lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
Open Source and information security mailing list archives
| ||
|
Message-ID: <20190215114706.244fb7c2@redhat.com> Date: Fri, 15 Feb 2019 11:47:06 +0100 From: Stefano Brivio <sbrivio@...hat.com> To: Vlad Buslov <vladbu@...lanox.com> Cc: "netdev@...r.kernel.org" <netdev@...r.kernel.org>, "jhs@...atatu.com" <jhs@...atatu.com>, "xiyou.wangcong@...il.com" <xiyou.wangcong@...il.com>, "jiri@...nulli.us" <jiri@...nulli.us>, "davem@...emloft.net" <davem@...emloft.net> Subject: Re: [PATCH net-next 02/12] net: sched: flower: refactor fl_change On Fri, 15 Feb 2019 10:38:04 +0000 Vlad Buslov <vladbu@...lanox.com> wrote: > On Thu 14 Feb 2019 at 20:34, Stefano Brivio <sbrivio@...hat.com> wrote: > > On Thu, 14 Feb 2019 09:47:02 +0200 > > Vlad Buslov <vladbu@...lanox.com> wrote: > > > >> As a preparation for using classifier spinlock instead of relying on > >> external rtnl lock, rearrange code in fl_change. The goal is to group the > >> code which changes classifier state in single block in order to allow > >> following commits in this set to protect it from parallel modification with > >> tp->lock. Data structures that require tp->lock protection are mask > >> hashtable and filters list, and classifier handle_idr. > >> > >> fl_hw_replace_filter() is a sleeping function and cannot be called while > >> holding a spinlock. In order to execute all sequence of changes to shared > >> classifier data structures atomically, call fl_hw_replace_filter() before > >> modifying them. > >> > >> Signed-off-by: Vlad Buslov <vladbu@...lanox.com> > >> Acked-by: Jiri Pirko <jiri@...lanox.com> > >> --- > >> net/sched/cls_flower.c | 85 ++++++++++++++++++++++++++------------------------ > >> 1 file changed, 44 insertions(+), 41 deletions(-) > >> > >> diff --git a/net/sched/cls_flower.c b/net/sched/cls_flower.c > >> index 88d7af78ba7e..91596a6271f8 100644 > >> --- a/net/sched/cls_flower.c > >> +++ b/net/sched/cls_flower.c > >> @@ -1354,90 +1354,93 @@ static int fl_change(struct net *net, struct sk_buff *in_skb, > >> if (err < 0) > >> goto errout; > >> > >> - if (!handle) { > >> - handle = 1; > >> - err = idr_alloc_u32(&head->handle_idr, fnew, &handle, > >> - INT_MAX, GFP_KERNEL); > >> - } else if (!fold) { > >> - /* user specifies a handle and it doesn't exist */ > >> - err = idr_alloc_u32(&head->handle_idr, fnew, &handle, > >> - handle, GFP_KERNEL); > >> - } > >> - if (err) > >> - goto errout; > >> - fnew->handle = handle; > >> - > >> > >> [...] > >> > >> if (fold) { > >> + fnew->handle = handle; > > > > I'm probably missing something, but what if fold is passed and the > > handle isn't specified? That can still happen, right? In that case we > > wouldn't be allocating the handle. > > Hi Stefano, > > Thank you for reviewing my code. > > Cls API lookups fold by handle, so this pointer can only be not NULL > when user specified a handle and filter with such handle exists on tp. Ah, of course. Thanks for clarifying. By the way, what tricked me here was this check in fl_change(): if (fold && handle && fold->handle != handle) ... which could be turned into: if (fold && fold->handle != handle) ... at this point. -- Stefano
Powered by blists - more mailing lists