| Message ID | 20190708231236.20516-17-jacob.e.keller@intel.com |
|---|---|
| State | Accepted |
| Delegated to: | Jeff Kirsher |
| Headers | show |
| Series | cleanup cppcheck warnings for fm10k driver | expand |
> -----Original Message----- > From: Intel-wired-lan [mailto:intel-wired-lan-bounces@osuosl.org] On > Behalf Of Jacob Keller > Sent: Monday, July 8, 2019 4:13 PM > To: Intel Wired LAN <intel-wired-lan@lists.osuosl.org> > Subject: [Intel-wired-lan] [PATCH 16/19] fm10k: cast page_addr to u8 * when > incrementing it > > The page_addr variable is a void pointer. Incrementing it before calling > prefetch is technically undefined. Fix this by casting it to a u8* pointer before > incrementing it. This ensures that we increment the pointer value in byte > units, instead of relying on this undefined behavior. > > This was detected by cppcheck, and resolves the following warning produced > by that tool: > > [fm10k_main.c:328]: (portability) 'page_addr' is of type 'void *'. When using > void pointers in calculations, the behaviour is undefined. > > Signed-off-by: Jacob Keller <jacob.e.keller@intel.com> > --- > drivers/net/ethernet/intel/fm10k/fm10k_main.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
diff --git a/drivers/net/ethernet/intel/fm10k/fm10k_main.c b/drivers/net/ethernet/intel/fm10k/fm10k_main.c index 3bacf35fbfad..cf87812bdf4a 100644 --- a/drivers/net/ethernet/intel/fm10k/fm10k_main.c +++ b/drivers/net/ethernet/intel/fm10k/fm10k_main.c @@ -315,7 +315,7 @@ static struct sk_buff *fm10k_fetch_rx_buffer(struct fm10k_ring *rx_ring, /* prefetch first cache line of first page */ prefetch(page_addr); #if L1_CACHE_BYTES < 128 - prefetch(page_addr + L1_CACHE_BYTES); + prefetch((void *)((u8 *)page_addr + L1_CACHE_BYTES)); #endif /* allocate a skb to store the frags */
The page_addr variable is a void pointer. Incrementing it before calling prefetch is technically undefined. Fix this by casting it to a u8* pointer before incrementing it. This ensures that we increment the pointer value in byte units, instead of relying on this undefined behavior. This was detected by cppcheck, and resolves the following warning produced by that tool: [fm10k_main.c:328]: (portability) 'page_addr' is of type 'void *'. When using void pointers in calculations, the behaviour is undefined. Signed-off-by: Jacob Keller <jacob.e.keller@intel.com> --- drivers/net/ethernet/intel/fm10k/fm10k_main.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)