pstore: Make spinlock per zone instead of global
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>
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@ -48,8 +48,6 @@ static inline size_t buffer_start(struct persistent_ram_zone *prz)
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return atomic_read(&prz->buffer->start);
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return atomic_read(&prz->buffer->start);
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}
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}
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static DEFINE_RAW_SPINLOCK(buffer_lock);
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/* increase and wrap the start pointer, returning the old value */
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/* increase and wrap the start pointer, returning the old value */
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static size_t buffer_start_add(struct persistent_ram_zone *prz, size_t a)
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static size_t buffer_start_add(struct persistent_ram_zone *prz, size_t a)
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{
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{
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@ -57,7 +55,7 @@ static size_t buffer_start_add(struct persistent_ram_zone *prz, size_t a)
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int new;
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int new;
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unsigned long flags;
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unsigned long flags;
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raw_spin_lock_irqsave(&buffer_lock, flags);
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raw_spin_lock_irqsave(&prz->buffer_lock, flags);
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old = atomic_read(&prz->buffer->start);
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old = atomic_read(&prz->buffer->start);
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new = old + a;
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new = old + a;
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@ -65,7 +63,7 @@ static size_t buffer_start_add(struct persistent_ram_zone *prz, size_t a)
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new -= prz->buffer_size;
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new -= prz->buffer_size;
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atomic_set(&prz->buffer->start, new);
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atomic_set(&prz->buffer->start, new);
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raw_spin_unlock_irqrestore(&buffer_lock, flags);
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raw_spin_unlock_irqrestore(&prz->buffer_lock, flags);
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return old;
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return old;
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}
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}
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@ -77,7 +75,7 @@ static void buffer_size_add(struct persistent_ram_zone *prz, size_t a)
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size_t new;
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size_t new;
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unsigned long flags;
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unsigned long flags;
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raw_spin_lock_irqsave(&buffer_lock, flags);
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raw_spin_lock_irqsave(&prz->buffer_lock, flags);
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old = atomic_read(&prz->buffer->size);
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old = atomic_read(&prz->buffer->size);
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if (old == prz->buffer_size)
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if (old == prz->buffer_size)
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@ -89,7 +87,7 @@ static void buffer_size_add(struct persistent_ram_zone *prz, size_t a)
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atomic_set(&prz->buffer->size, new);
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atomic_set(&prz->buffer->size, new);
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exit:
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exit:
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raw_spin_unlock_irqrestore(&buffer_lock, flags);
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raw_spin_unlock_irqrestore(&prz->buffer_lock, flags);
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}
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}
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static void notrace persistent_ram_encode_rs8(struct persistent_ram_zone *prz,
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static void notrace persistent_ram_encode_rs8(struct persistent_ram_zone *prz,
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@ -493,6 +491,7 @@ static int persistent_ram_post_init(struct persistent_ram_zone *prz, u32 sig,
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prz->buffer->sig = sig;
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prz->buffer->sig = sig;
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persistent_ram_zap(prz);
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persistent_ram_zap(prz);
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prz->buffer_lock = __RAW_SPIN_LOCK_UNLOCKED(buffer_lock);
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return 0;
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return 0;
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}
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}
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@ -40,6 +40,7 @@ struct persistent_ram_zone {
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void *vaddr;
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void *vaddr;
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struct persistent_ram_buffer *buffer;
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struct persistent_ram_buffer *buffer;
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size_t buffer_size;
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size_t buffer_size;
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raw_spinlock_t buffer_lock;
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/* ECC correction */
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/* ECC correction */
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char *par_buffer;
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char *par_buffer;
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