q3k/linux
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity
linux/drivers/usb/storage/usb.h
Alan Stern bb94a40668 usb-storage: fix freezing of the scanning thread 
This patch (as1521b) fixes the interaction between usb-storage's
scanning thread and the freezer.  The current implementation has a
race: If the device is unplugged shortly after being plugged in and
just as a system sleep begins, the scanning thread may get frozen
before the khubd task.  Khubd won't be able to freeze until the
disconnect processing is complete, and the disconnect processing can't
proceed until the scanning thread finishes, so the sleep transition
will fail.

The implementation in the 3.2 kernel suffers from an additional
problem.  There the scanning thread calls set_freezable_with_signal(),
and the signals sent by the freezer will mess up the thread's I/O
delays, which are all interruptible.

The solution to both problems is the same: Replace the kernel thread
used for scanning with a delayed-work routine on the system freezable
work queue.  Freezable work queues have the nice property that you can
cancel a work item even while the work queue is frozen, and no signals
are needed.

The 3.2 version of this patch solves the problem in Bugzilla #42730.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Acked-by: Seth Forshee <seth.forshee@canonical.com>
CC: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-02-21 16:29:15 -08:00

204 lines
7.3 KiB
C
Raw Blame History

/* Driver for USB Mass Storage compliant devices
* Main Header File
*
* Current development and maintenance by:
* (c) 1999-2002 Matthew Dharm (mdharm-usb@one-eyed-alien.net)
*
* 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.
*/
#ifndef _USB_H_
#define _USB_H_
#include <linux/usb.h>
#include <linux/usb_usual.h>
#include <linux/blkdev.h>
#include <linux/completion.h>
#include <linux/mutex.h>
#include <linux/workqueue.h>
#include <scsi/scsi_host.h>
struct us_data;
struct scsi_cmnd;
/*
* Unusual device list definitions
*/
struct us_unusual_dev {
const char* vendorName;
const char* productName;
__u8 useProtocol;
__u8 useTransport;
int (*initFunction)(struct us_data *);
};
/* Dynamic bitflag definitions (us->dflags): used in set_bit() etc. */
#define US_FLIDX_URB_ACTIVE 0 /* current_urb is in use */
#define US_FLIDX_SG_ACTIVE 1 /* current_sg is in use */
#define US_FLIDX_ABORTING 2 /* abort is in progress */
#define US_FLIDX_DISCONNECTING 3 /* disconnect in progress */
#define US_FLIDX_RESETTING 4 /* device reset in progress */
#define US_FLIDX_TIMED_OUT 5 /* SCSI midlayer timed out */
#define US_FLIDX_SCAN_PENDING 6 /* scanning not yet done */
#define US_FLIDX_REDO_READ10 7 /* redo READ(10) command */
#define US_FLIDX_READ10_WORKED 8 /* previous READ(10) succeeded */
#define USB_STOR_STRING_LEN 32
/*
* We provide a DMA-mapped I/O buffer for use with small USB transfers.
* It turns out that CB[I] needs a 12-byte buffer and Bulk-only needs a
* 31-byte buffer. But Freecom needs a 64-byte buffer, so that's the
* size we'll allocate.
*/
#define US_IOBUF_SIZE 64 /* Size of the DMA-mapped I/O buffer */
#define US_SENSE_SIZE 18 /* Size of the autosense data buffer */
typedef int (*trans_cmnd)(struct scsi_cmnd *, struct us_data*);
typedef int (*trans_reset)(struct us_data*);
typedef void (*proto_cmnd)(struct scsi_cmnd*, struct us_data*);
typedef void (*extra_data_destructor)(void *); /* extra data destructor */
typedef void (*pm_hook)(struct us_data *, int); /* power management hook */
#define US_SUSPEND 0
#define US_RESUME 1
/* we allocate one of these for every device that we remember */
struct us_data {
/* The device we're working with
* It's important to note:
* (o) you must hold dev_mutex to change pusb_dev
*/
struct mutex dev_mutex; /* protect pusb_dev */
struct usb_device *pusb_dev; /* this usb_device */
struct usb_interface *pusb_intf; /* this interface */
struct us_unusual_dev *unusual_dev; /* device-filter entry */
unsigned long fflags; /* fixed flags from filter */
unsigned long dflags; /* dynamic atomic bitflags */
unsigned int send_bulk_pipe; /* cached pipe values */
unsigned int recv_bulk_pipe;
unsigned int send_ctrl_pipe;
unsigned int recv_ctrl_pipe;
unsigned int recv_intr_pipe;
/* information about the device */
char *transport_name;
char *protocol_name;
__le32 bcs_signature;
u8 subclass;
u8 protocol;
u8 max_lun;
u8 ifnum; /* interface number */
u8 ep_bInterval; /* interrupt interval */
/* function pointers for this device */
trans_cmnd transport; /* transport function */
trans_reset transport_reset; /* transport device reset */
proto_cmnd proto_handler; /* protocol handler */
/* SCSI interfaces */
struct scsi_cmnd *srb; /* current srb */
unsigned int tag; /* current dCBWTag */
char scsi_name[32]; /* scsi_host name */
/* control and bulk communications data */
struct urb *current_urb; /* USB requests */
struct usb_ctrlrequest *cr; /* control requests */
struct usb_sg_request current_sg; /* scatter-gather req. */
unsigned char *iobuf; /* I/O buffer */
dma_addr_t iobuf_dma; /* buffer DMA addresses */
struct task_struct *ctl_thread; /* the control thread */
/* mutual exclusion and synchronization structures */
struct completion cmnd_ready; /* to sleep thread on */
struct completion notify; /* thread begin/end */
wait_queue_head_t delay_wait; /* wait during reset */
struct delayed_work scan_dwork; /* for async scanning */
/* subdriver information */
void *extra; /* Any extra data */
extra_data_destructor extra_destructor;/* extra data destructor */
#ifdef CONFIG_PM
pm_hook suspend_resume_hook;
#endif
/* hacks for READ CAPACITY bug handling */
int use_last_sector_hacks;
int last_sector_retries;
};
/* Convert between us_data and the corresponding Scsi_Host */
static inline struct Scsi_Host *us_to_host(struct us_data *us) {
return container_of((void *) us, struct Scsi_Host, hostdata);
}
static inline struct us_data *host_to_us(struct Scsi_Host *host) {
return (struct us_data *) host->hostdata;
}
/* Function to fill an inquiry response. See usb.c for details */
extern void fill_inquiry_response(struct us_data *us,
unsigned char *data, unsigned int data_len);
/* The scsi_lock() and scsi_unlock() macros protect the sm_state and the
* single queue element srb for write access */
#define scsi_unlock(host) spin_unlock_irq(host->host_lock)
#define scsi_lock(host) spin_lock_irq(host->host_lock)
/* General routines provided by the usb-storage standard core */
#ifdef CONFIG_PM
extern int usb_stor_suspend(struct usb_interface *iface, pm_message_t message);
extern int usb_stor_resume(struct usb_interface *iface);
extern int usb_stor_reset_resume(struct usb_interface *iface);
#else
#define usb_stor_suspend NULL
#define usb_stor_resume NULL
#define usb_stor_reset_resume NULL
#endif
extern int usb_stor_pre_reset(struct usb_interface *iface);
extern int usb_stor_post_reset(struct usb_interface *iface);
extern int usb_stor_probe1(struct us_data **pus,
struct usb_interface *intf,
const struct usb_device_id *id,
struct us_unusual_dev *unusual_dev);
extern int usb_stor_probe2(struct us_data *us);
extern void usb_stor_disconnect(struct usb_interface *intf);
#endif
Reference in a new issue View git blame Copy permalink