suspend: simplify block I/O handling

Stop abusing struct page functionality and the swap end_io handler, and
instead add a modified version of the blk-lib.c bio_batch helpers.

Also move the block I/O code into swap.c as they are directly tied into
each other.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Tested-by: Pavel Machek <pavel@ucw.cz>
Tested-by: Ming Lin <mlin@kernel.org>
Acked-by: Pavel Machek <pavel@ucw.cz>
Acked-by: Rafael J. Wysocki <rjw@rjwysocki.net>
Signed-off-by: Jens Axboe <axboe@fb.com>

6 files changed, 122 insertions, 155 deletions

diff --git a/include/linux/swap.h b/include/linux/swap.h
index cee108cbe2d5..38874729dc5f 100644
--- a/include/linux/swap.h
+++ b/include/linux/swap.h
@@ -377,7 +377,6 @@ extern void end_swap_bio_write(struct bio *bio, int err);
 extern int __swap_writepage(struct page *page, struct writeback_control *wbc,
         void (*end_write_func)(struct bio *, int));
 extern int swap_set_page_dirty(struct page *page);
-extern void end_swap_bio_read(struct bio *bio, int err);
 
 int add_swap_extent(struct swap_info_struct *sis, unsigned long start_page,
                 unsigned long nr_pages, sector_t start_block);
diff --git a/kernel/power/Makefile b/kernel/power/Makefile
index 29472bff11ef..cb880a14cc39 100644
--- a/kernel/power/Makefile
+++ b/kernel/power/Makefile
@@ -7,8 +7,7 @@ obj-$(CONFIG_VT_CONSOLE_SLEEP)	+= console.o
 obj-$(CONFIG_FREEZER)           += process.o
 obj-$(CONFIG_SUSPEND)           += suspend.o
 obj-$(CONFIG_PM_TEST_SUSPEND)   += suspend_test.o
-obj-$(CONFIG_HIBERNATION)       += hibernate.o snapshot.o swap.o user.o \
-                                   block_io.o
+obj-$(CONFIG_HIBERNATION)       += hibernate.o snapshot.o swap.o user.o
 obj-$(CONFIG_PM_AUTOSLEEP)      += autosleep.o
 obj-$(CONFIG_PM_WAKELOCKS)      += wakelock.o
 
diff --git a/kernel/power/block_io.c b/kernel/power/block_io.c
deleted file mode 100644
index 9a58bc258810..000000000000
--- a/kernel/power/block_io.c
+++ /dev/null
@@ -1,103 +0,0 @@
-/*
- * This file provides functions for block I/O operations on swap/file.
- *
- * Copyright (C) 1998,2001-2005 Pavel Machek <pavel@ucw.cz>
- * Copyright (C) 2006 Rafael J. Wysocki <rjw@sisk.pl>
- *
- * This file is released under the GPLv2.
- */
-
-#include <linux/bio.h>
-#include <linux/kernel.h>
-#include <linux/pagemap.h>
-#include <linux/swap.h>
-
-#include "power.h"
-
-/**
- *      submit - submit BIO request.
- *      @rw:    READ or WRITE.
- *      @off    physical offset of page.
- *      @page:  page we're reading or writing.
- *      @bio_chain: list of pending biod (for async reading)
- *
- *      Straight from the textbook - allocate and initialize the bio.
- *      If we're reading, make sure the page is marked as dirty.
- *      Then submit it and, if @bio_chain == NULL, wait.
- */
-static int submit(int rw, struct block_device *bdev, sector_t sector,
-                struct page *page, struct bio **bio_chain)
-{
-        const int bio_rw = rw | REQ_SYNC;
-        struct bio *bio;
-
-        bio = bio_alloc(__GFP_WAIT | __GFP_HIGH, 1);
-        bio->bi_iter.bi_sector = sector;
-        bio->bi_bdev = bdev;
-        bio->bi_end_io = end_swap_bio_read;
-
-        if (bio_add_page(bio, page, PAGE_SIZE, 0) < PAGE_SIZE) {
-                printk(KERN_ERR "PM: Adding page to bio failed at %llu\n",
-                        (unsigned long long)sector);
-                bio_put(bio);
-                return -EFAULT;
-        }
-
-        lock_page(page);
-        bio_get(bio);
-
-        if (bio_chain == NULL) {
-                submit_bio(bio_rw, bio);
-                wait_on_page_locked(page);
-                if (rw == READ)
-                        bio_set_pages_dirty(bio);
-                bio_put(bio);
-        } else {
-                if (rw == READ)
-                        get_page(page); /* These pages are freed later */
-                bio->bi_private = *bio_chain;
-                *bio_chain = bio;
-                submit_bio(bio_rw, bio);
-        }
-        return 0;
-}
-
-int hib_bio_read_page(pgoff_t page_off, void *addr, struct bio **bio_chain)
-{
-        return submit(READ, hib_resume_bdev, page_off * (PAGE_SIZE >> 9),
-                        virt_to_page(addr), bio_chain);
-}
-
-int hib_bio_write_page(pgoff_t page_off, void *addr, struct bio **bio_chain)
-{
-        return submit(WRITE, hib_resume_bdev, page_off * (PAGE_SIZE >> 9),
-                        virt_to_page(addr), bio_chain);
-}
-
-int hib_wait_on_bio_chain(struct bio **bio_chain)
-{
-        struct bio *bio;
-        struct bio *next_bio;
-        int ret = 0;
-
-        if (bio_chain == NULL)
-                return 0;
-
-        bio = *bio_chain;
-        if (bio == NULL)
-                return 0;
-        while (bio) {
-                struct page *page;
-
-                next_bio = bio->bi_private;
-                page = bio->bi_io_vec[0].bv_page;
-                wait_on_page_locked(page);
-                if (!PageUptodate(page) || PageError(page))
-                        ret = -EIO;
-                put_page(page);
-                bio_put(bio);
-                bio = next_bio;
-        }
-        *bio_chain = NULL;
-        return ret;
-}
diff --git a/kernel/power/power.h b/kernel/power/power.h
index ce9b8328a689..caadb566e82b 100644
--- a/kernel/power/power.h
+++ b/kernel/power/power.h
@@ -163,15 +163,6 @@ extern void swsusp_close(fmode_t);
 extern int swsusp_unmark(void);
 #endif
 
-/* kernel/power/block_io.c */
-extern struct block_device *hib_resume_bdev;
-
-extern int hib_bio_read_page(pgoff_t page_off, void *addr,
-                struct bio **bio_chain);
-extern int hib_bio_write_page(pgoff_t page_off, void *addr,
-                struct bio **bio_chain);
-extern int hib_wait_on_bio_chain(struct bio **bio_chain);
-
 struct timeval;
 /* kernel/power/swsusp.c */
 extern void swsusp_show_speed(ktime_t, ktime_t, unsigned int, char *);
diff --git a/kernel/power/swap.c b/kernel/power/swap.c
index 570aff817543..2f30ca91e4fa 100644
--- a/kernel/power/swap.c
+++ b/kernel/power/swap.c
@@ -212,7 +212,84 @@ int swsusp_swap_in_use(void)
  */
 
 static unsigned short root_swap = 0xffff;
-struct block_device *hib_resume_bdev;
+static struct block_device *hib_resume_bdev;
+
+struct hib_bio_batch {
+        atomic_t                count;
+        wait_queue_head_t       wait;
+        int                     error;
+};
+
+static void hib_init_batch(struct hib_bio_batch *hb)
+{
+        atomic_set(&hb->count, 0);
+        init_waitqueue_head(&hb->wait);
+        hb->error = 0;
+}
+
+static void hib_end_io(struct bio *bio, int error)
+{
+        struct hib_bio_batch *hb = bio->bi_private;
+        const int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
+        struct page *page = bio->bi_io_vec[0].bv_page;
+
+        if (!uptodate || error) {
+                printk(KERN_ALERT "Read-error on swap-device (%u:%u:%Lu)\n",
+                                imajor(bio->bi_bdev->bd_inode),
+                                iminor(bio->bi_bdev->bd_inode),
+                                (unsigned long long)bio->bi_iter.bi_sector);
+
+                if (!error)
+                        error = -EIO;
+        }
+
+        if (bio_data_dir(bio) == WRITE)
+                put_page(page);
+
+        if (error && !hb->error)
+                hb->error = error;
+        if (atomic_dec_and_test(&hb->count))
+                wake_up(&hb->wait);
+
+        bio_put(bio);
+}
+
+static int hib_submit_io(int rw, pgoff_t page_off, void *addr,
+                struct hib_bio_batch *hb)
+{
+        struct page *page = virt_to_page(addr);
+        struct bio *bio;
+        int error = 0;
+
+        bio = bio_alloc(__GFP_WAIT | __GFP_HIGH, 1);
+        bio->bi_iter.bi_sector = page_off * (PAGE_SIZE >> 9);
+        bio->bi_bdev = hib_resume_bdev;
+
+        if (bio_add_page(bio, page, PAGE_SIZE, 0) < PAGE_SIZE) {
+                printk(KERN_ERR "PM: Adding page to bio failed at %llu\n",
+                        (unsigned long long)bio->bi_iter.bi_sector);
+                bio_put(bio);
+                return -EFAULT;
+        }
+
+        if (hb) {
+                bio->bi_end_io = hib_end_io;
+                bio->bi_private = hb;
+                atomic_inc(&hb->count);
+                submit_bio(rw, bio);
+        } else {
+                error = submit_bio_wait(rw, bio);
+                bio_put(bio);
+        }
+
+        return error;
+}
+
+static int hib_wait_io(struct hib_bio_batch *hb)
+{
+        wait_event(hb->wait, atomic_read(&hb->count) == 0);
+        return hb->error;
+}
 
 /*
  * Saving part
@@ -222,7 +299,7 @@ static int mark_swapfiles(struct swap_map_handle *handle, unsigned int flags)
 {
         int error;
 
-        hib_bio_read_page(swsusp_resume_block, swsusp_header, NULL);
+        hib_submit_io(READ_SYNC, swsusp_resume_block, swsusp_header, NULL);
         if (!memcmp("SWAP-SPACE",swsusp_header->sig, 10) ||
             !memcmp("SWAPSPACE2",swsusp_header->sig, 10)) {
                 memcpy(swsusp_header->orig_sig,swsusp_header->sig, 10);
@@ -231,7 +308,7 @@ static int mark_swapfiles(struct swap_map_handle *handle, unsigned int flags)
                 swsusp_header->flags = flags;
                 if (flags & SF_CRC32_MODE)
                         swsusp_header->crc32 = handle->crc32;
-                error = hib_bio_write_page(swsusp_resume_block,
+                error = hib_submit_io(WRITE_SYNC, swsusp_resume_block,
                                         swsusp_header, NULL);
         } else {
                 printk(KERN_ERR "PM: Swap header not found!\n");
@@ -271,10 +348,10 @@ static int swsusp_swap_check(void)
  *      write_page - Write one page to given swap location.
  *      @buf:           Address we're writing.
  *      @offset:        Offset of the swap page we're writing to.
- *      @bio_chain:     Link the next write BIO here
+ *      @hb:            bio completion batch
  */
 
-static int write_page(void *buf, sector_t offset, struct bio **bio_chain)
+static int write_page(void *buf, sector_t offset, struct hib_bio_batch *hb)
 {
         void *src;
         int ret;
@@ -282,13 +359,13 @@ static int write_page(void *buf, sector_t offset, struct bio **bio_chain)
         if (!offset)
                 return -ENOSPC;
 
-        if (bio_chain) {
+        if (hb) {
                 src = (void *)__get_free_page(__GFP_WAIT | __GFP_NOWARN |
                                               __GFP_NORETRY);
                 if (src) {
                         copy_page(src, buf);
                 } else {
-                        ret = hib_wait_on_bio_chain(bio_chain); /* Free pages */
+                        ret = hib_wait_io(hb); /* Free pages */
                         if (ret)
                                 return ret;
                         src = (void *)__get_free_page(__GFP_WAIT |
@@ -298,14 +375,14 @@ static int write_page(void *buf, sector_t offset, struct bio **bio_chain)
                                 copy_page(src, buf);
                         } else {
                                 WARN_ON_ONCE(1);
-                                bio_chain = NULL;       /* Go synchronous */
+                                hb = NULL;      /* Go synchronous */
                                 src = buf;
                         }
                 }
         } else {
                 src = buf;
         }
-        return hib_bio_write_page(offset, src, bio_chain);
+        return hib_submit_io(WRITE_SYNC, offset, src, hb);
 }
 
 static void release_swap_writer(struct swap_map_handle *handle)
@@ -348,7 +425,7 @@ err_close:
 }
 
 static int swap_write_page(struct swap_map_handle *handle, void *buf,
-                                struct bio **bio_chain)
+                struct hib_bio_batch *hb)
 {
         int error = 0;
         sector_t offset;
@@ -356,7 +433,7 @@ static int swap_write_page(struct swap_map_handle *handle, void *buf,
         if (!handle->cur)
                 return -EINVAL;
         offset = alloc_swapdev_block(root_swap);
-        error = write_page(buf, offset, bio_chain);
+        error = write_page(buf, offset, hb);
         if (error)
                 return error;
         handle->cur->entries[handle->k++] = offset;
@@ -365,15 +442,15 @@ static int swap_write_page(struct swap_map_handle *handle, void *buf,
                 if (!offset)
                         return -ENOSPC;
                 handle->cur->next_swap = offset;
-                error = write_page(handle->cur, handle->cur_swap, bio_chain);
+                error = write_page(handle->cur, handle->cur_swap, hb);
                 if (error)
                         goto out;
                 clear_page(handle->cur);
                 handle->cur_swap = offset;
                 handle->k = 0;
 
-                if (bio_chain && low_free_pages() <= handle->reqd_free_pages) {
-                        error = hib_wait_on_bio_chain(bio_chain);
+                if (hb && low_free_pages() <= handle->reqd_free_pages) {
+                        error = hib_wait_io(hb);
                         if (error)
                                 goto out;
                         /*
@@ -445,23 +522,24 @@ static int save_image(struct swap_map_handle *handle,
         int ret;
         int nr_pages;
         int err2;
-        struct bio *bio;
+        struct hib_bio_batch hb;
         ktime_t start;
         ktime_t stop;
 
+        hib_init_batch(&hb);
+
         printk(KERN_INFO "PM: Saving image data pages (%u pages)...\n",
                 nr_to_write);
         m = nr_to_write / 10;
         if (!m)
                 m = 1;
         nr_pages = 0;
-        bio = NULL;
         start = ktime_get();
         while (1) {
                 ret = snapshot_read_next(snapshot);
                 if (ret <= 0)
                         break;
-                ret = swap_write_page(handle, data_of(*snapshot), &bio);
+                ret = swap_write_page(handle, data_of(*snapshot), &hb);
                 if (ret)
                         break;
                 if (!(nr_pages % m))
@@ -469,7 +547,7 @@ static int save_image(struct swap_map_handle *handle,
                                nr_pages / m * 10);
                 nr_pages++;
         }
-        err2 = hib_wait_on_bio_chain(&bio);
+        err2 = hib_wait_io(&hb);
         stop = ktime_get();
         if (!ret)
                 ret = err2;
@@ -580,7 +658,7 @@ static int save_image_lzo(struct swap_map_handle *handle,
         int ret = 0;
         int nr_pages;
         int err2;
-        struct bio *bio;
+        struct hib_bio_batch hb;
         ktime_t start;
         ktime_t stop;
         size_t off;
@@ -589,6 +667,8 @@ static int save_image_lzo(struct swap_map_handle *handle,
         struct cmp_data *data = NULL;
         struct crc_data *crc = NULL;
 
+        hib_init_batch(&hb);
+
         /*
          * We'll limit the number of threads for compression to limit memory
          * footprint.
@@ -674,7 +754,6 @@ static int save_image_lzo(struct swap_map_handle *handle,
         if (!m)
                 m = 1;
         nr_pages = 0;
-        bio = NULL;
         start = ktime_get();
         for (;;) {
                 for (thr = 0; thr < nr_threads; thr++) {
@@ -748,7 +827,7 @@ static int save_image_lzo(struct swap_map_handle *handle,
                              off += PAGE_SIZE) {
                                 memcpy(page, data[thr].cmp + off, PAGE_SIZE);
 
-                                ret = swap_write_page(handle, page, &bio);
+                                ret = swap_write_page(handle, page, &hb);
                                 if (ret)
                                         goto out_finish;
                         }
@@ -759,7 +838,7 @@ static int save_image_lzo(struct swap_map_handle *handle,
         }
 
 out_finish:
-        err2 = hib_wait_on_bio_chain(&bio);
+        err2 = hib_wait_io(&hb);
         stop = ktime_get();
         if (!ret)
                 ret = err2;
@@ -906,7 +985,7 @@ static int get_swap_reader(struct swap_map_handle *handle,
                         return -ENOMEM;
                 }
 
-                error = hib_bio_read_page(offset, tmp->map, NULL);
+                error = hib_submit_io(READ_SYNC, offset, tmp->map, NULL);
                 if (error) {
                         release_swap_reader(handle);
                         return error;
@@ -919,7 +998,7 @@ static int get_swap_reader(struct swap_map_handle *handle,
 }
 
 static int swap_read_page(struct swap_map_handle *handle, void *buf,
-                                struct bio **bio_chain)
+                struct hib_bio_batch *hb)
 {
         sector_t offset;
         int error;
@@ -930,7 +1009,7 @@ static int swap_read_page(struct swap_map_handle *handle, void *buf,
         offset = handle->cur->entries[handle->k];
         if (!offset)
                 return -EFAULT;
-        error = hib_bio_read_page(offset, buf, bio_chain);
+        error = hib_submit_io(READ_SYNC, offset, buf, hb);
         if (error)
                 return error;
         if (++handle->k >= MAP_PAGE_ENTRIES) {
@@ -968,27 +1047,28 @@ static int load_image(struct swap_map_handle *handle,
         int ret = 0;
         ktime_t start;
         ktime_t stop;
-        struct bio *bio;
+        struct hib_bio_batch hb;
         int err2;
         unsigned nr_pages;
 
+        hib_init_batch(&hb);
+
         printk(KERN_INFO "PM: Loading image data pages (%u pages)...\n",
                 nr_to_read);
         m = nr_to_read / 10;
         if (!m)
                 m = 1;
         nr_pages = 0;
-        bio = NULL;
         start = ktime_get();
         for ( ; ; ) {
                 ret = snapshot_write_next(snapshot);
                 if (ret <= 0)
                         break;
-                ret = swap_read_page(handle, data_of(*snapshot), &bio);
+                ret = swap_read_page(handle, data_of(*snapshot), &hb);
                 if (ret)
                         break;
                 if (snapshot->sync_read)
-                        ret = hib_wait_on_bio_chain(&bio);
+                        ret = hib_wait_io(&hb);
                 if (ret)
                         break;
                 if (!(nr_pages % m))
@@ -996,7 +1076,7 @@ static int load_image(struct swap_map_handle *handle,
                                nr_pages / m * 10);
                 nr_pages++;
         }
-        err2 = hib_wait_on_bio_chain(&bio);
+        err2 = hib_wait_io(&hb);
         stop = ktime_get();
         if (!ret)
                 ret = err2;
@@ -1067,7 +1147,7 @@ static int load_image_lzo(struct swap_map_handle *handle,
         unsigned int m;
         int ret = 0;
         int eof = 0;
-        struct bio *bio;
+        struct hib_bio_batch hb;
         ktime_t start;
         ktime_t stop;
         unsigned nr_pages;
@@ -1080,6 +1160,8 @@ static int load_image_lzo(struct swap_map_handle *handle,
         struct dec_data *data = NULL;
         struct crc_data *crc = NULL;
 
+        hib_init_batch(&hb);
+
         /*
          * We'll limit the number of threads for decompression to limit memory
          * footprint.
@@ -1190,7 +1272,6 @@ static int load_image_lzo(struct swap_map_handle *handle,
         if (!m)
                 m = 1;
         nr_pages = 0;
-        bio = NULL;
         start = ktime_get();
 
         ret = snapshot_write_next(snapshot);
@@ -1199,7 +1280,7 @@ static int load_image_lzo(struct swap_map_handle *handle,
 
         for(;;) {
                 for (i = 0; !eof && i < want; i++) {
-                        ret = swap_read_page(handle, page[ring], &bio);
+                        ret = swap_read_page(handle, page[ring], &hb);
                         if (ret) {
                                 /*
                                  * On real read error, finish. On end of data,
@@ -1226,7 +1307,7 @@ static int load_image_lzo(struct swap_map_handle *handle,
                         if (!asked)
                                 break;
 
-                        ret = hib_wait_on_bio_chain(&bio);
+                        ret = hib_wait_io(&hb);
                         if (ret)
                                 goto out_finish;
                         have += asked;
@@ -1281,7 +1362,7 @@ static int load_image_lzo(struct swap_map_handle *handle,
                  * Wait for more data while we are decompressing.
                  */
                 if (have < LZO_CMP_PAGES && asked) {
-                        ret = hib_wait_on_bio_chain(&bio);
+                        ret = hib_wait_io(&hb);
                         if (ret)
                                 goto out_finish;
                         have += asked;
@@ -1430,7 +1511,7 @@ int swsusp_check(void)
         if (!IS_ERR(hib_resume_bdev)) {
                 set_blocksize(hib_resume_bdev, PAGE_SIZE);
                 clear_page(swsusp_header);
-                error = hib_bio_read_page(swsusp_resume_block,
+                error = hib_submit_io(READ_SYNC, swsusp_resume_block,
                                         swsusp_header, NULL);
                 if (error)
                         goto put;
@@ -1438,7 +1519,7 @@ int swsusp_check(void)
                 if (!memcmp(HIBERNATE_SIG, swsusp_header->sig, 10)) {
                         memcpy(swsusp_header->sig, swsusp_header->orig_sig, 10);
                         /* Reset swap signature now */
-                        error = hib_bio_write_page(swsusp_resume_block,
+                        error = hib_submit_io(WRITE_SYNC, swsusp_resume_block,
                                                 swsusp_header, NULL);
                 } else {
                         error = -EINVAL;
@@ -1482,10 +1563,10 @@ int swsusp_unmark(void)
 {
         int error;
 
-        hib_bio_read_page(swsusp_resume_block, swsusp_header, NULL);
+        hib_submit_io(READ_SYNC, swsusp_resume_block, swsusp_header, NULL);
         if (!memcmp(HIBERNATE_SIG,swsusp_header->sig, 10)) {
                 memcpy(swsusp_header->sig,swsusp_header->orig_sig, 10);
-                error = hib_bio_write_page(swsusp_resume_block,
+                error = hib_submit_io(WRITE_SYNC, swsusp_resume_block,
                                         swsusp_header, NULL);
         } else {
                 printk(KERN_ERR "PM: Cannot find swsusp signature!\n");
diff --git a/mm/page_io.c b/mm/page_io.c
index 6424869e275e..520baa4b04d7 100644
--- a/mm/page_io.c
+++ b/mm/page_io.c
@@ -69,7 +69,7 @@ void end_swap_bio_write(struct bio *bio, int err)
         bio_put(bio);
 }
 
-void end_swap_bio_read(struct bio *bio, int err)
+static void end_swap_bio_read(struct bio *bio, int err)
 {
         const int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
         struct page *page = bio->bi_io_vec[0].bv_page;