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virtio_blk: allow re-reading config space at runtime
Wire up the virtio_driver config_changed method to get notified about config changes raised by the host. For now we just re-read the device size to support online resizing of devices, but once we add more attributes that might be changeable they could be added as well. Note that the config_changed method is called from irq context, so we'll have to use the workqueue infrastructure to provide us a proper user context for our changes. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
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parent
990c91f0af
commit
7a7c924cf0
1 changed files with 78 additions and 10 deletions
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@ -6,10 +6,12 @@
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#include <linux/virtio.h>
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#include <linux/virtio_blk.h>
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#include <linux/scatterlist.h>
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#include <linux/string_helpers.h>
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#define PART_BITS 4
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static int major, index;
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struct workqueue_struct *virtblk_wq;
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struct virtio_blk
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{
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@ -26,6 +28,9 @@ struct virtio_blk
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mempool_t *pool;
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/* Process context for config space updates */
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struct work_struct config_work;
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/* What host tells us, plus 2 for header & tailer. */
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unsigned int sg_elems;
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@ -291,6 +296,46 @@ static ssize_t virtblk_serial_show(struct device *dev,
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}
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DEVICE_ATTR(serial, S_IRUGO, virtblk_serial_show, NULL);
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static void virtblk_config_changed_work(struct work_struct *work)
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{
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struct virtio_blk *vblk =
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container_of(work, struct virtio_blk, config_work);
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struct virtio_device *vdev = vblk->vdev;
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struct request_queue *q = vblk->disk->queue;
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char cap_str_2[10], cap_str_10[10];
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u64 capacity, size;
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/* Host must always specify the capacity. */
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vdev->config->get(vdev, offsetof(struct virtio_blk_config, capacity),
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&capacity, sizeof(capacity));
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/* If capacity is too big, truncate with warning. */
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if ((sector_t)capacity != capacity) {
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dev_warn(&vdev->dev, "Capacity %llu too large: truncating\n",
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(unsigned long long)capacity);
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capacity = (sector_t)-1;
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}
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size = capacity * queue_logical_block_size(q);
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string_get_size(size, STRING_UNITS_2, cap_str_2, sizeof(cap_str_2));
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string_get_size(size, STRING_UNITS_10, cap_str_10, sizeof(cap_str_10));
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dev_notice(&vdev->dev,
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"new size: %llu %d-byte logical blocks (%s/%s)\n",
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(unsigned long long)capacity,
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queue_logical_block_size(q),
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cap_str_10, cap_str_2);
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set_capacity(vblk->disk, capacity);
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}
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static void virtblk_config_changed(struct virtio_device *vdev)
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{
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struct virtio_blk *vblk = vdev->priv;
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queue_work(virtblk_wq, &vblk->config_work);
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}
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static int __devinit virtblk_probe(struct virtio_device *vdev)
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{
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struct virtio_blk *vblk;
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@ -327,6 +372,7 @@ static int __devinit virtblk_probe(struct virtio_device *vdev)
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vblk->vdev = vdev;
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vblk->sg_elems = sg_elems;
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sg_init_table(vblk->sg, vblk->sg_elems);
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INIT_WORK(&vblk->config_work, virtblk_config_changed_work);
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/* We expect one virtqueue, for output. */
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vblk->vq = virtio_find_single_vq(vdev, blk_done, "requests");
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@ -477,6 +523,8 @@ static void __devexit virtblk_remove(struct virtio_device *vdev)
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{
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struct virtio_blk *vblk = vdev->priv;
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flush_work(&vblk->config_work);
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/* Nothing should be pending. */
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BUG_ON(!list_empty(&vblk->reqs));
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@ -508,27 +556,47 @@ static unsigned int features[] = {
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* Use __refdata to avoid this warning.
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*/
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static struct virtio_driver __refdata virtio_blk = {
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.feature_table = features,
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.feature_table_size = ARRAY_SIZE(features),
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.driver.name = KBUILD_MODNAME,
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.driver.owner = THIS_MODULE,
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.id_table = id_table,
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.probe = virtblk_probe,
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.remove = __devexit_p(virtblk_remove),
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.feature_table = features,
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.feature_table_size = ARRAY_SIZE(features),
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.driver.name = KBUILD_MODNAME,
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.driver.owner = THIS_MODULE,
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.id_table = id_table,
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.probe = virtblk_probe,
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.remove = __devexit_p(virtblk_remove),
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.config_changed = virtblk_config_changed,
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};
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static int __init init(void)
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{
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int error;
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virtblk_wq = alloc_workqueue("virtio-blk", 0, 0);
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if (!virtblk_wq)
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return -ENOMEM;
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major = register_blkdev(0, "virtblk");
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if (major < 0)
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return major;
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return register_virtio_driver(&virtio_blk);
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if (major < 0) {
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error = major;
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goto out_destroy_workqueue;
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}
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error = register_virtio_driver(&virtio_blk);
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if (error)
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goto out_unregister_blkdev;
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return 0;
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out_unregister_blkdev:
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unregister_blkdev(major, "virtblk");
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out_destroy_workqueue:
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destroy_workqueue(virtblk_wq);
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return error;
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}
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static void __exit fini(void)
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{
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unregister_blkdev(major, "virtblk");
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unregister_virtio_driver(&virtio_blk);
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destroy_workqueue(virtblk_wq);
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}
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module_init(init);
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module_exit(fini);
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