/* A simple wrapper so the base function doesn't need to enforce
* that all swap pages go through the swap cache!
*/
void rw_swap_page(int rw, unsigned long entry, char *buf, int wait)
{
struct page *page = mem_map + MAP_NR(buf);
if (page->inode && page->inode != &swapper_inode)
panic ("Tried to swap a non-swapper page");
/*
* Make sure that we have a swap cache association for this
* page. We need this to find which swap page to unlock once
* the swap IO has completed to the physical page. If the page
* is not already in the cache, just overload the offset entry
* as if it were: we are not allowed to manipulate the inode
* hashing for locked pages.
*/
if (!PageSwapCache(page)) {
printk("VM: swap page is not in swap cache\n");
return;
}
if (page->offset != entry) {
printk ("swap entry mismatch");
return;
}
rw_swap_page_base(rw, entry, page, wait);
}
/*
* A simple wrapper so the base function doesn't need to enforce
* that all swap pages go through the swap cache! We verify that:
* - the page is locked
* - it's marked as being swap-cache
* - it's associated with the swap inode
*/
void rw_swap_page(int rw, struct page *page)
{
swp_entry_t entry;
entry.val = page->index;
if (!PageLocked(page))
PAGE_BUG(page);
if (!PageSwapCache(page))
PAGE_BUG(page);
if (!rw_swap_page_base(rw, entry, page))
UnlockPage(page);
}
/*
* shmfs needs a version that doesn't put the page in the page cache!
* The swap lock map insists that pages be in the page cache!
* Therefore we can't use it. Later when we can remove the need for the
* lock map and we can reduce the number of functions exported.
*/
void rw_swap_page_nolock(int rw, unsigned long entry, char *buffer, int wait)
{
struct page *page = mem_map + MAP_NR((unsigned long) buffer);
if (!PageLocked(page)) {
printk("VM: rw_swap_page_nolock: page not locked!\n");
return;
}
if (PageSwapCache(page)) {
printk ("VM: rw_swap_page_nolock: page in swap cache!\n");
return;
}
rw_swap_page_base(rw, entry, page, wait);
}
/*
* The swap lock map insists that pages be in the page cache!
* Therefore we can't use it. Later when we can remove the need for the
* lock map and we can reduce the number of functions exported.
*/
void rw_swap_page_nolock(int rw, swp_entry_t entry, char *buf)
{
struct page *page = virt_to_page(buf);
if (!PageLocked(page))
PAGE_BUG(page);
if (PageSwapCache(page))
PAGE_BUG(page);
if (page->mapping)
PAGE_BUG(page);
/* needs sync_page to wait I/O completation */
page->mapping = &swapper_space;
if (!rw_swap_page_base(rw, entry, page))
UnlockPage(page);
wait_on_page(page);
page->mapping = NULL;
}
