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nbd: refactor device search and allocation in nbd_genl_connect
Use idr_for_each_entry instead of the awkward callback to find an existing device for the index == -1 case, and de-duplicate the device allocation if no existing device was found. Signed-off-by: Christoph Hellwig <hch@lst.de> Link: https://lore.kernel.org/r/20210811124428.2368491-6-hch@lst.de Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
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@ -1767,18 +1767,6 @@ out:
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return ERR_PTR(err);
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}
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static int find_free_cb(int id, void *ptr, void *data)
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{
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struct nbd_device *nbd = ptr;
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struct nbd_device **found = data;
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if (!refcount_read(&nbd->config_refs)) {
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*found = nbd;
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return 1;
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}
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return 0;
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}
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/* Netlink interface. */
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static const struct nla_policy nbd_attr_policy[NBD_ATTR_MAX + 1] = {
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[NBD_ATTR_INDEX] = { .type = NLA_U32 },
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@ -1848,31 +1836,26 @@ static int nbd_genl_connect(struct sk_buff *skb, struct genl_info *info)
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again:
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mutex_lock(&nbd_index_mutex);
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if (index == -1) {
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ret = idr_for_each(&nbd_index_idr, &find_free_cb, &nbd);
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if (ret == 0) {
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nbd = nbd_dev_add(-1);
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if (IS_ERR(nbd)) {
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mutex_unlock(&nbd_index_mutex);
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printk(KERN_ERR "nbd: failed to add new device\n");
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return PTR_ERR(nbd);
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struct nbd_device *tmp;
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int id;
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idr_for_each_entry(&nbd_index_idr, tmp, id) {
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if (!refcount_read(&tmp->config_refs)) {
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nbd = tmp;
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break;
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}
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}
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} else {
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nbd = idr_find(&nbd_index_idr, index);
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if (!nbd) {
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nbd = nbd_dev_add(index);
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if (IS_ERR(nbd)) {
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mutex_unlock(&nbd_index_mutex);
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printk(KERN_ERR "nbd: failed to add new device\n");
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return PTR_ERR(nbd);
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}
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}
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}
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if (!nbd) {
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printk(KERN_ERR "nbd: couldn't find device at index %d\n",
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index);
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mutex_unlock(&nbd_index_mutex);
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return -EINVAL;
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nbd = nbd_dev_add(index);
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if (IS_ERR(nbd)) {
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mutex_unlock(&nbd_index_mutex);
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pr_err("nbd: failed to add new device\n");
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return PTR_ERR(nbd);
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}
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}
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if (test_bit(NBD_DESTROY_ON_DISCONNECT, &nbd->flags) &&
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