd->result)) {
case DID_PASSTHROUGH:
/*
* no matter what, pass this through to the upper layer.
* nuke this special code so that it looks like we are saying
* did_ok.
*/
scmd->result &= 0xff00ffff;
return SUCCESS;
case DID_OK:
/*
* looks good. drop through, and check the next byte.
*/
break;
case DID_NO_CONNECT:
case DID_BAD_TARGET:
case DID_ABORT:
/*
* note - this means that we just report the status back
* to the top level driver, not that we actually think
* that it indicates SUCCESS.
*/
return SUCCESS;
/*
* when the low level driver returns did_soft_error,
* it is responsible for keeping an internal retry counter
* in order to avoid endless loops (db)
*
* actually this is a bug in this function here. we should
* be mindful of the maximum number of retries specified
* and not get stuck in a loop.
*/
case DID_SOFT_ERROR:
goto maybe_retry;
case DID_IMM_RETRY:
return NEEDS_RETRY;
case DID_REQUEUE:
return ADD_TO_MLQUEUE;
case DID_ERROR:
if (msg_byte(scmd->result) == COMMAND_COMPLETE &&
status_byte(scmd->result) == RESERVATION_CONFLICT)
/*
* execute reservation conflict processing code
* lower down
*/
break;
/* fallthrough */
case DID_BUS_BUSY:
case DID_PARITY:
goto maybe_retry;
case DID_TIME_OUT:
/*
* when we scan the bus, we get timeout messages for
* these commands if there is no device available.
* other hosts report did_no_connect for the same thing.
*/
if ((scmd->cmnd[0] == TEST_UNIT_READY ||
scmd->cmnd[0] == INQUIRY)) {
return SUCCESS;
} else {
return FAILED;
}
case DID_RESET:
return SUCCESS;
default:
return FAILED;
}
/*
* next, check the message byte.
*/
if (msg_byte(scmd->result) != COMMAND_COMPLETE)
return FAILED;
/*
* check the status byte to see if this indicates anything special.
*/
switch (status_byte(scmd->result)) {
case QUEUE_FULL:
/*
* the case of trying to send too many commands to a
* tagged queueing device.
*/
case BUSY:
/*
* device can't talk to us at the moment. Should only
* occur (SAM-3) when the task queue is empty, so will cause
* the empty queue handling to trigger a stall in the
* device.
*/
return ADD_TO_MLQUEUE;
case GOOD:
case COMMAND_TERMINATED:
case TASK_ABORTED:
return SUCCESS;
case CHECK_CONDITION:
rtn = scsi_check_sense(scmd);
if (rtn == NEEDS_RETRY)
goto maybe_retry;
/* if rtn == FAILED, we have no sense information;
* returning FAILED will wake the error handler thread
* to collect the sense and redo the decide
* disposition */
return rtn;
case CONDITION_GOOD:
case INTERMEDIATE_GOOD:
case INTERMEDIATE_C_GOOD:
case ACA_ACTIVE:
/*
* who knows? FIXME(eric)
*/
return SUCCESS;
case RESERVATION_CONFLICT:
printk(KERN_INFO "scsi: reservation conflict: host"
" %d channel %d id %d lun %d\n",
scmd->device->host->host_no, scmd->device->channel,
scmd->device->id, scmd->device->lun);
return SUCCESS; /* causes immediate i/o error */
default:
return FAILED;
}
return FAILED;
maybe_retry:
/* we requeue for retry because the error was retryable, and
* the request was not marked fast fail. Note that above,
* even if the request is marked fast fail, we still requeue
* for queue congestion conditions (QUEUE_FULL or BUSY) */
if ((++scmd->retries) < scmd->allowed
&& !blk_noretry_request(scmd->request)) {
return NEEDS_RETRY;
} else {
/*
* no more retries - report this one back to upper level.
*/
return SUCCESS;
}
}
/**
* scsi_eh_lock_done - done function for eh door lock request
* @scmd: SCSI command block for the door lock request
*
* Notes:
* We completed the asynchronous door lock request, and it has either
* locked the door or failed. We must free the command structures
* associated with this request.
**/
static void scsi_eh_lock_done(struct scsi_cmnd *scmd)
{
struct scsi_request *sreq = scmd->sc_request;
scsi_release_request(sreq);
}
/**
* scsi_eh_lock_door - Prevent medium removal for the specified device
* @sdev: SCSI device to prevent medium removal
*
* Locking:
* We must be called from process context; scsi_allocate_request()
* may sleep.
*
* Notes:
* We queue up an asynchronous "ALLOW MEDIUM REMOVAL" request on the
* head of the devices request queue, and continue.
*
* Bugs:
* scsi_allocate_request() may sleep waiting for existing requests to
* be processed. However, since we haven't kicked off any request
* processing for this host, this may deadlock.
*
* If scsi_allocate_request() fails for what ever reason, we
* completely forget to lock the door.
**/
static void scsi_eh_lock_door(struct scsi_device *sdev)
{
struct scsi_request *sreq = scsi_allocate_request(sdev, GFP_KERNEL);
if (unlikely(!sreq)) {
printk(KERN_ERR "%s: request allocate failed,"
"prevent media removal cmd not sent\n", __FUNCTION__);
return;
}
sreq->sr_cmnd[0] = ALLOW_MEDIUM_REMOVAL;
sreq->sr_cmnd[1] = 0;
sreq->sr_cmnd[2] = 0;
sreq->sr_cmnd[3] = 0;
sreq->sr_cmnd[4] = SCSI_REMOVAL_PREVENT;
sreq->sr_cmnd[5] = 0;
sreq->sr_data_direction = DMA_NONE;
sreq->sr_bufflen = 0;
sreq->sr_buffer = NULL;
sreq->sr_allowed = 5;
sreq->sr_done = scsi_eh_lock_done;
sreq->sr_timeout_per_command = 10 * HZ;
sreq->sr_cmd_len = COMMAND_SIZE(sreq->sr_cmnd[0]);
scsi_insert_special_req(sreq, 1);
}
/**
* scsi_restart_operations - restart io operations to the specified host.
* @shost: Host we are restarting.
*
* Notes:
* When we entered the error handler, we blocked all further i/o to
* this device. we need to 'reverse' this process.
**/
static void scsi_restart_operations(struct Scsi_Host *shost)
{
struct scsi_device *sdev;
/*
* If the door was locked, we need to insert a door lock request
* onto the head of the SCSI request queue for the device. There
* is no point trying to lock the door of an off-line device.
*/
shost_for_each_device(sdev, shost) {
if (scsi_device_online(sdev) && sdev->locked)
scsi_eh_lock_door(sdev);
}
/*
* next free up anything directly waiting upon the host. this
* will be requests for character device operations, and also for
* ioctls to queued block devices.
*/
SCSI_LOG_ERROR_RECOVERY(3, printk("%s: waking up host to restart\n",
__FUNCTION__));
clear_bit(SHOST_RECOVERY, &shost->shost_state);
wake_up(&shost->host_wait);
/*
* finally we need to re-initiate requests that may be pending. we will
* have had everything blocked while error handling is taking place, and
* now that error recovery is done, we will need to ensure that these
* requests are started.
*/
scsi_run_host_queues(shost);
}
/**
* scsi_eh_ready_devs - check device ready state and recover if not.
* @shost: host to be recovered.
* @eh_done_q: list_head for processed commands.
*
**/
static void scsi_eh_ready_devs(struct Scsi_Host *shost,
struct list_head *work_q,
struct list_head *done_q)
{
if (!scsi_eh_stu(shost, work_q, done_q))
if (!scsi_eh_bus_device_reset(shost, work_q, done_q))
if (!scsi_eh_bus_reset(shost, work_q, done_q))
if (!scsi_eh_host_reset(work_q, done_q))
scsi_eh_offline_sdevs(work_q, done_q);
}
/**
* scsi_eh_flush_done_q - finish processed commands or retry them.
* @done_q: list_head of processed commands.
*
**/
static void scsi_eh_flush_done_q(struct list_head *done_q)
{
struct list_head *lh, *lh_sf;
struct scsi_cmnd *scmd;
list_for_each_safe(lh, lh_sf, done_q) {
scmd = list_entry(lh, struct scsi_cmnd, eh_entry);
list_del_init(lh);
if (scsi_device_online(scmd->device) &&
!blk_noretry_request(scmd->request) &&
(++scmd->retries < scmd->allowed)) {
SCSI_LOG_ERROR_RECOVERY(3, printk("%s: flush"
" retry cmd: %p\n",
current->comm,
scmd));
scsi_queue_insert(scmd, SCSI_MLQUEUE_EH_RETRY);
} else {
/*
* If just we got sense for the device (called
* scsi_eh_get_sense), scmd->result is already
* set, do not set DRIVER_TIMEOUT.
*/
if (!scmd->result)
scmd->result |= (DRIVER_TIMEOUT << 24);
SCSI_LOG_ERROR_RECOVERY(3, printk("%s: flush finish"
" cmd: %p\n",
current->comm, scmd));
scsi_finish_command(scmd);
}
}
}
/**
* scsi_unjam_host - Attempt to fix a host which has a cmd that failed.
* @shost: Host to unjam.
*
* Notes:
* When we come in here, we *know* that all commands on the bus have
* either completed, failed or timed out. we also know that no further
* commands are being sent to the host, so things are relatively quiet
* and we have freedom to fiddle with things as we wish.
*
* This is only the *default* implementation. it is possible for
* individual drivers to supply their own version of this function, and
* if the maintainer wishes to do this, it is strongly suggested that
* this function be taken as a template and modified. this function
* was designed to correctly handle problems for about 95% of the
* different cases out there, and it should always provide at least a
* reasonable amount of error recovery.
*
* Any command marked 'failed' or 'timeout' must eventually have
* scsi_finish_cmd() called for it. we do all of the retry stuff
* here, so when we restart the host after we return it should have an
* empty queue.
**/
static void scsi_unjam_host(struct Scsi_Host *shost)
{
unsigned long flags;
LIST_HEAD(eh_work_q);
LIST_HEAD(eh_done_q);
spin_lock_irqsave(shost->host_lock, flags);
list_splice_init(&shost->eh_cmd_q, &eh_work_q);
spin_unlock_irqrestore(shost->host_lock, flags);
SCSI_LOG_ERROR_RECOVERY(1, scsi_eh_prt_fail_stats(shost, &eh_work_q));
if (!scsi_eh_get_sense(&eh_work_q, &eh_done_q))
if (!scsi_eh_abort_cmds(&eh_work_q, &eh_done_q))
scsi_eh_ready_devs(shost, &eh_work_q, &eh_done_q);
scsi_eh_flush_done_q(&eh_done_q);
}
/**
* scsi_error_handler - Handle errors/timeouts of SCSI cmds.
* @data: Host for which we are running.
*
* Notes:
* This is always run in the context of a kernel thread. The idea is
* that we start this thing up when the kernel starts up (one per host
* that we detect), and it immediately goes to sleep and waits for some
* event (i.e. failure). When this takes place, we have the job of
* trying to unjam the bus and restarting things.
**/
int scsi_error_handler(void *data)
{
struct Scsi_Host *shost = (struct Scsi_Host *) data;
int rtn;
DECLARE_MUTEX_LOCKED(sem);
/*
* Flush resources
*/
daemonize("scsi_eh_%d", shost->host_no);
current->flags |= PF_NOFREEZE;
shost->eh_wait = &sem;
shost->ehandler = current;
/*
* Wake up the thread that created us.
*/
SCSI_LOG_ERROR_RECOVERY(3, printk("Wake up parent of"
" scsi_eh_%d\n",shost->host_no));
complete(shost->eh_notify);
while (1) {
/*
* If we get a signal, it means we are supposed to go
* away and die. This typically happens if the user is
* trying to unload a module.
*/
SCSI_LOG_ERROR_RECOVERY(1, printk("Error handler"
" scsi_eh_%d"
" sleeping\n",shost->host_no));
/*
* Note - we always use down_interruptible with the semaphore
* even if the module was loaded as part of the kernel. The
* reason is that down() will cause this thread to be counted
* in the load average as a running process, and down
* interruptible doesn't. Given that we need to allow this
* thread to die if the driver was loaded as a module, using
* semaphores isn't unreasonable.
*/
down_interruptible(&sem);
if (shost->eh_kill)
break;
SCSI_LOG_ERROR_RECOVERY(1, printk("Error handler"
" scsi_eh_%d waking"
" up\n",shost->host_no));
shost->eh_active = 1;
/*
* We have a host that is failing for some reason. Figure out
* what we need to do to get it up and online again (if we can).
* If we fail, we end up taking the thing offline.
*/
if (shost->hostt->eh_strategy_handler)
rtn = shost->hostt->eh_strategy_handler(shost);
else
scsi_unjam_host(shost);
shost->eh_active = 0;
/*
* Note - if the above fails completely, the action is to take
* individual devices offline and flush the queue of any
* outstanding requests that may have been pending. When we
* restart, we restart any I/O to any other devices on the bus
* which are still online.
*/
scsi_restart_operations(shost);
}
SCSI_LOG_ERROR_RECOVERY(1, printk("Error handler scsi_eh_%d"
" exiting\n",shost->host_no));
/*
* Make sure that nobody tries to wake us up again.
*/
shost->eh_wait = NULL;
/*
* Knock this down too. From this point on, the host is flying
* without a pilot. If this is because the module is being unloaded,
* that's fine. If the user sent a signal to this thing, we are
* potentially in real danger.
*/
shost->eh_active = 0;
shost->ehandler = NULL;
/*
* If anyone is waiting for us to exit (i.e. someone trying to unload
* a driver), then wake up that process to let them know we are on
* the way out the door.
*/
complete_and_exit(shost->eh_notify, 0);
return 0;
}
/*
* Function: scsi_report_bus_reset()
*
* Purpose: Utility function used by low-level drivers to report that
* they have observed a bus reset on the bus being handled.
*
* Arguments: shost - Host in question
* channel - channel on which reset was observed.
*
* Returns: Nothing
*
* Lock status: Host lock must be held.
*
* Notes: This only needs to be called if the reset is one which
* originates from an unknown location. Resets originated
* by the mid-level itself don't need to call this, but there
* should be no harm.
*
* The main purpose of this is to make sure that a CHECK_CONDITION
* is properly treated.
*/
void scsi_report_bus_reset(struct Scsi_Host *shost, int channel)
{
struct scsi_device *sdev;
__shost_for_each_device(sdev, shost) {
if (channel == sdev->channel) {
sdev->was_reset = 1;
sdev->expecting_cc_ua = 1;
}
}
}
EXPORT_SYMBOL(scsi_report_bus_reset);
/*
* Function: scsi_report_device_reset()
*
* Purpose: Utility function used by low-level drivers to report that
* they have observed a device reset on the device being handled.
*
* Arguments: shost - Host in question
* channel - channel on which reset was observed
* target - target on which reset was observed
*
* Returns: Nothing
*
* Lock status: Host lock must be held
*
* Notes: This only needs to be called if the reset is one which
* originates from an unknown location. Resets originated
* by the mid-level itself don't need to call this, but there
* should be no harm.
*
* The main purpose of this is to make sure that a CHECK_CONDITION
* is properly treated.
*/
void scsi_report_device_reset(struct Scsi_Host *shost, int channel, int target)
{
struct scsi_device *sdev;
__shost_for_each_device(sdev, shost) {
if (channel == sdev->channel &&
target == sdev->id) {
sdev->was_reset = 1;
sdev->expecting_cc_ua = 1;
}
}
}
EXPORT_SYMBOL(scsi_report_device_reset);
static void
scsi_reset_provider_done_command(struct scsi_cmnd *scmd)
{
}
/*
* Function: scsi_reset_provider
*
* Purpose: Send requested reset to a bus or device at any phase.
*
* Arguments: device - device to send reset to
* flag - reset type (see scsi.h)
*
* Returns: SUCCESS/FAILURE.
*
* Notes: This is used by the SCSI Generic driver to provide
* Bus/Device reset capability.
*/
int
scsi_reset_provider(struct scsi_device *dev, int flag)
{
struct scsi_cmnd *scmd = scsi_get_command(dev, GFP_KERNEL);
struct request req;
int rtn;
scmd->request = &req;
memset(&scmd->eh_timeout, 0, sizeof(scmd->eh_timeout));
scmd->request->rq_status = RQ_SCSI_BUSY;
memset(&scmd->cmnd, '\0', sizeof(scmd->cmnd));
scmd->scsi_done = scsi_reset_provider_done_command;
scmd->done = NULL;
scmd->buffer = NULL;
scmd->bufflen = 0;
scmd->request_buffer = NULL;
scmd->request_bufflen = 0;
scmd->cmd_len = 0;
scmd->sc_data_direction = DMA_BIDIRECTIONAL;
scmd->sc_request = NULL;
scmd->sc_magic = SCSI_CMND_MAGIC;
init_timer(&scmd->eh_timeout);
/*
* Sometimes the command can get back into the timer chain,
* so use the pid as an identifier.
*/
scmd->pid = 0;
switch (flag) {
case SCSI_TRY_RESET_DEVICE:
rtn = scsi_try_bus_device_reset(scmd);
if (rtn == SUCCESS)
break;
/* FALLTHROUGH */
case SCSI_TRY_RESET_BUS:
rtn = scsi_try_bus_reset(scmd);
if (rtn == SUCCESS)
break;
/* FALLTHROUGH */
case SCSI_TRY_RESET_HOST:
rtn = scsi_try_host_reset(scmd);
break;
default:
rtn = FAILED;
}
scsi_next_command(scmd);
return rtn;
}
EXPORT_SYMBOL(scsi_reset_provider);
/**
* scsi_normalize_sense - normalize main elements from either fixed or
* descriptor sense data format into a common format.
*
* @sense_buffer: byte array containing sense data returned by device
* @sb_len: number of valid bytes in sense_buffer
* @sshdr: pointer to instance of structure that common
* elements are written to.
*
* Notes:
* The "main elements" from sense data are: response_code, sense_key,
* asc, ascq and additional_length (only for descriptor format).
*
* Typically this function can be called after a device has
* responded to a SCSI command with the CHECK_CONDITION status.
*
* Return value:
* 1 if valid sense data information found, else 0;
**/
int scsi_normalize_sense(const u8 *sense_buffer, int sb_len,
struct scsi_sense_hdr *sshdr)
{
if (!sense_buffer || !sb_len || (sense_buffer[0] & 0x70) != 0x70)
return 0;
memset(sshdr, 0, sizeof(struct scsi_sense_hdr));
sshdr->response_code = (sense_buffer[0] & 0x7f);
if (sshdr->response_code >= 0x72) {
/*
* descriptor format
*/
if (sb_len > 1)
sshdr->sense_key = (sense_buffer[1] & 0xf);
if (sb_len > 2)
sshdr->asc = sense_buffer[2];
if (sb_len > 3)
sshdr->ascq = sense_buffer[3];
if (sb_len > 7)
sshdr->additional_length = sense_buffer[7];
} else {
/*
* fixed format
*/
if (sb_len > 2)
sshdr->sense_key = (sense_buffer[2] & 0xf);
if (sb_len > 7) {
sb_len = (sb_len < (sense_buffer[7] + 8)) ?
sb_len : (sense_buffer[7] + 8);
if (sb_len > 12)
sshdr->asc = sense_buffer[12];
if (sb_len > 13)
sshdr->ascq = sense_buffer[13];
}
}
return 1;
}
EXPORT_SYMBOL(scsi_normalize_sense);
int scsi_request_normalize_sense(struct scsi_request *sreq,
struct scsi_sense_hdr *sshdr)
{
return scsi_normalize_sense(sreq->sr_sense_buffer,
sizeof(sreq->sr_sense_buffer), sshdr);
}
EXPORT_SYMBOL(scsi_request_normalize_sense);
int scsi_command_normalize_sense(struct scsi_cmnd *cmd,
struct scsi_sense_hdr *sshdr)
{
return scsi_normalize_sense(cmd->sense_buffer,
sizeof(cmd->sense_buffer), sshdr);
}
EXPORT_SYMBOL(scsi_command_normalize_sense);
/**
* scsi_sense_desc_find - search for a given descriptor type in
* descriptor sense data format.
*
* @sense_buffer: byte array of descriptor format sense data
* @sb_len: number of valid bytes in sense_buffer
* @desc_type: value of descriptor type to find
* (e.g. 0 -> information)
*
* Notes:
* only valid when sense data is in descriptor format
*
* Return value:
* pointer to start of (first) descriptor if found else NULL
**/
const u8 * scsi_sense_desc_find(const u8 * sense_buffer, int sb_len,
int desc_type)
{
int add_sen_len, add_len, desc_len, k;
const u8 * descp;
if ((sb_len < 8) || (0 == (add_sen_len = sense_buffer[7])))
return NULL;
if ((sense_buffer[0] < 0x72) || (sense_buffer[0] > 0x73))
return NULL;
add_sen_len = (add_sen_len < (sb_len - 8)) ?
add_sen_len : (sb_len - 8);
descp = &sense_buffer[8];
for (desc_len = 0, k = 0; k < add_sen_len; k += desc_len) {
descp += desc_len;
add_len = (k < (add_sen_len - 1)) ? descp[1]: -1;
desc_len = add_len + 2;
if (descp[0] == desc_type)
return descp;
if (add_len < 0) // short descriptor ??
break;
}
return NULL;
}
EXPORT_SYMBOL(scsi_sense_desc_find);
/**
* scsi_get_sense_info_fld - attempts to get information field from
* sense data (either fixed or descriptor format)
*
* @sense_buffer: byte array of sense data
* @sb_len: number of valid bytes in sense_buffer
* @info_out: pointer to 64 integer where 8 or 4 byte information
* field will be placed if found.
*
* Return value:
* 1 if information field found, 0 if not found.
**/
int scsi_get_sense_info_fld(const u8 * sense_buffer, int sb_len,
u64 * info_out)
{
int j;
const u8 * ucp;
u64 ull;
if (sb_len < 7)
return 0;
switch (sense_buffer[0] & 0x7f) {
case 0x70:
case 0x71:
if (sense_buffer[0] & 0x80) {
*info_out = (sense_buffer[3] << 24) +
(sense_buffer[4] << 16) +
(sense_buffer[5] << 8) + sense_buffer[6];
return 1;
} else
return 0;
case 0x72:
case 0x73:
ucp = scsi_sense_desc_find(sense_buffer, sb_len,
0 /* info desc */);
if (ucp && (0xa == ucp[1])) {
ull = 0;
for (j = 0; j < 8; ++j) {
if (j > 0)
ull <<= 8;
ull |= ucp[4 + j];
}
*info_out = ull;
return 1;
} else
return 0;
default:
return 0;
}
}
EXPORT_SYMBOL(scsi_get_sense_info_fld);
