From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from e23smtp05.au.ibm.com (e23smtp05.au.ibm.com [202.81.31.147]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client CN "e23smtp05.au.ibm.com", Issuer "GeoTrust SSL CA" (not verified)) by ozlabs.org (Postfix) with ESMTPS id 0E6462C030B for ; Mon, 24 Jun 2013 04:59:08 +1000 (EST) Received: from /spool/local by e23smtp05.au.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Mon, 24 Jun 2013 04:52:56 +1000 Received: from d23relay05.au.ibm.com (d23relay05.au.ibm.com [9.190.235.152]) by d23dlp03.au.ibm.com (Postfix) with ESMTP id CF0413578051 for ; Mon, 24 Jun 2013 04:58:58 +1000 (EST) Received: from d23av03.au.ibm.com (d23av03.au.ibm.com [9.190.234.97]) by d23relay05.au.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id r5NIi27W7471556 for ; Mon, 24 Jun 2013 04:44:02 +1000 Received: from d23av03.au.ibm.com (loopback [127.0.0.1]) by d23av03.au.ibm.com (8.14.4/8.13.1/NCO v10.0 AVout) with ESMTP id r5NIwuql006897 for ; Mon, 24 Jun 2013 04:58:58 +1000 Message-ID: <51C744A9.8000406@linux.vnet.ibm.com> Date: Mon, 24 Jun 2013 00:25:37 +0530 From: "Srivatsa S. Bhat" MIME-Version: 1.0 To: Greg Kroah-Hartman Subject: Re: [PATCH 25/45] staging/octeon: Use get/put_online_cpus_atomic() to prevent CPU offline References: <20130623133642.19094.16038.stgit@srivatsabhat.in.ibm.com> <20130623134331.19094.80396.stgit@srivatsabhat.in.ibm.com> <20130623181740.GB24256@kroah.com> In-Reply-To: <20130623181740.GB24256@kroah.com> Content-Type: text/plain; charset=ISO-8859-1 Cc: peterz@infradead.org, fweisbec@gmail.com, linux-kernel@vger.kernel.org, walken@google.com, mingo@kernel.org, linux-arch@vger.kernel.org, vincent.guittot@linaro.org, ddaney@caviumnetworks.com, xiaoguangrong@linux.vnet.ibm.com, wangyun@linux.vnet.ibm.com, paulmck@linux.vnet.ibm.com, devel@driverdev.osuosl.org, nikunj@linux.vnet.ibm.com, linux-pm@vger.kernel.org, rusty@rustcorp.com.au, rostedt@goodmis.org, namhyung@kernel.org, tglx@linutronix.de, laijs@cn.fujitsu.com, zhong@linux.vnet.ibm.com, netdev@vger.kernel.org, oleg@redhat.com, sbw@mit.edu, tj@kernel.org, akpm@linux-foundation.org, linuxppc-dev@lists.ozlabs.org List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On 06/23/2013 11:47 PM, Greg Kroah-Hartman wrote: > On Sun, Jun 23, 2013 at 07:13:33PM +0530, Srivatsa S. Bhat wrote: >> Once stop_machine() is gone from the CPU offline path, we won't be able >> to depend on disabling preemption to prevent CPUs from going offline >> from under us. >> >> Use the get/put_online_cpus_atomic() APIs to prevent CPUs from going >> offline, while invoking from atomic context. >> >> Cc: Greg Kroah-Hartman >> Cc: devel@driverdev.osuosl.org >> Signed-off-by: Srivatsa S. Bhat >> --- >> >> drivers/staging/octeon/ethernet-rx.c | 3 +++ >> 1 file changed, 3 insertions(+) >> >> diff --git a/drivers/staging/octeon/ethernet-rx.c b/drivers/staging/octeon/ethernet-rx.c >> index 34afc16..8588b4d 100644 >> --- a/drivers/staging/octeon/ethernet-rx.c >> +++ b/drivers/staging/octeon/ethernet-rx.c >> @@ -36,6 +36,7 @@ >> #include >> #include >> #include >> +#include >> #include >> #include >> #ifdef CONFIG_XFRM >> @@ -97,6 +98,7 @@ static void cvm_oct_enable_one_cpu(void) >> return; >> >> /* ... if a CPU is available, Turn on NAPI polling for that CPU. */ >> + get_online_cpus_atomic(); >> for_each_online_cpu(cpu) { >> if (!cpu_test_and_set(cpu, core_state.cpu_state)) { >> v = smp_call_function_single(cpu, cvm_oct_enable_napi, >> @@ -106,6 +108,7 @@ static void cvm_oct_enable_one_cpu(void) >> break; >> } >> } >> + put_online_cpus_atomic(); > > Does this driver really need to be doing this in the first place? If > so, why? The majority of network drivers don't, why is this one > "special"? > Honestly, I don't know. Let's CC the author of that code (David Daney). I wonder why get_maintainer.pl didn't generate his name for this file, even though the entire file is almost made up of his commits alone! Regards, Srivatsa S. Bhat