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 <eric.dumazet@gmail.com>
Cc: Wey-Yi Guy <wey-yi.w.guy@intel.com>
Cc: "John W. Linville" <linville@tuxdriver.com>
Cc: Neal Cardwell <ncardwell@google.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/drivers/net/wireless/iwlwifi/iwl-agn-rx.c b/drivers/net/wireless/iwlwifi/iwl-agn-rx.c
index f4b84d1..2247460 100644
--- a/drivers/net/wireless/iwlwifi/iwl-agn-rx.c
+++ b/drivers/net/wireless/iwlwifi/iwl-agn-rx.c
@@ -773,8 +773,7 @@
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 @@
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 8b1a798..aa7aea1 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 @@
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 0c81cba..fdf9788 100644
--- a/drivers/net/wireless/iwlwifi/iwl-trans.h
+++ b/drivers/net/wireless/iwlwifi/iwl-trans.h
@@ -260,6 +260,7 @@
struct iwl_rx_cmd_buffer {
struct page *_page;
+ unsigned int truesize;
};
static inline void *rxb_addr(struct iwl_rx_cmd_buffer *r)