From ed90542b0ce5415050c6fbfca324bccaafa69f2f Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Sat, 24 Mar 2012 00:29:46 -0400 Subject: iwlwifi: fix skb truesize underestimation By default, iwlwifi uses order-1 pages (8 KB) to store incoming frames, but doesnt say so in skb->truesize. This makes very possible to exhaust kernel memory since these skb evade normal socket memory accounting. As struct ieee80211_hdr is going to be pulled before calling IP stack, there is no need to use dev_alloc_skb() to reserve NET_SKB_PAD bytes. alloc_skb() is ok in this driver, allowing more tailroom. Pull beginning of frame in skb header, in the hope we can reuse order-1 pages in the driver immediately for small frames and reduce their truesize to the minimum (linear skbs) Signed-off-by: Eric Dumazet Cc: Wey-Yi Guy Cc: "John W. Linville" Cc: Neal Cardwell Signed-off-by: John W. Linville --- drivers/net/wireless/iwlwifi/iwl-agn-rx.c | 21 ++++++++++++++------- drivers/net/wireless/iwlwifi/iwl-trans-pcie-rx.c | 3 ++- drivers/net/wireless/iwlwifi/iwl-trans.h | 1 + 3 files changed, 17 insertions(+), 8 deletions(-) (limited to 'drivers') diff --git a/drivers/net/wireless/iwlwifi/iwl-agn-rx.c b/drivers/net/wireless/iwlwifi/iwl-agn-rx.c index f4b84d1596e3..22474608a70b 100644 --- a/drivers/net/wireless/iwlwifi/iwl-agn-rx.c +++ b/drivers/net/wireless/iwlwifi/iwl-agn-rx.c @@ -773,8 +773,7 @@ static void iwlagn_pass_packet_to_mac80211(struct iwl_priv *priv, struct sk_buff *skb; __le16 fc = hdr->frame_control; struct iwl_rxon_context *ctx; - struct page *p; - int offset; + unsigned int hdrlen, fraglen; /* We only process data packets if the interface is open */ if (unlikely(!priv->is_open)) { @@ -788,16 +787,24 @@ static void iwlagn_pass_packet_to_mac80211(struct iwl_priv *priv, iwlagn_set_decrypted_flag(priv, hdr, ampdu_status, stats)) return; - skb = dev_alloc_skb(128); + /* Dont use dev_alloc_skb(), we'll have enough headroom once + * ieee80211_hdr pulled. + */ + skb = alloc_skb(128, GFP_ATOMIC); if (!skb) { - IWL_ERR(priv, "dev_alloc_skb failed\n"); + IWL_ERR(priv, "alloc_skb failed\n"); return; } + hdrlen = min_t(unsigned int, len, skb_tailroom(skb)); + memcpy(skb_put(skb, hdrlen), hdr, hdrlen); + fraglen = len - hdrlen; - offset = (void *)hdr - rxb_addr(rxb); - p = rxb_steal_page(rxb); - skb_add_rx_frag(skb, 0, p, offset, len, len); + if (fraglen) { + int offset = (void *)hdr + hdrlen - rxb_addr(rxb); + skb_add_rx_frag(skb, 0, rxb_steal_page(rxb), offset, + fraglen, rxb->truesize); + } iwl_update_stats(priv, false, fc, len); /* diff --git a/drivers/net/wireless/iwlwifi/iwl-trans-pcie-rx.c b/drivers/net/wireless/iwlwifi/iwl-trans-pcie-rx.c index 8b1a7988e176..aa7aea168138 100644 --- a/drivers/net/wireless/iwlwifi/iwl-trans-pcie-rx.c +++ b/drivers/net/wireless/iwlwifi/iwl-trans-pcie-rx.c @@ -374,8 +374,9 @@ static void iwl_rx_handle_rxbuf(struct iwl_trans *trans, if (WARN_ON(!rxb)) return; + rxcb.truesize = PAGE_SIZE << hw_params(trans).rx_page_order; dma_unmap_page(trans->dev, rxb->page_dma, - PAGE_SIZE << hw_params(trans).rx_page_order, + rxcb.truesize, DMA_FROM_DEVICE); rxcb._page = rxb->page; diff --git a/drivers/net/wireless/iwlwifi/iwl-trans.h b/drivers/net/wireless/iwlwifi/iwl-trans.h index 0c81cbaa8088..fdf97886a5e4 100644 --- a/drivers/net/wireless/iwlwifi/iwl-trans.h +++ b/drivers/net/wireless/iwlwifi/iwl-trans.h @@ -260,6 +260,7 @@ static inline void iwl_free_resp(struct iwl_host_cmd *cmd) struct iwl_rx_cmd_buffer { struct page *_page; + unsigned int truesize; }; static inline void *rxb_addr(struct iwl_rx_cmd_buffer *r) -- cgit v1.2.3