diff options
| -rw-r--r-- | main.c | 20 | ||||
| -rw-r--r-- | main.h | 6 |
2 files changed, 17 insertions, 9 deletions
@@ -146,7 +146,7 @@ static int hello_trim(struct hello_dev *dev) static struct hello_ll *hello_follow(struct hello_dev *dev, int n) { struct hello_ll *nptr = dev->mylist, *tmp; - PDEBUG("follow() called with n: %i\n", n); + PRDEBUG("follow() called with n: %i\n", n); /* allocate first node explicitly if it needs to be */ if (!nptr) { @@ -162,8 +162,12 @@ static struct hello_ll *hello_follow(struct hello_dev *dev, int n) /* follow the list */ while (n--) { /* almost like testing for NULL, remember this is circular list */ - if (nptr->list.next == &nptr->list) { - PDEBUG("allocating additional node"); + PRDEBUG("while loop: n is: %i, nptr->list is at: %p, ntpr->list.next is at %p\n", + n, /* &nptr->list */ &dev->mylist->list, nptr->list.next); + + /* there was a bug below, took 2 hours to track down */ + if (nptr->list.next == /* &nptr->list */ &dev->mylist->list) { + PRDEBUG("allocating additional node"); tmp = kmalloc(sizeof(struct hello_ll), GFP_KERNEL); if (!tmp) return NULL; @@ -187,7 +191,7 @@ static ssize_t hello_read(struct file *filp, char __user *buff, size_t count, lo ssize_t ret = 0; /* end of file, also in case of out of bound */ struct hello_ll *cptr = NULL; /* node where right chunk is */ int chunk_pos = 0; - PDEBUG("read() called\n"); + PRDEBUG("read() called\n"); if (down_interruptible(&dev->sem)) return -ERESTARTSYS; @@ -220,7 +224,7 @@ static ssize_t hello_read(struct file *filp, char __user *buff, size_t count, lo count = dev->chunk_sz - chunk_pos; /* write to userspace memory by reading only up to the end of chunk */ - if (copy_to_user(buff, cptr->chunk + (*f_pos % dev->chunk_sz), count)) + if (copy_to_user(buff, cptr->chunk + chunk_pos, count)) { ret = -EFAULT; goto out; @@ -240,12 +244,12 @@ static ssize_t hello_write(struct file *filp, const char __user *buff, size_t co ssize_t ret = -ENOMEM; struct hello_ll *cptr = NULL; /* node where right chunk is */ int chunk_pos = 0; - PDEBUG("write() called\n"); + PRDEBUG("write() called, user buffer is at: %p, f_pos: %lli, c: %lu\n", buff, *f_pos, count); if (down_interruptible(&dev->sem)) return -ERESTARTSYS; - chunk_pos = *f_pos / dev->chunk_sz; + chunk_pos = *f_pos % dev->chunk_sz; cptr = hello_follow(dev, *f_pos / dev->chunk_sz); if (!cptr) @@ -342,7 +346,7 @@ static int __init hello_init(void) ret = alloc_chrdev_region(&devnum, 0 /* first minor */, 1, "helloc"); hello_major = MAJOR(devnum); hello_minor = MINOR(devnum); - printk(KERN_INFO "[hello] major: %d, minor: %d\n", hello_major, hello_minor); + PDEBUG("[hello] major: %d, minor: %d\n", hello_major, hello_minor); } if (ret < 0) { printk(KERN_WARNING "[hello] can't get the major %d number\n", hello_major); @@ -9,8 +9,12 @@ */ #ifdef HELLO_DEBUG #define PDEBUG(fmt, args...) printk( KERN_DEBUG "[hello] " fmt, ##args) + #define PRDEBUG(fmt, args...) if (printk_ratelimit()) \ + printk( KERN_DEBUG "[hello] " fmt, ##args) #else - #define PDEBUG(fmt, args...) /* not debugging: nothing */ + /* not debugging: nothing */ + #define PDEBUG(fmt, args...) + #define PRDEBUG(fmt, args...) #endif #ifndef HELLO_MAJOR |