Re: [PATCH-v2 1/2] mpt3sas: Refcount sas_device objects and fix unsafe list usage

[Nicholas A. Bellinger]

Hi Sreekanth,

On Tue, 2015-09-08 at 17:25 +0530, Sreekanth Reddy wrote:
> On Sun, Aug 30, 2015 at 1:24 PM, Nicholas A. Bellinger
> <nab@xxxxxxxxxxxxx> wrote:
> > From: Nicholas Bellinger <nab@xxxxxxxxxxxxxxx>
> >
> > These objects can be referenced concurrently throughout the driver, we
> > need a way to make sure threads can't delete them out from under
> > each other. This patch adds the refcount, and refactors the code to use
> > it.
> >
> > Additionally, we cannot iterate over the sas_device_list without
> > holding the lock, or we risk corrupting random memory if items are
> > added or deleted as we iterate. This patch refactors _scsih_probe_sas()
> > to use the sas_device_list in a safe way.
> >
> > This patch is a port of Calvin's PATCH-v4 for mpt2sas code, atop
> > mpt3sas changes in scsi.git/for-next.
> >
> > Cc: Calvin Owens <calvinowens@xxxxxx>
> > Cc: Christoph Hellwig <hch@xxxxxxxxxxxxx>
> > Cc: Sreekanth Reddy <sreekanth.reddy@xxxxxxxxxxxxx>
> > Cc: MPT-FusionLinux.pdl <MPT-FusionLinux.pdl@xxxxxxxxxxxxx>
> > Signed-off-by: Nicholas Bellinger <nab@xxxxxxxxxxxxxxx>
> > ---
> >  drivers/scsi/mpt3sas/mpt3sas_base.h      |  25 +-
> >  drivers/scsi/mpt3sas/mpt3sas_scsih.c     | 479 +++++++++++++++++++++----------
> >  drivers/scsi/mpt3sas/mpt3sas_transport.c |  18 +-
> >  3 files changed, 364 insertions(+), 158 deletions(-)


<SNIP>

> > diff --git a/drivers/scsi/mpt3sas/mpt3sas_transport.c b/drivers/scsi/mpt3sas/mpt3sas_transport.c
> > index 70fd019..6074b11 100644
> > --- a/drivers/scsi/mpt3sas/mpt3sas_transport.c
> > +++ b/drivers/scsi/mpt3sas/mpt3sas_transport.c
> > @@ -734,7 +734,7 @@ mpt3sas_transport_port_add(struct MPT3SAS_ADAPTER *ioc, u16 handle,
> >         rphy->identify = mpt3sas_port->remote_identify;
> >
> >         if (mpt3sas_port->remote_identify.device_type == SAS_END_DEVICE) {
> 
> [Sreekanth] Here also sas_device_lock spin lock needs to be acquired
> before calling
>                   __mpt3sas_get_sdev_by_addr() function.
> 

Thanks for your review.

Fixed with the following incremental patch atop for-next-merge code.

Please review.

Thank you,