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platform_kernel-5.15
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FROMLIST: rpmsg: char: Add support to use rpmsg_rx_done 

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().

Bug: 235577039
Link: https://lore.kernel.org/lkml/1654651005-15475-3-git-send-email-quic_clew@quicinc.com/
Change-Id: I5c94c560daebc4a48cee2ecfb6a44ea6c3087e8d
Signed-off-by: Chris Lew <quic_clew@quicinc.com>
This commit is contained in:
Chris Lew 2022-06-06 11:47:41 -07:00 committed by Carlos Llamas
parent a4f64634ad
commit 76801c2626
1 changed files with 48 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

50
drivers/rpmsg/rpmsg_char.c
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@ -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;