From 119e9db233ad0f4cbd4cfb9f9385a7bca378b37d Mon Sep 17 00:00:00 2001 From: Zeng Chi Date: Mon, 21 Sep 2026 18:24:42 +0800 Subject: KVM: Don't pre-reserve xarray entries when storing empty/NULL attributes Skip the xarray reservation loop when clearing all memory attributes, as storing NULL only erases the entry and never needs to allocate, so no reservation (and no cleanup of a failed one) is required in that case. Suggested-by: Sean Christopherson Cc: David Ballesteros Signed-off-by: Zeng Chi Link: https://patch.msgid.link/20260921102442.1232375-1-zeng_chi911@163.com [sean: split to separate patch] Signed-off-by: Sean Christopherson --- Documentation/networking/skbuff.rst | 31 +++++++++++++++++++++++++++++++ 1 file changed, 31 insertions(+) create mode 100644 Documentation/networking/skbuff.rst (limited to 'Documentation/networking/skbuff.rst') diff --git a/Documentation/networking/skbuff.rst b/Documentation/networking/skbuff.rst new file mode 100644 index 000000000..94681523e --- /dev/null +++ b/Documentation/networking/skbuff.rst @@ -0,0 +1,31 @@ +.. SPDX-License-Identifier: GPL-2.0 + +struct sk_buff +============== + +:c:type:`sk_buff` is the main networking structure representing +a packet. + +Basic sk_buff geometry +---------------------- + +.. kernel-doc:: include/linux/skbuff.h + :doc: Basic sk_buff geometry + +Shared skbs and skb clones +-------------------------- + +:c:member:`sk_buff.users` is a simple refcount allowing multiple entities +to keep a struct sk_buff alive. skbs with a ``sk_buff.users != 1`` are referred +to as shared skbs (see skb_shared()). + +skb_clone() allows for fast duplication of skbs. None of the data buffers +get copied, but caller gets a new metadata struct (struct sk_buff). +&skb_shared_info.refcount indicates the number of skbs pointing at the same +packet data (i.e. clones). + +dataref and headerless skbs +--------------------------- + +.. kernel-doc:: include/linux/skbuff.h + :doc: dataref and headerless skbs -- cgit v1.3.1