diff mbox series

[next,S5,iavf,02/11] iavf: use signedvariable

Message ID 20190514173709.62431-2-alice.michael@intel.com
State Accepted
Delegated to: Jeff Kirsher
Headers show
Series [next,S5,iavf,01/11] iavf: Create VLAN tagelements starting from the first element | expand

Commit Message

Michael, Alice May 14, 2019, 5:37 p.m. UTC 
From: Mitch Williams <mitch.a.williams@intel.com>

The counter variable in iavf_clean_tx_irq starts out negative and climbs
to 0. So allocating it as u16 is actually a really bad idea that just
happens to work because the value underflows and overflows consistently
on most architectures.

Replace the u16 with an int so signed math works as expected.

Signed-off-by: Mitch Williams <mitch.a.williams@intel.com>
---
 drivers/net/ethernet/intel/iavf/iavf_txrx.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Comments

Bowers, AndrewX May 17, 2019, 10:24 p.m. UTC | #1 
> -----Original Message-----
> From: Intel-wired-lan [mailto:intel-wired-lan-bounces@osuosl.org] On
> Behalf Of Alice Michael
> Sent: Tuesday, May 14, 2019 10:37 AM
> To: Michael, Alice <alice.michael@intel.com>; intel-wired-
> lan@lists.osuosl.org
> Subject: [Intel-wired-lan] [next PATCH S5 iavf 02/11] iavf: use signed variable
> 
> From: Mitch Williams <mitch.a.williams@intel.com>
> 
> The counter variable in iavf_clean_tx_irq starts out negative and climbs to 0.
> So allocating it as u16 is actually a really bad idea that just happens to work
> because the value underflows and overflows consistently on most
> architectures.
> 
> Replace the u16 with an int so signed math works as expected.
> 
> Signed-off-by: Mitch Williams <mitch.a.williams@intel.com>
> ---
>  drivers/net/ethernet/intel/iavf/iavf_txrx.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)

Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
diff mbox series

Patch

diff --git a/drivers/net/ethernet/intel/iavf/iavf_txrx.c b/drivers/net/ethernet/intel/iavf/iavf_txrx.c
index 6d43cbe29c49..d28b57937245 100644
--- a/drivers/net/ethernet/intel/iavf/iavf_txrx.c
+++ b/drivers/net/ethernet/intel/iavf/iavf_txrx.c
@@ -190,7 +190,7 @@  void iavf_detect_recover_hung(struct iavf_vsi *vsi)
 static bool iavf_clean_tx_irq(struct iavf_vsi *vsi,
 			      struct iavf_ring *tx_ring, int napi_budget)
 {
-	u16 i = tx_ring->next_to_clean;
+	int i = tx_ring->next_to_clean;
 	struct iavf_tx_buffer *tx_buf;
 	struct iavf_tx_desc *tx_desc;
 	unsigned int total_bytes = 0, total_packets = 0;