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linux/drivers/scsi/scsi_scan.c
152587deb8 [PATCH] fix NMI lockup with CFQ scheduler 
The current problem seen is that the queue lock is actually in the
SCSI device structure, so when that structure is freed on device
release, we go boom if the queue tries to access the lock again.

The fix here is to move the lock from the scsi_device to the queue.

Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>
2005-04-16 20:10:09 -05:00

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/*
* scsi_scan.c
*
* Copyright (C) 2000 Eric Youngdale,
* Copyright (C) 2002 Patrick Mansfield
*
* The general scanning/probing algorithm is as follows, exceptions are
* made to it depending on device specific flags, compilation options, and
* global variable (boot or module load time) settings.
*
* A specific LUN is scanned via an INQUIRY command; if the LUN has a
* device attached, a Scsi_Device is allocated and setup for it.
*
* For every id of every channel on the given host:
*
* Scan LUN 0; if the target responds to LUN 0 (even if there is no
* device or storage attached to LUN 0):
*
* If LUN 0 has a device attached, allocate and setup a
* Scsi_Device for it.
*
* If target is SCSI-3 or up, issue a REPORT LUN, and scan
* all of the LUNs returned by the REPORT LUN; else,
* sequentially scan LUNs up until some maximum is reached,
* or a LUN is seen that cannot have a device attached to it.
*/
#include <linux/config.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/init.h>
#include <linux/blkdev.h>
#include <asm/semaphore.h>
#include <scsi/scsi.h>
#include <scsi/scsi_device.h>
#include <scsi/scsi_driver.h>
#include <scsi/scsi_devinfo.h>
#include <scsi/scsi_host.h>
#include <scsi/scsi_request.h>
#include <scsi/scsi_transport.h>
#include <scsi/scsi_eh.h>
#include "scsi_priv.h"
#include "scsi_logging.h"
#define ALLOC_FAILURE_MSG KERN_ERR "%s: Allocation failure during" \
" SCSI scanning, some SCSI devices might not be configured\n"
/*
* Default timeout
*/
#define SCSI_TIMEOUT (2*HZ)
/*
* Prefix values for the SCSI id's (stored in driverfs name field)
*/
#define SCSI_UID_SER_NUM 'S'
#define SCSI_UID_UNKNOWN 'Z'
/*
* Return values of some of the scanning functions.
*
* SCSI_SCAN_NO_RESPONSE: no valid response received from the target, this
* includes allocation or general failures preventing IO from being sent.
*
* SCSI_SCAN_TARGET_PRESENT: target responded, but no device is available
* on the given LUN.
*
* SCSI_SCAN_LUN_PRESENT: target responded, and a device is available on a
* given LUN.
*/
#define SCSI_SCAN_NO_RESPONSE 0
#define SCSI_SCAN_TARGET_PRESENT 1
#define SCSI_SCAN_LUN_PRESENT 2
static char *scsi_null_device_strs = "nullnullnullnull";
#define MAX_SCSI_LUNS 512
#ifdef CONFIG_SCSI_MULTI_LUN
static unsigned int max_scsi_luns = MAX_SCSI_LUNS;
#else
static unsigned int max_scsi_luns = 1;
#endif
module_param_named(max_luns, max_scsi_luns, int, S_IRUGO|S_IWUSR);
MODULE_PARM_DESC(max_luns,
"last scsi LUN (should be between 1 and 2^32-1)");
/*
* max_scsi_report_luns: the maximum number of LUNS that will be
* returned from the REPORT LUNS command. 8 times this value must
* be allocated. In theory this could be up to an 8 byte value, but
* in practice, the maximum number of LUNs suppored by any device
* is about 16k.
*/
static unsigned int max_scsi_report_luns = 511;
module_param_named(max_report_luns, max_scsi_report_luns, int, S_IRUGO|S_IWUSR);
MODULE_PARM_DESC(max_report_luns,
"REPORT LUNS maximum number of LUNS received (should be"
" between 1 and 16384)");
static unsigned int scsi_inq_timeout = SCSI_TIMEOUT/HZ+3;
module_param_named(inq_timeout, scsi_inq_timeout, int, S_IRUGO|S_IWUSR);
MODULE_PARM_DESC(inq_timeout,
"Timeout (in seconds) waiting for devices to answer INQUIRY."
" Default is 5. Some non-compliant devices need more.");
/**
* scsi_unlock_floptical - unlock device via a special MODE SENSE command
* @sreq: used to send the command
* @result: area to store the result of the MODE SENSE
*
* Description:
* Send a vendor specific MODE SENSE (not a MODE SELECT) command using
* @sreq to unlock a device, storing the (unused) results into result.
* Called for BLIST_KEY devices.
**/
static void scsi_unlock_floptical(struct scsi_request *sreq,
unsigned char *result)
{
unsigned char scsi_cmd[MAX_COMMAND_SIZE];
printk(KERN_NOTICE "scsi: unlocking floptical drive\n");
scsi_cmd[0] = MODE_SENSE;
scsi_cmd[1] = 0;
scsi_cmd[2] = 0x2e;
scsi_cmd[3] = 0;
scsi_cmd[4] = 0x2a; /* size */
scsi_cmd[5] = 0;
sreq->sr_cmd_len = 0;
sreq->sr_data_direction = DMA_FROM_DEVICE;
scsi_wait_req(sreq, scsi_cmd, result, 0x2a /* size */, SCSI_TIMEOUT, 3);
}
/**
* print_inquiry - printk the inquiry information
* @inq_result: printk this SCSI INQUIRY
*
* Description:
* printk the vendor, model, and other information found in the
* INQUIRY data in @inq_result.
*
* Notes:
* Remove this, and replace with a hotplug event that logs any
* relevant information.
**/
static void print_inquiry(unsigned char *inq_result)
{
int i;
printk(KERN_NOTICE " Vendor: ");
for (i = 8; i < 16; i++)
if (inq_result[i] >= 0x20 && i < inq_result[4] + 5)
printk("%c", inq_result[i]);
else
printk(" ");
printk(" Model: ");
for (i = 16; i < 32; i++)
if (inq_result[i] >= 0x20 && i < inq_result[4] + 5)
printk("%c", inq_result[i]);
else
printk(" ");
printk(" Rev: ");
for (i = 32; i < 36; i++)
if (inq_result[i] >= 0x20 && i < inq_result[4] + 5)
printk("%c", inq_result[i]);
else
printk(" ");
printk("\n");
i = inq_result[0] & 0x1f;
printk(KERN_NOTICE " Type: %s ",
i <
MAX_SCSI_DEVICE_CODE ? scsi_device_types[i] :
"Unknown ");
printk(" ANSI SCSI revision: %02x",
inq_result[2] & 0x07);
if ((inq_result[2] & 0x07) == 1 && (inq_result[3] & 0x0f) == 1)
printk(" CCS\n");
else
printk("\n");
}
/**
* scsi_alloc_sdev - allocate and setup a scsi_Device
*
* Description:
* Allocate, initialize for io, and return a pointer to a scsi_Device.
* Stores the @shost, @channel, @id, and @lun in the scsi_Device, and
* adds scsi_Device to the appropriate list.
*
* Return value:
* scsi_Device pointer, or NULL on failure.
**/
static struct scsi_device *scsi_alloc_sdev(struct scsi_target *starget,
unsigned int lun, void *hostdata)
{
struct scsi_device *sdev;
int display_failure_msg = 1, ret;
struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
sdev = kmalloc(sizeof(*sdev) + shost->transportt->device_size,
GFP_ATOMIC);
if (!sdev)
goto out;
memset(sdev, 0, sizeof(*sdev));
sdev->vendor = scsi_null_device_strs;
sdev->model = scsi_null_device_strs;
sdev->rev = scsi_null_device_strs;
sdev->host = shost;
sdev->id = starget->id;
sdev->lun = lun;
sdev->channel = starget->channel;
sdev->sdev_state = SDEV_CREATED;
INIT_LIST_HEAD(&sdev->siblings);
INIT_LIST_HEAD(&sdev->same_target_siblings);
INIT_LIST_HEAD(&sdev->cmd_list);
INIT_LIST_HEAD(&sdev->starved_entry);
spin_lock_init(&sdev->list_lock);
sdev->sdev_gendev.parent = get_device(&starget->dev);
sdev->sdev_target = starget;
/* usually NULL and set by ->slave_alloc instead */
sdev->hostdata = hostdata;
/* if the device needs this changing, it may do so in the
* slave_configure function */
sdev->max_device_blocked = SCSI_DEFAULT_DEVICE_BLOCKED;
/*
* Some low level driver could use device->type
*/
sdev->type = -1;
/*
* Assume that the device will have handshaking problems,
* and then fix this field later if it turns out it
* doesn't
*/
sdev->borken = 1;
sdev->request_queue = scsi_alloc_queue(sdev);
if (!sdev->request_queue) {
/* release fn is set up in scsi_sysfs_device_initialise, so
* have to free and put manually here */
put_device(&starget->dev);
goto out;
}
sdev->request_queue->queuedata = sdev;
scsi_adjust_queue_depth(sdev, 0, sdev->host->cmd_per_lun);
scsi_sysfs_device_initialize(sdev);
if (shost->hostt->slave_alloc) {
ret = shost->hostt->slave_alloc(sdev);
if (ret) {
/*
* if LLDD reports slave not present, don't clutter
* console with alloc failure messages
*/
if (ret == -ENXIO)
display_failure_msg = 0;
goto out_device_destroy;
}
}
return sdev;
out_device_destroy:
transport_destroy_device(&sdev->sdev_gendev);
scsi_free_queue(sdev->request_queue);
put_device(&sdev->sdev_gendev);
out:
if (display_failure_msg)
printk(ALLOC_FAILURE_MSG, __FUNCTION__);
return NULL;
}
static void scsi_target_dev_release(struct device *dev)
{
struct device *parent = dev->parent;
struct scsi_target *starget = to_scsi_target(dev);
kfree(starget);
put_device(parent);
}
int scsi_is_target_device(const struct device *dev)
{
return dev->release == scsi_target_dev_release;
}
EXPORT_SYMBOL(scsi_is_target_device);
static struct scsi_target *__scsi_find_target(struct device *parent,
int channel, uint id)
{
struct scsi_target *starget, *found_starget = NULL;
struct Scsi_Host *shost = dev_to_shost(parent);
/*
* Search for an existing target for this sdev.
*/
list_for_each_entry(starget, &shost->__targets, siblings) {
if (starget->id == id &&
starget->channel == channel) {
found_starget = starget;
break;
}
}
if (found_starget)
get_device(&found_starget->dev);
return found_starget;
}
static struct scsi_target *scsi_alloc_target(struct device *parent,
int channel, uint id)
{
struct Scsi_Host *shost = dev_to_shost(parent);
struct device *dev = NULL;
unsigned long flags;
const int size = sizeof(struct scsi_target)
+ shost->transportt->target_size;
struct scsi_target *starget = kmalloc(size, GFP_ATOMIC);
struct scsi_target *found_target;
if (!starget) {
printk(KERN_ERR "%s: allocation failure\n", __FUNCTION__);
return NULL;
}
memset(starget, 0, size);
dev = &starget->dev;
device_initialize(dev);
starget->reap_ref = 1;
dev->parent = get_device(parent);
dev->release = scsi_target_dev_release;
sprintf(dev->bus_id, "target%d:%d:%d",
shost->host_no, channel, id);
starget->id = id;
starget->channel = channel;
INIT_LIST_HEAD(&starget->siblings);
INIT_LIST_HEAD(&starget->devices);
spin_lock_irqsave(shost->host_lock, flags);
found_target = __scsi_find_target(parent, channel, id);
if (found_target)
goto found;
list_add_tail(&starget->siblings, &shost->__targets);
spin_unlock_irqrestore(shost->host_lock, flags);
/* allocate and add */
transport_setup_device(&starget->dev);
device_add(&starget->dev);
transport_add_device(&starget->dev);
return starget;
found:
found_target->reap_ref++;
spin_unlock_irqrestore(shost->host_lock, flags);
put_device(parent);
kfree(starget);
return found_target;
}
/**
* scsi_target_reap - check to see if target is in use and destroy if not
*
* @starget: target to be checked
*
* This is used after removing a LUN or doing a last put of the target
* it checks atomically that nothing is using the target and removes
* it if so.
*/
void scsi_target_reap(struct scsi_target *starget)
{
struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
unsigned long flags;
spin_lock_irqsave(shost->host_lock, flags);
if (--starget->reap_ref == 0 && list_empty(&starget->devices)) {
list_del_init(&starget->siblings);
spin_unlock_irqrestore(shost->host_lock, flags);
device_del(&starget->dev);
transport_unregister_device(&starget->dev);
put_device(&starget->dev);
return;
}
spin_unlock_irqrestore(shost->host_lock, flags);
}
/**
* scsi_probe_lun - probe a single LUN using a SCSI INQUIRY
* @sreq: used to send the INQUIRY
* @inq_result: area to store the INQUIRY result
* @bflags: store any bflags found here
*
* Description:
* Probe the lun associated with @sreq using a standard SCSI INQUIRY;
*
* If the INQUIRY is successful, sreq->sr_result is zero and: the
* INQUIRY data is in @inq_result; the scsi_level and INQUIRY length
* are copied to the Scsi_Device at @sreq->sr_device (sdev);
* any flags value is stored in *@bflags.
**/
static void scsi_probe_lun(struct scsi_request *sreq, char *inq_result,
int *bflags)
{
struct scsi_device *sdev = sreq->sr_device; /* a bit ugly */
unsigned char scsi_cmd[MAX_COMMAND_SIZE];
int first_inquiry_len, try_inquiry_len, next_inquiry_len;
int response_len = 0;
int pass, count;
struct scsi_sense_hdr sshdr;
*bflags = 0;
/* Perform up to 3 passes. The first pass uses a conservative
* transfer length of 36 unless sdev->inquiry_len specifies a
* different value. */
first_inquiry_len = sdev->inquiry_len ? sdev->inquiry_len : 36;
try_inquiry_len = first_inquiry_len;
pass = 1;
next_pass:
SCSI_LOG_SCAN_BUS(3, printk(KERN_INFO "scsi scan: INQUIRY pass %d "
"to host %d channel %d id %d lun %d, length %d\n",
pass, sdev->host->host_no, sdev->channel,
sdev->id, sdev->lun, try_inquiry_len));
/* Each pass gets up to three chances to ignore Unit Attention */
for (count = 0; count < 3; ++count) {
memset(scsi_cmd, 0, 6);
scsi_cmd[0] = INQUIRY;
scsi_cmd[4] = (unsigned char) try_inquiry_len;
sreq->sr_cmd_len = 0;
sreq->sr_data_direction = DMA_FROM_DEVICE;
memset(inq_result, 0, try_inquiry_len);
scsi_wait_req(sreq, (void *) scsi_cmd, (void *) inq_result,
try_inquiry_len,
HZ/2 + HZ*scsi_inq_timeout, 3);
SCSI_LOG_SCAN_BUS(3, printk(KERN_INFO "scsi scan: INQUIRY %s "
"with code 0x%x\n",
sreq->sr_result ? "failed" : "successful",
sreq->sr_result));
if (sreq->sr_result) {
/*
* not-ready to ready transition [asc/ascq=0x28/0x0]
* or power-on, reset [asc/ascq=0x29/0x0], continue.
* INQUIRY should not yield UNIT_ATTENTION
* but many buggy devices do so anyway.
*/
if ((driver_byte(sreq->sr_result) & DRIVER_SENSE) &&
scsi_request_normalize_sense(sreq, &sshdr)) {
if ((sshdr.sense_key == UNIT_ATTENTION) &&
((sshdr.asc == 0x28) ||
(sshdr.asc == 0x29)) &&
(sshdr.ascq == 0))
continue;
}
}
break;
}
if (sreq->sr_result == 0) {
response_len = (unsigned char) inq_result[4] + 5;
if (response_len > 255)
response_len = first_inquiry_len; /* sanity */
/*
* Get any flags for this device.
*
* XXX add a bflags to Scsi_Device, and replace the
* corresponding bit fields in Scsi_Device, so bflags
* need not be passed as an argument.
*/
*bflags = scsi_get_device_flags(sdev, &inq_result[8],
&inq_result[16]);
/* When the first pass succeeds we gain information about
* what larger transfer lengths might work. */
if (pass == 1) {
if (BLIST_INQUIRY_36 & *bflags)
next_inquiry_len = 36;
else if (BLIST_INQUIRY_58 & *bflags)
next_inquiry_len = 58;
else if (sdev->inquiry_len)
next_inquiry_len = sdev->inquiry_len;
else
next_inquiry_len = response_len;
/* If more data is available perform the second pass */
if (next_inquiry_len > try_inquiry_len) {
try_inquiry_len = next_inquiry_len;
pass = 2;
goto next_pass;
}
}
} else if (pass == 2) {
printk(KERN_INFO "scsi scan: %d byte inquiry failed. "
"Consider BLIST_INQUIRY_36 for this device\n",
try_inquiry_len);
/* If this pass failed, the third pass goes back and transfers
* the same amount as we successfully got in the first pass. */
try_inquiry_len = first_inquiry_len;
pass = 3;
goto next_pass;
}
/* If the last transfer attempt got an error, assume the
* peripheral doesn't exist or is dead. */
if (sreq->sr_result)
return;
/* Don't report any more data than the device says is valid */
sdev->inquiry_len = min(try_inquiry_len, response_len);
/*
* XXX Abort if the response length is less than 36? If less than
* 32, the lookup of the device flags (above) could be invalid,
* and it would be possible to take an incorrect action - we do
* not want to hang because of a short INQUIRY. On the flip side,
* if the device is spun down or becoming ready (and so it gives a
* short INQUIRY), an abort here prevents any further use of the
* device, including spin up.
*
* Related to the above issue:
*
* XXX Devices (disk or all?) should be sent a TEST UNIT READY,
* and if not ready, sent a START_STOP to start (maybe spin up) and
* then send the INQUIRY again, since the INQUIRY can change after
* a device is initialized.
*
* Ideally, start a device if explicitly asked to do so. This
* assumes that a device is spun up on power on, spun down on
* request, and then spun up on request.
*/
/*
* The scanning code needs to know the scsi_level, even if no
* device is attached at LUN 0 (SCSI_SCAN_TARGET_PRESENT) so
* non-zero LUNs can be scanned.
*/
sdev->scsi_level = inq_result[2] & 0x07;
if (sdev->scsi_level >= 2 ||
(sdev->scsi_level == 1 && (inq_result[3] & 0x0f) == 1))
sdev->scsi_level++;
return;
}
/**
* scsi_add_lun - allocate and fully initialze a Scsi_Device
* @sdevscan: holds information to be stored in the new Scsi_Device
* @sdevnew: store the address of the newly allocated Scsi_Device
* @inq_result: holds the result of a previous INQUIRY to the LUN
* @bflags: black/white list flag
*
* Description:
* Allocate and initialize a Scsi_Device matching sdevscan. Optionally
* set fields based on values in *@bflags. If @sdevnew is not
* NULL, store the address of the new Scsi_Device in *@sdevnew (needed
* when scanning a particular LUN).
*
* Return:
* SCSI_SCAN_NO_RESPONSE: could not allocate or setup a Scsi_Device
* SCSI_SCAN_LUN_PRESENT: a new Scsi_Device was allocated and initialized
**/
static int scsi_add_lun(struct scsi_device *sdev, char *inq_result, int *bflags)
{
/*
* XXX do not save the inquiry, since it can change underneath us,
* save just vendor/model/rev.
*
* Rather than save it and have an ioctl that retrieves the saved
* value, have an ioctl that executes the same INQUIRY code used
* in scsi_probe_lun, let user level programs doing INQUIRY
* scanning run at their own risk, or supply a user level program
* that can correctly scan.
*/
sdev->inquiry = kmalloc(sdev->inquiry_len, GFP_ATOMIC);
if (sdev->inquiry == NULL) {
return SCSI_SCAN_NO_RESPONSE;
}
memcpy(sdev->inquiry, inq_result, sdev->inquiry_len);
sdev->vendor = (char *) (sdev->inquiry + 8);
sdev->model = (char *) (sdev->inquiry + 16);
sdev->rev = (char *) (sdev->inquiry + 32);
if (*bflags & BLIST_ISROM) {
/*
* It would be better to modify sdev->type, and set
* sdev->removable, but then the print_inquiry() output
* would not show TYPE_ROM; if print_inquiry() is removed
* the issue goes away.
*/
inq_result[0] = TYPE_ROM;
inq_result[1] |= 0x80; /* removable */
} else if (*bflags & BLIST_NO_ULD_ATTACH)
sdev->no_uld_attach = 1;
switch (sdev->type = (inq_result[0] & 0x1f)) {
case TYPE_TAPE:
case TYPE_DISK:
case TYPE_PRINTER:
case TYPE_MOD:
case TYPE_PROCESSOR:
case TYPE_SCANNER:
case TYPE_MEDIUM_CHANGER:
case TYPE_ENCLOSURE:
case TYPE_COMM:
sdev->writeable = 1;
break;
case TYPE_WORM:
case TYPE_ROM:
sdev->writeable = 0;
break;
default:
printk(KERN_INFO "scsi: unknown device type %d\n", sdev->type);
}
print_inquiry(inq_result);
/*
* For a peripheral qualifier (PQ) value of 1 (001b), the SCSI
* spec says: The device server is capable of supporting the
* specified peripheral device type on this logical unit. However,
* the physical device is not currently connected to this logical
* unit.
*
* The above is vague, as it implies that we could treat 001 and
* 011 the same. Stay compatible with previous code, and create a
* Scsi_Device for a PQ of 1
*
* Don't set the device offline here; rather let the upper
* level drivers eval the PQ to decide whether they should
* attach. So remove ((inq_result[0] >> 5) & 7) == 1 check.
*/
sdev->inq_periph_qual = (inq_result[0] >> 5) & 7;
sdev->removable = (0x80 & inq_result[1]) >> 7;
sdev->lockable = sdev->removable;
sdev->soft_reset = (inq_result[7] & 1) && ((inq_result[3] & 7) == 2);
if (sdev->scsi_level >= SCSI_3 || (sdev->inquiry_len > 56 &&
inq_result[56] & 0x04))
sdev->ppr = 1;
if (inq_result[7] & 0x60)
sdev->wdtr = 1;
if (inq_result[7] & 0x10)
sdev->sdtr = 1;
sprintf(sdev->devfs_name, "scsi/host%d/bus%d/target%d/lun%d",
sdev->host->host_no, sdev->channel,
sdev->id, sdev->lun);
/*
* End driverfs/devfs code.
*/
if ((sdev->scsi_level >= SCSI_2) && (inq_result[7] & 2) &&
!(*bflags & BLIST_NOTQ))
sdev->tagged_supported = 1;
/*
* Some devices (Texel CD ROM drives) have handshaking problems
* when used with the Seagate controllers. borken is initialized
* to 1, and then set it to 0 here.
*/
if ((*bflags & BLIST_BORKEN) == 0)
sdev->borken = 0;
/*
* Apparently some really broken devices (contrary to the SCSI
* standards) need to be selected without asserting ATN
*/
if (*bflags & BLIST_SELECT_NO_ATN)
sdev->select_no_atn = 1;
/*
* Some devices may not want to have a start command automatically
* issued when a device is added.
*/
if (*bflags & BLIST_NOSTARTONADD)
sdev->no_start_on_add = 1;
if (*bflags & BLIST_SINGLELUN)
sdev->single_lun = 1;
sdev->use_10_for_rw = 1;
if (*bflags & BLIST_MS_SKIP_PAGE_08)
sdev->skip_ms_page_8 = 1;
if (*bflags & BLIST_MS_SKIP_PAGE_3F)
sdev->skip_ms_page_3f = 1;
if (*bflags & BLIST_USE_10_BYTE_MS)
sdev->use_10_for_ms = 1;
/* set the device running here so that slave configure
* may do I/O */
scsi_device_set_state(sdev, SDEV_RUNNING);
if (*bflags & BLIST_MS_192_BYTES_FOR_3F)
sdev->use_192_bytes_for_3f = 1;
if (*bflags & BLIST_NOT_LOCKABLE)
sdev->lockable = 0;
if (*bflags & BLIST_RETRY_HWERROR)
sdev->retry_hwerror = 1;
transport_configure_device(&sdev->sdev_gendev);
if (sdev->host->hostt->slave_configure)
sdev->host->hostt->slave_configure(sdev);
/*
* Ok, the device is now all set up, we can
* register it and tell the rest of the kernel
* about it.
*/
scsi_sysfs_add_sdev(sdev);
return SCSI_SCAN_LUN_PRESENT;
}
/**
* scsi_probe_and_add_lun - probe a LUN, if a LUN is found add it
* @starget: pointer to target device structure
* @lun: LUN of target device
* @sdevscan: probe the LUN corresponding to this Scsi_Device
* @sdevnew: store the value of any new Scsi_Device allocated
* @bflagsp: store bflags here if not NULL
*
* Description:
* Call scsi_probe_lun, if a LUN with an attached device is found,
* allocate and set it up by calling scsi_add_lun.
*
* Return:
* SCSI_SCAN_NO_RESPONSE: could not allocate or setup a Scsi_Device
* SCSI_SCAN_TARGET_PRESENT: target responded, but no device is
* attached at the LUN
* SCSI_SCAN_LUN_PRESENT: a new Scsi_Device was allocated and initialized
**/
static int scsi_probe_and_add_lun(struct scsi_target *starget,
uint lun, int *bflagsp,
struct scsi_device **sdevp, int rescan,
void *hostdata)
{
struct scsi_device *sdev;
struct scsi_request *sreq;
unsigned char *result;
int bflags, res = SCSI_SCAN_NO_RESPONSE;
struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
/*
* The rescan flag is used as an optimization, the first scan of a
* host adapter calls into here with rescan == 0.
*/
if (rescan) {
sdev = scsi_device_lookup_by_target(starget, lun);
if (sdev) {
SCSI_LOG_SCAN_BUS(3, printk(KERN_INFO
"scsi scan: device exists on %s\n",
sdev->sdev_gendev.bus_id));
if (sdevp)
*sdevp = sdev;
else
scsi_device_put(sdev);
if (bflagsp)
*bflagsp = scsi_get_device_flags(sdev,
sdev->vendor,
sdev->model);
return SCSI_SCAN_LUN_PRESENT;
}
}
sdev = scsi_alloc_sdev(starget, lun, hostdata);
if (!sdev)
goto out;
sreq = scsi_allocate_request(sdev, GFP_ATOMIC);
if (!sreq)
goto out_free_sdev;
result = kmalloc(256, GFP_ATOMIC |
(shost->unchecked_isa_dma) ? __GFP_DMA : 0);
if (!result)
goto out_free_sreq;
scsi_probe_lun(sreq, result, &bflags);
if (sreq->sr_result)
goto out_free_result;
/*
* result contains valid SCSI INQUIRY data.
*/
if ((result[0] >> 5) == 3) {
/*
* For a Peripheral qualifier 3 (011b), the SCSI
* spec says: The device server is not capable of
* supporting a physical device on this logical
* unit.
*
* For disks, this implies that there is no
* logical disk configured at sdev->lun, but there
* is a target id responding.
*/
SCSI_LOG_SCAN_BUS(3, printk(KERN_INFO
"scsi scan: peripheral qualifier of 3,"
" no device added\n"));
res = SCSI_SCAN_TARGET_PRESENT;
goto out_free_result;
}
res = scsi_add_lun(sdev, result, &bflags);
if (res == SCSI_SCAN_LUN_PRESENT) {
if (bflags & BLIST_KEY) {
sdev->lockable = 0;
scsi_unlock_floptical(sreq, result);
}
if (bflagsp)
*bflagsp = bflags;
}
out_free_result:
kfree(result);
out_free_sreq:
scsi_release_request(sreq);
out_free_sdev:
if (res == SCSI_SCAN_LUN_PRESENT) {
if (sdevp) {
scsi_device_get(sdev);
*sdevp = sdev;
}
} else {
if (sdev->host->hostt->slave_destroy)
sdev->host->hostt->slave_destroy(sdev);
transport_destroy_device(&sdev->sdev_gendev);
put_device(&sdev->sdev_gendev);
}
out:
return res;
}
/**
* scsi_sequential_lun_scan - sequentially scan a SCSI target
* @starget: pointer to target structure to scan
* @bflags: black/white list flag for LUN 0
* @lun0_res: result of scanning LUN 0
*
* Description:
* Generally, scan from LUN 1 (LUN 0 is assumed to already have been
* scanned) to some maximum lun until a LUN is found with no device
* attached. Use the bflags to figure out any oddities.
*
* Modifies sdevscan->lun.
**/
static void scsi_sequential_lun_scan(struct scsi_target *starget,
int bflags, int lun0_res, int scsi_level,
int rescan)
{
unsigned int sparse_lun, lun, max_dev_lun;
struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
SCSI_LOG_SCAN_BUS(3, printk(KERN_INFO "scsi scan: Sequential scan of"
"%s\n", starget->dev.bus_id));
max_dev_lun = min(max_scsi_luns, shost->max_lun);
/*
* If this device is known to support sparse multiple units,
* override the other settings, and scan all of them. Normally,
* SCSI-3 devices should be scanned via the REPORT LUNS.
*/
if (bflags & BLIST_SPARSELUN) {
max_dev_lun = shost->max_lun;
sparse_lun = 1;
} else
sparse_lun = 0;
/*
* If not sparse lun and no device attached at LUN 0 do not scan
* any further.
*/
if (!sparse_lun && (lun0_res != SCSI_SCAN_LUN_PRESENT))
return;
/*
* If less than SCSI_1_CSS, and no special lun scaning, stop
* scanning; this matches 2.4 behaviour, but could just be a bug
* (to continue scanning a SCSI_1_CSS device).
*
* This test is broken. We might not have any device on lun0 for
* a sparselun device, and if that's the case then how would we
* know the real scsi_level, eh? It might make sense to just not
* scan any SCSI_1 device for non-0 luns, but that check would best
* go into scsi_alloc_sdev() and just have it return null when asked
* to alloc an sdev for lun > 0 on an already found SCSI_1 device.
*
if ((sdevscan->scsi_level < SCSI_1_CCS) &&
((bflags & (BLIST_FORCELUN | BLIST_SPARSELUN | BLIST_MAX5LUN))
== 0))
return;
*/
/*
* If this device is known to support multiple units, override
* the other settings, and scan all of them.
*/
if (bflags & BLIST_FORCELUN)
max_dev_lun = shost->max_lun;
/*
* REGAL CDC-4X: avoid hang after LUN 4
*/
if (bflags & BLIST_MAX5LUN)
max_dev_lun = min(5U, max_dev_lun);
/*
* Do not scan SCSI-2 or lower device past LUN 7, unless
* BLIST_LARGELUN.
*/
if (scsi_level < SCSI_3 && !(bflags & BLIST_LARGELUN))
max_dev_lun = min(8U, max_dev_lun);
/*
* We have already scanned LUN 0, so start at LUN 1. Keep scanning
* until we reach the max, or no LUN is found and we are not
* sparse_lun.
*/
for (lun = 1; lun < max_dev_lun; ++lun)
if ((scsi_probe_and_add_lun(starget, lun, NULL, NULL, rescan,
NULL) != SCSI_SCAN_LUN_PRESENT) &&
!sparse_lun)
return;
}
/**
* scsilun_to_int: convert a scsi_lun to an int
* @scsilun: struct scsi_lun to be converted.
*
* Description:
* Convert @scsilun from a struct scsi_lun to a four byte host byte-ordered
* integer, and return the result. The caller must check for
* truncation before using this function.
*
* Notes:
* The struct scsi_lun is assumed to be four levels, with each level
* effectively containing a SCSI byte-ordered (big endian) short; the
* addressing bits of each level are ignored (the highest two bits).
* For a description of the LUN format, post SCSI-3 see the SCSI
* Architecture Model, for SCSI-3 see the SCSI Controller Commands.
*
* Given a struct scsi_lun of: 0a 04 0b 03 00 00 00 00, this function returns
* the integer: 0x0b030a04
**/
static int scsilun_to_int(struct scsi_lun *scsilun)
{
int i;
unsigned int lun;
lun = 0;
for (i = 0; i < sizeof(lun); i += 2)
lun = lun | (((scsilun->scsi_lun[i] << 8) |
scsilun->scsi_lun[i + 1]) << (i * 8));
return lun;
}
/**
* scsi_report_lun_scan - Scan using SCSI REPORT LUN results
* @sdevscan: scan the host, channel, and id of this Scsi_Device
*
* Description:
* If @sdevscan is for a SCSI-3 or up device, send a REPORT LUN
* command, and scan the resulting list of LUNs by calling
* scsi_probe_and_add_lun.
*
* Modifies sdevscan->lun.
*
* Return:
* 0: scan completed (or no memory, so further scanning is futile)
* 1: no report lun scan, or not configured
**/
static int scsi_report_lun_scan(struct scsi_device *sdev, int bflags,
int rescan)
{
char devname[64];
unsigned char scsi_cmd[MAX_COMMAND_SIZE];
unsigned int length;
unsigned int lun;
unsigned int num_luns;
unsigned int retries;
struct scsi_lun *lunp, *lun_data;
struct scsi_request *sreq;
u8 *data;
struct scsi_sense_hdr sshdr;
struct scsi_target *starget = scsi_target(sdev);
/*
* Only support SCSI-3 and up devices if BLIST_NOREPORTLUN is not set.
* Also allow SCSI-2 if BLIST_REPORTLUN2 is set and host adapter does
* support more than 8 LUNs.
*/
if ((bflags & BLIST_NOREPORTLUN) ||
sdev->scsi_level < SCSI_2 ||
(sdev->scsi_level < SCSI_3 &&
(!(bflags & BLIST_REPORTLUN2) || sdev->host->max_lun <= 8)) )
return 1;
if (bflags & BLIST_NOLUN)
return 0;
sreq = scsi_allocate_request(sdev, GFP_ATOMIC);
if (!sreq)
goto out;
sprintf(devname, "host %d channel %d id %d",
sdev->host->host_no, sdev->channel, sdev->id);
/*
* Allocate enough to hold the header (the same size as one scsi_lun)
* plus the max number of luns we are requesting.
*
* Reallocating and trying again (with the exact amount we need)
* would be nice, but then we need to somehow limit the size
* allocated based on the available memory and the limits of
* kmalloc - we don't want a kmalloc() failure of a huge value to
* prevent us from finding any LUNs on this target.
*/
length = (max_scsi_report_luns + 1) * sizeof(struct scsi_lun);
lun_data = kmalloc(length, GFP_ATOMIC |
(sdev->host->unchecked_isa_dma ? __GFP_DMA : 0));
if (!lun_data)
goto out_release_request;
scsi_cmd[0] = REPORT_LUNS;
/*
* bytes 1 - 5: reserved, set to zero.
*/
memset(&scsi_cmd[1], 0, 5);
/*
* bytes 6 - 9: length of the command.
*/
scsi_cmd[6] = (unsigned char) (length >> 24) & 0xff;
scsi_cmd[7] = (unsigned char) (length >> 16) & 0xff;
scsi_cmd[8] = (unsigned char) (length >> 8) & 0xff;
scsi_cmd[9] = (unsigned char) length & 0xff;
scsi_cmd[10] = 0; /* reserved */
scsi_cmd[11] = 0; /* control */
sreq->sr_cmd_len = 0;
sreq->sr_data_direction = DMA_FROM_DEVICE;
/*
* We can get a UNIT ATTENTION, for example a power on/reset, so
* retry a few times (like sd.c does for TEST UNIT READY).
* Experience shows some combinations of adapter/devices get at
* least two power on/resets.
*
* Illegal requests (for devices that do not support REPORT LUNS)
* should come through as a check condition, and will not generate
* a retry.
*/
for (retries = 0; retries < 3; retries++) {
SCSI_LOG_SCAN_BUS(3, printk (KERN_INFO "scsi scan: Sending"
" REPORT LUNS to %s (try %d)\n", devname,
retries));
scsi_wait_req(sreq, scsi_cmd, lun_data, length,
SCSI_TIMEOUT + 4*HZ, 3);
SCSI_LOG_SCAN_BUS(3, printk (KERN_INFO "scsi scan: REPORT LUNS"
" %s (try %d) result 0x%x\n", sreq->sr_result
? "failed" : "successful", retries,
sreq->sr_result));
if (sreq->sr_result == 0)
break;
else if (scsi_request_normalize_sense(sreq, &sshdr)) {
if (sshdr.sense_key != UNIT_ATTENTION)
break;
}
}
if (sreq->sr_result) {
/*
* The device probably does not support a REPORT LUN command
*/
kfree(lun_data);
scsi_release_request(sreq);
return 1;
}
scsi_release_request(sreq);
/*
* Get the length from the first four bytes of lun_data.
*/
data = (u8 *) lun_data->scsi_lun;
length = ((data[0] << 24) | (data[1] << 16) |
(data[2] << 8) | (data[3] << 0));
num_luns = (length / sizeof(struct scsi_lun));
if (num_luns > max_scsi_report_luns) {
printk(KERN_WARNING "scsi: On %s only %d (max_scsi_report_luns)"
" of %d luns reported, try increasing"
" max_scsi_report_luns.\n", devname,
max_scsi_report_luns, num_luns);
num_luns = max_scsi_report_luns;
}
SCSI_LOG_SCAN_BUS(3, printk (KERN_INFO "scsi scan: REPORT LUN scan of"
" host %d channel %d id %d\n", sdev->host->host_no,
sdev->channel, sdev->id));
/*
* Scan the luns in lun_data. The entry at offset 0 is really
* the header, so start at 1 and go up to and including num_luns.
*/
for (lunp = &lun_data[1]; lunp <= &lun_data[num_luns]; lunp++) {
lun = scsilun_to_int(lunp);
/*
* Check if the unused part of lunp is non-zero, and so
* does not fit in lun.
*/
if (memcmp(&lunp->scsi_lun[sizeof(lun)], "\0\0\0\0", 4)) {
int i;
/*
* Output an error displaying the LUN in byte order,
* this differs from what linux would print for the
* integer LUN value.
*/
printk(KERN_WARNING "scsi: %s lun 0x", devname);
data = (char *)lunp->scsi_lun;
for (i = 0; i < sizeof(struct scsi_lun); i++)
printk("%02x", data[i]);
printk(" has a LUN larger than currently supported.\n");
} else if (lun == 0) {
/*
* LUN 0 has already been scanned.
*/
} else if (lun > sdev->host->max_lun) {
printk(KERN_WARNING "scsi: %s lun%d has a LUN larger"
" than allowed by the host adapter\n",
devname, lun);
} else {
int res;
res = scsi_probe_and_add_lun(starget,
lun, NULL, NULL, rescan, NULL);
if (res == SCSI_SCAN_NO_RESPONSE) {
/*
* Got some results, but now none, abort.
*/
printk(KERN_ERR "scsi: Unexpected response"
" from %s lun %d while scanning, scan"
" aborted\n", devname, lun);
break;
}
}
}
kfree(lun_data);
return 0;
out_release_request:
scsi_release_request(sreq);
out:
/*
* We are out of memory, don't try scanning any further.
*/
printk(ALLOC_FAILURE_MSG, __FUNCTION__);
return 0;
}
struct scsi_device *__scsi_add_device(struct Scsi_Host *shost, uint channel,
uint id, uint lun, void *hostdata)
{
struct scsi_device *sdev;
struct device *parent = &shost->shost_gendev;
int res;
struct scsi_target *starget = scsi_alloc_target(parent, channel, id);
if (!starget)
return ERR_PTR(-ENOMEM);
down(&shost->scan_mutex);
res = scsi_probe_and_add_lun(starget, lun, NULL, &sdev, 1, hostdata);
if (res != SCSI_SCAN_LUN_PRESENT)
sdev = ERR_PTR(-ENODEV);
up(&shost->scan_mutex);
scsi_target_reap(starget);
put_device(&starget->dev);
return sdev;
}
EXPORT_SYMBOL(__scsi_add_device);
void scsi_rescan_device(struct device *dev)
{
struct scsi_driver *drv;
if (!dev->driver)
return;
drv = to_scsi_driver(dev->driver);
if (try_module_get(drv->owner)) {
if (drv->rescan)
drv->rescan(dev);
module_put(drv->owner);
}
}
EXPORT_SYMBOL(scsi_rescan_device);
/**
* scsi_scan_target - scan a target id, possibly including all LUNs on the
* target.
* @sdevsca: Scsi_Device handle for scanning
* @shost: host to scan
* @channel: channel to scan
* @id: target id to scan
*
* Description:
* Scan the target id on @shost, @channel, and @id. Scan at least LUN
* 0, and possibly all LUNs on the target id.
*
* Use the pre-allocated @sdevscan as a handle for the scanning. This
* function sets sdevscan->host, sdevscan->id and sdevscan->lun; the
* scanning functions modify sdevscan->lun.
*
* First try a REPORT LUN scan, if that does not scan the target, do a
* sequential scan of LUNs on the target id.
**/
void scsi_scan_target(struct device *parent, unsigned int channel,
unsigned int id, unsigned int lun, int rescan)
{
struct Scsi_Host *shost = dev_to_shost(parent);
int bflags = 0;
int res;
struct scsi_device *sdev = NULL;
struct scsi_target *starget;
if (shost->this_id == id)
/*
* Don't scan the host adapter
*/
return;
starget = scsi_alloc_target(parent, channel, id);
if (!starget)
return;
get_device(&starget->dev);
if (lun != SCAN_WILD_CARD) {
/*
* Scan for a specific host/chan/id/lun.
*/
scsi_probe_and_add_lun(starget, lun, NULL, NULL, rescan, NULL);
goto out_reap;
}
/*
* Scan LUN 0, if there is some response, scan further. Ideally, we
* would not configure LUN 0 until all LUNs are scanned.
*/
res = scsi_probe_and_add_lun(starget, 0, &bflags, &sdev, rescan, NULL);
if (res == SCSI_SCAN_LUN_PRESENT) {
if (scsi_report_lun_scan(sdev, bflags, rescan) != 0)
/*
* The REPORT LUN did not scan the target,
* do a sequential scan.
*/
scsi_sequential_lun_scan(starget, bflags,
res, sdev->scsi_level, rescan);
} else if (res == SCSI_SCAN_TARGET_PRESENT) {
/*
* There's a target here, but lun 0 is offline so we
* can't use the report_lun scan. Fall back to a
* sequential lun scan with a bflags of SPARSELUN and
* a default scsi level of SCSI_2
*/
scsi_sequential_lun_scan(starget, BLIST_SPARSELUN,
SCSI_SCAN_TARGET_PRESENT, SCSI_2, rescan);
}
if (sdev)
scsi_device_put(sdev);
out_reap:
/* now determine if the target has any children at all
* and if not, nuke it */
scsi_target_reap(starget);
put_device(&starget->dev);
}
EXPORT_SYMBOL(scsi_scan_target);
static void scsi_scan_channel(struct Scsi_Host *shost, unsigned int channel,
unsigned int id, unsigned int lun, int rescan)
{
uint order_id;
if (id == SCAN_WILD_CARD)
for (id = 0; id < shost->max_id; ++id) {
/*
* XXX adapter drivers when possible (FCP, iSCSI)
* could modify max_id to match the current max,
* not the absolute max.
*
* XXX add a shost id iterator, so for example,
* the FC ID can be the same as a target id
* without a huge overhead of sparse id's.
*/
if (shost->reverse_ordering)
/*
* Scan from high to low id.
*/
order_id = shost->max_id - id - 1;
else
order_id = id;
scsi_scan_target(&shost->shost_gendev, channel, order_id, lun, rescan);
}
else
scsi_scan_target(&shost->shost_gendev, channel, id, lun, rescan);
}
int scsi_scan_host_selected(struct Scsi_Host *shost, unsigned int channel,
unsigned int id, unsigned int lun, int rescan)
{
SCSI_LOG_SCAN_BUS(3, printk (KERN_INFO "%s: <%u:%u:%u:%u>\n",
__FUNCTION__, shost->host_no, channel, id, lun));
if (((channel != SCAN_WILD_CARD) && (channel > shost->max_channel)) ||
((id != SCAN_WILD_CARD) && (id > shost->max_id)) ||
((lun != SCAN_WILD_CARD) && (lun > shost->max_lun)))
return -EINVAL;
down(&shost->scan_mutex);
if (channel == SCAN_WILD_CARD)
for (channel = 0; channel <= shost->max_channel; channel++)
scsi_scan_channel(shost, channel, id, lun, rescan);
else
scsi_scan_channel(shost, channel, id, lun, rescan);
up(&shost->scan_mutex);
return 0;
}
/**
* scsi_scan_host - scan the given adapter
* @shost: adapter to scan
**/
void scsi_scan_host(struct Scsi_Host *shost)
{
scsi_scan_host_selected(shost, SCAN_WILD_CARD, SCAN_WILD_CARD,
SCAN_WILD_CARD, 0);
}
EXPORT_SYMBOL(scsi_scan_host);
/**
* scsi_scan_single_target - scan the given SCSI target
* @shost: adapter to scan
* @chan: channel to scan
* @id: target id to scan
**/
void scsi_scan_single_target(struct Scsi_Host *shost,
unsigned int chan, unsigned int id)
{
scsi_scan_host_selected(shost, chan, id, SCAN_WILD_CARD, 1);
}
EXPORT_SYMBOL(scsi_scan_single_target);
void scsi_forget_host(struct Scsi_Host *shost)
{
struct scsi_target *starget, *tmp;
unsigned long flags;
/*
* Ok, this look a bit strange. We always look for the first device
* on the list as scsi_remove_device removes them from it - thus we
* also have to release the lock.
* We don't need to get another reference to the device before
* releasing the lock as we already own the reference from
* scsi_register_device that's release in scsi_remove_device. And
* after that we don't look at sdev anymore.
*/
spin_lock_irqsave(shost->host_lock, flags);
list_for_each_entry_safe(starget, tmp, &shost->__targets, siblings) {
spin_unlock_irqrestore(shost->host_lock, flags);
scsi_remove_target(&starget->dev);
spin_lock_irqsave(shost->host_lock, flags);
}
spin_unlock_irqrestore(shost->host_lock, flags);
}
/*
* Function: scsi_get_host_dev()
*
* Purpose: Create a Scsi_Device that points to the host adapter itself.
*
* Arguments: SHpnt - Host that needs a Scsi_Device
*
* Lock status: None assumed.
*
* Returns: The Scsi_Device or NULL
*
* Notes:
* Attach a single Scsi_Device to the Scsi_Host - this should
* be made to look like a "pseudo-device" that points to the
* HA itself.
*
* Note - this device is not accessible from any high-level
* drivers (including generics), which is probably not
* optimal. We can add hooks later to attach
*/
struct scsi_device *scsi_get_host_dev(struct Scsi_Host *shost)
{
struct scsi_device *sdev;
struct scsi_target *starget;
starget = scsi_alloc_target(&shost->shost_gendev, 0, shost->this_id);
if (!starget)
return NULL;
sdev = scsi_alloc_sdev(starget, 0, NULL);
if (sdev) {
sdev->sdev_gendev.parent = get_device(&starget->dev);
sdev->borken = 0;
}
put_device(&starget->dev);
return sdev;
}
EXPORT_SYMBOL(scsi_get_host_dev);
/*
* Function: scsi_free_host_dev()
*
* Purpose: Free a scsi_device that points to the host adapter itself.
*
* Arguments: SHpnt - Host that needs a Scsi_Device
*
* Lock status: None assumed.
*
* Returns: Nothing
*
* Notes:
*/
void scsi_free_host_dev(struct scsi_device *sdev)
{
BUG_ON(sdev->id != sdev->host->this_id);
if (sdev->host->hostt->slave_destroy)
sdev->host->hostt->slave_destroy(sdev);
transport_destroy_device(&sdev->sdev_gendev);
put_device(&sdev->sdev_gendev);
}
EXPORT_SYMBOL(scsi_free_host_dev);
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