| Message ID | 1654651005-15475-3-git-send-email-quic_clew@quicinc.com (mailing list archive) |
|---|---|
| State | Not Applicable |
| Headers | show |
| Series | Introduction of rpmsg_rx_done | expand |
On Tue, Jun 07, 2022 at 06:16:43PM -0700, Chris Lew wrote: > Add support into the rpmsg char driver to skip copying the data into an > skb if the endpoint supports rpmsg_rx_done. If the endpoint supports > the rx_done operation, allocate a zero sized skb and set the data to > the buffer returned in the rx callback. When the packet is read from > the character device, release the memory by calling rpmsg_rx_done(). > > Signed-off-by: Chris Lew <quic_clew@quicinc.com> > --- > drivers/rpmsg/rpmsg_char.c | 50 ++++++++++++++++++++++++++++++++++++++++++++-- > 1 file changed, 48 insertions(+), 2 deletions(-) > > diff --git a/drivers/rpmsg/rpmsg_char.c b/drivers/rpmsg/rpmsg_char.c > index b6183d4f62a2..be62ddcf356c 100644 > --- a/drivers/rpmsg/rpmsg_char.c > +++ b/drivers/rpmsg/rpmsg_char.c > @@ -91,8 +91,8 @@ int rpmsg_chrdev_eptdev_destroy(struct device *dev, void *data) > } > EXPORT_SYMBOL(rpmsg_chrdev_eptdev_destroy); > > -static int rpmsg_ept_cb(struct rpmsg_device *rpdev, void *buf, int len, > - void *priv, u32 addr) > +static int rpmsg_ept_copy_cb(struct rpmsg_device *rpdev, void *buf, int len, > + void *priv, u32 addr) > { > struct rpmsg_eptdev *eptdev = priv; > struct sk_buff *skb; > @@ -113,6 +113,43 @@ static int rpmsg_ept_cb(struct rpmsg_device *rpdev, void *buf, int len, > return 0; > } > > +static int rpmsg_ept_no_copy_cb(struct rpmsg_device *rpdev, void *buf, int len, > + void *priv, u32 addr) > +{ > + struct rpmsg_eptdev *eptdev = priv; > + struct sk_buff *skb; > + > + skb = alloc_skb(0, GFP_ATOMIC); > + if (!skb) > + return -ENOMEM; > + > + skb->head = buf; > + skb->data = buf; > + skb_reset_tail_pointer(skb); > + skb_set_end_offset(skb, len); > + skb_put(skb, len); > + I was worried about all that open ended code but looking at the sk_buff API I don't think it is possible to do otherwise. As such: Reviewed-by: Mathieu Poirier <mathieu.poirier@linaro.org> > + spin_lock(&eptdev->queue_lock); > + skb_queue_tail(&eptdev->queue, skb); > + spin_unlock(&eptdev->queue_lock); > + > + /* wake up any blocking processes, waiting for new data */ > + wake_up_interruptible(&eptdev->readq); > + > + return RPMSG_DEFER; > +} > + > +static int rpmsg_ept_cb(struct rpmsg_device *rpdev, void *buf, int len, > + void *priv, u32 addr) > +{ > + struct rpmsg_eptdev *eptdev = priv; > + rpmsg_rx_cb_t cb; > + > + cb = (eptdev->ept->rx_done) ? rpmsg_ept_no_copy_cb : rpmsg_ept_copy_cb; > + > + return cb(rpdev, buf, len, priv, addr); > +} > + > static int rpmsg_eptdev_open(struct inode *inode, struct file *filp) > { > struct rpmsg_eptdev *eptdev = cdev_to_eptdev(inode->i_cdev); > @@ -210,6 +247,15 @@ static ssize_t rpmsg_eptdev_read_iter(struct kiocb *iocb, struct iov_iter *to) > if (copy_to_iter(skb->data, use, to) != use) > use = -EFAULT; > > + if (eptdev->ept->rx_done) { > + rpmsg_rx_done(eptdev->ept, skb->data); > + /* > + * Data memory is freed by rpmsg_rx_done(), reset the skb data > + * pointers so kfree_skb() does not try to free a second time. > + */ > + skb->head = NULL; > + skb->data = NULL; > + } > kfree_skb(skb); > > return use; > -- > 2.7.4 >
diff --git a/drivers/rpmsg/rpmsg_char.c b/drivers/rpmsg/rpmsg_char.c index b6183d4f62a2..be62ddcf356c 100644 --- a/drivers/rpmsg/rpmsg_char.c +++ b/drivers/rpmsg/rpmsg_char.c @@ -91,8 +91,8 @@ int rpmsg_chrdev_eptdev_destroy(struct device *dev, void *data) } EXPORT_SYMBOL(rpmsg_chrdev_eptdev_destroy); -static int rpmsg_ept_cb(struct rpmsg_device *rpdev, void *buf, int len, - void *priv, u32 addr) +static int rpmsg_ept_copy_cb(struct rpmsg_device *rpdev, void *buf, int len, + void *priv, u32 addr) { struct rpmsg_eptdev *eptdev = priv; struct sk_buff *skb; @@ -113,6 +113,43 @@ static int rpmsg_ept_cb(struct rpmsg_device *rpdev, void *buf, int len, return 0; } +static int rpmsg_ept_no_copy_cb(struct rpmsg_device *rpdev, void *buf, int len, + void *priv, u32 addr) +{ + struct rpmsg_eptdev *eptdev = priv; + struct sk_buff *skb; + + skb = alloc_skb(0, GFP_ATOMIC); + if (!skb) + return -ENOMEM; + + skb->head = buf; + skb->data = buf; + skb_reset_tail_pointer(skb); + skb_set_end_offset(skb, len); + skb_put(skb, len); + + spin_lock(&eptdev->queue_lock); + skb_queue_tail(&eptdev->queue, skb); + spin_unlock(&eptdev->queue_lock); + + /* wake up any blocking processes, waiting for new data */ + wake_up_interruptible(&eptdev->readq); + + return RPMSG_DEFER; +} + +static int rpmsg_ept_cb(struct rpmsg_device *rpdev, void *buf, int len, + void *priv, u32 addr) +{ + struct rpmsg_eptdev *eptdev = priv; + rpmsg_rx_cb_t cb; + + cb = (eptdev->ept->rx_done) ? rpmsg_ept_no_copy_cb : rpmsg_ept_copy_cb; + + return cb(rpdev, buf, len, priv, addr); +} + static int rpmsg_eptdev_open(struct inode *inode, struct file *filp) { struct rpmsg_eptdev *eptdev = cdev_to_eptdev(inode->i_cdev); @@ -210,6 +247,15 @@ static ssize_t rpmsg_eptdev_read_iter(struct kiocb *iocb, struct iov_iter *to) if (copy_to_iter(skb->data, use, to) != use) use = -EFAULT; + if (eptdev->ept->rx_done) { + rpmsg_rx_done(eptdev->ept, skb->data); + /* + * Data memory is freed by rpmsg_rx_done(), reset the skb data + * pointers so kfree_skb() does not try to free a second time. + */ + skb->head = NULL; + skb->data = NULL; + } kfree_skb(skb); return use;
Add support into the rpmsg char driver to skip copying the data into an skb if the endpoint supports rpmsg_rx_done. If the endpoint supports the rx_done operation, allocate a zero sized skb and set the data to the buffer returned in the rx callback. When the packet is read from the character device, release the memory by calling rpmsg_rx_done(). Signed-off-by: Chris Lew <quic_clew@quicinc.com> --- drivers/rpmsg/rpmsg_char.c | 50 ++++++++++++++++++++++++++++++++++++++++++++-- 1 file changed, 48 insertions(+), 2 deletions(-)