Return-path: Received: from mail.atheros.com ([12.36.123.2]:36689 "EHLO mail.atheros.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750956Ab0DKFd5 (ORCPT ); Sun, 11 Apr 2010 01:33:57 -0400 Received: from mail.atheros.com ([10.10.20.105]) by sidewinder.atheros.com for ; Sat, 10 Apr 2010 22:33:57 -0700 From: Sujith MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Message-ID: <19393.24337.10019.88274@gargle.gargle.HOWL> Date: Sun, 11 Apr 2010 11:03:05 +0530 To: "tom.leiming@gmail.com" CC: Luis Rodriguez , "linux-wireless@vger.kernel.org" , "linville@tuxdriver.com" Subject: [PATCH 1/3] ath9k-htc: replace __dev_alloc_skb with alloc_skb in ath9k_hif_usb_alloc_rx_urbs In-Reply-To: <1270911887-5717-1-git-send-email-tom.leiming@gmail.com> References: <1270911887-5717-1-git-send-email-tom.leiming@gmail.com> Sender: linux-wireless-owner@vger.kernel.org List-ID: tom.leiming@gmail.com wrote: > In ath9k_hif_usb_alloc_rx_urbs, ath9k-htc will pass skb->data into > usb hcd and usb hcd will do dma mapping and unmapping to the buffer > pointed by skb->data, so we should pass a cache-line aligned address. > > This patch replace __dev_alloc_skb with alloc_skb to make skb->data > pointed to a cacheline aligned address simply since ath9k-htc does not > skb_push on the skb. > AFAIK, the only architecture that has a requirement to override NET_SKB_PAD is powerpc, and it does it anyway - by setting it to a cacheline size. So why do we need to do this ? Sujith