[PATCH for-next 12/12] IB/hfi1: Add a safe wrapper for _rcd_get_by_index

Dennis Dalessandro
2017-09-26T14:01:16Z

From: Michael J. Ruhl <michael.j.ruhl-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>

hfi1_rcd_get_by_index assumes that the given index is in the correct
range. In most cases this is correct because the index is bounded by
a loop. For these cases, adding a range check to the function is
redundant.

For the use case that is not bounded by the loop range, a _safe wrapper
function is needed to validate the index before accessing the rcd array.

Add a _safe wrapper to _get_by_index to validate the index range.

Update appropriate call sites with the new _safe function.

Reviewed-by: Ira Weiny <ira.weiny-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
Signed-off-by: Michael J. Ruhl <michael.j.ruhl-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
Signed-off-by: Dennis Dalessandro <dennis.dalessandro-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
---
drivers/infiniband/hw/hfi1/chip.c | 2 +-
drivers/infiniband/hw/hfi1/debugfs.c | 4 ++--
drivers/infiniband/hw/hfi1/driver.c | 4 ++--
drivers/infiniband/hw/hfi1/hfi.h | 2 ++
drivers/infiniband/hw/hfi1/init.c | 21 +++++++++++++++++++++
5 files changed, 28 insertions(+), 5 deletions(-)

diff --git a/drivers/infiniband/hw/hfi1/chip.c b/drivers/infiniband/hw/hfi1/chip.c
index 99425ce..680cfd4 100644
--- a/drivers/infiniband/hw/hfi1/chip.c
+++ b/drivers/infiniband/hw/hfi1/chip.c
@@ -13120,7 +13120,7 @@ static int request_msix_irqs(struct hfi1_devdata *dd)
me->type = IRQ_SDMA;
} else if (first_rx <= i && i < last_rx) {
idx = i - first_rx;
- rcd = hfi1_rcd_get_by_index(dd, idx);
+ rcd = hfi1_rcd_get_by_index_safe(dd, idx);
if (rcd) {
/*
* Set the interrupt register and mask for this
diff --git a/drivers/infiniband/hw/hfi1/debugfs.c b/drivers/infiniband/hw/hfi1/debugfs.c
index 36ae1fd..24128f4 100644
--- a/drivers/infiniband/hw/hfi1/debugfs.c
+++ b/drivers/infiniband/hw/hfi1/debugfs.c
@@ -243,7 +243,7 @@ static int _ctx_stats_seq_show(struct seq_file *s, void *v)
spos = v;
i = *spos;

- rcd = hfi1_rcd_get_by_index(dd, i);
+ rcd = hfi1_rcd_get_by_index_safe(dd, i);
if (!rcd)
return SEQ_SKIP;

@@ -402,7 +402,7 @@ static int _rcds_seq_show(struct seq_file *s, void *v)
loff_t *spos = v;
loff_t i = *spos;

- rcd = hfi1_rcd_get_by_index(dd, i);
+ rcd = hfi1_rcd_get_by_index_safe(dd, i);
if (rcd)
seqfile_dump_rcd(s, rcd);
hfi1_rcd_put(rcd);
diff --git a/drivers/infiniband/hw/hfi1/driver.c b/drivers/infiniband/hw/hfi1/driver.c
index 7372cc0..85a425e 100644
--- a/drivers/infiniband/hw/hfi1/driver.c
+++ b/drivers/infiniband/hw/hfi1/driver.c
@@ -866,7 +866,7 @@ static inline void set_nodma_rtail(struct hfi1_devdata *dd, u16 ctxt)
* interrupt handler for all statically allocated kernel contexts.
*/
if (ctxt >= dd->first_dyn_alloc_ctxt) {
- rcd = hfi1_rcd_get_by_index(dd, ctxt);
+ rcd = hfi1_rcd_get_by_index_safe(dd, ctxt);
if (rcd) {
rcd->do_interrupt =
&handle_receive_interrupt_nodma_rtail;
@@ -895,7 +895,7 @@ static inline void set_dma_rtail(struct hfi1_devdata *dd, u16 ctxt)
* interrupt handler for all statically allocated kernel contexts.
*/
if (ctxt >= dd->first_dyn_alloc_ctxt) {
- rcd = hfi1_rcd_get_by_index(dd, ctxt);
+ rcd = hfi1_rcd_get_by_index_safe(dd, ctxt);
if (rcd) {
rcd->do_interrupt =
&handle_receive_interrupt_dma_rtail;
diff --git a/drivers/infiniband/hw/hfi1/hfi.h b/drivers/infiniband/hw/hfi1/hfi.h
index 1e1140e..cb74ae8 100644
--- a/drivers/infiniband/hw/hfi1/hfi.h
+++ b/drivers/infiniband/hw/hfi1/hfi.h
@@ -1398,6 +1398,8 @@ void hfi1_init_pportdata(struct pci_dev *pdev, struct hfi1_pportdata *ppd,
void hfi1_free_ctxtdata(struct hfi1_devdata *dd, struct hfi1_ctxtdata *rcd);
int hfi1_rcd_put(struct hfi1_ctxtdata *rcd);
void hfi1_rcd_get(struct hfi1_ctxtdata *rcd);
+struct hfi1_ctxtdata *hfi1_rcd_get_by_index_safe(struct hfi1_devdata *dd,
+ u16 ctxt);
struct hfi1_ctxtdata *hfi1_rcd_get_by_index(struct hfi1_devdata *dd, u16 ctxt);
int handle_receive_interrupt(struct hfi1_ctxtdata *rcd, int thread);
int handle_receive_interrupt_nodma_rtail(struct hfi1_ctxtdata *rcd, int thread);
diff --git a/drivers/infiniband/hw/hfi1/init.c b/drivers/infiniband/hw/hfi1/init.c
index 04a383b..36c8a4a 100644
--- a/drivers/infiniband/hw/hfi1/init.c
+++ b/drivers/infiniband/hw/hfi1/init.c
@@ -284,6 +284,27 @@ static int allocate_rcd_index(struct hfi1_devdata *dd,
}

/**
+ * hfi1_rcd_get_by_index_safe - validate the ctxt index before accessing the
+ * array
+ * @dd: pointer to a valid devdata structure
+ * @ctxt: the index of an possilbe rcd
+ *
+ * This is a wrapper for hfi1_rcd_get_by_index() to validate that the given
+ * ctxt index is valid.
+ *
+ * The caller is responsible for making the _put().
+ *
+ */
+struct hfi1_ctxtdata *hfi1_rcd_get_by_index_safe(struct hfi1_devdata *dd,
+ u16 ctxt)
+{
+ if (ctxt < dd->num_rcv_contexts)
+ return hfi1_rcd_get_by_index(dd, ctxt);
+
+ return NULL;
+}
+
+/**
* hfi1_rcd_get_by_index
* @dd: pointer to a valid devdata structure
* @ctxt: the index of an possilbe rcd