On Mon, Dec 01, 2014 at 10:09:38AM +0100, Olivier MATZ wrote: > Hi Bruce, Hi Neil, > > On 11/30/2014 02:05 AM, Neil Horman wrote: > > On Fri, Nov 28, 2014 at 03:31:00PM +0000, Bruce Richardson wrote: > >> When compiling with clang, errors were being emitted due to truncation > >> of values when assigning to the tx_offload_mask bit fields. > >> > >> dpdk.org/lib/librte_pmd_ixgbe/ixgbe_rxtx.c:404:27: fatal error: implicit > >> truncation from 'int' to bitfield changes value from -1 to 127 > >> [-Wbitfield-constant-conversion] > >> tx_offload_mask.l2_len = ~0; > >> > >> The fix proposed here is to define a static const value of the same type > >> with all fields set to 1s, and use that instead of constants for assigning > >> to. > >> > >> Other options would be to explicitily define the suitable constants that > >> would not truncate for each individual field e.g. 0x7f for l2_len, 0x1FF > >> for l3_len, etc., but this solution here has the advantage that it works > >> without any changes to values if the field sizes are ever modified. > >> > >> Signed-off-by: Bruce Richardson <bruce.richardson at intel.com> > >> --- > >> lib/librte_pmd_ixgbe/ixgbe_rxtx.c | 29 +++++++++++++++-------------- > >> 1 file changed, 15 insertions(+), 14 deletions(-) > >> > >> diff --git a/lib/librte_pmd_ixgbe/ixgbe_rxtx.c > >> b/lib/librte_pmd_ixgbe/ixgbe_rxtx.c > >> index 8559ef6..4f71194 100644 > >> --- a/lib/librte_pmd_ixgbe/ixgbe_rxtx.c > >> +++ b/lib/librte_pmd_ixgbe/ixgbe_rxtx.c > >> @@ -367,6 +367,7 @@ ixgbe_set_xmit_ctx(struct igb_tx_queue* txq, > >> volatile struct ixgbe_adv_tx_context_desc *ctx_txd, > >> uint64_t ol_flags, union ixgbe_tx_offload tx_offload) > >> { > >> + static const union ixgbe_tx_offload offload_allones = { .data = ~0 }; > > Do you want to make this a static data structure? If you make it a macro > > like > > this: > > #define ALLONES {.data = ~0} > > Then you save the extra data space in the .data area (not that its that > > much), > > and you can define it in a header file and use it in multiple c files (if > > you > > need to) > > I found that the following code works: > > tx_offload_mask.l2_len |= ~0; > > (note the '|=' instead of '=') > > I would avoid to create a macro. What do you think? > > Regards, > Olivier
Nice one - cleanest solution thus far, so I suggest we go with that option. Have you got a patch for it ready? /Bruce