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authorChristoph Hellwig <hch@lst.de>2021-08-25 18:31:04 +0200
committerJens Axboe <axboe@kernel.dk>2021-08-25 14:20:20 -0600
commit409e0ff10ead30a620ee48acb6d4545d9cb95359 (patch)
tree3c02a40a9915c593b978fb93765df45e8ca372a0 /drivers/block
parent93f63bc41f699318807df202a175d564c26bda87 (diff)
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nbd: reset NBD to NULL when restarting in nbd_genl_connect
When nbd_genl_connect restarts to wait for a disconnecting device, nbd needs to be reset to NULL. Do that by facoring out a helper to find an unused device. Fixes: 6177b56c96ff ("nbd: refactor device search and allocation in nbd_genl_connect") Reported-by: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp> Reported-by: Hillf Danton <hdanton@sina.com> Signed-off-by: Christoph Hellwig <hch@lst.de> Link: https://lore.kernel.org/r/20210825163108.50713-3-hch@lst.de Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'drivers/block')
-rw-r--r--drivers/block/nbd.c32
1 files changed, 18 insertions, 14 deletions
diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c
index 0c1389da3066..938ca7f5a11f 100644
--- a/drivers/block/nbd.c
+++ b/drivers/block/nbd.c
@@ -1781,6 +1781,20 @@ out:
return ERR_PTR(err);
}
+static struct nbd_device *nbd_find_unused(void)
+{
+ struct nbd_device *nbd;
+ int id;
+
+ lockdep_assert_held(&nbd_index_mutex);
+
+ idr_for_each_entry(&nbd_index_idr, nbd, id)
+ if (!refcount_read(&nbd->config_refs))
+ return nbd;
+
+ return NULL;
+}
+
/* Netlink interface. */
static const struct nla_policy nbd_attr_policy[NBD_ATTR_MAX + 1] = {
[NBD_ATTR_INDEX] = { .type = NLA_U32 },
@@ -1828,7 +1842,7 @@ static int nbd_genl_size_set(struct genl_info *info, struct nbd_device *nbd)
static int nbd_genl_connect(struct sk_buff *skb, struct genl_info *info)
{
DECLARE_COMPLETION_ONSTACK(destroy_complete);
- struct nbd_device *nbd = NULL;
+ struct nbd_device *nbd;
struct nbd_config *config;
int index = -1;
int ret;
@@ -1849,20 +1863,10 @@ static int nbd_genl_connect(struct sk_buff *skb, struct genl_info *info)
}
again:
mutex_lock(&nbd_index_mutex);
- if (index == -1) {
- struct nbd_device *tmp;
- int id;
-
- idr_for_each_entry(&nbd_index_idr, tmp, id) {
- if (!refcount_read(&tmp->config_refs)) {
- nbd = tmp;
- break;
- }
- }
- } else {
+ if (index == -1)
+ nbd = nbd_find_unused();
+ else
nbd = idr_find(&nbd_index_idr, index);
- }
-
if (nbd) {
if (test_bit(NBD_DESTROY_ON_DISCONNECT, &nbd->flags) &&
test_bit(NBD_DISCONNECT_REQUESTED, &nbd->flags)) {