From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Woodhouse Subject: Re: [PATCH 07/17] net: convert sock.sk_wmem_alloc from atomic_t to refcount_t Date: Fri, 15 Jun 2018 21:00:27 +0100 Message-ID: <00520334446ffa4671513bb42ebeeecfab4107e7.camel@infradead.org> References: <1498817290-3368-1-git-send-email-elena.reshetova@intel.com> <1498817290-3368-8-git-send-email-elena.reshetova@intel.com> <1529065762.27158.40.camel@infradead.org> <9805cd6e-1c21-f7b4-cc0e-d4a343b8e3d8@gmail.com> <3cbab0cc-230d-6980-6748-67f777c8ad22@gmail.com> <1529070283.27158.46.camel@infradead.org> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Cc: Krzysztof Mazur , Kevin Darbyshire-Bryant , 3chas3@gmail.com, Mathias Kresin To: Eric Dumazet , Elena Reshetova , netdev@vger.kernel.org Return-path: Received: from casper.infradead.org ([85.118.1.10]:48746 "EHLO casper.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S966117AbeFOUAf (ORCPT ); Fri, 15 Jun 2018 16:00:35 -0400 In-Reply-To: <1529070283.27158.46.camel@infradead.org> Sender: netdev-owner@vger.kernel.org List-ID: On Fri, 2018-06-15 at 14:44 +0100, David Woodhouse wrote: > > > Or simply use a new field in ATM_SKB(skb) to remember a stable > > truesize used in both sides (add/sub) > > Right, that was my second suggestion ("copy the accounted value..."). > > It's a bit of a hack, and I think that actually *using* sock_wfree() > instead of what's currently in atm_pop_raw() would be the better > solution. Does anyone remember why we didn't do that in the first > place? That does end up being quite hairy. I don't think it's worth doing. This should probably suffice to fix it... Kevin this is going to conflict with the ifx_atm_alloc_skb() hack in the tree you're working on, but that needs to be killed with fire anyway. It's utterly pointless as discussed. >>From 3368eaeb0a2f09138894dde0f26f879e5228005a Mon Sep 17 00:00:00 2001 From: David Woodhouse Date: Fri, 15 Jun 2018 20:49:20 +0100 Subject: [PATCH] atm: Preserve value of skb->truesize when accounting to vcc There's a hack in pskb_expand_head() to avoid adjusting skb->truesize for certain skbs. Ideally it would cover ATM too. It doesn't. Just stashing the accounted value and using it in atm_raw_pop() is probably the easiest way to cope. Signed-off-by: David Woodhouse --- include/linux/atmdev.h | 15 +++++++++++++++ net/atm/br2684.c | 3 +-- net/atm/clip.c | 3 +-- net/atm/common.c | 3 +-- net/atm/lec.c | 3 +-- net/atm/mpc.c | 3 +-- net/atm/pppoatm.c | 3 +-- net/atm/raw.c | 4 ++-- 8 files changed, 23 insertions(+), 14 deletions(-) diff --git a/include/linux/atmdev.h b/include/linux/atmdev.h index 0c27515d2cf6..8124815eb121 100644 --- a/include/linux/atmdev.h +++ b/include/linux/atmdev.h @@ -214,6 +214,7 @@ struct atmphy_ops { struct atm_skb_data { struct atm_vcc *vcc; /* ATM VCC */ unsigned long atm_options; /* ATM layer options */ + unsigned int acct_truesize; /* truesize accounted to vcc */ }; #define VCC_HTABLE_SIZE 32 @@ -241,6 +242,20 @@ void vcc_insert_socket(struct sock *sk); void atm_dev_release_vccs(struct atm_dev *dev); +static inline void atm_account_tx(struct atm_vcc *vcc, struct sk_buff *skb) +{ + /* + * Because ATM skbs may not belong to a sock (and we don't + * necessarily want to), skb->truesize may be adjusted, + * escaping the hack in pskb_expand_head() which avoids + * doing so for some cases. So stash the value of truesize + * at the time we accounted it, and atm_pop_raw() can use + * that value later, in case it changes. + */ + refcount_add(skb->truesize, &sk_atm(vcc)->sk_wmem_alloc); + ATM_SKB(skb)->acct_truesize = skb->truesize; + ATM_SKB(skb)->atm_options = vcc->atm_options; +} static inline void atm_force_charge(struct atm_vcc *vcc,int truesize) { diff --git a/net/atm/br2684.c b/net/atm/br2684.c index 4e111196f902..bc21f8e8daf2 100644 --- a/net/atm/br2684.c +++ b/net/atm/br2684.c @@ -252,8 +252,7 @@ static int br2684_xmit_vcc(struct sk_buff *skb, struct net_device *dev, ATM_SKB(skb)->vcc = atmvcc = brvcc->atmvcc; pr_debug("atm_skb(%p)->vcc(%p)->dev(%p)\n", skb, atmvcc, atmvcc->dev); - refcount_add(skb->truesize, &sk_atm(atmvcc)->sk_wmem_alloc); - ATM_SKB(skb)->atm_options = atmvcc->atm_options; + atm_account_tx(atmvcc, skb); dev->stats.tx_packets++; dev->stats.tx_bytes += skb->len; diff --git a/net/atm/clip.c b/net/atm/clip.c index 65f706e4344c..60920a42f640 100644 --- a/net/atm/clip.c +++ b/net/atm/clip.c @@ -381,8 +381,7 @@ static netdev_tx_t clip_start_xmit(struct sk_buff *skb, memcpy(here, llc_oui, sizeof(llc_oui)); ((__be16 *) here)[3] = skb->protocol; } - refcount_add(skb->truesize, &sk_atm(vcc)->sk_wmem_alloc); - ATM_SKB(skb)->atm_options = vcc->atm_options; + atm_account_tx(vcc, skb); entry->vccs->last_use = jiffies; pr_debug("atm_skb(%p)->vcc(%p)->dev(%p)\n", skb, vcc, vcc->dev); old = xchg(&entry->vccs->xoff, 1); /* assume XOFF ... */ diff --git a/net/atm/common.c b/net/atm/common.c index 8a4f99114cd2..9e812c782a37 100644 --- a/net/atm/common.c +++ b/net/atm/common.c @@ -630,10 +630,9 @@ int vcc_sendmsg(struct socket *sock, struct msghdr *m, size_t size) goto out; } pr_debug("%d += %d\n", sk_wmem_alloc_get(sk), skb->truesize); - refcount_add(skb->truesize, &sk->sk_wmem_alloc); + atm_account_tx(vcc, skb); skb->dev = NULL; /* for paths shared with net_device interfaces */ - ATM_SKB(skb)->atm_options = vcc->atm_options; if (!copy_from_iter_full(skb_put(skb, size), size, &m->msg_iter)) { kfree_skb(skb); error = -EFAULT; diff --git a/net/atm/lec.c b/net/atm/lec.c index a3d93a1bb133..d7cc165e24e0 100644 --- a/net/atm/lec.c +++ b/net/atm/lec.c @@ -179,9 +179,8 @@ lec_send(struct atm_vcc *vcc, struct sk_buff *skb) struct net_device *dev = skb->dev; ATM_SKB(skb)->vcc = vcc; - ATM_SKB(skb)->atm_options = vcc->atm_options; + atm_account_tx(vcc, skb); - refcount_add(skb->truesize, &sk_atm(vcc)->sk_wmem_alloc); if (vcc->send(vcc, skb) < 0) { dev->stats.tx_dropped++; return; diff --git a/net/atm/mpc.c b/net/atm/mpc.c index 5677147209e8..db9a1838687c 100644 --- a/net/atm/mpc.c +++ b/net/atm/mpc.c @@ -555,8 +555,7 @@ static int send_via_shortcut(struct sk_buff *skb, struct mpoa_client *mpc) sizeof(struct llc_snap_hdr)); } - refcount_add(skb->truesize, &sk_atm(entry->shortcut)->sk_wmem_alloc); - ATM_SKB(skb)->atm_options = entry->shortcut->atm_options; + atm_account_tx(entry->shortcut, skb); entry->shortcut->send(entry->shortcut, skb); entry->packets_fwded++; mpc->in_ops->put(entry); diff --git a/net/atm/pppoatm.c b/net/atm/pppoatm.c index 21d9d341a619..af8c4b38b746 100644 --- a/net/atm/pppoatm.c +++ b/net/atm/pppoatm.c @@ -350,8 +350,7 @@ static int pppoatm_send(struct ppp_channel *chan, struct sk_buff *skb) return 1; } - refcount_add(skb->truesize, &sk_atm(ATM_SKB(skb)->vcc)->sk_wmem_alloc); - ATM_SKB(skb)->atm_options = ATM_SKB(skb)->vcc->atm_options; + atm_account_tx(vcc, skb); pr_debug("atm_skb(%p)->vcc(%p)->dev(%p)\n", skb, ATM_SKB(skb)->vcc, ATM_SKB(skb)->vcc->dev); ret = ATM_SKB(skb)->vcc->send(ATM_SKB(skb)->vcc, skb) diff --git a/net/atm/raw.c b/net/atm/raw.c index ee10e8d46185..b3ba44aab0ee 100644 --- a/net/atm/raw.c +++ b/net/atm/raw.c @@ -35,8 +35,8 @@ static void atm_pop_raw(struct atm_vcc *vcc, struct sk_buff *skb) struct sock *sk = sk_atm(vcc); pr_debug("(%d) %d -= %d\n", - vcc->vci, sk_wmem_alloc_get(sk), skb->truesize); - WARN_ON(refcount_sub_and_test(skb->truesize, &sk->sk_wmem_alloc)); + vcc->vci, sk_wmem_alloc_get(sk), ATM_SKB(skb)->acct_truesize); + WARN_ON(refcount_sub_and_test(ATM_SKB(skb)->acct_truesize, &sk->sk_wmem_alloc)); dev_kfree_skb_any(skb); sk->sk_write_space(sk); } -- 2.17.0 -- dwmw2