b06bad17c7
Kyeongdon reported below error which is BUG_ON(!PageSwapCache(page)) in
page_swap_info. The reason is that page_endio in rw_page unlocks the
page if read I/O is completed so we need to hold a PG_lock again to
check PageSwapCache. Otherwise, the page can be removed from swapcache.
Kernel BUG at c00f9040 [verbose debug info unavailable]
Internal error: Oops - BUG: 0 [#1] PREEMPT SMP ARM
Modules linked in:
CPU: 4 PID: 13446 Comm: RenderThread Tainted: G W 3.10.84-g9f14aec-dirty #73
task: c3b73200 ti: dd192000 task.ti: dd192000
PC is at page_swap_info+0x10/0x2c
LR is at swap_slot_free_notify+0x18/0x6c
pc : [<c00f9040>] lr : [<c00f5560>] psr: 400f0113
sp : dd193d78 ip : c2deb1e4 fp : da015180
r10: 00000000 r9 : 000200da r8 : c120fe08
r7 : 00000000 r6 : 00000000 r5 : c249a6c0 r4 : = c249a6c0
r3 : 00000000 r2 : 40080009 r1 : 200f0113 r0 : = c249a6c0
..<snip> ..
Call Trace:
page_swap_info+0x10/0x2c
swap_slot_free_notify+0x18/0x6c
swap_readpage+0x90/0x11c
read_swap_cache_async+0x134/0x1ac
swapin_readahead+0x70/0xb0
handle_pte_fault+0x320/0x6fc
handle_mm_fault+0xc0/0xf0
do_page_fault+0x11c/0x36c
do_DataAbort+0x34/0x118
Fixes: 3f2b1a04f4
("zram: revive swap_slot_free_notify")
Signed-off-by: Minchan Kim <minchan@kernel.org>
Tested-by: Kyeongdon Kim <kyeongdon.kim@lge.com>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
389 lines
9.3 KiB
C
389 lines
9.3 KiB
C
/*
|
|
* linux/mm/page_io.c
|
|
*
|
|
* Copyright (C) 1991, 1992, 1993, 1994 Linus Torvalds
|
|
*
|
|
* Swap reorganised 29.12.95,
|
|
* Asynchronous swapping added 30.12.95. Stephen Tweedie
|
|
* Removed race in async swapping. 14.4.1996. Bruno Haible
|
|
* Add swap of shared pages through the page cache. 20.2.1998. Stephen Tweedie
|
|
* Always use brw_page, life becomes simpler. 12 May 1998 Eric Biederman
|
|
*/
|
|
|
|
#include <linux/mm.h>
|
|
#include <linux/kernel_stat.h>
|
|
#include <linux/gfp.h>
|
|
#include <linux/pagemap.h>
|
|
#include <linux/swap.h>
|
|
#include <linux/bio.h>
|
|
#include <linux/swapops.h>
|
|
#include <linux/buffer_head.h>
|
|
#include <linux/writeback.h>
|
|
#include <linux/frontswap.h>
|
|
#include <linux/blkdev.h>
|
|
#include <linux/uio.h>
|
|
#include <asm/pgtable.h>
|
|
|
|
static struct bio *get_swap_bio(gfp_t gfp_flags,
|
|
struct page *page, bio_end_io_t end_io)
|
|
{
|
|
struct bio *bio;
|
|
|
|
bio = bio_alloc(gfp_flags, 1);
|
|
if (bio) {
|
|
bio->bi_iter.bi_sector = map_swap_page(page, &bio->bi_bdev);
|
|
bio->bi_iter.bi_sector <<= PAGE_SHIFT - 9;
|
|
bio->bi_end_io = end_io;
|
|
|
|
bio_add_page(bio, page, PAGE_SIZE, 0);
|
|
BUG_ON(bio->bi_iter.bi_size != PAGE_SIZE);
|
|
}
|
|
return bio;
|
|
}
|
|
|
|
void end_swap_bio_write(struct bio *bio)
|
|
{
|
|
struct page *page = bio->bi_io_vec[0].bv_page;
|
|
|
|
if (bio->bi_error) {
|
|
SetPageError(page);
|
|
/*
|
|
* We failed to write the page out to swap-space.
|
|
* Re-dirty the page in order to avoid it being reclaimed.
|
|
* Also print a dire warning that things will go BAD (tm)
|
|
* very quickly.
|
|
*
|
|
* Also clear PG_reclaim to avoid rotate_reclaimable_page()
|
|
*/
|
|
set_page_dirty(page);
|
|
pr_alert("Write-error on swap-device (%u:%u:%llu)\n",
|
|
imajor(bio->bi_bdev->bd_inode),
|
|
iminor(bio->bi_bdev->bd_inode),
|
|
(unsigned long long)bio->bi_iter.bi_sector);
|
|
ClearPageReclaim(page);
|
|
}
|
|
end_page_writeback(page);
|
|
bio_put(bio);
|
|
}
|
|
|
|
static void swap_slot_free_notify(struct page *page)
|
|
{
|
|
struct swap_info_struct *sis;
|
|
struct gendisk *disk;
|
|
|
|
/*
|
|
* There is no guarantee that the page is in swap cache - the software
|
|
* suspend code (at least) uses end_swap_bio_read() against a non-
|
|
* swapcache page. So we must check PG_swapcache before proceeding with
|
|
* this optimization.
|
|
*/
|
|
if (unlikely(!PageSwapCache(page)))
|
|
return;
|
|
|
|
sis = page_swap_info(page);
|
|
if (!(sis->flags & SWP_BLKDEV))
|
|
return;
|
|
|
|
/*
|
|
* The swap subsystem performs lazy swap slot freeing,
|
|
* expecting that the page will be swapped out again.
|
|
* So we can avoid an unnecessary write if the page
|
|
* isn't redirtied.
|
|
* This is good for real swap storage because we can
|
|
* reduce unnecessary I/O and enhance wear-leveling
|
|
* if an SSD is used as the as swap device.
|
|
* But if in-memory swap device (eg zram) is used,
|
|
* this causes a duplicated copy between uncompressed
|
|
* data in VM-owned memory and compressed data in
|
|
* zram-owned memory. So let's free zram-owned memory
|
|
* and make the VM-owned decompressed page *dirty*,
|
|
* so the page should be swapped out somewhere again if
|
|
* we again wish to reclaim it.
|
|
*/
|
|
disk = sis->bdev->bd_disk;
|
|
if (disk->fops->swap_slot_free_notify) {
|
|
swp_entry_t entry;
|
|
unsigned long offset;
|
|
|
|
entry.val = page_private(page);
|
|
offset = swp_offset(entry);
|
|
|
|
SetPageDirty(page);
|
|
disk->fops->swap_slot_free_notify(sis->bdev,
|
|
offset);
|
|
}
|
|
}
|
|
|
|
static void end_swap_bio_read(struct bio *bio)
|
|
{
|
|
struct page *page = bio->bi_io_vec[0].bv_page;
|
|
|
|
if (bio->bi_error) {
|
|
SetPageError(page);
|
|
ClearPageUptodate(page);
|
|
pr_alert("Read-error on swap-device (%u:%u:%llu)\n",
|
|
imajor(bio->bi_bdev->bd_inode),
|
|
iminor(bio->bi_bdev->bd_inode),
|
|
(unsigned long long)bio->bi_iter.bi_sector);
|
|
goto out;
|
|
}
|
|
|
|
SetPageUptodate(page);
|
|
swap_slot_free_notify(page);
|
|
out:
|
|
unlock_page(page);
|
|
bio_put(bio);
|
|
}
|
|
|
|
int generic_swapfile_activate(struct swap_info_struct *sis,
|
|
struct file *swap_file,
|
|
sector_t *span)
|
|
{
|
|
struct address_space *mapping = swap_file->f_mapping;
|
|
struct inode *inode = mapping->host;
|
|
unsigned blocks_per_page;
|
|
unsigned long page_no;
|
|
unsigned blkbits;
|
|
sector_t probe_block;
|
|
sector_t last_block;
|
|
sector_t lowest_block = -1;
|
|
sector_t highest_block = 0;
|
|
int nr_extents = 0;
|
|
int ret;
|
|
|
|
blkbits = inode->i_blkbits;
|
|
blocks_per_page = PAGE_SIZE >> blkbits;
|
|
|
|
/*
|
|
* Map all the blocks into the extent list. This code doesn't try
|
|
* to be very smart.
|
|
*/
|
|
probe_block = 0;
|
|
page_no = 0;
|
|
last_block = i_size_read(inode) >> blkbits;
|
|
while ((probe_block + blocks_per_page) <= last_block &&
|
|
page_no < sis->max) {
|
|
unsigned block_in_page;
|
|
sector_t first_block;
|
|
|
|
first_block = bmap(inode, probe_block);
|
|
if (first_block == 0)
|
|
goto bad_bmap;
|
|
|
|
/*
|
|
* It must be PAGE_SIZE aligned on-disk
|
|
*/
|
|
if (first_block & (blocks_per_page - 1)) {
|
|
probe_block++;
|
|
goto reprobe;
|
|
}
|
|
|
|
for (block_in_page = 1; block_in_page < blocks_per_page;
|
|
block_in_page++) {
|
|
sector_t block;
|
|
|
|
block = bmap(inode, probe_block + block_in_page);
|
|
if (block == 0)
|
|
goto bad_bmap;
|
|
if (block != first_block + block_in_page) {
|
|
/* Discontiguity */
|
|
probe_block++;
|
|
goto reprobe;
|
|
}
|
|
}
|
|
|
|
first_block >>= (PAGE_SHIFT - blkbits);
|
|
if (page_no) { /* exclude the header page */
|
|
if (first_block < lowest_block)
|
|
lowest_block = first_block;
|
|
if (first_block > highest_block)
|
|
highest_block = first_block;
|
|
}
|
|
|
|
/*
|
|
* We found a PAGE_SIZE-length, PAGE_SIZE-aligned run of blocks
|
|
*/
|
|
ret = add_swap_extent(sis, page_no, 1, first_block);
|
|
if (ret < 0)
|
|
goto out;
|
|
nr_extents += ret;
|
|
page_no++;
|
|
probe_block += blocks_per_page;
|
|
reprobe:
|
|
continue;
|
|
}
|
|
ret = nr_extents;
|
|
*span = 1 + highest_block - lowest_block;
|
|
if (page_no == 0)
|
|
page_no = 1; /* force Empty message */
|
|
sis->max = page_no;
|
|
sis->pages = page_no - 1;
|
|
sis->highest_bit = page_no - 1;
|
|
out:
|
|
return ret;
|
|
bad_bmap:
|
|
pr_err("swapon: swapfile has holes\n");
|
|
ret = -EINVAL;
|
|
goto out;
|
|
}
|
|
|
|
/*
|
|
* We may have stale swap cache pages in memory: notice
|
|
* them here and get rid of the unnecessary final write.
|
|
*/
|
|
int swap_writepage(struct page *page, struct writeback_control *wbc)
|
|
{
|
|
int ret = 0;
|
|
|
|
if (try_to_free_swap(page)) {
|
|
unlock_page(page);
|
|
goto out;
|
|
}
|
|
if (frontswap_store(page) == 0) {
|
|
set_page_writeback(page);
|
|
unlock_page(page);
|
|
end_page_writeback(page);
|
|
goto out;
|
|
}
|
|
ret = __swap_writepage(page, wbc, end_swap_bio_write);
|
|
out:
|
|
return ret;
|
|
}
|
|
|
|
static sector_t swap_page_sector(struct page *page)
|
|
{
|
|
return (sector_t)__page_file_index(page) << (PAGE_SHIFT - 9);
|
|
}
|
|
|
|
int __swap_writepage(struct page *page, struct writeback_control *wbc,
|
|
bio_end_io_t end_write_func)
|
|
{
|
|
struct bio *bio;
|
|
int ret, rw = WRITE;
|
|
struct swap_info_struct *sis = page_swap_info(page);
|
|
|
|
if (sis->flags & SWP_FILE) {
|
|
struct kiocb kiocb;
|
|
struct file *swap_file = sis->swap_file;
|
|
struct address_space *mapping = swap_file->f_mapping;
|
|
struct bio_vec bv = {
|
|
.bv_page = page,
|
|
.bv_len = PAGE_SIZE,
|
|
.bv_offset = 0
|
|
};
|
|
struct iov_iter from;
|
|
|
|
iov_iter_bvec(&from, ITER_BVEC | WRITE, &bv, 1, PAGE_SIZE);
|
|
init_sync_kiocb(&kiocb, swap_file);
|
|
kiocb.ki_pos = page_file_offset(page);
|
|
|
|
set_page_writeback(page);
|
|
unlock_page(page);
|
|
ret = mapping->a_ops->direct_IO(&kiocb, &from, kiocb.ki_pos);
|
|
if (ret == PAGE_SIZE) {
|
|
count_vm_event(PSWPOUT);
|
|
ret = 0;
|
|
} else {
|
|
/*
|
|
* In the case of swap-over-nfs, this can be a
|
|
* temporary failure if the system has limited
|
|
* memory for allocating transmit buffers.
|
|
* Mark the page dirty and avoid
|
|
* rotate_reclaimable_page but rate-limit the
|
|
* messages but do not flag PageError like
|
|
* the normal direct-to-bio case as it could
|
|
* be temporary.
|
|
*/
|
|
set_page_dirty(page);
|
|
ClearPageReclaim(page);
|
|
pr_err_ratelimited("Write error on dio swapfile (%llu)\n",
|
|
page_file_offset(page));
|
|
}
|
|
end_page_writeback(page);
|
|
return ret;
|
|
}
|
|
|
|
ret = bdev_write_page(sis->bdev, swap_page_sector(page), page, wbc);
|
|
if (!ret) {
|
|
count_vm_event(PSWPOUT);
|
|
return 0;
|
|
}
|
|
|
|
ret = 0;
|
|
bio = get_swap_bio(GFP_NOIO, page, end_write_func);
|
|
if (bio == NULL) {
|
|
set_page_dirty(page);
|
|
unlock_page(page);
|
|
ret = -ENOMEM;
|
|
goto out;
|
|
}
|
|
if (wbc->sync_mode == WB_SYNC_ALL)
|
|
rw |= REQ_SYNC;
|
|
count_vm_event(PSWPOUT);
|
|
set_page_writeback(page);
|
|
unlock_page(page);
|
|
submit_bio(rw, bio);
|
|
out:
|
|
return ret;
|
|
}
|
|
|
|
int swap_readpage(struct page *page)
|
|
{
|
|
struct bio *bio;
|
|
int ret = 0;
|
|
struct swap_info_struct *sis = page_swap_info(page);
|
|
|
|
VM_BUG_ON_PAGE(!PageLocked(page), page);
|
|
VM_BUG_ON_PAGE(PageUptodate(page), page);
|
|
if (frontswap_load(page) == 0) {
|
|
SetPageUptodate(page);
|
|
unlock_page(page);
|
|
goto out;
|
|
}
|
|
|
|
if (sis->flags & SWP_FILE) {
|
|
struct file *swap_file = sis->swap_file;
|
|
struct address_space *mapping = swap_file->f_mapping;
|
|
|
|
ret = mapping->a_ops->readpage(swap_file, page);
|
|
if (!ret)
|
|
count_vm_event(PSWPIN);
|
|
return ret;
|
|
}
|
|
|
|
ret = bdev_read_page(sis->bdev, swap_page_sector(page), page);
|
|
if (!ret) {
|
|
if (trylock_page(page)) {
|
|
swap_slot_free_notify(page);
|
|
unlock_page(page);
|
|
}
|
|
|
|
count_vm_event(PSWPIN);
|
|
return 0;
|
|
}
|
|
|
|
ret = 0;
|
|
bio = get_swap_bio(GFP_KERNEL, page, end_swap_bio_read);
|
|
if (bio == NULL) {
|
|
unlock_page(page);
|
|
ret = -ENOMEM;
|
|
goto out;
|
|
}
|
|
count_vm_event(PSWPIN);
|
|
submit_bio(READ, bio);
|
|
out:
|
|
return ret;
|
|
}
|
|
|
|
int swap_set_page_dirty(struct page *page)
|
|
{
|
|
struct swap_info_struct *sis = page_swap_info(page);
|
|
|
|
if (sis->flags & SWP_FILE) {
|
|
struct address_space *mapping = sis->swap_file->f_mapping;
|
|
return mapping->a_ops->set_page_dirty(page);
|
|
} else {
|
|
return __set_page_dirty_no_writeback(page);
|
|
}
|
|
}
|