From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pf1-f202.google.com (mail-pf1-f202.google.com [209.85.210.202]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 233082F4315 for ; Fri, 11 Jul 2025 19:10:29 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.210.202 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1752261032; cv=none; b=RvtwiHD8TOQ3QAo7khcbNYqhmJLjTuGOQSlpeENhPJvkOANlQRUMTsddGcvxVdwQufbgqAtr1eZNT1+GPCpx9od3QuxdmWDDyKfpibSK2SsviAHPvKHGCJaNdjLDabpYgHCsVuLrUXc6UbytMUkS9n14TkHuDEtDa1RD7pQTIKs= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1752261032; c=relaxed/simple; bh=WgKFk7LrORp8I0NuxMg91oh7cQUGykF40Ygih5YKZM0=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=KdRpMEHnWltkM/Q2vtsGMthnh3zg7XVflNaMSm1LUXhHBk35dztJyZHVecdMTl91+qVlKUFdu3G59eSrH9xm02sikTDqvr7IzB9wSMfXpiBWAr4KkpIMTCIkerclJ4yLb9OmYnZyM0kj8KQWzb8idRZmtB9Xe2aoExfZwL702mE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--kuniyu.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=NHyWs+ej; arc=none smtp.client-ip=209.85.210.202 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--kuniyu.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="NHyWs+ej" Received: by mail-pf1-f202.google.com with SMTP id d2e1a72fcca58-74943a7cd9aso3580875b3a.3 for ; Fri, 11 Jul 2025 12:10:29 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1752261029; x=1752865829; darn=vger.kernel.org; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=x+Bx+K7JJy3ueXzTSf+6aUI6t9LzJaKz34z8lI+8dG4=; b=NHyWs+ejmVNhEP94JY/Jn15AxJUI1/R6uQXu0AtNBvG0Mj+xhETAL9GX/23b3dD7SL F+EkzsMmTmcS+f3BL8J45FnNYNYOHSADY9ItfiY3fvTzUhBeklULvDSoxYUTNhw47zah XVDD4+/9Yfa3oHg9KSpby7kgtwmbUqLFo9OkoiTVEaMp1S/+MfkCCR8HKAN83iW2vpjI Qe5nAaAYWzLkksWddu2G0TsgiWRidx396Fl546pbNwBy/czBccasrCdlaX67sOrs0DsZ eQ+qkML923173Mj1uvpR728Hn4RE5KUxDcsemNUdDKu+J8SAX3zERMNIqBpkE6Mz3qOI 9kKQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1752261029; x=1752865829; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=x+Bx+K7JJy3ueXzTSf+6aUI6t9LzJaKz34z8lI+8dG4=; b=Fh16C1RQ7+wiMsHiTSxfRJBm2EBAAVkCtqiz7d4ltmIqMQLdIZtHkcVQJrzN0vW2GB IVNYRzWU54KieOAlhCSBemE8xO+qJnXPOWbuP2q6PrqvJffEs7KQBFelge0jsNanDkX0 p27yc/5nvZjxfaWwN0jk8u7gMYiWp5XRJlNq4TyM6u5YVcBgA0X1YpWTJD5m3FzAhg6X rysoM12HdZKu4IO6hHLfGlk8RWBYpRpgmpeWhG/NKguP4DqCDDgzyaO0QCDVlx4XZBXe qL3SP6ZXBQ88b0+wzd9Qp26YJmfsLr55KD+Nf/rw/0pe2Prw8njIQDL6w9JEichjy1sj A2Og== X-Forwarded-Encrypted: i=1; AJvYcCUPETo9YCnAaiOzDpGgQ2SUQxJ/tKKC/PtKVWWNAZn2j866EykUAk3gwltk6rdQcPCwEluNzYM=@vger.kernel.org X-Gm-Message-State: AOJu0YwsOd8QNh5z1PsehEBGkK8/4+ASROWwyjwsneiNY3Pd4+c+pBDc yWL932DjwM0y/KQqY+kVfgPjkJTuGfIlIIaKvlo+F5j0WiCI7/U3vD7Rx1Jdhuxj+GtiSWM2CX3 3D955mA== X-Google-Smtp-Source: AGHT+IGXdR9/6RAMeKdzfJcG6Sz/Q3qZFy8NLGVDLNuSKnF0xW1bHRuNL7/h04P+hfhyEGiIAcq0VxQieTM= X-Received: from pfjg8.prod.google.com ([2002:a05:6a00:b88:b0:748:fa96:6db3]) (user=kuniyu job=prod-delivery.src-stubby-dispatcher) by 2002:a05:6a00:928a:b0:74c:f1d8:c42a with SMTP id d2e1a72fcca58-74ee244a460mr5407169b3a.13.1752261029198; Fri, 11 Jul 2025 12:10:29 -0700 (PDT) Date: Fri, 11 Jul 2025 19:06:17 +0000 In-Reply-To: <20250711191007.3591938-1-kuniyu@google.com> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20250711191007.3591938-1-kuniyu@google.com> X-Mailer: git-send-email 2.50.0.727.gbf7dc18ff4-goog Message-ID: <20250711191007.3591938-13-kuniyu@google.com> Subject: [PATCH v1 net-next 12/14] neighbour: Drop read_lock_bh(&tbl->lock) in pneigh_lookup(). From: Kuniyuki Iwashima To: "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , David Ahern Cc: Simon Horman , Kuniyuki Iwashima , Kuniyuki Iwashima , netdev@vger.kernel.org Content-Type: text/plain; charset="UTF-8" Now, all callers of pneigh_lookup() are under RCU, and the read lock there is no longer needed. Let's drop the lock, inline __pneigh_lookup_1() to pneigh_lookup(), and call it from pneigh_create(). The next patch will remove tbl->lock from pneigh_create(). Signed-off-by: Kuniyuki Iwashima --- net/core/neighbour.c | 42 ++++++++++++++++-------------------------- 1 file changed, 16 insertions(+), 26 deletions(-) diff --git a/net/core/neighbour.c b/net/core/neighbour.c index c1e5fda2cf628..9d716852e0e7d 100644 --- a/net/core/neighbour.c +++ b/net/core/neighbour.c @@ -720,22 +720,6 @@ static u32 pneigh_hash(const void *pkey, unsigned int key_len) return hash_val; } -static struct pneigh_entry *__pneigh_lookup_1(struct pneigh_entry *n, - struct net *net, - const void *pkey, - unsigned int key_len, - struct net_device *dev) -{ - while (n) { - if (!memcmp(n->key, pkey, key_len) && - net_eq(pneigh_net(n), net) && - (n->dev == dev || !n->dev)) - return n; - n = n->next; - } - return NULL; -} - struct pneigh_entry *pneigh_lookup(struct neigh_table *tbl, struct net *net, const void *pkey, struct net_device *dev) @@ -746,13 +730,19 @@ struct pneigh_entry *pneigh_lookup(struct neigh_table *tbl, key_len = tbl->key_len; hash_val = pneigh_hash(pkey, key_len); + n = rcu_dereference_check(tbl->phash_buckets[hash_val], + lockdep_is_held(&tbl->lock)); - read_lock_bh(&tbl->lock); - n = __pneigh_lookup_1(tbl->phash_buckets[hash_val], - net, pkey, key_len, dev); - read_unlock_bh(&tbl->lock); + while (n) { + if (!memcmp(n->key, pkey, key_len) && + net_eq(pneigh_net(n), net) && + (n->dev == dev || !n->dev)) + return n; - return n; + n = rcu_dereference_check(n->next, lockdep_is_held(&tbl->lock)); + } + + return NULL; } EXPORT_IPV6_MOD(pneigh_lookup); @@ -761,19 +751,18 @@ struct pneigh_entry *pneigh_create(struct neigh_table *tbl, struct net_device *dev) { struct pneigh_entry *n; - unsigned int key_len = tbl->key_len; - u32 hash_val = pneigh_hash(pkey, key_len); + unsigned int key_len; + u32 hash_val; ASSERT_RTNL(); read_lock_bh(&tbl->lock); - n = __pneigh_lookup_1(tbl->phash_buckets[hash_val], - net, pkey, key_len, dev); + n = pneigh_lookup(tbl, net, pkey, dev); read_unlock_bh(&tbl->lock); - if (n) goto out; + key_len = tbl->key_len; n = kzalloc(sizeof(*n) + key_len, GFP_KERNEL); if (!n) goto out; @@ -790,6 +779,7 @@ struct pneigh_entry *pneigh_create(struct neigh_table *tbl, goto out; } + hash_val = pneigh_hash(pkey, key_len); write_lock_bh(&tbl->lock); n->next = tbl->phash_buckets[hash_val]; rcu_assign_pointer(tbl->phash_buckets[hash_val], n); -- 2.50.0.727.gbf7dc18ff4-goog