From e648f86708c4ca1abfbb4103fc7ae3bee5c5ba70 Mon Sep 17 00:00:00 2001 From: Luis R. Rodriguez Date: Fri, 21 Nov 2008 17:47:04 -0800 Subject: [PATCH] ath9k: Fix SW-IOMMU bounce buffer starvation This should fix the SW-IOMMU bounce buffer starvation seen ok kernel.org bugzilla 11811: http://bugzilla.kernel.org/show_bug.cgi?id=11811 Users on MacBook Pro 3.1/MacBook v2 would see something like: DMA: Out of SW-IOMMU space for 4224 bytes at device 0000:0b:00.0 Unfortunately its only easy to trigger on MacBook Pro 3.1/MacBook v2 so far so its difficult to debug (even with swiotlb=force). We were pci_unmap_single()'ing less bytes than what we called for with pci_map_single() and as such we were starving the swiotlb from its 64MB amount of bounce buffers. We remain consistent and now always use sc->rxbufsize for RX. While at it we update the beacon DMA maps as well to only use the data portion of the skb, previous to this we were pci_map_single()'ing more data for beaconing than what we tell the hardware it can use, therefore pushing more iotlb abuse. Still not sure why this is so easily triggerable on MacBook Pro 3.1, it may be the hardware configuration tends to use more memory > 3GB mark for DMA. Signed-off-by: Maciej Zenczykowski Signed-off-by: Bennyam Malavazi Signed-off-by: Luis R. Rodriguez --- drivers/net/wireless/ath9k/recv.c | 8 +++----- 1 files changed, 3 insertions(+), 5 deletions(-) diff --git a/drivers/net/wireless/ath9k/recv.c b/drivers/net/wireless/ath9k/recv.c index 20ddb7a..4d23827 100644 --- a/drivers/net/wireless/ath9k/recv.c +++ b/drivers/net/wireless/ath9k/recv.c @@ -1011,7 +1011,7 @@ int ath_rx_tasklet(struct ath_softc *sc, int flush) pci_dma_sync_single_for_cpu(sc->pdev, bf->bf_buf_addr, - skb_tailroom(skb), + sc->sc_rxbufsize, PCI_DMA_FROMDEVICE); pci_unmap_single(sc->pdev, bf->bf_buf_addr, @@ -1303,8 +1303,7 @@ dma_addr_t ath_skb_map_single(struct ath_softc *sc, * NB: do NOT use skb->len, which is 0 on initialization. * Use skb's entire data area instead. */ - *pa = pci_map_single(sc->pdev, skb->data, - skb_end_pointer(skb) - skb->head, direction); + *pa = pci_map_single(sc->pdev, skb->data, sc->sc_rxbufsize, direction); return *pa; } @@ -1314,6 +1313,5 @@ void ath_skb_unmap_single(struct ath_softc *sc, dma_addr_t *pa) { /* Unmap skb's entire data area */ - pci_unmap_single(sc->pdev, *pa, - skb_end_pointer(skb) - skb->head, direction); + pci_unmap_single(sc->pdev, *pa, sc->sc_rxbufsize, direction); } -- 1.5.6.rc2.15.g457bb.dirty