android_kernel_motorola_sm6225/drivers/usb/storage/scsiglue.c
Alan Stern f756cbd458 usb-storage: revert DMA-alignment change for Wireless USB
This patch (as1110) reverts an earlier patch meant to help with
Wireless USB host controllers.  These controllers can have bulk
maxpacket values larger than 512, which puts unusual constraints on
the sizes of scatter-gather list elements.  However it turns out that
the block layer does not provide the support we need to enforce these
constraints; merely changing the DMA alignment mask doesn't help.
Hence there's no reason to keep the original patch.  The Wireless USB
problem will have to be solved a different way.

In addition, there is a reason to get rid of the earlier patch.  By
dereferencing a pointer stored in the ep_in array of struct
usb_device, the current code risks an invalid memory access when it
runs concurrently with device removal.  The members of that array are
cleared before the driver's disconnect method is called, so it should
not try to use them.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2008-07-21 15:16:51 -07:00

521 lines
16 KiB
C

/* Driver for USB Mass Storage compliant devices
* SCSI layer glue code
*
* Current development and maintenance by:
* (c) 1999-2002 Matthew Dharm (mdharm-usb@one-eyed-alien.net)
*
* Developed with the assistance of:
* (c) 2000 David L. Brown, Jr. (usb-storage@davidb.org)
* (c) 2000 Stephen J. Gowdy (SGowdy@lbl.gov)
*
* Initial work by:
* (c) 1999 Michael Gee (michael@linuxspecific.com)
*
* This driver is based on the 'USB Mass Storage Class' document. This
* describes in detail the protocol used to communicate with such
* devices. Clearly, the designers had SCSI and ATAPI commands in
* mind when they created this document. The commands are all very
* similar to commands in the SCSI-II and ATAPI specifications.
*
* It is important to note that in a number of cases this class
* exhibits class-specific exemptions from the USB specification.
* Notably the usage of NAK, STALL and ACK differs from the norm, in
* that they are used to communicate wait, failed and OK on commands.
*
* Also, for certain devices, the interrupt endpoint is used to convey
* status of a command.
*
* Please see http://www.one-eyed-alien.net/~mdharm/linux-usb for more
* information about this driver.
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the
* Free Software Foundation; either version 2, or (at your option) any
* later version.
*
* 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.,
* 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#include <linux/slab.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <scsi/scsi.h>
#include <scsi/scsi_cmnd.h>
#include <scsi/scsi_devinfo.h>
#include <scsi/scsi_device.h>
#include <scsi/scsi_eh.h>
#include "usb.h"
#include "scsiglue.h"
#include "debug.h"
#include "transport.h"
#include "protocol.h"
/***********************************************************************
* Host functions
***********************************************************************/
static const char* host_info(struct Scsi_Host *host)
{
return "SCSI emulation for USB Mass Storage devices";
}
static int slave_alloc (struct scsi_device *sdev)
{
struct us_data *us = host_to_us(sdev->host);
/*
* Set the INQUIRY transfer length to 36. We don't use any of
* the extra data and many devices choke if asked for more or
* less than 36 bytes.
*/
sdev->inquiry_len = 36;
/* USB has unusual DMA-alignment requirements: Although the
* starting address of each scatter-gather element doesn't matter,
* the length of each element except the last must be divisible
* by the Bulk maxpacket value. There's currently no way to
* express this by block-layer constraints, so we'll cop out
* and simply require addresses to be aligned at 512-byte
* boundaries. This is okay since most block I/O involves
* hardware sectors that are multiples of 512 bytes in length,
* and since host controllers up through USB 2.0 have maxpacket
* values no larger than 512.
*
* But it doesn't suffice for Wireless USB, where Bulk maxpacket
* values can be as large as 2048. To make that work properly
* will require changes to the block layer.
*/
blk_queue_update_dma_alignment(sdev->request_queue, (512 - 1));
/*
* The UFI spec treates the Peripheral Qualifier bits in an
* INQUIRY result as reserved and requires devices to set them
* to 0. However the SCSI spec requires these bits to be set
* to 3 to indicate when a LUN is not present.
*
* Let the scanning code know if this target merely sets
* Peripheral Device Type to 0x1f to indicate no LUN.
*/
if (us->subclass == US_SC_UFI)
sdev->sdev_target->pdt_1f_for_no_lun = 1;
return 0;
}
static int slave_configure(struct scsi_device *sdev)
{
struct us_data *us = host_to_us(sdev->host);
/* Many devices have trouble transfering more than 32KB at a time,
* while others have trouble with more than 64K. At this time we
* are limiting both to 32K (64 sectores).
*/
if (us->fflags & (US_FL_MAX_SECTORS_64 | US_FL_MAX_SECTORS_MIN)) {
unsigned int max_sectors = 64;
if (us->fflags & US_FL_MAX_SECTORS_MIN)
max_sectors = PAGE_CACHE_SIZE >> 9;
if (sdev->request_queue->max_sectors > max_sectors)
blk_queue_max_sectors(sdev->request_queue,
max_sectors);
}
/* We can't put these settings in slave_alloc() because that gets
* called before the device type is known. Consequently these
* settings can't be overridden via the scsi devinfo mechanism. */
if (sdev->type == TYPE_DISK) {
/* Disk-type devices use MODE SENSE(6) if the protocol
* (SubClass) is Transparent SCSI, otherwise they use
* MODE SENSE(10). */
if (us->subclass != US_SC_SCSI && us->subclass != US_SC_CYP_ATACB)
sdev->use_10_for_ms = 1;
/* Many disks only accept MODE SENSE transfer lengths of
* 192 bytes (that's what Windows uses). */
sdev->use_192_bytes_for_3f = 1;
/* Some devices don't like MODE SENSE with page=0x3f,
* which is the command used for checking if a device
* is write-protected. Now that we tell the sd driver
* to do a 192-byte transfer with this command the
* majority of devices work fine, but a few still can't
* handle it. The sd driver will simply assume those
* devices are write-enabled. */
if (us->fflags & US_FL_NO_WP_DETECT)
sdev->skip_ms_page_3f = 1;
/* A number of devices have problems with MODE SENSE for
* page x08, so we will skip it. */
sdev->skip_ms_page_8 = 1;
/* Some disks return the total number of blocks in response
* to READ CAPACITY rather than the highest block number.
* If this device makes that mistake, tell the sd driver. */
if (us->fflags & US_FL_FIX_CAPACITY)
sdev->fix_capacity = 1;
/* A few disks have two indistinguishable version, one of
* which reports the correct capacity and the other does not.
* The sd driver has to guess which is the case. */
if (us->fflags & US_FL_CAPACITY_HEURISTICS)
sdev->guess_capacity = 1;
/* Some devices report a SCSI revision level above 2 but are
* unable to handle the REPORT LUNS command (for which
* support is mandatory at level 3). Since we already have
* a Get-Max-LUN request, we won't lose much by setting the
* revision level down to 2. The only devices that would be
* affected are those with sparse LUNs. */
if (sdev->scsi_level > SCSI_2)
sdev->sdev_target->scsi_level =
sdev->scsi_level = SCSI_2;
/* USB-IDE bridges tend to report SK = 0x04 (Non-recoverable
* Hardware Error) when any low-level error occurs,
* recoverable or not. Setting this flag tells the SCSI
* midlayer to retry such commands, which frequently will
* succeed and fix the error. The worst this can lead to
* is an occasional series of retries that will all fail. */
sdev->retry_hwerror = 1;
/* USB disks should allow restart. Some drives spin down
* automatically, requiring a START-STOP UNIT command. */
sdev->allow_restart = 1;
/* Some USB cardreaders have trouble reading an sdcard's last
* sector in a larger then 1 sector read, since the performance
* impact is negible we set this flag for all USB disks */
sdev->last_sector_bug = 1;
} else {
/* Non-disk-type devices don't need to blacklist any pages
* or to force 192-byte transfer lengths for MODE SENSE.
* But they do need to use MODE SENSE(10). */
sdev->use_10_for_ms = 1;
}
/* The CB and CBI transports have no way to pass LUN values
* other than the bits in the second byte of a CDB. But those
* bits don't get set to the LUN value if the device reports
* scsi_level == 0 (UNKNOWN). Hence such devices must necessarily
* be single-LUN.
*/
if ((us->protocol == US_PR_CB || us->protocol == US_PR_CBI) &&
sdev->scsi_level == SCSI_UNKNOWN)
us->max_lun = 0;
/* Some devices choke when they receive a PREVENT-ALLOW MEDIUM
* REMOVAL command, so suppress those commands. */
if (us->fflags & US_FL_NOT_LOCKABLE)
sdev->lockable = 0;
/* this is to satisfy the compiler, tho I don't think the
* return code is ever checked anywhere. */
return 0;
}
/* queue a command */
/* This is always called with scsi_lock(host) held */
static int queuecommand(struct scsi_cmnd *srb,
void (*done)(struct scsi_cmnd *))
{
struct us_data *us = host_to_us(srb->device->host);
US_DEBUGP("%s called\n", __func__);
/* check for state-transition errors */
if (us->srb != NULL) {
printk(KERN_ERR USB_STORAGE "Error in %s: us->srb = %p\n",
__func__, us->srb);
return SCSI_MLQUEUE_HOST_BUSY;
}
/* fail the command if we are disconnecting */
if (test_bit(US_FLIDX_DISCONNECTING, &us->dflags)) {
US_DEBUGP("Fail command during disconnect\n");
srb->result = DID_NO_CONNECT << 16;
done(srb);
return 0;
}
/* enqueue the command and wake up the control thread */
srb->scsi_done = done;
us->srb = srb;
complete(&us->cmnd_ready);
return 0;
}
/***********************************************************************
* Error handling functions
***********************************************************************/
/* Command timeout and abort */
static int command_abort(struct scsi_cmnd *srb)
{
struct us_data *us = host_to_us(srb->device->host);
US_DEBUGP("%s called\n", __func__);
/* us->srb together with the TIMED_OUT, RESETTING, and ABORTING
* bits are protected by the host lock. */
scsi_lock(us_to_host(us));
/* Is this command still active? */
if (us->srb != srb) {
scsi_unlock(us_to_host(us));
US_DEBUGP ("-- nothing to abort\n");
return FAILED;
}
/* Set the TIMED_OUT bit. Also set the ABORTING bit, but only if
* a device reset isn't already in progress (to avoid interfering
* with the reset). Note that we must retain the host lock while
* calling usb_stor_stop_transport(); otherwise it might interfere
* with an auto-reset that begins as soon as we release the lock. */
set_bit(US_FLIDX_TIMED_OUT, &us->dflags);
if (!test_bit(US_FLIDX_RESETTING, &us->dflags)) {
set_bit(US_FLIDX_ABORTING, &us->dflags);
usb_stor_stop_transport(us);
}
scsi_unlock(us_to_host(us));
/* Wait for the aborted command to finish */
wait_for_completion(&us->notify);
return SUCCESS;
}
/* This invokes the transport reset mechanism to reset the state of the
* device */
static int device_reset(struct scsi_cmnd *srb)
{
struct us_data *us = host_to_us(srb->device->host);
int result;
US_DEBUGP("%s called\n", __func__);
/* lock the device pointers and do the reset */
mutex_lock(&(us->dev_mutex));
result = us->transport_reset(us);
mutex_unlock(&us->dev_mutex);
return result < 0 ? FAILED : SUCCESS;
}
/* Simulate a SCSI bus reset by resetting the device's USB port. */
static int bus_reset(struct scsi_cmnd *srb)
{
struct us_data *us = host_to_us(srb->device->host);
int result;
US_DEBUGP("%s called\n", __func__);
result = usb_stor_port_reset(us);
return result < 0 ? FAILED : SUCCESS;
}
/* Report a driver-initiated device reset to the SCSI layer.
* Calling this for a SCSI-initiated reset is unnecessary but harmless.
* The caller must own the SCSI host lock. */
void usb_stor_report_device_reset(struct us_data *us)
{
int i;
struct Scsi_Host *host = us_to_host(us);
scsi_report_device_reset(host, 0, 0);
if (us->fflags & US_FL_SCM_MULT_TARG) {
for (i = 1; i < host->max_id; ++i)
scsi_report_device_reset(host, 0, i);
}
}
/* Report a driver-initiated bus reset to the SCSI layer.
* Calling this for a SCSI-initiated reset is unnecessary but harmless.
* The caller must not own the SCSI host lock. */
void usb_stor_report_bus_reset(struct us_data *us)
{
struct Scsi_Host *host = us_to_host(us);
scsi_lock(host);
scsi_report_bus_reset(host, 0);
scsi_unlock(host);
}
/***********************************************************************
* /proc/scsi/ functions
***********************************************************************/
/* we use this macro to help us write into the buffer */
#undef SPRINTF
#define SPRINTF(args...) \
do { if (pos < buffer+length) pos += sprintf(pos, ## args); } while (0)
static int proc_info (struct Scsi_Host *host, char *buffer,
char **start, off_t offset, int length, int inout)
{
struct us_data *us = host_to_us(host);
char *pos = buffer;
const char *string;
/* if someone is sending us data, just throw it away */
if (inout)
return length;
/* print the controller name */
SPRINTF(" Host scsi%d: usb-storage\n", host->host_no);
/* print product, vendor, and serial number strings */
if (us->pusb_dev->manufacturer)
string = us->pusb_dev->manufacturer;
else if (us->unusual_dev->vendorName)
string = us->unusual_dev->vendorName;
else
string = "Unknown";
SPRINTF(" Vendor: %s\n", string);
if (us->pusb_dev->product)
string = us->pusb_dev->product;
else if (us->unusual_dev->productName)
string = us->unusual_dev->productName;
else
string = "Unknown";
SPRINTF(" Product: %s\n", string);
if (us->pusb_dev->serial)
string = us->pusb_dev->serial;
else
string = "None";
SPRINTF("Serial Number: %s\n", string);
/* show the protocol and transport */
SPRINTF(" Protocol: %s\n", us->protocol_name);
SPRINTF(" Transport: %s\n", us->transport_name);
/* show the device flags */
if (pos < buffer + length) {
pos += sprintf(pos, " Quirks:");
#define US_FLAG(name, value) \
if (us->fflags & value) pos += sprintf(pos, " " #name);
US_DO_ALL_FLAGS
#undef US_FLAG
*(pos++) = '\n';
}
/*
* Calculate start of next buffer, and return value.
*/
*start = buffer + offset;
if ((pos - buffer) < offset)
return (0);
else if ((pos - buffer - offset) < length)
return (pos - buffer - offset);
else
return (length);
}
/***********************************************************************
* Sysfs interface
***********************************************************************/
/* Output routine for the sysfs max_sectors file */
static ssize_t show_max_sectors(struct device *dev, struct device_attribute *attr, char *buf)
{
struct scsi_device *sdev = to_scsi_device(dev);
return sprintf(buf, "%u\n", sdev->request_queue->max_sectors);
}
/* Input routine for the sysfs max_sectors file */
static ssize_t store_max_sectors(struct device *dev, struct device_attribute *attr, const char *buf,
size_t count)
{
struct scsi_device *sdev = to_scsi_device(dev);
unsigned short ms;
if (sscanf(buf, "%hu", &ms) > 0 && ms <= SCSI_DEFAULT_MAX_SECTORS) {
blk_queue_max_sectors(sdev->request_queue, ms);
return strlen(buf);
}
return -EINVAL;
}
static DEVICE_ATTR(max_sectors, S_IRUGO | S_IWUSR, show_max_sectors,
store_max_sectors);
static struct device_attribute *sysfs_device_attr_list[] = {
&dev_attr_max_sectors,
NULL,
};
/*
* this defines our host template, with which we'll allocate hosts
*/
struct scsi_host_template usb_stor_host_template = {
/* basic userland interface stuff */
.name = "usb-storage",
.proc_name = "usb-storage",
.proc_info = proc_info,
.info = host_info,
/* command interface -- queued only */
.queuecommand = queuecommand,
/* error and abort handlers */
.eh_abort_handler = command_abort,
.eh_device_reset_handler = device_reset,
.eh_bus_reset_handler = bus_reset,
/* queue commands only, only one command per LUN */
.can_queue = 1,
.cmd_per_lun = 1,
/* unknown initiator id */
.this_id = -1,
.slave_alloc = slave_alloc,
.slave_configure = slave_configure,
/* lots of sg segments can be handled */
.sg_tablesize = SG_ALL,
/* limit the total size of a transfer to 120 KB */
.max_sectors = 240,
/* merge commands... this seems to help performance, but
* periodically someone should test to see which setting is more
* optimal.
*/
.use_clustering = 1,
/* emulated HBA */
.emulated = 1,
/* we do our own delay after a device or bus reset */
.skip_settle_delay = 1,
/* sysfs device attributes */
.sdev_attrs = sysfs_device_attr_list,
/* module management */
.module = THIS_MODULE
};
/* To Report "Illegal Request: Invalid Field in CDB */
unsigned char usb_stor_sense_invalidCDB[18] = {
[0] = 0x70, /* current error */
[2] = ILLEGAL_REQUEST, /* Illegal Request = 0x05 */
[7] = 0x0a, /* additional length */
[12] = 0x24 /* Invalid Field in CDB */
};