Re: [PATCH] iwlwifi: fix possible data overwrite in hcmd callback

[wwguy <wey-yi.w.guy@intel.com>]

On Thu, 2011-04-21 at 00:17 -0700, Stanislaw Gruszka wrote:

> > Could you elaborate a bit more, why you do not need to protect getting
> > the cmd index.
> 
> get_cmd_index() is simple mathematical function of index local variable
> (provided by firmware) and globally canst q->n_window, not need to be
> protected.
> 
> What need to be protected is iwl_hcdm_queue_reclaim() as is touch
> q->read_ptr and meta->flags to make assure is synchronized across
> different cpus, when new huge command come instantly.
> 
> Note circular queue management could be done lock-less, but need
> trickery described in Documentation/circular-buffers.txt to synchronize
> q->read_ptr and q->write_ptr properly. What is probably too complex to
> be worth to consider instead of simply using a spin lock.
> 
Thanks for the clear, explanation.

Acked-by: Wey-Yi Guy <wey-yi.w.guy@intel.com>

Wey