Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934308AbbBCXfp (ORCPT ); Tue, 3 Feb 2015 18:35:45 -0500 Received: from mail.linuxfoundation.org ([140.211.169.12]:55370 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933574AbbBCXZ0 (ORCPT ); Tue, 3 Feb 2015 18:25:26 -0500 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Rob Herring , Anton Vorontsov , Tony Luck , HuKeping Subject: [PATCH 3.10 36/51] pstore/ram: avoid atomic accesses for ioremapped regions Date: Tue, 3 Feb 2015 15:17:18 -0800 Message-Id: <20150203231725.693777741@linuxfoundation.org> X-Mailer: git-send-email 2.2.2 In-Reply-To: <20150203231724.582537862@linuxfoundation.org> References: <20150203231724.582537862@linuxfoundation.org> User-Agent: quilt/0.63-1 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 Content-Length: 3569 Lines: 115 3.10-stable review patch. If anyone has any objections, please let me know. ------------------ From: Rob Herring commit 0405a5cec3406f19e69da07c8111a6bf1088ac29 upstream. For persistent RAM outside of main memory, the memory may have limitations on supported accesses. For internal RAM on highbank platform exclusive accesses are not supported and will hang the system. So atomic_cmpxchg cannot be used. This commit uses spinlock protection for buffer size and start updates on ioremapped regions instead. Signed-off-by: Rob Herring Acked-by: Anton Vorontsov Signed-off-by: Tony Luck [hkp: Backported to 3.10: adjust context] Signed-off-by: HuKeping --- fs/pstore/ram_core.c | 54 +++++++++++++++++++++++++++++++++++++++++++++++++-- 1 file changed, 52 insertions(+), 2 deletions(-) --- a/fs/pstore/ram_core.c +++ b/fs/pstore/ram_core.c @@ -46,7 +46,7 @@ static inline size_t buffer_start(struct } /* increase and wrap the start pointer, returning the old value */ -static inline size_t buffer_start_add(struct persistent_ram_zone *prz, size_t a) +static size_t buffer_start_add_atomic(struct persistent_ram_zone *prz, size_t a) { int old; int new; @@ -62,7 +62,7 @@ static inline size_t buffer_start_add(st } /* increase the size counter until it hits the max size */ -static inline void buffer_size_add(struct persistent_ram_zone *prz, size_t a) +static void buffer_size_add_atomic(struct persistent_ram_zone *prz, size_t a) { size_t old; size_t new; @@ -78,6 +78,53 @@ static inline void buffer_size_add(struc } while (atomic_cmpxchg(&prz->buffer->size, old, new) != old); } +static DEFINE_RAW_SPINLOCK(buffer_lock); + +/* increase and wrap the start pointer, returning the old value */ +static size_t buffer_start_add_locked(struct persistent_ram_zone *prz, size_t a) +{ + int old; + int new; + unsigned long flags; + + raw_spin_lock_irqsave(&buffer_lock, flags); + + old = atomic_read(&prz->buffer->start); + new = old + a; + while (unlikely(new > prz->buffer_size)) + new -= prz->buffer_size; + atomic_set(&prz->buffer->start, new); + + raw_spin_unlock_irqrestore(&buffer_lock, flags); + + return old; +} + +/* increase the size counter until it hits the max size */ +static void buffer_size_add_locked(struct persistent_ram_zone *prz, size_t a) +{ + size_t old; + size_t new; + unsigned long flags; + + raw_spin_lock_irqsave(&buffer_lock, flags); + + old = atomic_read(&prz->buffer->size); + if (old == prz->buffer_size) + goto exit; + + new = old + a; + if (new > prz->buffer_size) + new = prz->buffer_size; + atomic_set(&prz->buffer->size, new); + +exit: + raw_spin_unlock_irqrestore(&buffer_lock, flags); +} + +static size_t (*buffer_start_add)(struct persistent_ram_zone *, size_t) = buffer_start_add_atomic; +static void (*buffer_size_add)(struct persistent_ram_zone *, size_t) = buffer_size_add_atomic; + static void notrace persistent_ram_encode_rs8(struct persistent_ram_zone *prz, uint8_t *data, size_t len, uint8_t *ecc) { @@ -379,6 +426,9 @@ static void *persistent_ram_iomap(phys_a return NULL; } + buffer_start_add = buffer_start_add_locked; + buffer_size_add = buffer_size_add_locked; + if (memtype) va = ioremap(start, size); else -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/