2020-02-13 15:04:07

by Madhuparna Bhowmik

Subject: [PATCH] fs: nfsd: nfs4state.c: Use built-in RCU list checking

From: Madhuparna Bhowmik <[email protected]>

list_for_each_entry_rcu() has built-in RCU and lock checking.

Pass cond argument to list_for_each_entry_rcu() to silence
false lockdep warning when CONFIG_PROVE_RCU_LIST is enabled
by default.

Signed-off-by: Madhuparna Bhowmik <[email protected]>
---
fs/nfsd/nfs4state.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index 369e574c5092..3a80721fe53d 100644
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -4295,7 +4295,8 @@ find_file_locked(struct knfsd_fh *fh, unsigned int hashval)
{
struct nfs4_file *fp;

- hlist_for_each_entry_rcu(fp, &file_hashtbl[hashval], fi_hash) {
+ hlist_for_each_entry_rcu(fp, &file_hashtbl[hashval], fi_hash,
+ lockdep_is_held(&state_lock)) {
if (fh_match(&fp->fi_fhandle, fh)) {
if (refcount_inc_not_zero(&fp->fi_ref))
return fp;
--
2.17.1

2020-03-03 16:55:04

by J. Bruce Fields

Subject: Re: [PATCH] fs: nfsd: nfs4state.c: Use built-in RCU list checking

Applying for 5.7, thanks.--b.

On Thu, Feb 13, 2020 at 08:33:31PM +0530, [email protected] wrote:
> From: Madhuparna Bhowmik <[email protected]>
>
> list_for_each_entry_rcu() has built-in RCU and lock checking.
>
> Pass cond argument to list_for_each_entry_rcu() to silence
> false lockdep warning when CONFIG_PROVE_RCU_LIST is enabled
> by default.
>
> Signed-off-by: Madhuparna Bhowmik <[email protected]>
> ---
> fs/nfsd/nfs4state.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
> index 369e574c5092..3a80721fe53d 100644
> --- a/fs/nfsd/nfs4state.c
> +++ b/fs/nfsd/nfs4state.c
> @@ -4295,7 +4295,8 @@ find_file_locked(struct knfsd_fh *fh, unsigned int hashval)
> {
> struct nfs4_file *fp;
>
> - hlist_for_each_entry_rcu(fp, &file_hashtbl[hashval], fi_hash) {
> + hlist_for_each_entry_rcu(fp, &file_hashtbl[hashval], fi_hash,
> + lockdep_is_held(&state_lock)) {
> if (fh_match(&fp->fi_fhandle, fh)) {
> if (refcount_inc_not_zero(&fp->fi_ref))
> return fp;
> --
> 2.17.1