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Add comment for virtqueue_add_outbuf

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zeroway
2023-07-27 14:28:15 +08:00
parent 540fd9dde6
commit 1bde99e812
1 changed files with 13 additions and 0 deletions
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13
x86/crypto/virtio_mini.c
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@ -66,12 +66,14 @@ static ssize_t virtio_mini_write(struct file* fil, const char *buf, size_t count
return ENOSPC;
}
/* 分配空间用于保存用户要发送的数据 */
to_send = kmalloc(count, GFP_KERNEL);
if (!to_send)
{
return 1;
}
/* 将用户的数据保存到to_send */
res = copy_from_user(to_send, buf, count);
if (res != 0) {
printk(KERN_INFO "Could not write %lu bytes!", res);
@ -79,6 +81,17 @@ static ssize_t virtio_mini_write(struct file* fil, const char *buf, size_t count
count = count - res;
}
/*
* virtqueue中数据是存VirtQueueElement中的in_sg或out_sg散列中的
* 驱动中用对应的api来打包,这里virtqueue_add_outbuf
* 所以填充的out_sg
*
* 在设备中通过virtqueue_pop来获取到对应的VirtQueueElement后取出散列中的数据
* 1. 取出element
* vqe = virtqueue_pop(vq, sizeof(VirtQueueElement));
* 2. 取出element里的数据
* iov_to_buf(vqe->out_sg, vqe->out_num, 0, rcv_bufs, vqe->out_sg->iov_len);
*/
sg_init_one(&sg, to_send, count);
vmini->buf_lens[vmini->buffers++] = count;
virtqueue_add_outbuf(vq, &sg, 1, to_send, GFP_KERNEL);