From: Christoph Hellwig <hch@lst.de>
To: Josef Bacik <josef@toxicpanda.com>, Jens Axboe <axboe@kernel.dk>
Cc: linux-block@vger.kernel.org, nbd@other.debian.org,
Xiubo Li <xiubli@redhat.com>,
Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>,
Hillf Danton <hdanton@sina.com>
Subject: [PATCH 2/6] nbd: reset NBD to NULL when restarting in nbd_genl_connect
Date: Wed, 25 Aug 2021 18:31:04 +0200 [thread overview]
Message-ID: <20210825163108.50713-3-hch@lst.de> (raw)
In-Reply-To: <20210825163108.50713-1-hch@lst.de>
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>
---
drivers/block/nbd.c | 32 ++++++++++++++++++--------------
1 file changed, 18 insertions(+), 14 deletions(-)
diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c
index 2c63372a31dd..69971a47c36f 100644
--- a/drivers/block/nbd.c
+++ b/drivers/block/nbd.c
@@ -1785,6 +1785,20 @@ static struct nbd_device *nbd_dev_add(int index, unsigned int refs)
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 },
@@ -1832,7 +1846,7 @@ 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;
@@ -1853,20 +1867,10 @@ 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)) {
--
2.30.2
next prev parent reply other threads:[~2021-08-25 16:37 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-08-25 16:31 nbd lifetimes fixes Christoph Hellwig
2021-08-25 16:31 ` [PATCH 1/6] nbd: add missing locking to the nbd_dev_add error path Christoph Hellwig
2021-08-25 16:31 ` Christoph Hellwig [this message]
2021-08-25 16:31 ` [PATCH 3/6] nbd: prevent IDR lookups from finding partially initialized devices Christoph Hellwig
2021-08-25 16:31 ` [PATCH 4/6] nbd: set nbd->index before releasing nbd_index_mutex Christoph Hellwig
2021-08-25 16:31 ` [PATCH 5/6] nbd: only return usable devices from nbd_find_unused Christoph Hellwig
2021-08-25 16:31 ` [PATCH 6/6] nbd: remove nbd->destroy_complete Christoph Hellwig
2021-08-25 20:14 ` nbd lifetimes fixes Josef Bacik
2021-08-25 20:21 ` Jens Axboe
2021-10-08 9:17 ` Xiubo Li
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