Skip to content

L
linux
Commit 96b37d50 authored by Matthew Dharm's avatar Matthew Dharm Committed by Greg Kroah-Hartman
Browse files
Options

[PATCH] usb-storage abort path cleanup 

cleanup of abort mechanism.  This version should be much more crash
resistant (dare I say crash-proof?)
parent bd183368
Hide whitespace changes
Inline Side-by-side
Showing with 192 additions and 165 deletions
drivers/usb/storage/debug.h
View file @ 96b37d50
......@@ -4,7 +4,7 @@
* $Id: debug.h,v 1.6 2001/01/12 23:51:04 mdharm Exp $
*
* Current development and maintenance by:
* (c) 1999, 2000 Matthew Dharm (mdharm-usb@one-eyed-alien.net)
* (c) 1999-2002 Matthew Dharm (mdharm-usb@one-eyed-alien.net)
*
* Initial work by:
* (c) 1999 Michael Gee (michael@linuxspecific.com)
......
drivers/usb/storage/scsiglue.c
View file @ 96b37d50
......@@ -4,7 +4,7 @@
* $Id: scsiglue.c,v 1.26 2002/04/22 03:39:43 mdharm Exp $
*
* Current development and maintenance by:
* (c) 1999, 2000 Matthew Dharm (mdharm-usb@one-eyed-alien.net)
* (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)
......@@ -56,9 +56,6 @@
*/
#define US_ACT_COMMAND 1
#define US_ACT_DEVICE_RESET 2
#define US_ACT_BUS_RESET 3
#define US_ACT_HOST_RESET 4
#define US_ACT_EXIT 5
/***********************************************************************
......
drivers/usb/storage/transport.c
View file @ 96b37d50
......@@ -351,6 +351,29 @@ unsigned int usb_stor_transfer_length(Scsi_Cmnd *srb)
* Data transfer routines
***********************************************************************/
/*
* This is subtle, so pay attention:
* ---------------------------------
* We're very concered about races with a command abort. Hanging this code is
* a sure fire way to hang the kernel.
*
* The abort function first sets the machine state, then tries to acquire the
* lock on the current_urb to abort it.
*
* Once a function grabs the current_urb_sem, then it -MUST- test the state to
* see if we just got aborted before the lock was grabbed. If so, it's
* essential to release the lock and return.
*
* The idea is that, once the current_urb_sem is held, the state can't really
* change anymore without also engaging the usb_unlink_urb() call _after_ the
* URB is actually submitted.
*
* So, we've guaranteed that (after the sm_state test), if we do submit the
* URB it will get aborted when we release the current_urb_sem. And we've
* also guaranteed that if the abort code was called before we held the
* current_urb_sem, we can safely get out before the URB is submitted.
*/
/* This is the completion handler which will wake us up when an URB
* completes.
*/
......@@ -363,6 +386,9 @@ static void usb_stor_blocking_completion(struct urb *urb)
/* This is the common part of the URB message submission code
* This function expects the current_urb_sem to be held upon entry.
*
* All URBs from the usb-storage driver _must_ pass through this function
* (or something like it) for the abort mechanisms to work properly.
*/
static int usb_stor_msg_common(struct us_data *us)
{
......@@ -385,16 +411,6 @@ static int usb_stor_msg_common(struct us_data *us)
return status;
}
/* has the current command been aborted? */
if (atomic_read(&us->sm_state) == US_STATE_ABORTING) {
/* avoid a race with usb_stor_abort_transport():
* if the abort took place before we submitted
* the URB, we must cancel it ourselves */
if (us->current_urb->status == -EINPROGRESS)
usb_unlink_urb(us->current_urb);
}
/* wait for the completion of the URB */
up(&(us->current_urb_sem));
wait_for_completion(&urb_done);
......@@ -428,6 +444,12 @@ int usb_stor_control_msg(struct us_data *us, unsigned int pipe,
/* lock the URB */
down(&(us->current_urb_sem));
/* has the current command been aborted? */
if (atomic_read(&us->sm_state) == US_STATE_ABORTING) {
up(&(us->current_urb_sem));
return 0;
}
/* fill the URB */
FILL_CONTROL_URB(us->current_urb, us->pusb_dev, pipe,
(unsigned char*) dr, data, size,
......@@ -456,6 +478,12 @@ int usb_stor_bulk_msg(struct us_data *us, void *data, int pipe,
/* lock the URB */
down(&(us->current_urb_sem));
/* has the current command been aborted? */
if (atomic_read(&us->sm_state) == US_STATE_ABORTING) {
up(&(us->current_urb_sem));
return 0;
}
/* fill the URB */
FILL_BULK_URB(us->current_urb, us->pusb_dev, pipe, data, len,
usb_stor_blocking_completion, NULL);
......@@ -831,24 +859,31 @@ void usb_stor_abort_transport(struct us_data *us)
/* If the current state is wrong or if there's
* no srb, then there's nothing to do */
if ( !(state == US_STATE_RUNNING || state == US_STATE_RESETTING)
|| !us->srb) {
US_DEBUGP("-- invalid current state\n");
return;
}
BUG_ON((state != US_STATE_RUNNING && state != US_STATE_RESETTING));
BUG_ON(!(us->srb));
/* set state to abort */
atomic_set(&us->sm_state, US_STATE_ABORTING);
/* If the state machine is blocked waiting for an URB or an IRQ,
* let's wake it up */
/* if we have an URB pending, cancel it */
* let's wake it up */
/* If we have an URB pending, cancel it. Note that we guarantee with
* the current_urb_sem that either (a) an URB has just been submitted,
* or (b) the URB will never get submitted. But, because of the use
* of us->sm_state and current_urb_sem, we can't get an URB sumbitted
* _after_ we set the state to US_STATE_ABORTING and this section of
* code runs. Thus we avoid deadlocks.
*/
down(&(us->current_urb_sem));
if (us->current_urb->status == -EINPROGRESS) {
US_DEBUGP("-- cancelling URB\n");
usb_unlink_urb(us->current_urb);
}
up(&(us->current_urb_sem));
/* if we are waiting for an IRQ, simulate it */
else if (test_bit(IP_WANTED, &us->bitflags)) {
/* If we are waiting for an IRQ, simulate it */
if (test_bit(IP_WANTED, &us->bitflags)) {
US_DEBUGP("-- simulating missing IRQ\n");
usb_stor_CBI_irq(us->irq_urb);
}
......
drivers/usb/storage/usb.c
View file @ 96b37d50
......@@ -104,9 +104,6 @@ static int my_host_number;
*/
#define US_ACT_COMMAND 1
#define US_ACT_DEVICE_RESET 2
#define US_ACT_BUS_RESET 3
#define US_ACT_HOST_RESET 4
#define US_ACT_EXIT 5
/* The list of structures and the protective lock for them */
......@@ -344,10 +341,12 @@ static int usb_stor_control_thread(void * __us)
for(;;) {
struct Scsi_Host *host;
US_DEBUGP("*** thread sleeping.\n");
atomic_set(&us->sm_state, US_STATE_IDLE);
if(down_interruptible(&us->sema))
break;
US_DEBUGP("*** thread awakened.\n");
atomic_set(&us->sm_state, US_STATE_RUNNING);
/* lock access to the queue element */
spin_lock_irq(&us->queue_exclusion);
......@@ -361,145 +360,131 @@ static int usb_stor_control_thread(void * __us)
/* release the queue lock as fast as possible */
spin_unlock_irq(&us->queue_exclusion);
switch (action) {
case US_ACT_COMMAND:
/* reject the command if the direction indicator
* is UNKNOWN
*/
if (us->srb->sc_data_direction == SCSI_DATA_UNKNOWN) {
US_DEBUGP("UNKNOWN data direction\n");
us->srb->result = DID_ERROR << 16;
scsi_lock(host);
us->srb->scsi_done(us->srb);
us->srb = NULL;
scsi_unlock(host);
break;
}
/* exit if we get a signal to exit */
if (action == US_ACT_EXIT) {
US_DEBUGP("-- US_ACT_EXIT command received\n");
break;
}
/* reject if target != 0 or if LUN is higher than
* the maximum known LUN
*/
if (us->srb->target &&
!(us->flags & US_FL_SCM_MULT_TARG)) {
US_DEBUGP("Bad target number (%d/%d)\n",
us->srb->target, us->srb->lun);
us->srb->result = DID_BAD_TARGET << 16;
scsi_lock(host);
us->srb->scsi_done(us->srb);
us->srb = NULL;
scsi_unlock(host);
break;
}
BUG_ON(action != US_ACT_COMMAND);
if (us->srb->lun > us->max_lun) {
US_DEBUGP("Bad LUN (%d/%d)\n",
us->srb->target, us->srb->lun);
us->srb->result = DID_BAD_TARGET << 16;
/* reject the command if the direction indicator
* is UNKNOWN
*/
if (us->srb->sc_data_direction == SCSI_DATA_UNKNOWN) {
US_DEBUGP("UNKNOWN data direction\n");
us->srb->result = DID_ERROR << 16;
scsi_lock(host);
us->srb->scsi_done(us->srb);
us->srb = NULL;
scsi_unlock(host);
continue;
}
scsi_lock(host);
us->srb->scsi_done(us->srb);
us->srb = NULL;
scsi_unlock(host);
break;
}
/* reject if target != 0 or if LUN is higher than
* the maximum known LUN
*/
if (us->srb->target &&
!(us->flags & US_FL_SCM_MULT_TARG)) {
US_DEBUGP("Bad target number (%d/%d)\n",
us->srb->target, us->srb->lun);
us->srb->result = DID_BAD_TARGET << 16;
scsi_lock(host);
us->srb->scsi_done(us->srb);
us->srb = NULL;
scsi_unlock(host);
continue;
}
/* handle those devices which can't do a START_STOP */
if ((us->srb->cmnd[0] == START_STOP) &&
(us->flags & US_FL_START_STOP)) {
US_DEBUGP("Skipping START_STOP command\n");
us->srb->result = GOOD << 1;
if (us->srb->lun > us->max_lun) {
US_DEBUGP("Bad LUN (%d/%d)\n",
us->srb->target, us->srb->lun);
us->srb->result = DID_BAD_TARGET << 16;
scsi_lock(host);
us->srb->scsi_done(us->srb);
us->srb = NULL;
scsi_unlock(host);
break;
}
scsi_lock(host);
us->srb->scsi_done(us->srb);
us->srb = NULL;
scsi_unlock(host);
continue;
}
/* lock the device pointers */
down(&(us->dev_semaphore));
/* our device has gone - pretend not ready */
if (atomic_read(&us->sm_state) == US_STATE_DETACHED) {
US_DEBUGP("Request is for removed device\n");
/* For REQUEST_SENSE, it's the data. But
* for anything else, it should look like
* we auto-sensed for it.
*/
if (us->srb->cmnd[0] == REQUEST_SENSE) {
memcpy(us->srb->request_buffer,
usb_stor_sense_notready,
sizeof(usb_stor_sense_notready));
us->srb->result = GOOD << 1;
} else if(us->srb->cmnd[0] == INQUIRY) {
unsigned char data_ptr[36] = {
0x20, 0x80, 0x02, 0x02,
0x1F, 0x00, 0x00, 0x00};
US_DEBUGP("Faking INQUIRY command for disconnected device\n");
fill_inquiry_response(us, data_ptr, 36);
us->srb->result = GOOD << 1;
} else {
memcpy(us->srb->sense_buffer,
usb_stor_sense_notready,
sizeof(usb_stor_sense_notready));
us->srb->result = CHECK_CONDITION << 1;
}
} else { /* atomic_read(&us->sm_state) == STATE_DETACHED */
/* Handle those devices which need us to fake
* their inquiry data */
if ((us->srb->cmnd[0] == INQUIRY) &&
(us->flags & US_FL_FIX_INQUIRY)) {
unsigned char data_ptr[36] = {
0x00, 0x80, 0x02, 0x02,
0x1F, 0x00, 0x00, 0x00};
US_DEBUGP("Faking INQUIRY command\n");
fill_inquiry_response(us, data_ptr, 36);
us->srb->result = GOOD << 1;
} else {
/* we've got a command, let's do it! */
US_DEBUG(usb_stor_show_command(us->srb));
atomic_set(&us->sm_state, US_STATE_RUNNING);
us->proto_handler(us->srb, us);
atomic_set(&us->sm_state, US_STATE_IDLE);
}
}
/* handle those devices which can't do a START_STOP */
if ((us->srb->cmnd[0] == START_STOP) &&
(us->flags & US_FL_START_STOP)) {
US_DEBUGP("Skipping START_STOP command\n");
us->srb->result = GOOD << 1;
scsi_lock(host);
us->srb->scsi_done(us->srb);
us->srb = NULL;
scsi_unlock(host);
continue;
}
/* unlock the device pointers */
up(&(us->dev_semaphore));
/* indicate that the command is done */
if (us->srb->result != DID_ABORT << 16) {
US_DEBUGP("scsi cmd done, result=0x%x\n",
us->srb->result);
scsi_lock(host);
us->srb->scsi_done(us->srb);
us->srb = NULL;
scsi_unlock(host);
/* lock the device pointers */
down(&(us->dev_semaphore));
/* our device has gone - pretend not ready */
if (atomic_read(&us->device_state) == US_STATE_DETACHED) {
US_DEBUGP("Request is for removed device\n");
/* For REQUEST_SENSE, it's the data. But
* for anything else, it should look like
* we auto-sensed for it.
*/
if (us->srb->cmnd[0] == REQUEST_SENSE) {
memcpy(us->srb->request_buffer,
usb_stor_sense_notready,
sizeof(usb_stor_sense_notready));
us->srb->result = GOOD << 1;
} else if(us->srb->cmnd[0] == INQUIRY) {
unsigned char data_ptr[36] = {
0x20, 0x80, 0x02, 0x02,
0x1F, 0x00, 0x00, 0x00};
US_DEBUGP("Faking INQUIRY command for disconnected device\n");
fill_inquiry_response(us, data_ptr, 36);
us->srb->result = GOOD << 1;
} else {
US_DEBUGP("scsi command aborted\n");
us->srb = NULL;
complete(&(us->notify));
memcpy(us->srb->sense_buffer,
usb_stor_sense_notready,
sizeof(usb_stor_sense_notready));
us->srb->result = CHECK_CONDITION << 1;
}
break;
case US_ACT_DEVICE_RESET:
break;
case US_ACT_BUS_RESET:
break;
case US_ACT_HOST_RESET:
break;
} /* end switch on action */
} else { /* atomic_read(&us->device_state) == STATE_DETACHED */
/* Handle those devices which need us to fake
* their inquiry data */
if ((us->srb->cmnd[0] == INQUIRY) &&
(us->flags & US_FL_FIX_INQUIRY)) {
unsigned char data_ptr[36] = {
0x00, 0x80, 0x02, 0x02,
0x1F, 0x00, 0x00, 0x00};
US_DEBUGP("Faking INQUIRY command\n");
fill_inquiry_response(us, data_ptr, 36);
us->srb->result = GOOD << 1;
} else {
/* we've got a command, let's do it! */
US_DEBUG(usb_stor_show_command(us->srb));
us->proto_handler(us->srb, us);
}
}
/* exit if we get a signal to exit */
if (action == US_ACT_EXIT) {
US_DEBUGP("-- US_ACT_EXIT command received\n");
break;
/* unlock the device pointers */
up(&(us->dev_semaphore));
/* indicate that the command is done */
if (us->srb->result != DID_ABORT << 16) {
US_DEBUGP("scsi cmd done, result=0x%x\n",
us->srb->result);
scsi_lock(host);
us->srb->scsi_done(us->srb);
us->srb = NULL;
scsi_unlock(host);
} else {
US_DEBUGP("scsi command aborted\n");
us->srb = NULL;
complete(&(us->notify));
}
} /* for (;;) */
......@@ -725,7 +710,7 @@ static void * storage_probe(struct usb_device *dev, unsigned int ifnum,
/* establish the connection to the new device upon reconnect */
ss->ifnum = ifnum;
ss->pusb_dev = dev;
atomic_set(&ss->sm_state, US_STATE_IDLE);
atomic_set(&ss->device_state, US_STATE_ATTACHED);
/* copy over the endpoint data */
if (ep_in)
......@@ -1016,6 +1001,7 @@ static void * storage_probe(struct usb_device *dev, unsigned int ifnum,
/* start up our control thread */
atomic_set(&ss->sm_state, US_STATE_IDLE);
atomic_set(&ss->device_state, US_STATE_ATTACHED);
ss->pid = kernel_thread(usb_stor_control_thread, ss,
CLONE_VM);
if (ss->pid < 0) {
......
drivers/usb/storage/usb.h
View file @ 96b37d50
......@@ -4,7 +4,7 @@
* $Id: usb.h,v 1.21 2002/04/21 02:57:59 mdharm Exp $
*
* Current development and maintenance by:
* (c) 1999, 2000 Matthew Dharm (mdharm-usb@one-eyed-alien.net)
* (c) 1999-2002 Matthew Dharm (mdharm-usb@one-eyed-alien.net)
*
* Initial work by:
* (c) 1999 Michael Gee (michael@linuxspecific.com)
......@@ -103,11 +103,15 @@ struct us_unusual_dev {
#define US_FL_SCM_MULT_TARG 0x00000020 /* supports multiple targets */
#define US_FL_FIX_INQUIRY 0x00000040 /* INQUIRY response needs fixing */
#define US_STATE_DETACHED 1 /* State machine states */
#define US_STATE_IDLE 2
#define US_STATE_RUNNING 3
#define US_STATE_RESETTING 4
#define US_STATE_ABORTING 5
/* device attached/detached states */
#define US_STATE_DETACHED 1
#define US_STATE_ATTACHED 2
/* processing state machine states */
#define US_STATE_IDLE 1
#define US_STATE_RUNNING 2
#define US_STATE_RESETTING 3
#define US_STATE_ABORTING 4
#define USB_STOR_STRING_LEN 32
......@@ -120,8 +124,13 @@ typedef void (*extra_data_destructor)(void *); /* extra data destructor */
struct us_data {
struct us_data *next; /* next device */
/* the device we're working with */
/* The device we're working with
* It's important to note:
* (o) you must hold dev_semaphore to change pusb_dev
* (o) device_state should change whenever pusb_dev does
*/
struct semaphore dev_semaphore; /* protect pusb_dev */
atomic_t device_state; /* attached or detached */
struct usb_device *pusb_dev; /* this usb_device */
unsigned int flags; /* from filter initially */
......
Markdown is supported
0% or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment
GitLab Nexedi Edition | About GitLab | About Nexedi | 沪ICP备2021021310号-2 | 沪ICP备2021021310号-7