| Message ID | 20240415160619.8249-1-jain.abhinav177@gmail.com (mailing list archive) |
|---|---|
| State | Rejected |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | inet: inet_defrag: Removing the usage of refcount_inc_not_zero | expand |
On Mon, Apr 15, 2024 at 6:06 PM Abhinav Jain <jain.abhinav177@gmail.com> wrote: > > Remove refcount_inc_not_zero as per the listed TODO in the file. > Used spin_(un)lock and refcount_* functions for synchronization. > > Signed-off-by: Abhinav Jain <jain.abhinav177@gmail.com> > --- > net/ipv4/inet_fragment.c | 9 +++++++-- > 1 file changed, 7 insertions(+), 2 deletions(-) > > diff --git a/net/ipv4/inet_fragment.c b/net/ipv4/inet_fragment.c > index c88c9034d630..e4838bbe0abb 100644 > --- a/net/ipv4/inet_fragment.c > +++ b/net/ipv4/inet_fragment.c > @@ -358,7 +358,6 @@ static struct inet_frag_queue *inet_frag_create(struct fqdir *fqdir, > return q; > } > > -/* TODO : call from rcu_read_lock() and no longer use refcount_inc_not_zero() */ > struct inet_frag_queue *inet_frag_find(struct fqdir *fqdir, void *key) > { > /* This pairs with WRITE_ONCE() in fqdir_pre_exit(). */ > @@ -375,8 +374,14 @@ struct inet_frag_queue *inet_frag_find(struct fqdir *fqdir, void *key) > fq = inet_frag_create(fqdir, key, &prev); > if (!IS_ERR_OR_NULL(prev)) { > fq = prev; > - if (!refcount_inc_not_zero(&fq->refcnt)) > + spin_lock(&fq->lock); > + if (refcount_read(&fq->refcnt) > 0) { > + refcount_inc(&fq->refcnt); > + spin_unlock(&fq->lock); > + } else { > + spin_unlock(&fq->lock); > fq = NULL; > + } > This is bogus. I do not think you understood the comment.
diff --git a/net/ipv4/inet_fragment.c b/net/ipv4/inet_fragment.c index c88c9034d630..e4838bbe0abb 100644 --- a/net/ipv4/inet_fragment.c +++ b/net/ipv4/inet_fragment.c @@ -358,7 +358,6 @@ static struct inet_frag_queue *inet_frag_create(struct fqdir *fqdir, return q; } -/* TODO : call from rcu_read_lock() and no longer use refcount_inc_not_zero() */ struct inet_frag_queue *inet_frag_find(struct fqdir *fqdir, void *key) { /* This pairs with WRITE_ONCE() in fqdir_pre_exit(). */ @@ -375,8 +374,14 @@ struct inet_frag_queue *inet_frag_find(struct fqdir *fqdir, void *key) fq = inet_frag_create(fqdir, key, &prev); if (!IS_ERR_OR_NULL(prev)) { fq = prev; - if (!refcount_inc_not_zero(&fq->refcnt)) + spin_lock(&fq->lock); + if (refcount_read(&fq->refcnt) > 0) { + refcount_inc(&fq->refcnt); + spin_unlock(&fq->lock); + } else { + spin_unlock(&fq->lock); fq = NULL; + } } rcu_read_unlock(); return fq;
Remove refcount_inc_not_zero as per the listed TODO in the file. Used spin_(un)lock and refcount_* functions for synchronization. Signed-off-by: Abhinav Jain <jain.abhinav177@gmail.com> --- net/ipv4/inet_fragment.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-)