| From 109704492ef637956265ec2eb72ae7b3b39eb6f4 Mon Sep 17 00:00:00 2001 |
| From: Joel Fernandes <joelaf@google.com> |
| Date: Thu, 20 Oct 2016 00:34:00 -0700 |
| Subject: pstore: Make spinlock per zone instead of global |
| |
| From: Joel Fernandes <joelaf@google.com> |
| |
| commit 109704492ef637956265ec2eb72ae7b3b39eb6f4 upstream. |
| |
| 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 <joelaf@google.com> |
| [kees: updated commit message] |
| Signed-off-by: Kees Cook <keescook@chromium.org> |
| Cc: Leo Yan <leo.yan@linaro.org> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| |
| --- |
| fs/pstore/ram_core.c | 11 +++++------ |
| include/linux/pstore_ram.h | 1 + |
| 2 files changed, 6 insertions(+), 6 deletions(-) |
| |
| --- a/fs/pstore/ram_core.c |
| +++ b/fs/pstore/ram_core.c |
| @@ -48,8 +48,6 @@ static inline size_t buffer_start(struct |
| 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 pe |
| 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 pe |
| 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 persi |
| 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 persi |
| 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(stru |
| |
| prz->buffer->sig = sig; |
| persistent_ram_zap(prz); |
| + prz->buffer_lock = __RAW_SPIN_LOCK_UNLOCKED(buffer_lock); |
| |
| return 0; |
| } |
| --- 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; |