Messages in this thread | | | Date | Wed, 21 Jul 2021 15:27:24 -0700 | From | hemantk@codeauro ... | Subject | Re: [PATCH] net: qrtr: mhi: synchronize qrtr and mhi preparation |
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On 2021-07-21 11:07, Bhaumik Bhatt wrote: > On 2021-07-21 10:52 AM, hemantk@codeaurora.org wrote: >> On 2021-07-20 18:42, Bhaumik Bhatt wrote: >>> A dl callback can be received anytime after mhi_prepare_for_transfer >>> has been called. There is a window where the callback may happen >>> before the probe initializes the qrtr_mhi_dev state. Move the >>> mhi_prepare_for_transfer call after the registering the endpoint. >>> >>> Once moved, the reverse can happen where qrtr will try to send a >>> packet >>> before the channels are prepared. Add a wait in the sending path to >>> ensure the channels are prepared before trying to do a ul transfer. >>> >>> Fixes: a2e2cc0dbb11 ("net: qrtr: Start MHI channels during init") >>> Signed-off-by: Bhaumik Bhatt <bbhatt@codeaurora.org> >>> --- >>> net/qrtr/mhi.c | 20 +++++++++++++++----- >>> 1 file changed, 15 insertions(+), 5 deletions(-) >>> >>> diff --git a/net/qrtr/mhi.c b/net/qrtr/mhi.c >>> index 29b4fa3..22b0395 100644 >>> --- a/net/qrtr/mhi.c >>> +++ b/net/qrtr/mhi.c >>> @@ -15,6 +15,7 @@ struct qrtr_mhi_dev { >>> struct qrtr_endpoint ep; >>> struct mhi_device *mhi_dev; >>> struct device *dev; >>> + struct completion ready; >>> }; >>> >>> /* From MHI to QRTR */ >>> @@ -50,6 +51,10 @@ static int qcom_mhi_qrtr_send(struct qrtr_endpoint >>> *ep, struct sk_buff *skb) >>> struct qrtr_mhi_dev *qdev = container_of(ep, struct qrtr_mhi_dev, >>> ep); >>> int rc; >>> >>> + rc = wait_for_completion_interruptible(&qdev->ready); >>> + if (rc) >>> + goto free_skb; >>> + >>> if (skb->sk) >>> sock_hold(skb->sk); >>> >>> @@ -78,11 +83,6 @@ static int qcom_mhi_qrtr_probe(struct mhi_device >>> *mhi_dev, >>> struct qrtr_mhi_dev *qdev; >>> int rc; >>> >>> - /* start channels */ >>> - rc = mhi_prepare_for_transfer(mhi_dev, MHI_CH_INBOUND_ALLOC_BUFS); >>> - if (rc) >>> - return rc; >>> - >>> qdev = devm_kzalloc(&mhi_dev->dev, sizeof(*qdev), GFP_KERNEL); >>> if (!qdev) >>> return -ENOMEM; >> would it be good to init completion variable here (call >> init_completion) ? > You mean just before setting qdev->mhi_dev? I don't see why that would > make a difference > mainly because the qcom_mhi_qrtr_send() will only happen after endpoint > is > registered and DL xfer cb will also only come in after we have prepared > the > channels and completed ready with dev_data already set. looks like qcom_mhi_qrtr_send is not going to get called directly. i was thinking what if this api is called before init_completion() returns. if it is only possible through ep.xmit call back only, can you move it right above qdev->ep.xmit = qcom_mhi_qrtr_send; ? > >>> @@ -90,12 +90,22 @@ static int qcom_mhi_qrtr_probe(struct mhi_device >>> *mhi_dev, >>> qdev->mhi_dev = mhi_dev; >>> qdev->dev = &mhi_dev->dev; >>> qdev->ep.xmit = qcom_mhi_qrtr_send; >>> + init_completion(&qdev->ready); >>> >> >>> >>> return 0; > > Thanks, > Bhaumik > --- > The Qualcomm Innovation Center, Inc. is a member of the Code Aurora > Forum, > a Linux Foundation Collaborative Project
Thanks, Hemant --- The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project
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