From: Stanislaw Gruszka <sgruszka@redhat.com>
To: Lorenzo Bianconi <lorenzo@kernel.org>
Cc: kvalo@codeaurora.org, linux-wireless@vger.kernel.org,
nbd@nbd.name, lorenzo.bianconi@redhat.com,
oleksandr@natalenko.name, netdev@vger.kernel.org
Subject: Re: [PATCH wireless-drivers 2/2] mt76: dma: fix buffer unmap with non-linear skbs
Date: Fri, 25 Oct 2019 11:02:36 +0200 [thread overview]
Message-ID: <20191025090236.GB14818@redhat.com> (raw)
In-Reply-To: <20191024090148.GC9346@localhost.localdomain>
On Thu, Oct 24, 2019 at 11:01:48AM +0200, Lorenzo Bianconi wrote:
> > On Thu, Oct 24, 2019 at 12:23:16AM +0200, Lorenzo Bianconi wrote:
> > > mt76 dma layer is supposed to unmap skb data buffers while keep txwi
> > > mapped on hw dma ring. At the moment mt76 wrongly unmap txwi or does
> > > not unmap data fragments in even positions for non-linear skbs. This
> > > issue may result in hw hangs with A-MSDU if the system relies on IOMMU
> > > or SWIOTLB. Fix this behaviour properly unmapping data fragments on
> > > non-linear skbs.
> >
> > If we have to keep txwi mapped, before unmap fragments, when then
> > txwi is unmaped ?
>
> txwi are mapped when they are crated in mt76_alloc_txwi(). Whenever we need to
> modify them we sync the DMA in mt76_dma_tx_queue_skb(). txwi are unmapped in
> mt76_tx_free() at driver unload.
So not only txwi is wrongly unmapped on runtime, but we can call
dma_sync_single_for_cpu/device() after dma_unmap_single().
That serious bug, good you spotted it and fixed!
Stanislaw
next prev parent reply other threads:[~2019-10-25 9:02 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-23 22:23 [PATCH wireless-drivers 0/2] fix mt76x2e hangs on U7612E mini-pcie Lorenzo Bianconi
2019-10-23 22:23 ` [PATCH wireless-drivers 1/2] mt76: mt76x2e: disable pcie_aspm by default Lorenzo Bianconi
2019-10-24 5:03 ` Kalle Valo
2019-10-24 8:08 ` Lorenzo Bianconi
2019-10-24 19:41 ` Heiner Kallweit
2019-10-24 21:54 ` Lorenzo Bianconi
2019-10-24 22:19 ` Heiner Kallweit
2019-10-24 23:07 ` Lorenzo Bianconi
2019-10-25 10:56 ` Heiner Kallweit
2019-10-25 11:46 ` Lorenzo Bianconi
2019-10-25 17:00 ` Heiner Kallweit
2019-10-25 17:35 ` Lorenzo Bianconi
2019-10-26 1:38 ` kbuild test robot
2019-10-23 22:23 ` [PATCH wireless-drivers 2/2] mt76: dma: fix buffer unmap with non-linear skbs Lorenzo Bianconi
2019-10-24 6:30 ` Felix Fietkau
2019-10-24 8:57 ` Lorenzo Bianconi
2019-10-24 8:18 ` Stanislaw Gruszka
2019-10-24 9:01 ` Lorenzo Bianconi
2019-10-25 9:02 ` Stanislaw Gruszka [this message]
2019-10-24 6:19 ` [PATCH wireless-drivers 0/2] fix mt76x2e hangs on U7612E mini-pcie Oleksandr Natalenko
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