Attached is a cleanup for usb-storage.
Mainly it's an update to the synchonization: there were a few small
races left.
I've added a complete changelog into usb.h.
The patch is vs 2.5.24-dj2. I've tested it with my SaroTech device,
please test it with other usb storage devices.
-- Manfred
--------------080101040807050004080307 Content-Type: text/plain; name="patch-usbstor-2.5.24d" Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="patch-usbstor-2.5.24d"
diff -u 2.5/drivers/usb/storage/freecom.c build-2.5/drivers/usb/storage/freecom.c --- 2.5/drivers/usb/storage/freecom.c Tue Jun 4 20:39:19 2002 +++ build-2.5/drivers/usb/storage/freecom.c Wed Jul 3 20:31:14 2002 @@ -191,7 +191,7 @@ result, partial); /* has the current command been aborted? */ - if (atomic_read(&us->sm_state) == US_STATE_ABORTING) { + if (us->abort_cmd) { US_DEBUGP("freecom_readdata(): transfer aborted\n"); return US_BULK_TRANSFER_ABORTED; } @@ -232,7 +232,7 @@ result, partial); /* has the current command been aborted? */ - if (atomic_read(&us->sm_state) == US_STATE_ABORTING) { + if (us->abort_cmd) { US_DEBUGP("freecom_writedata(): transfer aborted\n"); return US_BULK_TRANSFER_ABORTED; } @@ -295,7 +295,7 @@ result, partial); /* we canceled this transfer */ - if (atomic_read(&us->sm_state) == US_STATE_ABORTING) { + if (us->abort_cmd) { US_DEBUGP("freecom_transport(): transfer aborted\n"); return US_BULK_TRANSFER_ABORTED; } @@ -310,7 +310,7 @@ US_DEBUGP("foo Status result %d %d\n", result, partial); /* we canceled this transfer */ - if (atomic_read(&us->sm_state) == US_STATE_ABORTING) { + if (us->abort_cmd) { US_DEBUGP("freecom_transport(): transfer aborted\n"); return US_BULK_TRANSFER_ABORTED; } @@ -348,7 +348,7 @@ result, partial); /* we canceled this transfer */ - if (atomic_read(&us->sm_state) == US_STATE_ABORTING) { + if (us->abort_cmd) { US_DEBUGP("freecom_transport(): transfer aborted\n"); return US_BULK_TRANSFER_ABORTED; } @@ -363,7 +363,7 @@ US_DEBUGP("bar Status result %d %d\n", result, partial); /* we canceled this transfer */ - if (atomic_read(&us->sm_state) == US_STATE_ABORTING) { + if (us->abort_cmd) { US_DEBUGP("freecom_transport(): transfer aborted\n"); return US_BULK_TRANSFER_ABORTED; } @@ -424,7 +424,7 @@ FCM_PACKET_LENGTH, &partial); US_DEBUG(pdump ((void *) fst, partial)); - if (atomic_read(&us->sm_state) == US_STATE_ABORTING) { + if (us->abort_cmd) { US_DEBUGP ("freecom_transport: transfer aborted\n"); return US_BULK_TRANSFER_ABORTED; } @@ -453,7 +453,7 @@ result = usb_stor_bulk_msg (us, fst, ipipe, FCM_PACKET_LENGTH, &partial); - if (atomic_read(&us->sm_state) == US_STATE_ABORTING) { + if (us->abort_cmd) { US_DEBUGP ("freecom_transport: transfer aborted\n"); return US_BULK_TRANSFER_ABORTED; } diff -u 2.5/drivers/usb/storage/scsiglue.c build-2.5/drivers/usb/storage/scsiglue.c --- 2.5/drivers/usb/storage/scsiglue.c Tue Jun 25 20:24:18 2002 +++ build-2.5/drivers/usb/storage/scsiglue.c Wed Jul 3 20:35:42 2002 @@ -104,6 +104,7 @@ * NOTE: There is no contention here, because we're already deregistered * the driver and we're doing each virtual host in turn, not in parallel * Synchronization: BLK, no spinlock. + * The function sleeps, no need for _irqsave. */ static int release(struct Scsi_Host *psh) { @@ -117,7 +118,11 @@ * notification that it's exited. */ US_DEBUGP("-- sending US_ACT_EXIT command to thread\n"); + + spin_lock_irq(&us->queue_exclusion); us->action = US_ACT_EXIT; + BUG_ON(us->srb != NULL); + spin_unlock_irq(&us->queue_exclusion); up(&(us->sema)); wait_for_completion(&(us->notify)); @@ -150,7 +155,8 @@ spin_lock_irqsave(&us->queue_exclusion, flags); /* enqueue the command */ - us->queue_srb = srb; + BUG_ON(us->srb != NULL); + us->srb = srb; srb->scsi_done = done; us->action = US_ACT_COMMAND; @@ -174,12 +180,9 @@ US_DEBUGP("command_abort() called\n"); - if (atomic_read(&us->sm_state) == US_STATE_RUNNING) { + if (us->srb) { scsi_unlock(srb->host); - usb_stor_abort_transport(us); - - /* wait for us to be done */ - wait_for_completion(&(us->notify)); + usb_stor_abort_transport(us, 0); scsi_lock(srb->host); return SUCCESS; } @@ -198,16 +201,25 @@ US_DEBUGP("device_reset() called\n" ); /* if the device was removed, then we're already reset */ - if (!test_bit(DEV_ATTACHED, &us->bitflags)) - return SUCCESS; scsi_unlock(srb->host); /* lock the device pointers */ down(&(us->dev_semaphore)); - us->srb = srb; - atomic_set(&us->sm_state, US_STATE_RESETTING); - result = us->transport_reset(us); - atomic_set(&us->sm_state, US_STATE_IDLE); + /* previous commands were stopped with command_abort(), + * and the scsi midlayer prevents new commands from comming + * in until device_reset returns. + */ + BUG_ON(us->srb != NULL); + BUG_ON(us->sm_state != US_STATE_IDLE); + if (us->pusb_dev == NULL) { + result = SUCCESS; + } else { + us->srb = srb; + us->sm_state = US_STATE_RESETTING; + result = us->transport_reset(us); + us->srb = NULL; + us->sm_state = US_STATE_IDLE; + } /* unlock the device pointers */ up(&(us->dev_semaphore)); @@ -215,68 +227,18 @@ return result; } -/* This resets the device port, and simulates the device - * disconnect/reconnect for all drivers which have claimed - * interfaces, including ourself. */ +/* FIXME: is that the best we can do? */ static int bus_reset( Scsi_Cmnd *srb ) { - struct us_data *us = (struct us_data *)srb->host->hostdata[0]; - int i; - int result; - struct usb_device *pusb_dev_save = us->pusb_dev; - - /* we use the usb_reset_device() function to handle this for us */ - US_DEBUGP("bus_reset() called\n"); - - /* if the device has been removed, this worked */ - if (!test_bit(DEV_ATTACHED, &us->bitflags)) { - US_DEBUGP("-- device removed already\n"); - return SUCCESS; - } - - /* attempt to reset the port */ - scsi_unlock(srb->host); - result = usb_reset_device(pusb_dev_save); - US_DEBUGP("usb_reset_device returns %d\n", result); - if (result < 0) { - scsi_lock(srb->host); - return FAILED; - } - - /* FIXME: This needs to lock out driver probing while it's working - * or we can have race conditions */ - /* Is that still true? I don't see how... AS */ - for (i = 0; i < pusb_dev_save->actconfig->bNumInterfaces; i++) { - struct usb_interface *intf = - &pusb_dev_save->actconfig->interface[i]; - const struct usb_device_id *id; - - /* if this is an unclaimed interface, skip it */ - if (!intf->driver) { - continue; - } - - US_DEBUGP("Examining driver %s...", intf->driver->name); - - /* simulate a disconnect and reconnect for all interfaces */ - US_DEBUGPX("simulating disconnect/reconnect.\n"); - down(&intf->driver->serialize); - intf->driver->disconnect(pusb_dev_save, intf->private_data); - id = usb_match_id(pusb_dev_save, intf, intf->driver->id_table); - intf->driver->probe(pusb_dev_save, i, id); - up(&intf->driver->serialize); - } - US_DEBUGP("bus_reset() complete\n"); - scsi_lock(srb->host); - return SUCCESS; + printk(KERN_INFO "usb-storage: bus_reset() requested but not implemented\n" ); + return device_reset(srb); } -/* FIXME: This doesn't do anything right now */ +/* FIXME: is that the best we can do? */ static int host_reset( Scsi_Cmnd *srb ) { - printk(KERN_CRIT "usb-storage: host_reset() requested but not implemented\n" ); - bus_reset(srb); - return FAILED; + printk(KERN_INFO "usb-storage: host_reset() requested but not implemented\n" ); + return device_reset(srb); } /*********************************************************************** @@ -309,7 +271,12 @@ us = us->next; } - /* release our lock on the data structures */ + /* Release our lock on the data structures early. + * The only function that frees us structures is + * usb_stor_exit(), and that happens after + * scsi_unregister_host, i.e. never while the + * /proc interface is in use. + */ up(&us_list_semaphore); /* if we couldn't find it, we return an error */ @@ -331,8 +298,7 @@ /* show the GUID of the device */ SPRINTF(" GUID: " GUID_FORMAT "\n", GUID_ARGS(us->guid)); - SPRINTF(" Attached: %s\n", (test_bit(DEV_ATTACHED, &us->bitflags) - ? "Yes" : "No")); + SPRINTF(" Attached: %s\n", (us->pusb_dev != NULL) ? "Yes" : "No"); /* * Calculate start of next buffer, and return value. @@ -370,6 +336,7 @@ this_id: -1, sg_tablesize: SG_ALL, + max_sectors: 128, cmd_per_lun: 1, present: 0, unchecked_isa_dma: FALSE, diff -u 2.5/drivers/usb/storage/transport.c build-2.5/drivers/usb/storage/transport.c --- 2.5/drivers/usb/storage/transport.c Tue Jun 4 20:39:19 2002 +++ build-2.5/drivers/usb/storage/transport.c Wed Jul 3 20:36:17 2002 @@ -357,21 +357,21 @@ * 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 + * The abort function first sets abort_cmd, 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 + * Once a function grabs the 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 + * The idea is that, once the 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 + * So, we've guaranteed that (after the abort_cmd test), if we do submit the + * URB it will get aborted when we release the 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. + * 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 @@ -385,7 +385,7 @@ } /* This is the common part of the URB message submission code - * This function expects the current_urb_sem to be held upon entry. + * This function expects the dev_semaphore 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. @@ -395,6 +395,8 @@ struct completion urb_done; int status; + BUG_NOT_DOWN(&us->dev_semaphore); + /* set up data structures for the wakeup system */ init_completion(&urb_done); @@ -405,16 +407,19 @@ us->current_urb->transfer_flags = USB_ASYNC_UNLINK; /* submit the URB */ - status = usb_submit_urb(us->current_urb, GFP_NOIO); - if (status) { - /* something went wrong */ - return status; + down(&us->urb_sem); + if (us->abort_cmd) { + /* we are in abort mode, do not submit the new urb */ + status = -ENOENT; + } else { + status = usb_submit_urb(us->current_urb, GFP_NOIO); } + up(&us->urb_sem); + if (status) + return status; /* wait for the completion of the URB */ - up(&(us->current_urb_sem)); wait_for_completion(&urb_done); - down(&(us->current_urb_sem)); /* return the URB status */ return us->current_urb->status; @@ -441,12 +446,11 @@ dr->wIndex = cpu_to_le16(index); dr->wLength = cpu_to_le16(size); - /* lock the URB */ - down(&(us->current_urb_sem)); + /* is the device access locked? */ + BUG_NOT_DOWN(&us->dev_semaphore); /* has the current command been aborted? */ - if (atomic_read(&us->sm_state) == US_STATE_ABORTING) { - up(&(us->current_urb_sem)); + if (us->abort_cmd) { return 0; } @@ -462,8 +466,6 @@ if (status >= 0) status = us->current_urb->actual_length; - /* release the lock and return status */ - up(&(us->current_urb_sem)); return status; } @@ -475,14 +477,12 @@ { int status; - /* lock the URB */ - down(&(us->current_urb_sem)); + /* is the device access locked? */ + BUG_NOT_DOWN(&us->dev_semaphore); /* has the current command been aborted? */ - if (atomic_read(&us->sm_state) == US_STATE_ABORTING) { - up(&(us->current_urb_sem)); + if (us->abort_cmd) return 0; - } /* fill the URB */ FILL_BULK_URB(us->current_urb, us->pusb_dev, pipe, data, len, @@ -494,8 +494,6 @@ /* return the actual length of the data transferred */ *act_len = us->current_urb->actual_length; - /* release the lock and return status */ - up(&(us->current_urb_sem)); return status; } @@ -571,7 +569,7 @@ } /* did we abort this command? */ - if (atomic_read(&us->sm_state) == US_STATE_ABORTING) { + if (us->abort_cmd) { US_DEBUGP("usb_stor_transfer_partial(): transfer aborted\n"); return US_BULK_TRANSFER_ABORTED; } @@ -618,6 +616,9 @@ /* calculate how much we want to transfer */ transfer_amount = usb_stor_transfer_length(srb); + US_DEBUGP("usb_stor_transfer(): request for %d/%d bytes\n", + transfer_amount, srb->request_bufflen); + /* was someone foolish enough to request more data than available * buffer space? */ if (transfer_amount > srb->request_bufflen) @@ -849,44 +850,65 @@ srb->sense_buffer[0] = 0x0; } -/* Abort the currently running scsi command or device reset. + +/* + * Abort the currently running scsi command or device reset. + * The function waits until the currently executing command + * has finished. */ -void usb_stor_abort_transport(struct us_data *us) +void usb_stor_abort_transport(struct us_data *us, int call_scsidone) { - int state = atomic_read(&us->sm_state); - US_DEBUGP("usb_stor_abort_transport called\n"); - /* If the current state is wrong or if there's - * no srb, then there's nothing to do */ - 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. 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. + /* urb_sem is required to synchronize usb_unlink_urb() + * and submit_urb(): + * The caller must guarantee that the urb that is + * passed to unlink_urb was submitted with submit_urb(). + * Without the lock, we could call unlink_urb in the middle + * of submit_urb(). + * + * urb_sem also doubles as the memory barrier that + * makes the update to abort_cmd visible on all cpus in the + * system. + */ + down(&us->urb_sem); + if (call_scsidone) + us->abort_cmd = ABORT_CALLSCSIDONE; + else + us->abort_cmd = ABORT_NOSCSIDONE; + + /* Check if the worker thread is processing the + * command right now, abort it if yes. */ - 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 */ - if (test_bit(IP_WANTED, &us->bitflags)) { + if (test_and_clear_bit(IP_WANTED, &us->bitflags)) { + struct us_data *us = (struct us_data *)us->irq_urb->context; US_DEBUGP("-- simulating missing IRQ\n"); - usb_stor_CBI_irq(us->irq_urb); + /* wake up the command thread */ + up(&us->ip_waitq); } + up(&us->urb_sem); + + spin_lock_irq(&us->queue_exclusion); + while (us->srb) { + DECLARE_WAITQUEUE(wait, current); + current->state = TASK_UNINTERRUPTIBLE; + add_wait_queue(&us->wq_cmd, &wait); + spin_unlock_irq(&us->queue_exclusion); + schedule(); + spin_lock_irq(&us->queue_exclusion); + remove_wait_queue(&us->wq_cmd, &wait); + } + spin_unlock_irq(&us->queue_exclusion); + down(&us->urb_sem); + us->abort_cmd = 0; + up(&us->urb_sem); } /* @@ -904,21 +926,6 @@ US_DEBUGP("-- Interrupt Status (0x%x, 0x%x)\n", us->irqbuf[0], us->irqbuf[1]); - /* has the current command been aborted? */ - if (atomic_read(&us->sm_state) == US_STATE_ABORTING) { - - /* was this a wanted interrupt? */ - if (!test_and_clear_bit(IP_WANTED, &us->bitflags)) { - US_DEBUGP("ERROR: Unwanted interrupt received!\n"); - return; - } - US_DEBUGP("-- command aborted\n"); - - /* wake up the command thread */ - up(&us->ip_waitq); - return; - } - /* is the device removed? */ if (urb->status == -ENOENT) { US_DEBUGP("-- device has been removed\n"); @@ -987,7 +994,7 @@ } /* did we abort this command? */ - if (atomic_read(&us->sm_state) == US_STATE_ABORTING) { + if (us->abort_cmd) { US_DEBUGP("usb_stor_control_msg(): transfer aborted\n"); return US_BULK_TRANSFER_ABORTED; } @@ -999,7 +1006,7 @@ usb_sndctrlpipe(us->pusb_dev, 0)); /* did we abort this command? */ - if (atomic_read(&us->sm_state) == US_STATE_ABORTING) { + if (us->abort_cmd) { US_DEBUGP("usb_stor_control_msg(): transfer aborted\n"); return US_BULK_TRANSFER_ABORTED; } @@ -1036,7 +1043,7 @@ down(&(us->ip_waitq)); /* has the current command been aborted? */ - if (atomic_read(&us->sm_state) == US_STATE_ABORTING) { + if (us->abort_cmd) { US_DEBUGP("CBI interrupt aborted\n"); return USB_STOR_TRANSPORT_ABORTED; } @@ -1104,7 +1111,7 @@ US_DEBUGP("Call to usb_stor_control_msg() returned %d\n", result); if (result < 0) { /* did we abort this command? */ - if (atomic_read(&us->sm_state) == US_STATE_ABORTING) { + if (us->abort_cmd) { US_DEBUGP("usb_stor_CB_transport(): transfer aborted\n"); return US_BULK_TRANSFER_ABORTED; } @@ -1116,7 +1123,7 @@ usb_sndctrlpipe(us->pusb_dev, 0)); /* did we abort this command? */ - if (atomic_read(&us->sm_state) == US_STATE_ABORTING) { + if (us->abort_cmd) { US_DEBUGP("usb_stor_CB_transport(): transfer aborted\n"); return US_BULK_TRANSFER_ABORTED; } @@ -1225,7 +1232,7 @@ US_DEBUGP("Bulk command transfer result=%d\n", result); /* did we abort this command? */ - if (atomic_read(&us->sm_state) == US_STATE_ABORTING) { + if (us->abort_cmd) { US_DEBUGP("usb_stor_Bulk_transport(): transfer aborted\n"); return US_BULK_TRANSFER_ABORTED; } @@ -1236,7 +1243,7 @@ result = usb_stor_clear_halt(us, pipe); /* did we abort this command? */ - if (atomic_read(&us->sm_state) == US_STATE_ABORTING) { + if (us->abort_cmd) { US_DEBUGP("usb_stor_Bulk_transport(): transfer aborted\n"); return US_BULK_TRANSFER_ABORTED; } @@ -1273,7 +1280,7 @@ &partial); /* did we abort this command? */ - if (atomic_read(&us->sm_state) == US_STATE_ABORTING) { + if (us->abort_cmd) { US_DEBUGP("usb_stor_Bulk_transport(): transfer aborted\n"); return US_BULK_TRANSFER_ABORTED; } @@ -1284,7 +1291,7 @@ result = usb_stor_clear_halt(us, pipe); /* did we abort this command? */ - if (atomic_read(&us->sm_state) == US_STATE_ABORTING) { + if (us->abort_cmd) { US_DEBUGP("usb_stor_Bulk_transport(): transfer aborted\n"); return US_BULK_TRANSFER_ABORTED; } @@ -1295,7 +1302,7 @@ US_BULK_CS_WRAP_LEN, &partial); /* did we abort this command? */ - if (atomic_read(&us->sm_state) == US_STATE_ABORTING) { + if (us->abort_cmd) { US_DEBUGP("usb_stor_Bulk_transport(): transfer aborted\n"); return US_BULK_TRANSFER_ABORTED; } @@ -1306,7 +1313,7 @@ result = usb_stor_clear_halt(us, pipe); /* did we abort this command? */ - if (atomic_read(&us->sm_state) == US_STATE_ABORTING) { + if (us->abort_cmd) { US_DEBUGP("usb_stor_Bulk_transport(): transfer aborted\n"); return US_BULK_TRANSFER_ABORTED; } @@ -1358,23 +1365,33 @@ struct us_timeout { struct us_data *us; - spinlock_t timer_lock; + struct completion done; + struct tq_struct event; }; +static void usb_stor_event_handler(void* to__) +{ + struct us_timeout *to = (struct us_timeout *) to__; + struct us_data *us = to->us; + + US_DEBUGP("timeout event handler called\n"); + + /* abort the current request */ + usb_stor_abort_transport(us, 1); + + complete(&to->done); +} + /* The timeout event handler */ static void usb_stor_timeout_handler(unsigned long to__) { struct us_timeout *to = (struct us_timeout *) to__; - struct us_data *us = to->us; US_DEBUGP("Timeout occurred\n"); - /* abort the current request */ - usb_stor_abort_transport(us); - - /* let the reset routine know we have finished */ - spin_unlock(&to->timer_lock); + INIT_TQUEUE(&to->event, usb_stor_event_handler, to); + schedule_task(&to->event); } /* This is the common part of the device reset code. @@ -1389,11 +1406,12 @@ u16 value, u16 index, void *data, u16 size) { int result; - struct us_timeout timeout_data = {us, SPIN_LOCK_UNLOCKED}; + struct us_timeout timeout_data; struct timer_list timeout_list; /* prepare the timeout handler */ - spin_lock(&timeout_data.timer_lock); + timeout_data.us = us; + init_completion(&timeout_data.done); init_timer(&timeout_list); /* A 20-second timeout may seem rather long, but a LaCie @@ -1429,8 +1447,7 @@ /* prevent the timer from coming back to haunt us */ if (!del_timer(&timeout_list)) { - /* the handler has already started; wait for it to finish */ - spin_lock(&timeout_data.timer_lock); + wait_for_completion(&timeout_data.done); /* change the abort into a timeout */ if (result == -ENOENT) result = -ETIMEDOUT; diff -u 2.5/drivers/usb/storage/transport.h build-2.5/drivers/usb/storage/transport.h --- 2.5/drivers/usb/storage/transport.h Sun May 26 11:05:08 2002 +++ build-2.5/drivers/usb/storage/transport.h Wed Jul 3 20:34:01 2002 @@ -149,7 +149,7 @@ extern unsigned int usb_stor_transfer_length(Scsi_Cmnd*); extern void usb_stor_invoke_transport(Scsi_Cmnd*, struct us_data*); -extern void usb_stor_abort_transport(struct us_data*); +extern void usb_stor_abort_transport(struct us_data*, int call_scsidone); extern int usb_stor_transfer_partial(struct us_data*, char*, int); extern int usb_stor_bulk_msg(struct us_data *us, void *data, int pipe, diff -u 2.5/drivers/usb/storage/usb.c build-2.5/drivers/usb/storage/usb.c --- 2.5/drivers/usb/storage/usb.c Tue Jun 25 20:28:28 2002 +++ build-2.5/drivers/usb/storage/usb.c Wed Jul 3 22:45:47 2002 @@ -101,7 +101,7 @@ /* The list of structures and the protective lock for them */ struct us_data *us_list; -struct semaphore us_list_semaphore; +DECLARE_MUTEX(us_list_semaphore); static void * storage_probe(struct usb_device *dev, unsigned int ifnum, const struct usb_device_id *id); @@ -326,6 +326,9 @@ /* set up for wakeups by new commands */ init_MUTEX_LOCKED(&us->sema); + down(&us->dev_semaphore); + us->sm_state = US_STATE_IDLE; + up(&us->dev_semaphore); /* signal that we've started the thread */ complete(&(us->notify)); @@ -333,12 +336,13 @@ for(;;) { struct Scsi_Host *host; US_DEBUGP("*** thread sleeping.\n"); - atomic_set(&us->sm_state, US_STATE_IDLE); - if(down_interruptible(&us->sema)) + wake_up(&us->wq_cmd); + if(down_interruptible(&us->sema)) { + printk(KERN_ERR "Received unexpected signal in usb_stor_control_thread().\n"); 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); @@ -346,9 +350,6 @@ /* take the command off the queue */ action = us->action; us->action = 0; - us->srb = us->queue_srb; - host = us->srb->host; - /* release the queue lock as fast as possible */ spin_unlock_irq(&us->queue_exclusion); @@ -359,6 +360,8 @@ } BUG_ON(action != US_ACT_COMMAND); + host = us->srb->host; + /* reject the command if the direction indicator * is UNKNOWN @@ -416,9 +419,10 @@ /* lock the device pointers */ down(&(us->dev_semaphore)); + us->sm_state = US_STATE_RUNNING; /* our device has gone - pretend not ready */ - if (!test_bit(DEV_ATTACHED, &us->bitflags)) { + if (us->pusb_dev == NULL) { US_DEBUGP("Request is for removed device\n"); /* For REQUEST_SENSE, it's the data. But * for anything else, it should look like @@ -442,7 +446,7 @@ sizeof(usb_stor_sense_notready)); us->srb->result = CHECK_CONDITION << 1; } - } else { /* test_bit(DEV_ATTACHED, &us->bitflags) */ + } else { /* us->pusb_dev != NULL */ /* Handle those devices which need us to fake * their inquiry data */ @@ -461,23 +465,22 @@ us->proto_handler(us->srb, us); } } + us->sm_state = US_STATE_IDLE; /* 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); + scsi_lock(host); + US_DEBUGP("scsi cmd done, result=0x%x\n", us->srb->result); + if (us->abort_cmd != ABORT_NOSCSIDONE) { + /* If we are in error recovery mode, + * no scsi_done callback needed. + */ 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)); } + us->srb = NULL; + scsi_unlock(host); } /* for (;;) */ /* notify the exit routine that we're actually exiting now */ @@ -500,13 +503,12 @@ US_DEBUGP("Allocating IRQ for CBI transport\n"); - /* lock access to the data structure */ - down(&(ss->irq_urb_sem)); + /* check that the device is locked properly */ + BUG_NOT_DOWN(&ss->dev_semaphore); /* allocate the URB */ ss->irq_urb = usb_alloc_urb(0, GFP_KERNEL); if (!ss->irq_urb) { - up(&(ss->irq_urb_sem)); US_DEBUGP("couldn't allocate interrupt URB"); return 1; } @@ -527,12 +529,9 @@ US_DEBUGP("usb_submit_urb() returns %d\n", result); if (result) { usb_free_urb(ss->irq_urb); - up(&(ss->irq_urb_sem)); return 2; } - /* unlock the data structure and return success */ - up(&(ss->irq_urb_sem)); return 0; } @@ -569,6 +568,8 @@ intf[ifnum].altsetting + intf[ifnum].act_altsetting; US_DEBUGP("act_altsetting is %d\n", intf[ifnum].act_altsetting); + BUG_NOT_DOWN(&usb_storage_driver.serialize); + /* clear the temporary strings */ memset(mf, 0, sizeof(mf)); memset(prod, 0, sizeof(prod)); @@ -686,10 +687,11 @@ * already on the system */ ss = us_list; - while ((ss != NULL) && - (test_bit(DEV_ATTACHED, &ss->bitflags) || - !GUID_EQUAL(guid, ss->guid))) + while (ss != NULL) { + if (ss->pusb_dev == NULL && GUID_EQUAL(guid, ss->guid)) + break; ss = ss->next; + } if (ss != NULL) { /* Existing device -- re-connect */ @@ -701,8 +703,8 @@ /* establish the connection to the new device upon reconnect */ ss->ifnum = ifnum; + BUG_ON(ss->pusb_dev != NULL); ss->pusb_dev = dev; - set_bit(DEV_ATTACHED, &ss->bitflags); /* copy over the endpoint data */ ss->ep_in = ep_in->bEndpointAddress & @@ -749,9 +751,9 @@ init_completion(&(ss->notify)); init_MUTEX_LOCKED(&(ss->ip_waitq)); spin_lock_init(&ss->queue_exclusion); - init_MUTEX(&(ss->irq_urb_sem)); - init_MUTEX(&(ss->current_urb_sem)); - init_MUTEX(&(ss->dev_semaphore)); + init_MUTEX(&ss->urb_sem); + init_MUTEX_LOCKED(&(ss->dev_semaphore)); + init_waitqueue_head(&ss->wq_cmd); /* copy over the subclass and protocol data */ ss->subclass = subclass; @@ -969,9 +971,11 @@ if (unusual_dev && unusual_dev->initFunction) unusual_dev->initFunction(ss); + /* Now we are ready */ + up(&ss->dev_semaphore); + /* start up our control thread */ - atomic_set(&ss->sm_state, US_STATE_IDLE); - set_bit(DEV_ATTACHED, &ss->bitflags); + ss->sm_state = US_STATE_BAD; ss->pid = kernel_thread(usb_stor_control_thread, ss, CLONE_VM); if (ss->pid < 0) { @@ -1019,20 +1023,17 @@ /* we come here if there are any problems */ BadDevice: US_DEBUGP("storage_probe() failed\n"); - down(&ss->irq_urb_sem); if (ss->irq_urb) { usb_unlink_urb(ss->irq_urb); usb_free_urb(ss->irq_urb); ss->irq_urb = NULL; } - up(&ss->irq_urb_sem); if (ss->current_urb) { usb_unlink_urb(ss->current_urb); usb_free_urb(ss->current_urb); ss->current_urb = NULL; } - clear_bit(DEV_ATTACHED, &ss->bitflags); ss->pusb_dev = NULL; if (new_device) kfree(ss); @@ -1050,17 +1051,21 @@ US_DEBUGP("storage_disconnect() called\n"); + BUG_NOT_DOWN(&usb_storage_driver.serialize); + /* this is the odd case -- we disconnected but weren't using it */ if (!ss) { US_DEBUGP("-- device was not in use\n"); return; } + /* kill a pending command */ + usb_stor_abort_transport(ss, 1); + /* lock access to the device data structure */ down(&(ss->dev_semaphore)); /* release the IRQ, if we have one */ - down(&(ss->irq_urb_sem)); if (ss->irq_urb) { US_DEBUGP("-- releasing irq URB\n"); result = usb_unlink_urb(ss->irq_urb); @@ -1068,7 +1073,6 @@ usb_free_urb(ss->irq_urb); ss->irq_urb = NULL; } - up(&(ss->irq_urb_sem)); /* free up the main URB for this device */ US_DEBUGP("-- releasing main URB\n"); @@ -1080,7 +1084,6 @@ /* mark the device as gone */ usb_put_dev(ss->pusb_dev); ss->pusb_dev = NULL; - clear_bit(DEV_ATTACHED, &ss->bitflags); /* unlock access to the device data structure */ up(&(ss->dev_semaphore)); @@ -1096,7 +1099,6 @@ /* initialize internal global data elements */ us_list = NULL; - init_MUTEX(&us_list_semaphore); my_host_number = 0; /* register the driver, return -1 if error */ diff -u 2.5/drivers/usb/storage/usb.h build-2.5/drivers/usb/storage/usb.h --- 2.5/drivers/usb/storage/usb.h Tue Jun 25 20:28:28 2002 +++ build-2.5/drivers/usb/storage/usb.h Wed Jul 3 20:35:04 2002 @@ -39,6 +39,28 @@ * 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. + * + * Changelog: + * - remove the DEV_ATTACHED bitflag, it duplicates (->pusb_dev !=NULL) + * - make sm_state a normal variable, atomic_t do not provide synchronization + * for assignments + * - merge queue_srb and srb, that created a hole for crashes if a device_reset() + * happens too early. Add BUG_ON tests to catch errors. + * - device aborts happen asynchroneously, make abort_cmd a seperate variable + * - add BUG_ON tests to catch missing semaphore calls + * - bus_reset dropped for now, synchronization is too fragile, no real need for + * it + * - restrict commands to 128 sectors, large commands cause errors with my SaroTech + * USB enclosure + * - move urb_sem into usb_stor_msg_common(), asking the callers to lock & check for + * abort_cmd is too error prone. + * - add an explicit waitqueue for the device reset handler, reuse of the + * completion caused deadlocks in command_abort(). + * - move the _timeout handler for usb_stor to process context. + * - fixoops during module unload. + * - abort a possibly pending command during storage_disconnect(), could cause + * excessive delays if the cable is pulled out while a command is pending. + * (C) Manfred Spraul <manfred@colorfullife.com> 2002 */ #ifndef _USB_H_ @@ -107,13 +129,16 @@ /* kernel thread actions */ #define US_ACT_COMMAND 1 -#define US_ACT_EXIT 5 +#define US_ACT_EXIT 2 -/* processing state machine states */ +/* processing state machine states + * For debugging only, it can be wrong because queue_command() + * queues new requests asynchroneously. + * */ +#define US_STATE_BAD 0 #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 @@ -127,9 +152,12 @@ struct us_data *next; /* next device */ /* The device we're working with - * It's important to note: - * (o) you must hold dev_semaphore to change pusb_dev - * (o) DEV_ATTACHED in bitflags should change whenever pusb_dev does + * It's important to note that you must hold dev_semaphore + * to change or use pusb_dev. + * + * Virtually the complete device access is serialized through + * dev_semaphore, the only notable exception is command abortion + * which is serialized by urb_sem. */ struct semaphore dev_semaphore; /* protect pusb_dev */ struct usb_device *pusb_dev; /* this usb_device */ @@ -166,25 +194,28 @@ Scsi_Cmnd *srb; /* current srb */ /* thread information */ - Scsi_Cmnd *queue_srb; /* the single queue slot */ int action; /* what to do */ int pid; /* control thread */ - atomic_t sm_state; + unsigned long sm_state; + wait_queue_head_t wq_cmd; /* command completion queue */ + struct semaphore urb_sem; /* synchronize {unlink,submit}_urb */ + + unsigned long abort_cmd; +/* 0 means do not abort */ +#define ABORT_CALLSCSIDONE 1 +#define ABORT_NOSCSIDONE 2 /* interrupt info for CBI devices -- only good if attached */ struct semaphore ip_waitq; /* for CBI interrupts */ - unsigned long bitflags; /* single-bit flags: */ + unsigned long bitflags; /* atomic bitflags */ #define IP_WANTED 1 /* is an IRQ expected? */ -#define DEV_ATTACHED 2 /* is the dev. attached?*/ /* interrupt communications data */ - struct semaphore irq_urb_sem; /* to protect irq_urb */ struct urb *irq_urb; /* for USB int requests */ unsigned char irqbuf[2]; /* buffer for USB IRQ */ unsigned char irqdata[2]; /* data from USB IRQ */ /* control and bulk communications data */ - struct semaphore current_urb_sem; /* to protect irq_urb */ struct urb *current_urb; /* non-int USB requests */ /* the semaphore for sleeping the control thread */ @@ -221,4 +252,12 @@ #define sg_address(psg) ((psg)->address) #endif +#define BUG_NOT_DOWN(sem) \ + do { \ + if (!down_trylock(sem)) { \ + up(sem); \ + BUG(); \ + } \ + } while(0) + #endif
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