From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753209AbdHDXRl (ORCPT ); Fri, 4 Aug 2017 19:17:41 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:46526 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753073AbdHDXRf (ORCPT ); Fri, 4 Aug 2017 19:17:35 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Joel Fernandes , Kees Cook Subject: [PATCH 4.9 041/105] pstore: Allow prz to control need for locking Date: Fri, 4 Aug 2017 16:15:09 -0700 Message-Id: <20170804231554.402923049@linuxfoundation.org> X-Mailer: git-send-email 2.13.4 In-Reply-To: <20170804231551.544678194@linuxfoundation.org> References: <20170804231551.544678194@linuxfoundation.org> User-Agent: quilt/0.65 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 4.9-stable review patch. If anyone has any objections, please let me know. ------------------ From: Joel Fernandes commit 663deb47880f2283809669563c5a52ac7c6aef1a upstream. In preparation of not locking at all for certain buffers depending on if there's contention, make locking optional depending on the initialization of the prz. Signed-off-by: Joel Fernandes [kees: moved locking flag into prz instead of via caller arguments] Signed-off-by: Kees Cook Signed-off-by: Greg Kroah-Hartman --- fs/pstore/ram.c | 5 +++-- fs/pstore/ram_core.c | 24 +++++++++++++++--------- include/linux/pstore_ram.h | 10 +++++++++- 3 files changed, 27 insertions(+), 12 deletions(-) --- a/fs/pstore/ram.c +++ b/fs/pstore/ram.c @@ -434,7 +434,7 @@ static int ramoops_init_przs(struct devi for (i = 0; i < cxt->max_dump_cnt; i++) { cxt->przs[i] = persistent_ram_new(*paddr, cxt->record_size, 0, &cxt->ecc_info, - cxt->memtype); + cxt->memtype, 0); if (IS_ERR(cxt->przs[i])) { err = PTR_ERR(cxt->przs[i]); dev_err(dev, "failed to request mem region (0x%zx@0x%llx): %d\n", @@ -471,7 +471,8 @@ static int ramoops_init_prz(struct devic return -ENOMEM; } - *prz = persistent_ram_new(*paddr, sz, sig, &cxt->ecc_info, cxt->memtype); + *prz = persistent_ram_new(*paddr, sz, sig, &cxt->ecc_info, + cxt->memtype, 0); if (IS_ERR(*prz)) { int err = PTR_ERR(*prz); --- a/fs/pstore/ram_core.c +++ b/fs/pstore/ram_core.c @@ -53,9 +53,10 @@ static size_t buffer_start_add(struct pe { int old; int new; - unsigned long flags; + unsigned long flags = 0; - raw_spin_lock_irqsave(&prz->buffer_lock, flags); + if (!(prz->flags & PRZ_FLAG_NO_LOCK)) + raw_spin_lock_irqsave(&prz->buffer_lock, flags); old = atomic_read(&prz->buffer->start); new = old + a; @@ -63,7 +64,8 @@ static size_t buffer_start_add(struct pe new -= prz->buffer_size; atomic_set(&prz->buffer->start, new); - raw_spin_unlock_irqrestore(&prz->buffer_lock, flags); + if (!(prz->flags & PRZ_FLAG_NO_LOCK)) + raw_spin_unlock_irqrestore(&prz->buffer_lock, flags); return old; } @@ -73,9 +75,10 @@ static void buffer_size_add(struct persi { size_t old; size_t new; - unsigned long flags; + unsigned long flags = 0; - raw_spin_lock_irqsave(&prz->buffer_lock, flags); + if (!(prz->flags & PRZ_FLAG_NO_LOCK)) + raw_spin_lock_irqsave(&prz->buffer_lock, flags); old = atomic_read(&prz->buffer->size); if (old == prz->buffer_size) @@ -87,7 +90,8 @@ static void buffer_size_add(struct persi atomic_set(&prz->buffer->size, new); exit: - raw_spin_unlock_irqrestore(&prz->buffer_lock, flags); + if (!(prz->flags & PRZ_FLAG_NO_LOCK)) + raw_spin_unlock_irqrestore(&prz->buffer_lock, flags); } static void notrace persistent_ram_encode_rs8(struct persistent_ram_zone *prz, @@ -463,7 +467,8 @@ static int persistent_ram_buffer_map(phy } static int persistent_ram_post_init(struct persistent_ram_zone *prz, u32 sig, - struct persistent_ram_ecc_info *ecc_info) + struct persistent_ram_ecc_info *ecc_info, + unsigned long flags) { int ret; @@ -492,6 +497,7 @@ static int persistent_ram_post_init(stru prz->buffer->sig = sig; persistent_ram_zap(prz); prz->buffer_lock = __RAW_SPIN_LOCK_UNLOCKED(buffer_lock); + prz->flags = flags; return 0; } @@ -516,7 +522,7 @@ void persistent_ram_free(struct persiste struct persistent_ram_zone *persistent_ram_new(phys_addr_t start, size_t size, u32 sig, struct persistent_ram_ecc_info *ecc_info, - unsigned int memtype) + unsigned int memtype, u32 flags) { struct persistent_ram_zone *prz; int ret = -ENOMEM; @@ -531,7 +537,7 @@ struct persistent_ram_zone *persistent_r if (ret) goto err; - ret = persistent_ram_post_init(prz, sig, ecc_info); + ret = persistent_ram_post_init(prz, sig, ecc_info, flags); if (ret) goto err; --- a/include/linux/pstore_ram.h +++ b/include/linux/pstore_ram.h @@ -24,6 +24,13 @@ #include #include +/* + * Choose whether access to the RAM zone requires locking or not. If a zone + * can be written to from different CPUs like with ftrace for example, then + * PRZ_FLAG_NO_LOCK is used. For all other cases, locking is required. + */ +#define PRZ_FLAG_NO_LOCK BIT(0) + struct persistent_ram_buffer; struct rs_control; @@ -40,6 +47,7 @@ struct persistent_ram_zone { void *vaddr; struct persistent_ram_buffer *buffer; size_t buffer_size; + u32 flags; raw_spinlock_t buffer_lock; /* ECC correction */ @@ -56,7 +64,7 @@ struct persistent_ram_zone { struct persistent_ram_zone *persistent_ram_new(phys_addr_t start, size_t size, u32 sig, struct persistent_ram_ecc_info *ecc_info, - unsigned int memtype); + unsigned int memtype, u32 flags); void persistent_ram_free(struct persistent_ram_zone *prz); void persistent_ram_zap(struct persistent_ram_zone *prz);