From: Byungchul Park <byungchul.park@lge.com>
To: <peterz@infradead.org>, <mingo@kernel.org>
Cc: <peterz@infradead.org>, <mingo@kernel.org>, <neilb@suse.de>,
<nab@linux-iscsi.org>, <viro@zeniv.linux.org.uk>,
<oleg@redhat.com>, <shli@kernel.org>,
<linux-kernel@vger.kernel.org>,
"Huang, Ying" <ying.huang@intel.com>, <kernel-team@lge.com>
Subject: Re: [PATCH v3 1/9] llist: Provide a safe version for llist_for_each
Date: Tue, 21 Mar 2017 11:53:34 +0900 [thread overview]
Message-ID: <20170321025334.GJ11100@X58A-UD3R> (raw)
In-Reply-To: <87r331fc5z.fsf@yhuang-dev.intel.com>
On Tue, Feb 14, 2017 at 03:45:44PM +0800, Huang, Ying wrote:
> Byungchul Park <byungchul.park@lge.com> writes:
>
> > Sometimes we have to dereference next field of llist node before entering
> > loop becasue the node might be deleted or the next field might be
> > modified within the loop. So this adds the safe version of llist_for_each,
> > that is, llist_for_each_safe.
> >
> > Signed-off-by: Byungchul Park <byungchul.park@lge.com>
>
> Reviewed-by: "Huang, Ying" <ying.huang@intel.com>
Hello,
Could you check this out?
>
> Best Regards,
> Huang, Ying
>
> > ---
> > include/linux/llist.h | 19 +++++++++++++++++++
> > 1 file changed, 19 insertions(+)
> >
> > diff --git a/include/linux/llist.h b/include/linux/llist.h
> > index fd4ca0b..b90c9f2 100644
> > --- a/include/linux/llist.h
> > +++ b/include/linux/llist.h
> > @@ -105,6 +105,25 @@ static inline void init_llist_head(struct llist_head *list)
> > for ((pos) = (node); pos; (pos) = (pos)->next)
> >
> > /**
> > + * llist_for_each_safe - iterate over some deleted entries of a lock-less list
> > + * safe against removal of list entry
> > + * @pos: the &struct llist_node to use as a loop cursor
> > + * @n: another &struct llist_node to use as temporary storage
> > + * @node: the first entry of deleted list entries
> > + *
> > + * In general, some entries of the lock-less list can be traversed
> > + * safely only after being deleted from list, so start with an entry
> > + * instead of list head.
> > + *
> > + * If being used on entries deleted from lock-less list directly, the
> > + * traverse order is from the newest to the oldest added entry. If
> > + * you want to traverse from the oldest to the newest, you must
> > + * reverse the order by yourself before traversing.
> > + */
> > +#define llist_for_each_safe(pos, n, node) \
> > + for ((pos) = (node); (pos) && ((n) = (pos)->next, true); (pos) = (n))
> > +
> > +/**
> > * llist_for_each_entry - iterate over some deleted entries of lock-less list of given type
> > * @pos: the type * to use as a loop cursor.
> > * @node: the fist entry of deleted list entries.
next prev parent reply other threads:[~2017-03-21 2:54 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-02-14 7:26 [PATCH v3 0/9] Don't reinvent the wheel but use existing llist API Byungchul Park
2017-02-14 7:26 ` [PATCH v3 1/9] llist: Provide a safe version for llist_for_each Byungchul Park
2017-02-14 7:45 ` Huang, Ying
2017-03-02 22:59 ` Byungchul Park
2017-03-21 2:53 ` Byungchul Park [this message]
2017-02-14 7:26 ` [PATCH v3 2/9] bcache: Don't reinvent the wheel but use existing llist API Byungchul Park
2017-03-02 23:16 ` Byungchul Park
2017-03-05 19:59 ` Jiri Kosina
2017-03-05 22:51 ` Byungchul Park
2017-03-05 22:54 ` Byungchul Park
2017-03-24 0:27 ` Byungchul Park
2017-02-14 7:26 ` [PATCH v3 3/9] raid5: " Byungchul Park
2017-02-16 22:48 ` Shaohua Li
2017-02-14 7:26 ` [PATCH v3 4/9] vhost/scsi: " Byungchul Park
2017-02-19 5:42 ` Nicholas A. Bellinger
2017-02-14 7:26 ` [PATCH v3 5/9] fput: " Byungchul Park
2017-02-14 17:44 ` Oleg Nesterov
2017-03-02 23:09 ` Byungchul Park
2017-02-14 7:26 ` [PATCH v3 6/9] namespace.c: " Byungchul Park
2017-02-14 7:26 ` [PATCH v3 7/9] irq_work: " Byungchul Park
2017-02-14 7:26 ` [PATCH v3 8/9] sched: " Byungchul Park
2017-02-22 5:04 ` Byungchul Park
2017-02-14 7:26 ` [PATCH v3 9/9] mm: " Byungchul Park
2017-05-02 8:03 ` [PATCH v3 0/9] " Byungchul Park
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