Commit ed90542b authored by Eric Dumazet's avatar Eric Dumazet Committed by John W. Linville

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: default avatarEric 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: default avatarJohn W. Linville <linville@tuxdriver.com>
parent 9d1ceac5
......@@ -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);
/*
......
......@@ -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;
......
......@@ -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)
......
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