(2013/06/12 18:13), Michael Holzheu wrote:
On Tue, 11 Jun 2013 21:42:15 +0900
HATAYAMA Daisuke <d.hatay...@gmail.com> wrote:
2013/6/11 Michael Holzheu <holz...@linux.vnet.ibm.com>:
On Mon, 10 Jun 2013 22:40:24 +0900
HATAYAMA Daisuke <d.hatay...@gmail.com> wrote:
2013/6/8 Michael Holzheu <holz...@linux.vnet.ibm.com>:
<cut>
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;
page = find_or_create_page(mapping, index, GFP_KERNEL);
if (!page)
return VM_FAULT_OOM;
if (!PageUptodate(page)) {
src = index << PAGE_CACHE_SHIFT;
buf = (void *) (page_to_pfn(page) << PAGE_SHIFT);
if (__read_vmcore(buf, PAGE_SIZE, &src, 0) < 0) {
unlock_page(page);
return VM_FAULT_SIGBUS;
}
SetPageUptodate(page);
}
unlock_page(page);
vmf->page = page;
return 0;
}
Perhaps one open issue remains:
Can we remove the page from the page cache if __read_vmcore() fails?
Yes, use page_cache_release() after unlocking the page like:
if (__read_vmcore(buf, PAGE_SIZE, &src, 0) < 0) {
unlock_page(page);
+ page_cache_release(page);
return VM_FAULT_SIGBUS;
}
BTW, you now keep file->f_mapping in vma->vm_private_data, but the vma already has the file
object in its vma->vm_file member. You can get the mapping by vma->vm_file->f_mapping
without necessity of vma->vm_private_data.
--
Thanks.
HATAYAMA, Daisuke
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