Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965955AbcKKAGi (ORCPT ); Thu, 10 Nov 2016 19:06:38 -0500 Received: from mail-wm0-f43.google.com ([74.125.82.43]:38173 "EHLO mail-wm0-f43.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S965231AbcKKAGg (ORCPT ); Thu, 10 Nov 2016 19:06:36 -0500 MIME-Version: 1.0 In-Reply-To: <1476948846-15006-2-git-send-email-joelaf@google.com> References: <1476948846-15006-1-git-send-email-joelaf@google.com> <1476948846-15006-2-git-send-email-joelaf@google.com> From: Kees Cook Date: Thu, 10 Nov 2016 16:06:33 -0800 X-Google-Sender-Auth: _rzcoYS97vvtaS1ziz_CnpU68-0 Message-ID: Subject: Re: [PATCH v2 1/7] pstore: Make spinlock per zone instead of global To: Joel Fernandes Cc: LKML , Anton Vorontsov , Colin Cross , Tony Luck Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3606 Lines: 100 On Thu, Oct 20, 2016 at 12:34 AM, Joel Fernandes wrote: > Currently pstore has a global spinlock for all zones. Since the zones are > independent and modify different areas of memory, there's no need to have a > global lock, so we should use a per-zone lock as introduced here. Also, > ramoops's ftrace usecase has a FTRACE_PER_CPU flag introduced in this patch > series which splits the ftrace memory area into a single zone per CPU thus > eliminating the need for locking. In preparation for this, make the locking > optional. > > Signed-off-by: Joel Fernandes > --- > fs/pstore/ram_core.c | 11 +++++------ > include/linux/pstore_ram.h | 1 + > 2 files changed, 6 insertions(+), 6 deletions(-) > > diff --git a/fs/pstore/ram_core.c b/fs/pstore/ram_core.c > index 3975dee..cb92055 100644 > --- a/fs/pstore/ram_core.c > +++ b/fs/pstore/ram_core.c > @@ -48,8 +48,6 @@ static inline size_t buffer_start(struct persistent_ram_zone *prz) > return atomic_read(&prz->buffer->start); > } > > -static DEFINE_RAW_SPINLOCK(buffer_lock); > - > /* increase and wrap the start pointer, returning the old value */ > static size_t buffer_start_add(struct persistent_ram_zone *prz, size_t a) > { > @@ -57,7 +55,7 @@ static size_t buffer_start_add(struct persistent_ram_zone *prz, size_t a) > int new; > unsigned long flags; > > - raw_spin_lock_irqsave(&buffer_lock, flags); > + raw_spin_lock_irqsave(&prz->buffer_lock, flags); > > old = atomic_read(&prz->buffer->start); > new = old + a; > @@ -65,7 +63,7 @@ static size_t buffer_start_add(struct persistent_ram_zone *prz, size_t a) > new -= prz->buffer_size; > atomic_set(&prz->buffer->start, new); > > - raw_spin_unlock_irqrestore(&buffer_lock, flags); > + raw_spin_unlock_irqrestore(&prz->buffer_lock, flags); > > return old; > } > @@ -77,7 +75,7 @@ static void buffer_size_add(struct persistent_ram_zone *prz, size_t a) > size_t new; > unsigned long flags; > > - raw_spin_lock_irqsave(&buffer_lock, flags); > + raw_spin_lock_irqsave(&prz->buffer_lock, flags); > > old = atomic_read(&prz->buffer->size); > if (old == prz->buffer_size) > @@ -89,7 +87,7 @@ static void buffer_size_add(struct persistent_ram_zone *prz, size_t a) > atomic_set(&prz->buffer->size, new); > > exit: > - raw_spin_unlock_irqrestore(&buffer_lock, flags); > + raw_spin_unlock_irqrestore(&prz->buffer_lock, flags); > } > > static void notrace persistent_ram_encode_rs8(struct persistent_ram_zone *prz, > @@ -493,6 +491,7 @@ static int persistent_ram_post_init(struct persistent_ram_zone *prz, u32 sig, > > prz->buffer->sig = sig; > persistent_ram_zap(prz); > + prz->buffer_lock = __RAW_SPIN_LOCK_UNLOCKED(buffer_lock); > > return 0; > } > diff --git a/include/linux/pstore_ram.h b/include/linux/pstore_ram.h > index c668c86..244d242 100644 > --- a/include/linux/pstore_ram.h > +++ b/include/linux/pstore_ram.h > @@ -40,6 +40,7 @@ struct persistent_ram_zone { > void *vaddr; > struct persistent_ram_buffer *buffer; > size_t buffer_size; > + raw_spinlock_t buffer_lock; > > /* ECC correction */ > char *par_buffer; > -- > 2.7.4 > This one looks good, thanks. I'll get this in for -next since it's a good clean-up on its own. Have you put these patches through scripts/checkpatch.pl? Some of lines wrap or have wide commit messages, but that's just cosmetic to fix up. -Kees -- Kees Cook Nexus Security