| Message ID | 1372421021.3301.263.camel@edumazet-glaptop (mailing list archive) |
|---|---|
| State | Not Applicable, archived |
| Headers | show |
On Fri, Jun 28, 2013 at 5:03 AM, Eric Dumazet <eric.dumazet@gmail.com> wrote: > From: Eric Dumazet <edumazet@google.com> > > Steinar reported reallocations of skb->head with IPv6, leading to > a warning in skb_try_coalesce() > > It turns out iwl3945 has several problems : > > 1) skb->truesize is underestimated. > We really consume PAGE_SIZE bytes for a fragment, > not the frame length. > 2) 128 bytes of initial headroom is a bit low and forces reallocations. > 3) We can avoid consuming a full page for small enough frames. > > Reported-by: Steinar H. Gunderson <sesse@google.com> > Signed-off-by: Eric Dumazet <edumazet@google.com> > --- > Note : compiled only, I do not have this hardware. > > drivers/net/wireless/iwlegacy/3945.c | 30 +++++++++++++++---------- > 1 file changed, 18 insertions(+), 12 deletions(-) > > diff --git a/drivers/net/wireless/iwlegacy/3945.c b/drivers/net/wireless/iwlegacy/3945.c > index c092033..ad7294f 100644 > --- a/drivers/net/wireless/iwlegacy/3945.c > +++ b/drivers/net/wireless/iwlegacy/3945.c > @@ -483,14 +483,13 @@ il3945_pass_packet_to_mac80211(struct il_priv *il, struct il_rx_buf *rxb, > struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)IL_RX_DATA(pkt); > struct il3945_rx_frame_hdr *rx_hdr = IL_RX_HDR(pkt); > struct il3945_rx_frame_end *rx_end = IL_RX_END(pkt); > - u16 len = le16_to_cpu(rx_hdr->len); > + u32 len = le16_to_cpu(rx_hdr->len); > struct sk_buff *skb; > __le16 fc = hdr->frame_control; > + u32 fraglen = PAGE_SIZE << il->hw_params.rx_page_order; > > /* We received data from the HW, so stop the watchdog */ > - if (unlikely > - (len + IL39_RX_FRAME_SIZE > > - PAGE_SIZE << il->hw_params.rx_page_order)) { > + if (unlikely(len + IL39_RX_FRAME_SIZE > fraglen)) { > D_DROP("Corruption detected!\n"); > return; > } > @@ -506,26 +505,33 @@ il3945_pass_packet_to_mac80211(struct il_priv *il, struct il_rx_buf *rxb, > D_INFO("Woke queues - frame received on passive channel\n"); > } > > - skb = dev_alloc_skb(128); > + skb = dev_alloc_skb(256); > if (!skb) { > IL_ERR("dev_alloc_skb failed\n"); > return; > } > > if (!il3945_mod_params.sw_crypto) > - il_set_decrypted_flag(il, (struct ieee80211_hdr *)rxb_addr(rxb), > + il_set_decrypted_flag(il, (struct ieee80211_hdr *)pkt, > le32_to_cpu(rx_end->status), stats); > > - skb_add_rx_frag(skb, 0, rxb->page, > - (void *)rx_hdr->payload - (void *)pkt, len, > - len); > - > + /* If frame is small enough to fit into skb->head, copy it > + * and do not consume a full page > + */ > + if (len <= 256) { Presumably this 256 is related to the "dev_alloc_skb(256)"? It might be worth making this a constant of some sort so they don't inadvertently drift apart in the future. > + skb_copy_to_linear_data(skb, rx_hdr->payload, len); > + skb->tail += len; > + } else { > + skb_add_rx_frag(skb, 0, rxb->page, > + (void *)rx_hdr->payload - (void *)pkt, len, > + fraglen); > + il->alloc_rxb_page--; > + rxb->page = NULL; > + } > il_update_stats(il, false, fc, len); > memcpy(IEEE80211_SKB_RXCB(skb), stats, sizeof(*stats)); > > ieee80211_rx(il->hw, skb); > - il->alloc_rxb_page--; > - rxb->page = NULL; > } > > #define IL_DELAY_NEXT_SCAN_AFTER_ASSOC (HZ*6) > > > -- > To unsubscribe from this list: send the line "unsubscribe netdev" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe linux-wireless" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/drivers/net/wireless/iwlegacy/3945.c b/drivers/net/wireless/iwlegacy/3945.c index c092033..ad7294f 100644 --- a/drivers/net/wireless/iwlegacy/3945.c +++ b/drivers/net/wireless/iwlegacy/3945.c @@ -483,14 +483,13 @@ il3945_pass_packet_to_mac80211(struct il_priv *il, struct il_rx_buf *rxb, struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)IL_RX_DATA(pkt); struct il3945_rx_frame_hdr *rx_hdr = IL_RX_HDR(pkt); struct il3945_rx_frame_end *rx_end = IL_RX_END(pkt); - u16 len = le16_to_cpu(rx_hdr->len); + u32 len = le16_to_cpu(rx_hdr->len); struct sk_buff *skb; __le16 fc = hdr->frame_control; + u32 fraglen = PAGE_SIZE << il->hw_params.rx_page_order; /* We received data from the HW, so stop the watchdog */ - if (unlikely - (len + IL39_RX_FRAME_SIZE > - PAGE_SIZE << il->hw_params.rx_page_order)) { + if (unlikely(len + IL39_RX_FRAME_SIZE > fraglen)) { D_DROP("Corruption detected!\n"); return; } @@ -506,26 +505,33 @@ il3945_pass_packet_to_mac80211(struct il_priv *il, struct il_rx_buf *rxb, D_INFO("Woke queues - frame received on passive channel\n"); } - skb = dev_alloc_skb(128); + skb = dev_alloc_skb(256); if (!skb) { IL_ERR("dev_alloc_skb failed\n"); return; } if (!il3945_mod_params.sw_crypto) - il_set_decrypted_flag(il, (struct ieee80211_hdr *)rxb_addr(rxb), + il_set_decrypted_flag(il, (struct ieee80211_hdr *)pkt, le32_to_cpu(rx_end->status), stats); - skb_add_rx_frag(skb, 0, rxb->page, - (void *)rx_hdr->payload - (void *)pkt, len, - len); - + /* If frame is small enough to fit into skb->head, copy it + * and do not consume a full page + */ + if (len <= 256) { + skb_copy_to_linear_data(skb, rx_hdr->payload, len); + skb->tail += len; + } else { + skb_add_rx_frag(skb, 0, rxb->page, + (void *)rx_hdr->payload - (void *)pkt, len, + fraglen); + il->alloc_rxb_page--; + rxb->page = NULL; + } il_update_stats(il, false, fc, len); memcpy(IEEE80211_SKB_RXCB(skb), stats, sizeof(*stats)); ieee80211_rx(il->hw, skb); - il->alloc_rxb_page--; - rxb->page = NULL; } #define IL_DELAY_NEXT_SCAN_AFTER_ASSOC (HZ*6)