Messages in this thread | | | From | Geanta Neag Horia Ioan-B05471 <> | Subject | RE: [PATCH v7 1/8] Talitos: Support for async_tx XOR offload | Date | Fri, 31 Aug 2012 10:38:46 +0000 |
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On Fri, 31 Aug 2012 06:08:05 +0300, Liu Qiang-B32616 <B32616@freescale.com> wrote: > > -----Original Message----- > > From: Geanta Neag Horia Ioan-B05471 > > Sent: Thursday, August 30, 2012 10:23 PM > > To: Liu Qiang-B32616; linux-crypto@vger.kernel.org; > > dan.j.williams@gmail.com; herbert@gondor.hengli.com.au; > > davem@davemloft.net; linux-kernel@vger.kernel.org; linuxppc- > > dev@lists.ozlabs.org > > Cc: Li Yang-R58472; Phillips Kim-R1AAHA; vinod.koul@intel.com; > > dan.j.williams@intel.com; arnd@arndb.de; gregkh@linuxfoundation.org; Liu > > Qiang-B32616 > > Subject: RE: [PATCH v7 1/8] Talitos: Support for async_tx XOR offload > > > > On Thu, 9 Aug 2012 11:20:48 +0300, qiang.liu@freescale.com wrote: > > > From: Qiang Liu <qiang.liu@freescale.com> > > > > > > Expose Talitos's XOR functionality to be used for RAID parity > > > calculation via the Async_tx layer. > > > > > > Cc: Herbert Xu <herbert@gondor.apana.org.au> > > > Cc: David S. Miller <davem@davemloft.net> > > > Signed-off-by: Dipen Dudhat <Dipen.Dudhat@freescale.com> > > > Signed-off-by: Maneesh Gupta <Maneesh.Gupta@freescale.com> > > > Signed-off-by: Kim Phillips <kim.phillips@freescale.com> > > > Signed-off-by: Vishnu Suresh <Vishnu@freescale.com> > > > Signed-off-by: Qiang Liu <qiang.liu@freescale.com> > > > --- > > > drivers/crypto/Kconfig | 9 + > > > drivers/crypto/talitos.c | 413 > > ++++++++++++++++++++++++++++++++++++++++++++++ > > > drivers/crypto/talitos.h | 53 ++++++ > > > 3 files changed, 475 insertions(+), 0 deletions(-) > >
> > > +static int talitos_alloc_chan_resources(struct dma_chan *chan) > > > +{ > > > + struct talitos_xor_chan *xor_chan; > > > + struct talitos_xor_desc *desc; > > > + LIST_HEAD(tmp_list); > > > + int i; > > > + > > > + xor_chan = container_of(chan, struct talitos_xor_chan, common); > > > + > > > + if (!list_empty(&xor_chan->free_desc)) > > > + return xor_chan->total_desc; > > > + > > > + for (i = 0; i < TALITOS_MAX_DESCRIPTOR_NR; i++) { > > > + desc = talitos_xor_alloc_descriptor(xor_chan, > > > + GFP_KERNEL | GFP_DMA); > > > > talitos_xor_alloc_descriptor() is called here without holding > > the xor_chan->desc_lock and it increments xor_chan->total_desc. > > Isn't this an issue ? > > No, please refer to the code as below, > + list_add_tail(&desc->node, &tmp_list); > > The list is temporary list, it will be merged to xor_chan->free_desc in next step, here is protected > by lock, > + spin_lock_bh(&xor_chan->desc_lock); > + list_splice_init(&tmp_list, &xor_chan->free_desc); > + spin_unlock_bh(&xor_chan->desc_lock);
I was not referring to the list, but to xor_chan->total_desc variable. The following access: talitos_alloc_chan_resources()->talitos_xor_alloc_descriptor()->total_desc++ is not protected by the xor_chan->desc_lock.
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