linux – 如果需要调用copy_to_user,如何使用自旋锁？

我写了一个小驱动程序来读取一些数据并将其提供给用户.我的驱动程序可以被多个应用程序使用,即它是一个可重入的驱动程序,因此使用自旋锁.但我发现不应该在保持旋转锁的情况下调用copy_to_user. char_device_buf在以下代码中是共享数据;我必须保护它.除了互斥锁之外是否有任何机制可以使用自旋锁并使用copy_to_user？

static ssize_t char_dev_read(struct file *file,char *buf,size_t lbuf,loff_t *ppos)
    {
            int maxbytes; /* number of bytes from ppos to MAX_LENGTH */
            int bytes_to_do; /* number of bytes to read */
            int nbytes; /* number of bytes actually read */

            maxbytes = MAX_LENGTH - *ppos;

            if( maxbytes > lbuf ) bytes_to_do = lbuf;
            else bytes_to_do = maxbytes;

            if( bytes_to_do == 0 ) {
                    printk("Reached end of devicen");
                    return -ENOSPC; /* Causes read() to return EOF */
            }

       /* Tesing for accidental release */
    //              accidental_release(); 

            printk(KERN_DEBUG "READER: trying for critical region lock n");

            spin_lock(&myspin);/*begin of critical region */

                    printk(KERN_DEBUG "READER : acquired lock: executing critical coden");
                    nbytes = bytes_to_do -
                             copy_to_user( buf,/* to */
                                           char_device_buf + *ppos,/* from */
                                           bytes_to_do ); /* how many bytes */


            spin_unlock(&myspin); /* end of critical region */
            *ppos += nbytes;
            return nbytes;
    }