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SubjectRe: [PATCH] rpmsg: glink: Use spinlock in tx path
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On 14/02/18 03:04, Bjorn Andersson wrote:
> Switch the tx_lock to a spinlock we allow clients to use rpmsg_trysend()
> from atomic context.
>
> In order to allow clients to sleep while waiting for space in the FIFO
> we release the lock temporarily around the delay; which should be
> replaced by sending a READ_NOTIF and waiting for the remote to signal
> us that space has been made available.
>
> Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
> ---

with ret set to 0 in qcom_glink_tx()

Tested-by: Srinivas kandagatla <srinivas.kandagatla@linaro.org>

> drivers/rpmsg/qcom_glink_native.c | 16 ++++++++++------
> 1 file changed, 10 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/rpmsg/qcom_glink_native.c b/drivers/rpmsg/qcom_glink_native.c
> index e0f31ed096a5..6e950e9afa82 100644
> --- a/drivers/rpmsg/qcom_glink_native.c
> +++ b/drivers/rpmsg/qcom_glink_native.c
> @@ -113,7 +113,7 @@ struct qcom_glink {
> spinlock_t rx_lock;
> struct list_head rx_queue;
>
> - struct mutex tx_lock;
> + spinlock_t tx_lock;
>
> spinlock_t idr_lock;
> struct idr lcids;
> @@ -288,15 +288,14 @@ static int qcom_glink_tx(struct qcom_glink *glink,
> const void *data, size_t dlen, bool wait)
> {
> unsigned int tlen = hlen + dlen;
> + unsigned long flags;
> int ret;
>
> /* Reject packets that are too big */
> if (tlen >= glink->tx_pipe->length)
> return -EINVAL;
>
> - ret = mutex_lock_interruptible(&glink->tx_lock);
> - if (ret)
> - return ret;
> + spin_lock_irqsave(&glink->tx_lock, flags);
>
> while (qcom_glink_tx_avail(glink) < tlen) {
> if (!wait) {
> @@ -304,7 +303,12 @@ static int qcom_glink_tx(struct qcom_glink *glink,
> goto out;
> }
>
> + /* Wait without holding the tx_lock */
> + spin_unlock_irqrestore(&glink->tx_lock, flags);
> +
> usleep_range(10000, 15000);
> +
> + spin_lock_irqsave(&glink->tx_lock, flags);
> }
>
> qcom_glink_tx_write(glink, hdr, hlen, data, dlen);
> @@ -313,7 +317,7 @@ static int qcom_glink_tx(struct qcom_glink *glink,
> mbox_client_txdone(glink->mbox_chan, 0);
>
> out:
> - mutex_unlock(&glink->tx_lock);
> + spin_unlock_irqrestore(&glink->tx_lock, flags);
>
> return ret;
> }
> @@ -1567,7 +1571,7 @@ struct qcom_glink *qcom_glink_native_probe(struct device *dev,
> glink->features = features;
> glink->intentless = intentless;
>
> - mutex_init(&glink->tx_lock);
> + spin_lock_init(&glink->tx_lock);
> spin_lock_init(&glink->rx_lock);
> INIT_LIST_HEAD(&glink->rx_queue);
> INIT_WORK(&glink->rx_work, qcom_glink_work);
>

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