RE: [PATCH] staging: zcache: fix cleancache crash

[Dan Magenheimer <dan.magenheimer@oracle.com>]

> From: Dan Magenheimer
> Sent: Tuesday, September 13, 2011 2:56 PM
> To: Seth Jennings; gregkh@suse.de
> Cc: devel@driverdev.osuosl.org; linux-mm@kvack.org; ngupta@vflare.org; linux-kernel@vger.kernel.org;
> francis.moro@gmail.com
> Subject: RE: [PATCH] staging: zcache: fix cleancache crash
> 
> > From: Seth Jennings [mailto:sjenning@linux.vnet.ibm.com]
> > Sent: Tuesday, September 13, 2011 1:19 PM
> > To: gregkh@suse.de
> > Cc: devel@driverdev.osuosl.org; linux-mm@kvack.org; ngupta@vflare.org; linux-kernel@vger.kernel.org;
> > francis.moro@gmail.com; Dan Magenheimer; Seth Jennings
> > Subject: [PATCH] staging: zcache: fix cleancache crash
> >
> > After commit, c5f5c4db, cleancache crashes on the first
> > successful get. This was caused by a remaining virt_to_page()
> > call in zcache_pampd_get_data_and_free() that only gets
> > run in the cleancache path.
> >
> > The patch converts the virt_to_page() to struct page
> > casting like was done for other instances in c5f5c4db.
> >
> > Based on 3.1-rc4
> >
> > Signed-off-by: Seth Jennings <sjenning@linux.vnet.ibm.com>
> 
> Yep, this appears to fix it!  Hopefully Francis can confirm.
> 
> Greg, ideally apply this additional fix rather than do the revert
> of the original patch suggested in https://lkml.org/lkml/2011/9/13/234
> 
> Acked-by: Dan Magenheimer <dan.magenheimer@oracle.com>


Greg, Francis has confirmed offlist that Seth's fix below
has fixed his issue as well.  Please apply, hopefully as
soon as possible and before 3.1 goes final!

Thanks,
Dan

 
> > ---
> >  drivers/staging/zcache/zcache-main.c |    2 +-
> >  1 files changed, 1 insertions(+), 1 deletions(-)
> >
> > diff --git a/drivers/staging/zcache/zcache-main.c b/drivers/staging/zcache/zcache-main.c
> > index a3f5162..462fbc2 100644
> > --- a/drivers/staging/zcache/zcache-main.c
> > +++ b/drivers/staging/zcache/zcache-main.c
> > @@ -1242,7 +1242,7 @@ static int zcache_pampd_get_data_and_free(char *data, size_t *bufsize, bool
> raw,
> >  	int ret = 0;
> >
> >  	BUG_ON(!is_ephemeral(pool));
> > -	zbud_decompress(virt_to_page(data), pampd);
> > +	zbud_decompress((struct page *)(data), pampd);
> >  	zbud_free_and_delist((struct zbud_hdr *)pampd);
> >  	atomic_dec(&zcache_curr_eph_pampd_count);
> >  	return ret;
> > --
> > 1.7.4.1
> >

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