Return-Path: Received: from mail-qg0-f49.google.com ([209.85.192.49]:38265 "EHLO mail-qg0-f49.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751490AbbCIUFH (ORCPT ); Mon, 9 Mar 2015 16:05:07 -0400 Received: by qgdz60 with SMTP id z60so31465980qgd.5 for ; Mon, 09 Mar 2015 13:05:07 -0700 (PDT) From: Trond Myklebust To: Tigran Mkrtchyan Cc: linux-nfs@vger.kernel.org Subject: [PATCH 1/4] NFSv4.1: Convert pNFS deviceid to use kfree_rcu() Date: Mon, 9 Mar 2015 16:05:00 -0400 Message-Id: <1425931503-37261-2-git-send-email-trond.myklebust@primarydata.com> In-Reply-To: <1425931503-37261-1-git-send-email-trond.myklebust@primarydata.com> References: <1425931503-37261-1-git-send-email-trond.myklebust@primarydata.com> Sender: linux-nfs-owner@vger.kernel.org List-ID: Use of synchronize_rcu() when unmounting and potentially freeing a lot of deviceids is problematic. There really is no reason why we can't just use kfree_rcu() here. Signed-off-by: Trond Myklebust --- fs/nfs/blocklayout/dev.c | 2 +- fs/nfs/filelayout/filelayoutdev.c | 2 +- fs/nfs/flexfilelayout/flexfilelayoutdev.c | 2 +- fs/nfs/objlayout/objio_osd.c | 2 +- fs/nfs/pnfs.h | 1 + fs/nfs/pnfs_dev.c | 6 ++---- 6 files changed, 7 insertions(+), 8 deletions(-) diff --git a/fs/nfs/blocklayout/dev.c b/fs/nfs/blocklayout/dev.c index 5aed4f98df41..e535599a0719 100644 --- a/fs/nfs/blocklayout/dev.c +++ b/fs/nfs/blocklayout/dev.c @@ -33,7 +33,7 @@ bl_free_deviceid_node(struct nfs4_deviceid_node *d) container_of(d, struct pnfs_block_dev, node); bl_free_device(dev); - kfree(dev); + kfree_rcu(dev, node.rcu); } static int diff --git a/fs/nfs/filelayout/filelayoutdev.c b/fs/nfs/filelayout/filelayoutdev.c index 4f372e224603..4946ef40ba87 100644 --- a/fs/nfs/filelayout/filelayoutdev.c +++ b/fs/nfs/filelayout/filelayoutdev.c @@ -55,7 +55,7 @@ nfs4_fl_free_deviceid(struct nfs4_file_layout_dsaddr *dsaddr) nfs4_pnfs_ds_put(ds); } kfree(dsaddr->stripe_indices); - kfree(dsaddr); + kfree_rcu(dsaddr, id_node.rcu); } /* Decode opaque device data and return the result */ diff --git a/fs/nfs/flexfilelayout/flexfilelayoutdev.c b/fs/nfs/flexfilelayout/flexfilelayoutdev.c index e2c01f204a95..77a2d026aa12 100644 --- a/fs/nfs/flexfilelayout/flexfilelayoutdev.c +++ b/fs/nfs/flexfilelayout/flexfilelayoutdev.c @@ -30,7 +30,7 @@ void nfs4_ff_layout_free_deviceid(struct nfs4_ff_layout_ds *mirror_ds) { nfs4_print_deviceid(&mirror_ds->id_node.deviceid); nfs4_pnfs_ds_put(mirror_ds->ds); - kfree(mirror_ds); + kfree_rcu(mirror_ds, id_node.rcu); } /* Decode opaque device data and construct new_ds using it */ diff --git a/fs/nfs/objlayout/objio_osd.c b/fs/nfs/objlayout/objio_osd.c index 24e1d7403c0b..8b5e0e687d5e 100644 --- a/fs/nfs/objlayout/objio_osd.c +++ b/fs/nfs/objlayout/objio_osd.c @@ -57,7 +57,7 @@ objio_free_deviceid_node(struct nfs4_deviceid_node *d) dprintk("%s: free od=%p\n", __func__, de->od.od); osduld_put_device(de->od.od); - kfree(de); + kfree_rcu(d, rcu); } struct objio_segment { diff --git a/fs/nfs/pnfs.h b/fs/nfs/pnfs.h index 635f0865671c..a1fc16c971a7 100644 --- a/fs/nfs/pnfs.h +++ b/fs/nfs/pnfs.h @@ -302,6 +302,7 @@ struct nfs4_deviceid_node { unsigned long flags; unsigned long timestamp_unavailable; struct nfs4_deviceid deviceid; + struct rcu_head rcu; atomic_t ref; }; diff --git a/fs/nfs/pnfs_dev.c b/fs/nfs/pnfs_dev.c index aa2ec0015183..bf23ac97d57d 100644 --- a/fs/nfs/pnfs_dev.c +++ b/fs/nfs/pnfs_dev.c @@ -175,8 +175,8 @@ __nfs4_find_get_deviceid(struct nfs_server *server, rcu_read_lock(); d = _lookup_deviceid(server->pnfs_curr_ld, server->nfs_client, id, hash); - if (d != NULL) - atomic_inc(&d->ref); + if (d != NULL && !atomic_inc_not_zero(&d->ref)) + d = NULL; rcu_read_unlock(); return d; } @@ -236,7 +236,6 @@ nfs4_delete_deviceid(const struct pnfs_layoutdriver_type *ld, } hlist_del_init_rcu(&d->node); spin_unlock(&nfs4_deviceid_lock); - synchronize_rcu(); /* balance the initial ref set in pnfs_insert_deviceid */ if (atomic_dec_and_test(&d->ref)) @@ -321,7 +320,6 @@ _deviceid_purge_client(const struct nfs_client *clp, long hash) if (hlist_empty(&tmp)) return; - synchronize_rcu(); while (!hlist_empty(&tmp)) { d = hlist_entry(tmp.first, struct nfs4_deviceid_node, tmpnode); hlist_del(&d->tmpnode); -- 2.1.0