27.02.2012 19:59, David Laight пишет:
spin_lock(&nn->nfs_client_lock);
- list_for_each_entry(clp,&nn->nfs_client_list, cl_share_link) {
+ list_for_each_entry_safe(clp, tmp,&nn->nfs_client_list,
cl_share_link) {
if (clp->rpc_ops !=&nfs_v4_clientops)
continue;
+ atomic_inc(&clp->cl_count);
+ spin_unlock(&nn->nfs_client_lock);
error = __rpc_pipefs_event(clp, event, sb);
+ nfs_put_client(clp);
if (error)
break;
+ spin_lock(&nn->nfs_client_lock);
}
spin_unlock(&nn->nfs_client_lock);
return error;
The locking doesn't look right if the loop breaks on error.
(Same applied to patch v2 1/4)
Thanks for the catch. I'll fix this.
Although list_fo_each_entry_safe() allows the current entry
to be freed, I don't believe it allows the 'next' to be freed.
I doubt there is protection against that happening.
We need to use safe macro, because client can be destroyed on nfs_put_client() call.
About "protection against ... the 'next' to be freed" - I dont' think, that we
need any protection against it. This will be done under nfs_client_lock, and
current entry list pointers will be updated properly.
Do you need to use an atomic_inc() for cl_count.
I'd guess the nfs_client_lock is usually held?
Sorry, I don't understand this question.
--
Best regards,
Stanislav Kinsbursky
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