On Sunday 07/12 at 23:52 -0700, Christoph Hellwig wrote:
> On Sat, Jul 11, 2015 at 09:24:55PM -0700, Calvin Owens wrote:
> > 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.
> >
> > Cc: Christoph Hellwig <h...@infradead.org>
> > Cc: Bart Van Assche <bart.vanass...@sandisk.com>
> > Signed-off-by: Calvin Owens <calvinow...@fb.com>
> > ---
> > drivers/scsi/mpt2sas/mpt2sas_base.h | 22 +-
> > drivers/scsi/mpt2sas/mpt2sas_scsih.c | 434
> > ++++++++++++++++++++-----------
> > drivers/scsi/mpt2sas/mpt2sas_transport.c | 12 +-
> > 3 files changed, 315 insertions(+), 153 deletions(-)
> >
> > diff --git a/drivers/scsi/mpt2sas/mpt2sas_base.h
> > b/drivers/scsi/mpt2sas/mpt2sas_base.h
> > index caff8d1..78f41ac 100644
> > --- a/drivers/scsi/mpt2sas/mpt2sas_base.h
> > +++ b/drivers/scsi/mpt2sas/mpt2sas_base.h
> > @@ -238,6 +238,7 @@
> > * @flags: MPT_TARGET_FLAGS_XXX flags
> > * @deleted: target flaged for deletion
> > * @tm_busy: target is busy with TM request.
> > + * @sdev: The sas_device associated with this target
> > */
> > struct MPT2SAS_TARGET {
> > struct scsi_target *starget;
> > @@ -248,6 +249,7 @@ struct MPT2SAS_TARGET {
> > u32 flags;
> > u8 deleted;
> > u8 tm_busy;
> > + struct _sas_device *sdev;
> > };
> >
> >
> > @@ -376,8 +378,24 @@ struct _sas_device {
> > u8 phy;
> > u8 responding;
> > u8 pfa_led_on;
> > + struct kref refcount;
> > };
> >
> > +static inline void sas_device_get(struct _sas_device *s)
> > +{
> > + kref_get(&s->refcount);
> > +}
> > +
> > +static inline void sas_device_free(struct kref *r)
> > +{
> > + kfree(container_of(r, struct _sas_device, refcount));
> > +}
> > +
> > +static inline void sas_device_put(struct _sas_device *s)
> > +{
> > + kref_put(&s->refcount, sas_device_free);
> > +}
> > +
> > /**
> > * struct _raid_device - raid volume link list
> > * @list: sas device list
> > @@ -1095,7 +1113,9 @@ struct _sas_node
> > *mpt2sas_scsih_expander_find_by_handle(struct MPT2SAS_ADAPTER *
> > u16 handle);
> > struct _sas_node *mpt2sas_scsih_expander_find_by_sas_address(struct
> > MPT2SAS_ADAPTER
> > *ioc, u64 sas_address);
> > -struct _sas_device *mpt2sas_scsih_sas_device_find_by_sas_address(
> > +struct _sas_device *mpt2sas_get_sdev_by_addr(
> > + struct MPT2SAS_ADAPTER *ioc, u64 sas_address);
> > +struct _sas_device *__mpt2sas_get_sdev_by_addr(
> > struct MPT2SAS_ADAPTER *ioc, u64 sas_address);
> >
> > void mpt2sas_port_enable_complete(struct MPT2SAS_ADAPTER *ioc);
> > diff --git a/drivers/scsi/mpt2sas/mpt2sas_scsih.c
> > b/drivers/scsi/mpt2sas/mpt2sas_scsih.c
> > index 3f26147..fad80ce 100644
> > --- a/drivers/scsi/mpt2sas/mpt2sas_scsih.c
> > +++ b/drivers/scsi/mpt2sas/mpt2sas_scsih.c
> > @@ -526,8 +526,43 @@ _scsih_determine_boot_device(struct MPT2SAS_ADAPTER
> > *ioc,
> > }
> > }
> >
> > +struct _sas_device *
> > +__mpt2sas_get_sdev_from_target(struct MPT2SAS_TARGET *tgt_priv)
> > +{
> > + struct _sas_device *ret;
> > +
>
> Does this need a:
>
> assert_spin_locked(&ioc->sas_device_lock);
>
> ?
Yeah: I'll add that.
Thanks very much,
Calvin
> Otherwise this looks sensible to me.
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