PM / Hibernate: Separate block_io

Move block I/O operations to a separate file. It is because it will
be used later not only by the swap writer.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>

4 files changed, 139 insertions, 112 deletions

diff --git a/kernel/power/Makefile b/kernel/power/Makefile
index 43191815f874..524e058dcf06 100644
--- a/kernel/power/Makefile
+++ b/kernel/power/Makefile
@@ -8,7 +8,8 @@ obj-$(CONFIG_PM_SLEEP)		+= console.o
 obj-$(CONFIG_FREEZER)           += process.o
 obj-$(CONFIG_SUSPEND)           += suspend.o
 obj-$(CONFIG_PM_TEST_SUSPEND)   += suspend_test.o
-obj-$(CONFIG_HIBERNATION)       += hibernate.o snapshot.o swap.o user.o
+obj-$(CONFIG_HIBERNATION)       += hibernate.o snapshot.o swap.o user.o \
+                                   block_io.o
 obj-$(CONFIG_HIBERNATION_NVS)   += hibernate_nvs.o
 
 obj-$(CONFIG_MAGIC_SYSRQ)       += poweroff.o
diff --git a/kernel/power/block_io.c b/kernel/power/block_io.c
new file mode 100644
index 000000000000..2a2f8aed8e59
--- /dev/null
+++ b/kernel/power/block_io.c
@@ -0,0 +1,103 @@
+/*
+ * 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 | (1 << BIO_RW_SYNCIO) | (1 << BIO_RW_UNPLUG);
+        struct bio *bio;
+
+        bio = bio_alloc(__GFP_WAIT | __GFP_HIGH, 1);
+        bio->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 %ld\n",
+                        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 b1e207dde1c2..006270fe382d 100644
--- a/kernel/power/power.h
+++ b/kernel/power/power.h
@@ -142,6 +142,15 @@ extern int swsusp_read(unsigned int *flags_p);
 extern int swsusp_write(unsigned int flags);
 extern void swsusp_close(fmode_t);
 
+/* 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(struct timeval *, struct timeval *,
diff --git a/kernel/power/swap.c b/kernel/power/swap.c
index 7f2a17e4067b..1b1ab6fcf386 100644
--- a/kernel/power/swap.c
+++ b/kernel/power/swap.c
@@ -145,93 +145,7 @@ int swsusp_swap_in_use(void)
  */
 
 static unsigned short root_swap = 0xffff;
-static struct block_device *resume_bdev;
-
-/**
- *      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, pgoff_t page_off, struct page *page,
-                        struct bio **bio_chain)
-{
-        const int bio_rw = rw | (1 << BIO_RW_SYNCIO) | (1 << BIO_RW_UNPLUG);
-        struct bio *bio;
-
-        bio = bio_alloc(__GFP_WAIT | __GFP_HIGH, 1);
-        bio->bi_sector = page_off * (PAGE_SIZE >> 9);
-        bio->bi_bdev = resume_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 %ld\n",
-                        page_off);
-                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;
-}
-
-static int bio_read_page(pgoff_t page_off, void *addr, struct bio **bio_chain)
-{
-        return submit(READ, page_off, virt_to_page(addr), bio_chain);
-}
-
-static int bio_write_page(pgoff_t page_off, void *addr, struct bio **bio_chain)
-{
-        return submit(WRITE, page_off, virt_to_page(addr), bio_chain);
-}
-
-static int 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;
-}
+struct block_device *hib_resume_bdev;
 
 /*
  * Saving part
@@ -241,14 +155,14 @@ static int mark_swapfiles(sector_t start, unsigned int flags)
 {
         int error;
 
-        bio_read_page(swsusp_resume_block, swsusp_header, NULL);
+        hib_bio_read_page(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);
                 memcpy(swsusp_header->sig,SWSUSP_SIG, 10);
                 swsusp_header->image = start;
                 swsusp_header->flags = flags;
-                error = bio_write_page(swsusp_resume_block,
+                error = hib_bio_write_page(swsusp_resume_block,
                                         swsusp_header, NULL);
         } else {
                 printk(KERN_ERR "PM: Swap header not found!\n");
@@ -267,18 +181,18 @@ static int swsusp_swap_check(void) /* This is called before saving image */
         int res;
 
         res = swap_type_of(swsusp_resume_device, swsusp_resume_block,
-                        &resume_bdev);
+                        &hib_resume_bdev);
         if (res < 0)
                 return res;
 
         root_swap = res;
-        res = blkdev_get(resume_bdev, FMODE_WRITE);
+        res = blkdev_get(hib_resume_bdev, FMODE_WRITE);
         if (res)
                 return res;
 
-        res = set_blocksize(resume_bdev, PAGE_SIZE);
+        res = set_blocksize(hib_resume_bdev, PAGE_SIZE);
         if (res < 0)
-                blkdev_put(resume_bdev, FMODE_WRITE);
+                blkdev_put(hib_resume_bdev, FMODE_WRITE);
 
         return res;
 }
@@ -309,7 +223,7 @@ static int write_page(void *buf, sector_t offset, struct bio **bio_chain)
         } else {
                 src = buf;
         }
-        return bio_write_page(offset, src, bio_chain);
+        return hib_bio_write_page(offset, src, bio_chain);
 }
 
 /*
@@ -380,7 +294,7 @@ static int swap_write_page(struct swap_map_handle *handle, void *buf,
                 return error;
         handle->cur->entries[handle->k++] = offset;
         if (handle->k >= MAP_PAGE_ENTRIES) {
-                error = wait_on_bio_chain(bio_chain);
+                error = hib_wait_on_bio_chain(bio_chain);
                 if (error)
                         goto out;
                 offset = alloc_swapdev_block(root_swap);
@@ -441,7 +355,7 @@ static int save_image(struct swap_map_handle *handle,
                         printk(KERN_CONT "\b\b\b\b%3d%%", nr_pages / m);
                 nr_pages++;
         }
-        err2 = wait_on_bio_chain(&bio);
+        err2 = hib_wait_on_bio_chain(&bio);
         do_gettimeofday(&stop);
         if (!ret)
                 ret = err2;
@@ -553,7 +467,7 @@ static int get_swap_reader(struct swap_map_handle *handle, sector_t start)
         if (!handle->cur)
                 return -ENOMEM;
 
-        error = bio_read_page(start, handle->cur, NULL);
+        error = hib_bio_read_page(start, handle->cur, NULL);
         if (error) {
                 release_swap_reader(handle);
                 return error;
@@ -573,17 +487,17 @@ static int swap_read_page(struct swap_map_handle *handle, void *buf,
         offset = handle->cur->entries[handle->k];
         if (!offset)
                 return -EFAULT;
-        error = bio_read_page(offset, buf, bio_chain);
+        error = hib_bio_read_page(offset, buf, bio_chain);
         if (error)
                 return error;
         if (++handle->k >= MAP_PAGE_ENTRIES) {
-                error = wait_on_bio_chain(bio_chain);
+                error = hib_wait_on_bio_chain(bio_chain);
                 handle->k = 0;
                 offset = handle->cur->next_swap;
                 if (!offset)
                         release_swap_reader(handle);
                 else if (!error)
-                        error = bio_read_page(offset, handle->cur, NULL);
+                        error = hib_bio_read_page(offset, handle->cur, NULL);
         }
         return error;
 }
@@ -622,14 +536,14 @@ static int load_image(struct swap_map_handle *handle,
                 if (error)
                         break;
                 if (snapshot->sync_read)
-                        error = wait_on_bio_chain(&bio);
+                        error = hib_wait_on_bio_chain(&bio);
                 if (error)
                         break;
                 if (!(nr_pages % m))
                         printk("\b\b\b\b%3d%%", nr_pages / m);
                 nr_pages++;
         }
-        err2 = wait_on_bio_chain(&bio);
+        err2 = hib_wait_on_bio_chain(&bio);
         do_gettimeofday(&stop);
         if (!error)
                 error = err2;
@@ -686,11 +600,11 @@ int swsusp_check(void)
 {
         int error;
 
-        resume_bdev = open_by_devnum(swsusp_resume_device, FMODE_READ);
-        if (!IS_ERR(resume_bdev)) {
-                set_blocksize(resume_bdev, PAGE_SIZE);
+        hib_resume_bdev = open_by_devnum(swsusp_resume_device, FMODE_READ);
+        if (!IS_ERR(hib_resume_bdev)) {
+                set_blocksize(hib_resume_bdev, PAGE_SIZE);
                 memset(swsusp_header, 0, PAGE_SIZE);
-                error = bio_read_page(swsusp_resume_block,
+                error = hib_bio_read_page(swsusp_resume_block,
                                         swsusp_header, NULL);
                 if (error)
                         goto put;
@@ -698,7 +612,7 @@ int swsusp_check(void)
                 if (!memcmp(SWSUSP_SIG, swsusp_header->sig, 10)) {
                         memcpy(swsusp_header->sig, swsusp_header->orig_sig, 10);
                         /* Reset swap signature now */
-                        error = bio_write_page(swsusp_resume_block,
+                        error = hib_bio_write_page(swsusp_resume_block,
                                                 swsusp_header, NULL);
                 } else {
                         error = -EINVAL;
@@ -706,11 +620,11 @@ int swsusp_check(void)
 
 put:
                 if (error)
-                        blkdev_put(resume_bdev, FMODE_READ);
+                        blkdev_put(hib_resume_bdev, FMODE_READ);
                 else
                         pr_debug("PM: Signature found, resuming\n");
         } else {
-                error = PTR_ERR(resume_bdev);
+                error = PTR_ERR(hib_resume_bdev);
         }
 
         if (error)
@@ -725,12 +639,12 @@ put:
 
 void swsusp_close(fmode_t mode)
 {
-        if (IS_ERR(resume_bdev)) {
+        if (IS_ERR(hib_resume_bdev)) {
                 pr_debug("PM: Image device not initialised\n");
                 return;
         }
 
-        blkdev_put(resume_bdev, mode);
+        blkdev_put(hib_resume_bdev, mode);
 }
 
 static int swsusp_header_init(void)