diff options
| author | Trond Myklebust <trond.myklebust@hammerspace.com> | 2020-10-14 22:22:11 +0300 |
|---|---|---|
| committer | Anna Schumaker <Anna.Schumaker@Netapp.com> | 2020-10-15 20:31:08 +0300 |
| commit | 094eca37193c516106ef8ed7f60ed058ed9fc458 (patch) | |
| tree | 085d1bbd89c470bea2b2039a4688f7769c3f1987 | |
| parent | 61ca2c4afd9d108899e0fa48e7b1cfc9afe80596 (diff) | |
| download | linux-094eca37193c516106ef8ed7f60ed058ed9fc458.tar.xz | |
NFSv4: Fix up RCU annotations for struct nfs_netns_client
The identifier is read as an RCU protected string. Its value may
be changed during the lifetime of the network namespace by writing
a new string into the sysfs pseudofile (at which point, we free the
old string only after a call to synchronize_rcu()).
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
| -rw-r--r-- | fs/nfs/sysfs.c | 11 | ||||
| -rw-r--r-- | fs/nfs/sysfs.h | 2 |
2 files changed, 9 insertions, 4 deletions
diff --git a/fs/nfs/sysfs.c b/fs/nfs/sysfs.c index c489496b5659..8cb70755e3c9 100644 --- a/fs/nfs/sysfs.c +++ b/fs/nfs/sysfs.c @@ -79,7 +79,12 @@ static ssize_t nfs_netns_identifier_show(struct kobject *kobj, struct nfs_netns_client *c = container_of(kobj, struct nfs_netns_client, kobject); - return scnprintf(buf, PAGE_SIZE, "%s\n", c->identifier); + ssize_t ret; + + rcu_read_lock(); + ret = scnprintf(buf, PAGE_SIZE, "%s\n", rcu_dereference(c->identifier)); + rcu_read_unlock(); + return ret; } /* Strip trailing '\n' */ @@ -107,7 +112,7 @@ static ssize_t nfs_netns_identifier_store(struct kobject *kobj, p = kmemdup_nul(buf, len, GFP_KERNEL); if (!p) return -ENOMEM; - old = xchg(&c->identifier, p); + old = rcu_dereference_protected(xchg(&c->identifier, (char __rcu *)p), 1); if (old) { synchronize_rcu(); kfree(old); @@ -121,7 +126,7 @@ static void nfs_netns_client_release(struct kobject *kobj) struct nfs_netns_client, kobject); - kfree(c->identifier); + kfree(rcu_dereference_raw(c->identifier)); kfree(c); } diff --git a/fs/nfs/sysfs.h b/fs/nfs/sysfs.h index ebcbdc40483b..5501ef573c32 100644 --- a/fs/nfs/sysfs.h +++ b/fs/nfs/sysfs.h @@ -11,7 +11,7 @@ struct nfs_netns_client { struct kobject kobject; struct net *net; - const char *identifier; + const char __rcu *identifier; }; extern struct kobject *nfs_client_kobj; |