From 65b4fe553bf43018c06740f3d1f6caf42cf95924 Mon Sep 17 00:00:00 2001 From: Pete Zaitcev Date: Wed, 28 Dec 2005 14:22:17 -0800 Subject: [PATCH] [PATCH] USB: ub 03 Oops with CFQ The blk_cleanup_queue does not necesserily destroy the queue. When we destroy the corresponding ub_dev, it may leave the queue spinlock pointer dangling. This patch moves spinlocks from ub_dev to static memory. The locking scheme is not changed. These spinlocks are still separate from the ub_lock. Signed-off-by: Pete Zaitcev Signed-off-by: Greg Kroah-Hartman --- drivers/block/ub.c | 68 ++++++++++++++++++++++++++++++---------------- 1 file changed, 45 insertions(+), 23 deletions(-) diff --git a/drivers/block/ub.c b/drivers/block/ub.c index a05fe5843e..db4943c53d 100644 --- a/drivers/block/ub.c +++ b/drivers/block/ub.c @@ -355,7 +355,7 @@ struct ub_lun { * The USB device instance. */ struct ub_dev { - spinlock_t lock; + spinlock_t *lock; atomic_t poison; /* The USB device is disconnected */ int openc; /* protected by ub_lock! */ /* kref is too implicit for our taste */ @@ -452,6 +452,10 @@ MODULE_DEVICE_TABLE(usb, ub_usb_ids); #define UB_MAX_HOSTS 26 static char ub_hostv[UB_MAX_HOSTS]; +#define UB_QLOCK_NUM 5 +static spinlock_t ub_qlockv[UB_QLOCK_NUM]; +static int ub_qlock_next = 0; + static DEFINE_SPINLOCK(ub_lock); /* Locks globals and ->openc */ /* @@ -531,7 +535,7 @@ static ssize_t ub_diag_show(struct device *dev, struct device_attribute *attr, return 0; cnt = 0; - spin_lock_irqsave(&sc->lock, flags); + spin_lock_irqsave(sc->lock, flags); cnt += sprintf(page + cnt, "poison %d reset %d\n", @@ -579,7 +583,7 @@ static ssize_t ub_diag_show(struct device *dev, struct device_attribute *attr, if (++nc == SCMD_TRACE_SZ) nc = 0; } - spin_unlock_irqrestore(&sc->lock, flags); + spin_unlock_irqrestore(sc->lock, flags); return cnt; } @@ -626,6 +630,24 @@ static void ub_id_put(int id) spin_unlock_irqrestore(&ub_lock, flags); } +/* + * This is necessitated by the fact that blk_cleanup_queue does not + * necesserily destroy the queue. Instead, it may merely decrease q->refcnt. + * Since our blk_init_queue() passes a spinlock common with ub_dev, + * we have life time issues when ub_cleanup frees ub_dev. + */ +static spinlock_t *ub_next_lock(void) +{ + unsigned long flags; + spinlock_t *ret; + + spin_lock_irqsave(&ub_lock, flags); + ret = &ub_qlockv[ub_qlock_next]; + ub_qlock_next = (ub_qlock_next + 1) % UB_QLOCK_NUM; + spin_unlock_irqrestore(&ub_lock, flags); + return ret; +} + /* * Downcount for deallocation. This rides on two assumptions: * - once something is poisoned, its refcount cannot grow @@ -1083,9 +1105,9 @@ static void ub_urb_timeout(unsigned long arg) struct ub_dev *sc = (struct ub_dev *) arg; unsigned long flags; - spin_lock_irqsave(&sc->lock, flags); + spin_lock_irqsave(sc->lock, flags); usb_unlink_urb(&sc->work_urb); - spin_unlock_irqrestore(&sc->lock, flags); + spin_unlock_irqrestore(sc->lock, flags); } /* @@ -1108,10 +1130,10 @@ static void ub_scsi_action(unsigned long _dev) struct ub_dev *sc = (struct ub_dev *) _dev; unsigned long flags; - spin_lock_irqsave(&sc->lock, flags); + spin_lock_irqsave(sc->lock, flags); del_timer(&sc->work_timer); ub_scsi_dispatch(sc); - spin_unlock_irqrestore(&sc->lock, flags); + spin_unlock_irqrestore(sc->lock, flags); } static void ub_scsi_dispatch(struct ub_dev *sc) @@ -1754,7 +1776,7 @@ static void ub_reset_task(void *arg) * queues of resets or anything. We do need a spinlock though, * to interact with block layer. */ - spin_lock_irqsave(&sc->lock, flags); + spin_lock_irqsave(sc->lock, flags); sc->reset = 0; tasklet_schedule(&sc->tasklet); list_for_each(p, &sc->luns) { @@ -1762,7 +1784,7 @@ static void ub_reset_task(void *arg) blk_start_queue(lun->disk->queue); } wake_up(&sc->reset_wait); - spin_unlock_irqrestore(&sc->lock, flags); + spin_unlock_irqrestore(sc->lock, flags); } /* @@ -1990,11 +2012,11 @@ static int ub_sync_tur(struct ub_dev *sc, struct ub_lun *lun) cmd->done = ub_probe_done; cmd->back = &compl; - spin_lock_irqsave(&sc->lock, flags); + spin_lock_irqsave(sc->lock, flags); cmd->tag = sc->tagcnt++; rc = ub_submit_scsi(sc, cmd); - spin_unlock_irqrestore(&sc->lock, flags); + spin_unlock_irqrestore(sc->lock, flags); if (rc != 0) { printk("ub: testing ready: submit error (%d)\n", rc); /* P3 */ @@ -2052,11 +2074,11 @@ static int ub_sync_read_cap(struct ub_dev *sc, struct ub_lun *lun, cmd->done = ub_probe_done; cmd->back = &compl; - spin_lock_irqsave(&sc->lock, flags); + spin_lock_irqsave(sc->lock, flags); cmd->tag = sc->tagcnt++; rc = ub_submit_scsi(sc, cmd); - spin_unlock_irqrestore(&sc->lock, flags); + spin_unlock_irqrestore(sc->lock, flags); if (rc != 0) { printk("ub: reading capacity: submit error (%d)\n", rc); /* P3 */ @@ -2333,7 +2355,7 @@ static int ub_probe(struct usb_interface *intf, if ((sc = kmalloc(sizeof(struct ub_dev), GFP_KERNEL)) == NULL) goto err_core; memset(sc, 0, sizeof(struct ub_dev)); - spin_lock_init(&sc->lock); + sc->lock = ub_next_lock(); INIT_LIST_HEAD(&sc->luns); usb_init_urb(&sc->work_urb); tasklet_init(&sc->tasklet, ub_scsi_action, (unsigned long)sc); @@ -2483,7 +2505,7 @@ static int ub_probe_lun(struct ub_dev *sc, int lnum) disk->driverfs_dev = &sc->intf->dev; rc = -ENOMEM; - if ((q = blk_init_queue(ub_request_fn, &sc->lock)) == NULL) + if ((q = blk_init_queue(ub_request_fn, sc->lock)) == NULL) goto err_blkqinit; disk->queue = q; @@ -2554,7 +2576,7 @@ static void ub_disconnect(struct usb_interface *intf) * and the whole queue drains. So, we just use this code to * print warnings. */ - spin_lock_irqsave(&sc->lock, flags); + spin_lock_irqsave(sc->lock, flags); { struct ub_scsi_cmd *cmd; int cnt = 0; @@ -2571,7 +2593,7 @@ static void ub_disconnect(struct usb_interface *intf) "%d was queued after shutdown\n", sc->name, cnt); } } - spin_unlock_irqrestore(&sc->lock, flags); + spin_unlock_irqrestore(sc->lock, flags); /* * Unregister the upper layer. @@ -2590,19 +2612,15 @@ static void ub_disconnect(struct usb_interface *intf) } /* - * Taking a lock on a structure which is about to be freed - * is very nonsensual. Here it is largely a way to do a debug freeze, - * and a bracket which shows where the nonsensual code segment ends. - * * Testing for -EINPROGRESS is always a bug, so we are bending * the rules a little. */ - spin_lock_irqsave(&sc->lock, flags); + spin_lock_irqsave(sc->lock, flags); if (sc->work_urb.status == -EINPROGRESS) { /* janitors: ignore */ printk(KERN_WARNING "%s: " "URB is active after disconnect\n", sc->name); } - spin_unlock_irqrestore(&sc->lock, flags); + spin_unlock_irqrestore(sc->lock, flags); /* * There is virtually no chance that other CPU runs times so long @@ -2636,6 +2654,10 @@ static struct usb_driver ub_driver = { static int __init ub_init(void) { int rc; + int i; + + for (i = 0; i < UB_QLOCK_NUM; i++) + spin_lock_init(&ub_qlockv[i]); if ((rc = register_blkdev(UB_MAJOR, DRV_NAME)) != 0) goto err_regblkdev; -- 2.39.5