Messages in this thread | | | Subject | Re: [PATCH 8/9] dasd: Add 'timeout' attribute | From | Stefan Weinhuber <> | Date | Tue, 29 Jan 2013 16:17:01 +0100 |
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Hannes Reinecke <hare@suse.de> wrote on 2013-01-29 08:12:00: [..] > +static ssize_t > +dasd_timeout_store(struct device *dev, struct device_attribute *attr, > + const char *buf, size_t count) > +{ > + struct dasd_device *device; > + struct request_queue *q; > + unsigned long val, flags; > + > + device = dasd_device_from_cdev(to_ccwdev(dev)); > + if (IS_ERR(device)) > + return -ENODEV; > + > + if ((strict_strtoul(buf, 10, &val) != 0) || > + val > ULONG_MAX / HZ) { > + dasd_put_device(device); > + return -EINVAL; > + } > + q = device->block->request_queue;
You need to check device->block before using it. For alias devices the device->block pointer is NULL, as an alias device has no fixed association with a block device.
> + if (!q) { > + dasd_put_device(device); > + return -ENODEV; > + } > + spin_lock_irqsave(&device->block->request_queue_lock, flags); > + if (!val) > + blk_queue_rq_timed_out(q, NULL); > + else > + blk_queue_rq_timed_out(q, dasd_times_out); > + > + device->blk_timeout = val; > + > + blk_queue_rq_timeout(q, device->blk_timeout * HZ); > + spin_unlock_irqrestore(&device->block->request_queue_lock, flags); > + > + dasd_put_device(device); > + return count; > +} > + [..]
Mit freundlichen Grüßen / Kind regards
Stefan Weinhuber
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