On 08/19/2015 05:18 PM, Eric Dumazet wrote: > On Wed, 2015-08-19 at 15:59 +0300, Emmanuel Grumbach wrote: >> The segmentation is done completely in software. The >> driver creates several MPDUs out of a single large send. >> Each MPDU is a newly allocated SKB. >> A page is allocated to create the headers that need to be >> duplicated (SNAP / IP / TCP). The WiFi header is in the >> header of the newly created SKBs. >> >> type=feature >> >> Change-Id: I238ffa79cacc5bbdacdfbf3e9673c8d4f02b462a >> Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@xxxxxxxxx> >> --- >> drivers/net/wireless/iwlwifi/mvm/tx.c | 513 +++++++++++++++++++++++++++++++--- >> 1 file changed, 481 insertions(+), 32 deletions(-) > > Ouch dynamic allocations while doing xmit are certainly not needed. > Your driver should pre-allocated space for headers. This is right as long as you don't need *several* headers in one single skb. In the case of A-MSDU, I need to have several TCP / IP / SNAP headers in the same skb. At least that's how my HW layer in the driver is built. See the other thread. > > Drivers willing to implement tso have to use net/core/tso.c provided > helpers. > > $ git grep -n tso_build_hdr > drivers/net/ethernet/cavium/thunder/nicvf_queues.c:1030: tso_build_hdr(skb, hdr, &tso, data_left, total_len == 0); > drivers/net/ethernet/freescale/fec_main.c:729: tso_build_hdr(skb, hdr, &tso, data_left, total_len == 0); > drivers/net/ethernet/marvell/mv643xx_eth.c:842: tso_build_hdr(skb, hdr, &tso, data_left, total_len == 0); > drivers/net/ethernet/marvell/mvneta.c:1650: tso_build_hdr(skb, hdr, &tso, data_left, total_len == 0); > include/net/tso.h:15:void tso_build_hdr(struct sk_buff *skb, char *hdr, struct tso_t *tso, > net/core/tso.c:14:void tso_build_hdr(struct sk_buff *skb, char *hdr, struct tso_t *tso, > net/core/tso.c:37:EXPORT_SYMBOL(tso_build_hdr); > > This looks promising indeed. I'll take a close look. Thanks a bunch. -- To unsubscribe from this list: send the line "unsubscribe linux-wireless" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
