X-Git-Url: https://git.openpandora.org/cgi-bin/gitweb.cgi?p=pandora-kernel.git;a=blobdiff_plain;f=drivers%2Fscsi%2Fscsi_scan.c;h=5d207f1aca7a43112af73198f28e722474c275e5;hp=72273a0e56662569931f812b6f628a3e3a4748c8;hb=a95eb569b98ba720c7b4eb4275101248a212fb44;hpb=aa1b052a34d7ec85b23f4fba564df24b9477201b diff --git a/drivers/scsi/scsi_scan.c b/drivers/scsi/scsi_scan.c index 72273a0e5666..5d207f1aca7a 100644 --- a/drivers/scsi/scsi_scan.c +++ b/drivers/scsi/scsi_scan.c @@ -319,11 +319,7 @@ static struct scsi_device *scsi_alloc_sdev(struct scsi_target *starget, return sdev; out_device_destroy: - scsi_device_set_state(sdev, SDEV_DEL); - transport_destroy_device(&sdev->sdev_gendev); - put_device(&sdev->sdev_dev); - scsi_free_queue(sdev->request_queue); - put_device(&sdev->sdev_gendev); + __scsi_remove_device(sdev); out: if (display_failure_msg) printk(ALLOC_FAILURE_MSG, __func__); @@ -336,6 +332,7 @@ static void scsi_target_destroy(struct scsi_target *starget) struct Scsi_Host *shost = dev_to_shost(dev->parent); unsigned long flags; + starget->state = STARGET_DEL; transport_destroy_device(dev); spin_lock_irqsave(shost->host_lock, flags); if (shost->hostt->target_destroy) @@ -386,6 +383,37 @@ static struct scsi_target *__scsi_find_target(struct device *parent, return found_starget; } +/** + * scsi_target_reap_ref_release - remove target from visibility + * @kref: the reap_ref in the target being released + * + * Called on last put of reap_ref, which is the indication that no device + * under this target is visible anymore, so render the target invisible in + * sysfs. Note: we have to be in user context here because the target reaps + * should be done in places where the scsi device visibility is being removed. + */ +static void scsi_target_reap_ref_release(struct kref *kref) +{ + struct scsi_target *starget + = container_of(kref, struct scsi_target, reap_ref); + + /* + * if we get here and the target is still in the CREATED state that + * means it was allocated but never made visible (because a scan + * turned up no LUNs), so don't call device_del() on it. + */ + if (starget->state != STARGET_CREATED) { + transport_remove_device(&starget->dev); + device_del(&starget->dev); + } + scsi_target_destroy(starget); +} + +static void scsi_target_reap_ref_put(struct scsi_target *starget) +{ + kref_put(&starget->reap_ref, scsi_target_reap_ref_release); +} + /** * scsi_alloc_target - allocate a new or find an existing target * @parent: parent of the target (need not be a scsi host) @@ -408,7 +436,7 @@ static struct scsi_target *scsi_alloc_target(struct device *parent, + shost->transportt->target_size; struct scsi_target *starget; struct scsi_target *found_target; - int error; + int error, ref_got; starget = kzalloc(size, GFP_KERNEL); if (!starget) { @@ -417,7 +445,7 @@ static struct scsi_target *scsi_alloc_target(struct device *parent, } dev = &starget->dev; device_initialize(dev); - starget->reap_ref = 1; + kref_init(&starget->reap_ref); dev->parent = get_device(parent); dev_set_name(dev, "target%d:%d:%d", shost->host_no, channel, id); dev->bus = &scsi_bus_type; @@ -457,29 +485,36 @@ static struct scsi_target *scsi_alloc_target(struct device *parent, return starget; found: - found_target->reap_ref++; + /* + * release routine already fired if kref is zero, so if we can still + * take the reference, the target must be alive. If we can't, it must + * be dying and we need to wait for a new target + */ + ref_got = kref_get_unless_zero(&found_target->reap_ref); + spin_unlock_irqrestore(shost->host_lock, flags); - if (found_target->state != STARGET_DEL) { + if (ref_got) { put_device(dev); return found_target; } - /* Unfortunately, we found a dying target; need to - * wait until it's dead before we can get a new one */ + /* + * Unfortunately, we found a dying target; need to wait until it's + * dead before we can get a new one. There is an anomaly here. We + * *should* call scsi_target_reap() to balance the kref_get() of the + * reap_ref above. However, since the target being released, it's + * already invisible and the reap_ref is irrelevant. If we call + * scsi_target_reap() we might spuriously do another device_del() on + * an already invisible target. + */ put_device(&found_target->dev); - flush_scheduled_work(); + /* + * length of time is irrelevant here, we just want to yield the CPU + * for a tick to avoid busy waiting for the target to die. + */ + msleep(1); goto retry; } -static void scsi_target_reap_usercontext(struct work_struct *work) -{ - struct scsi_target *starget = - container_of(work, struct scsi_target, ew.work); - - transport_remove_device(&starget->dev); - device_del(&starget->dev); - scsi_target_destroy(starget); -} - /** * scsi_target_reap - check to see if target is in use and destroy if not * @starget: target to be checked @@ -490,28 +525,13 @@ static void scsi_target_reap_usercontext(struct work_struct *work) */ void scsi_target_reap(struct scsi_target *starget) { - struct Scsi_Host *shost = dev_to_shost(starget->dev.parent); - unsigned long flags; - enum scsi_target_state state; - int empty = 0; - - spin_lock_irqsave(shost->host_lock, flags); - state = starget->state; - if (--starget->reap_ref == 0 && list_empty(&starget->devices)) { - empty = 1; - starget->state = STARGET_DEL; - } - spin_unlock_irqrestore(shost->host_lock, flags); - - if (!empty) - return; - - BUG_ON(state == STARGET_DEL); - if (state == STARGET_CREATED) - scsi_target_destroy(starget); - else - execute_in_process_context(scsi_target_reap_usercontext, - &starget->ew); + /* + * serious problem if this triggers: STARGET_DEL is only set in the if + * the reap_ref drops to zero, so we're trying to do another final put + * on an already released kref + */ + BUG_ON(starget->state == STARGET_DEL); + scsi_target_reap_ref_put(starget); } /** @@ -780,6 +800,16 @@ static int scsi_add_lun(struct scsi_device *sdev, unsigned char *inq_result, sdev->model = (char *) (sdev->inquiry + 16); sdev->rev = (char *) (sdev->inquiry + 32); + if (strncmp(sdev->vendor, "ATA ", 8) == 0) { + /* + * sata emulation layer device. This is a hack to work around + * the SATL power management specifications which state that + * when the SATL detects the device has gone into standby + * mode, it shall respond with NOT READY. + */ + sdev->allow_restart = 1; + } + if (*bflags & BLIST_ISROM) { sdev->type = TYPE_ROM; sdev->removable = 1; @@ -1492,12 +1522,12 @@ static int scsi_report_lun_scan(struct scsi_target *starget, int bflags, out_err: kfree(lun_data); out: - scsi_device_put(sdev); if (scsi_device_created(sdev)) /* * the sdev we used didn't appear in the report luns scan */ __scsi_remove_device(sdev); + scsi_device_put(sdev); return ret; } @@ -1526,6 +1556,10 @@ struct scsi_device *__scsi_add_device(struct Scsi_Host *shost, uint channel, } mutex_unlock(&shost->scan_mutex); scsi_autopm_put_target(starget); + /* + * paired with scsi_alloc_target(). Target will be destroyed unless + * scsi_probe_and_add_lun made an underlying device visible + */ scsi_target_reap(starget); put_device(&starget->dev); @@ -1606,8 +1640,10 @@ static void __scsi_scan_target(struct device *parent, unsigned int channel, out_reap: scsi_autopm_put_target(starget); - /* now determine if the target has any children at all - * and if not, nuke it */ + /* + * paired with scsi_alloc_target(): determine if the target has + * any children at all and if not, nuke it + */ scsi_target_reap(starget); put_device(&starget->dev); @@ -1714,6 +1750,9 @@ static void scsi_sysfs_add_devices(struct Scsi_Host *shost) { struct scsi_device *sdev; shost_for_each_device(sdev, shost) { + /* target removed before the device could be added */ + if (sdev->sdev_state == SDEV_DEL) + continue; if (!scsi_host_scan_allowed(shost) || scsi_sysfs_add_sdev(sdev) != 0) __scsi_remove_device(sdev); @@ -1819,6 +1858,7 @@ static void scsi_finish_async_scan(struct async_scan_data *data) } spin_unlock(&async_scan_lock); + scsi_autopm_put_host(shost); scsi_host_put(shost); kfree(data); } @@ -1845,7 +1885,6 @@ static int do_scan_async(void *_data) do_scsi_scan_host(shost); scsi_finish_async_scan(data); - scsi_autopm_put_host(shost); return 0; } @@ -1873,7 +1912,7 @@ void scsi_scan_host(struct Scsi_Host *shost) p = kthread_run(do_scan_async, data, "scsi_scan_%d", shost->host_no); if (IS_ERR(p)) do_scan_async(data); - /* scsi_autopm_put_host(shost) is called in do_scan_async() */ + /* scsi_autopm_put_host(shost) is called in scsi_finish_async_scan() */ } EXPORT_SYMBOL(scsi_scan_host);