Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965592AbcKKWW3 (ORCPT ); Fri, 11 Nov 2016 17:22:29 -0500 Received: from mail-pf0-f182.google.com ([209.85.192.182]:33224 "EHLO mail-pf0-f182.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S934016AbcKKWW0 (ORCPT ); Fri, 11 Nov 2016 17:22:26 -0500 From: Kees Cook To: Joel Fernandes Cc: Kees Cook , Anton Vorontsov , Colin Cross , Tony Luck , linux-kernel@vger.kernel.org Subject: [PATCH v3 1/8] pstore: Make spinlock per zone instead of global Date: Fri, 11 Nov 2016 14:21:46 -0800 Message-Id: <1478902913-143778-2-git-send-email-keescook@chromium.org> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1478902913-143778-1-git-send-email-keescook@chromium.org> References: <1478902913-143778-1-git-send-email-keescook@chromium.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3051 Lines: 89 From: Joel Fernandes 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, when ramoops's ftrace use-case has a FTRACE_PER_CPU flag introduced later, which splits the ftrace memory area into a single zone per CPU, it will eliminate the need for locking. In preparation for this, make the locking optional. Signed-off-by: Joel Fernandes [kees: updated commit message] Signed-off-by: Kees Cook --- 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 3975deec02f8..cb92055e6016 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 c668c861c96c..244d2423dbaf 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