2013/6/8 Michael Holzheu <holzheu at linux.vnet.ibm.com>:
<cut>
> @@ -225,6 +251,56 @@ static ssize_t read_vmcore(struct file *file, char __user *buffer,
> return acc;
> }
>
> +static ssize_t read_vmcore(struct file *file, char __user *buffer,
> + size_t buflen, loff_t *fpos)
> +{
> + return __read_vmcore(buffer, buflen, fpos, 1);
> +}
> +
> +/*
> + * The vmcore fault handler uses the page cache and fills data using the
> + * standard __vmcore_read() function.
> + */
> +static int mmap_vmcore_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
> +{
> + struct address_space *mapping = vma->vm_private_data;
> + pgoff_t index = vmf->pgoff;
> + struct page *page;
> + loff_t src;
> + char *buf;
> + int rc;
> +
> +find_page:
> + page = find_lock_page(mapping, index);
> + if (page) {
> + unlock_page(page);
> + rc = VM_FAULT_MINOR;
> + } else {
> + page = page_cache_alloc_cold(mapping);
> + if (!page)
> + return VM_FAULT_OOM;
> + rc = add_to_page_cache_lru(page, mapping, index, GFP_KERNEL);
> + if (rc) {
> + page_cache_release(page);
> + if (rc == -EEXIST)
> + goto find_page;
> + /* Probably ENOMEM for radix tree node */
> + return VM_FAULT_OOM;
> + }
> + buf = (void *) (page_to_pfn(page) << PAGE_SHIFT);
> + src = index << PAGE_CACHE_SHIFT;
> + __read_vmcore(buf, PAGE_SIZE, &src, 0);
> + unlock_page(page);
> + rc = VM_FAULT_MAJOR;
> + }
> + vmf->page = page;
> + return rc;
> +}
How about reusing find_or_create_page()?
Thanks.
HATAYAMA, Daisuke
