Re: [PATCH v3 1/1] NFSv4.2 COPY do not allocate memory under the lock

[kbuild test robot <lkp@xxxxxxxxx>]

Hi Olga,

Thank you for the patch! Perhaps something to improve:

[auto build test WARNING on nfs/linux-next]
[also build test WARNING on v4.20-rc3 next-20181119]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system]

url:    https://github.com/0day-ci/linux/commits/Olga-Kornievskaia/NFSv4-2-COPY-do-not-allocate-memory-under-the-lock/20181119-202855
base:   git://git.linux-nfs.org/projects/trondmy/linux-nfs.git linux-next
config: x86_64-allmodconfig (attached as .config)
compiler: gcc-7 (Debian 7.3.0-1) 7.3.0
reproduce:
        # save the attached .config to linux build tree
        make ARCH=x86_64 

All warnings (new ones prefixed by >>):

   include/linux/slab.h:332:43: warning: dubious: x & !y
   include/linux/slab.h:332:43: warning: dubious: x & !y
   include/linux/slab.h:332:43: warning: dubious: x & !y
   include/linux/slab.h:332:43: warning: dubious: x & !y
>> fs/nfs/nfs42proc.c:147:28: warning: context imbalance in 'handle_async_copy' - unexpected unlock

vim +/handle_async_copy +147 fs/nfs/nfs42proc.c

   133	
   134	static int handle_async_copy(struct nfs42_copy_res *res,
   135				     struct nfs_server *server,
   136				     struct file *src,
   137				     struct file *dst,
   138				     nfs4_stateid *src_stateid)
   139	{
   140		struct nfs4_copy_state *copy, *tmp_copy;
   141		int status = NFS4_OK;
   142		bool found_pending = false;
   143		struct nfs_open_context *ctx = nfs_file_open_context(dst);
   144	
   145		copy = kzalloc(sizeof(struct nfs4_copy_state), GFP_NOFS);
   146		if (!copy) {
 > 147			spin_unlock(&server->nfs_client->cl_lock);
   148			return -ENOMEM;
   149		}
   150	
   151		spin_lock(&server->nfs_client->cl_lock);
   152		list_for_each_entry(tmp_copy, &server->nfs_client->pending_cb_stateids,
   153					copies) {
   154			if (memcmp(&res->write_res.stateid, &tmp_copy->stateid,
   155					NFS4_STATEID_SIZE))
   156				continue;
   157			found_pending = true;
   158			list_del(&tmp_copy->copies);
   159			break;
   160		}
   161		if (found_pending) {
   162			spin_unlock(&server->nfs_client->cl_lock);
   163			kfree(copy);
   164			copy = tmp_copy;
   165			goto out;
   166		}
   167	
   168		memcpy(&copy->stateid, &res->write_res.stateid, NFS4_STATEID_SIZE);
   169		init_completion(&copy->completion);
   170		copy->parent_state = ctx->state;
   171	
   172		list_add_tail(&copy->copies, &server->ss_copies);
   173		spin_unlock(&server->nfs_client->cl_lock);
   174	
   175		status = wait_for_completion_interruptible(&copy->completion);
   176		spin_lock(&server->nfs_client->cl_lock);
   177		list_del_init(&copy->copies);
   178		spin_unlock(&server->nfs_client->cl_lock);
   179		if (status == -ERESTARTSYS) {
   180			goto out_cancel;
   181		} else if (copy->flags) {
   182			status = -EAGAIN;
   183			goto out_cancel;
   184		}
   185	out:
   186		res->write_res.count = copy->count;
   187		memcpy(&res->write_res.verifier, &copy->verf, sizeof(copy->verf));
   188		status = -copy->error;
   189	
   190		kfree(copy);
   191		return status;
   192	out_cancel:
   193		nfs42_do_offload_cancel_async(dst, &copy->stateid);
   194		kfree(copy);
   195		return status;
   196	}
   197	

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0-DAY kernel test infrastructure                Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all                   Intel Corporation

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