RE: [PATCH 02/10] zcache: fix refcount leak

[Dan Magenheimer]

> From: Seth Jennings [mailto:sjenning@xxxxxxxxxxxxxxxxxx]
> Sent: Tuesday, June 19, 2012 8:29 AM
> To: Xiao Guangrong
> Cc: Andrew Morton; Dan Magenheimer; LKML; linux-mm@xxxxxxxxx
> Subject: Re: [PATCH 02/10] zcache: fix refcount leak
> 
> On 06/19/2012 03:33 AM, Xiao Guangrong wrote:
> 
> > In zcache_get_pool_by_id, the refcount of zcache_host is not increased, but
> > it is always decreased in zcache_put_pool
> >
> > Signed-off-by: Xiao Guangrong <xiaoguangrong@xxxxxxxxxxxxxxxxxx>
> 
> Acked-by: Seth Jennings <sjenning@xxxxxxxxxxxxxxxxxx>

(Nitin Gupta and Konrad Wilk cc'ed to call their attention
to this patch sequence...)

My preference would be to fix it the opposite way, by
checking and ignoring zcache_host in zcache_put_pool.
The ref-counting is to ensure that a client isn't
accidentally destroyed while in use (for multiple-client
users such as ramster and kvm) and since zcache_host is a static
struct, it should never be deleted so need not be ref-counted.

Dan
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