Re: [PATCH] printk: Enough to disable preemption in printk deferred context

[Sergey Senozhatsky]

On (23/04/19 09:42), Petr Mladek wrote:
> The comment above printk_deferred_enter()/exit() definition claims
> that it can be used only when interrupts are disabled.
> 
> It was required by the original printk_safe_log_store() implementation.
> The code provided lockless synchronization between a single writer and
> a single reader. The interrupt and the normal context shared the same
> buffer.
> 
> The commit 93d102f094be ("printk: remove safe buffers") removed
> these temporary buffers. Instead, the messages are stored directly into
> the new global lockless buffer which supports multiple parallel writers.
> 
> As a result, it is safe to interrupt one writer now. The preemption still
> has to be disabled because the deferred context is CPU specific.
> 
> Fixes: 93d102f094be ("printk: remove safe buffers")
> Signed-off-by: Petr Mladek <pmladek@xxxxxxxx>

Looks good to me

Reviewed-by: Sergey Senozhatsky <senozhatsky@xxxxxxxxxxxx>