RE: [PATCH 22/29] drivers, scsi: convert iscsi_task.refcount from atomic_t to refcount_t

Reshetova, Elena
2017-03-09T07:18:29Z

> On Mon, Mar 06, 2017 at 04:21:09PM +0200, Elena Reshetova wrote:
> > refcount_t type and corresponding API should be
> > used instead of atomic_t when the variable is used as
> > a reference counter. This allows to avoid accidental
> > refcounter overflows that might lead to use-after-free
> > situations.
> >
> > Signed-off-by: Elena Reshetova <elena.reshetova-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
> > Signed-off-by: Hans Liljestrand <ishkamiel-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
> > Signed-off-by: Kees Cook <keescook-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org>
> > Signed-off-by: David Windsor <dwindsor-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
>
> This looks OK to me.
>
> Acked-by: Chris Leech <cleech-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>

Thank you for review! Do you have a tree that can take this change?

Best Regards,
Elena.

>
> > ---
> > drivers/scsi/libiscsi.c | 8 ++++----
> > drivers/scsi/qedi/qedi_iscsi.c | 2 +-
> > include/scsi/libiscsi.h | 3 ++-
> > 3 files changed, 7 insertions(+), 6 deletions(-)
> >
> > diff --git a/drivers/scsi/libiscsi.c b/drivers/scsi/libiscsi.c
> > index 834d121..7eb1d2c 100644
> > --- a/drivers/scsi/libiscsi.c
> > +++ b/drivers/scsi/libiscsi.c
> > @@ -516,13 +516,13 @@ static void iscsi_free_task(struct iscsi_task *task)
> >
> > void __iscsi_get_task(struct iscsi_task *task)
> > {
> > - atomic_inc(&task->refcount);
> > + refcount_inc(&task->refcount);
> > }
> > EXPORT_SYMBOL_GPL(__iscsi_get_task);
> >
> > void __iscsi_put_task(struct iscsi_task *task)
> > {
> > - if (atomic_dec_and_test(&task->refcount))
> > + if (refcount_dec_and_test(&task->refcount))
> > iscsi_free_task(task);
> > }
> > EXPORT_SYMBOL_GPL(__iscsi_put_task);
> > @@ -744,7 +744,7 @@ __iscsi_conn_send_pdu(struct iscsi_conn *conn, struct
> iscsi_hdr *hdr,
> > * released by the lld when it has transmitted the task for
> > * pdus we do not expect a response for.
> > */
> > - atomic_set(&task->refcount, 1);
> > + refcount_set(&task->refcount, 1);
> > task->conn = conn;
> > task->sc = NULL;
> > INIT_LIST_HEAD(&task->running);
> > @@ -1616,7 +1616,7 @@ static inline struct iscsi_task *iscsi_alloc_task(struct
> iscsi_conn *conn,
> > sc->SCp.phase = conn->session->age;
> > sc->SCp.ptr = (char *) task;
> >
> > - atomic_set(&task->refcount, 1);
> > + refcount_set(&task->refcount, 1);
> > task->state = ISCSI_TASK_PENDING;
> > task->conn = conn;
> > task->sc = sc;
> > diff --git a/drivers/scsi/qedi/qedi_iscsi.c b/drivers/scsi/qedi/qedi_iscsi.c
> > index b9f79d3..3895bd5 100644
> > --- a/drivers/scsi/qedi/qedi_iscsi.c
> > +++ b/drivers/scsi/qedi/qedi_iscsi.c
> > @@ -1372,7 +1372,7 @@ static void qedi_cleanup_task(struct iscsi_task *task)
> > {
> > if (!task->sc || task->state == ISCSI_TASK_PENDING) {
> > QEDI_INFO(NULL, QEDI_LOG_IO, "Returning
> ref_cnt=%d\n",
> > - atomic_read(&task->refcount));
> > + refcount_read(&task->refcount));
> > return;
> > }
> >
> > diff --git a/include/scsi/libiscsi.h b/include/scsi/libiscsi.h
> > index b0e275d..24d74b5 100644
> > --- a/include/scsi/libiscsi.h
> > +++ b/include/scsi/libiscsi.h
> > @@ -29,6 +29,7 @@
> > #include <linux/timer.h>
> > #include <linux/workqueue.h>
> > #include <linux/kfifo.h>
> > +#include <linux/refcount.h>
> > #include <scsi/iscsi_proto.h>
> > #include <scsi/iscsi_if.h>
> > #include <scsi/scsi_transport_iscsi.h>
> > @@ -139,7 +140,7 @@ struct iscsi_task {
> >
> > /* state set/tested under session->lock */
> > int state;
> > - atomic_t refcount;
> > + refcount_t refcount;
> > struct list_head running; /* running cmd list */
> > void *dd_data; /*
> driver/transport data */
> > };
> > --
> > 2.7.4
> >

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