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nbd: refactor device search and allocation in nbd_genl_connect

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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>
This commit is contained in:
Christoph Hellwig 2021-08-11 14:44:27 +02:00 • committed by Jens Axboe
parent 7bdc00cf7e
commit 6177b56c96
1 changed files with 14 additions and 31 deletions
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45
drivers/block/nbd.c
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@ -1767,18 +1767,6 @@ out:
return ERR_PTR(err); return ERR_PTR(err);
} }
static int find_free_cb(int id, void *ptr, void *data)
{
struct nbd_device *nbd = ptr;
struct nbd_device **found = data;
if (!refcount_read(&nbd->config_refs)) {
*found = nbd;
return 1;
}
return 0;
}
/* Netlink interface. */ /* Netlink interface. */
static const struct nla_policy nbd_attr_policy[NBD_ATTR_MAX + 1] = { static const struct nla_policy nbd_attr_policy[NBD_ATTR_MAX + 1] = {
[NBD_ATTR_INDEX] = { .type = NLA_U32 }, [NBD_ATTR_INDEX] = { .type = NLA_U32 },
@ -1848,31 +1836,26 @@ static int nbd_genl_connect(struct sk_buff *skb, struct genl_info *info)
again: again:
mutex_lock(&nbd_index_mutex); mutex_lock(&nbd_index_mutex);
if (index == -1) { if (index == -1) {
ret = idr_for_each(&nbd_index_idr, &find_free_cb, &nbd); struct nbd_device *tmp;
if (ret == 0) { int id;
nbd = nbd_dev_add(-1);
if (IS_ERR(nbd)) { idr_for_each_entry(&nbd_index_idr, tmp, id) {
mutex_unlock(&nbd_index_mutex); if (!refcount_read(&tmp->config_refs)) {
printk(KERN_ERR "nbd: failed to add new device\n"); nbd = tmp;
return PTR_ERR(nbd); break;
} }
} }
} else { } else {
nbd = idr_find(&nbd_index_idr, index); nbd = idr_find(&nbd_index_idr, index);
if (!nbd) {
nbd = nbd_dev_add(index);
if (IS_ERR(nbd)) {
mutex_unlock(&nbd_index_mutex);
printk(KERN_ERR "nbd: failed to add new device\n");
return PTR_ERR(nbd);
}
}
} }
if (!nbd) { if (!nbd) {
printk(KERN_ERR "nbd: couldn't find device at index %d\n", nbd = nbd_dev_add(index);
index); if (IS_ERR(nbd)) {
mutex_unlock(&nbd_index_mutex); mutex_unlock(&nbd_index_mutex);
return -EINVAL; pr_err("nbd: failed to add new device\n");
return PTR_ERR(nbd);
}
} }
if (test_bit(NBD_DESTROY_ON_DISCONNECT, &nbd->flags) && if (test_bit(NBD_DESTROY_ON_DISCONNECT, &nbd->flags) &&