PM / Hibernate: Group swap ops

Move all the swap processing into one function. It will make swap
calls from a non-swap code easier.

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

1 files changed, 74 insertions, 43 deletions

diff --git a/kernel/power/swap.c b/kernel/power/swap.c
index 63e80628a326..b0bb21778391 100644
--- a/kernel/power/swap.c
+++ b/kernel/power/swap.c
@@ -208,9 +208,10 @@ static int mark_swapfiles(struct swap_map_handle *handle, unsigned int flags)
 /**
  *      swsusp_swap_check - check if the resume device is a swap device
  *      and get its index (if so)
+ *
+ *      This is called before saving image
  */
-
-static int swsusp_swap_check(void) /* This is called before saving image */
+static int swsusp_swap_check(void)
 {
         int res;
 
@@ -269,17 +270,33 @@ static void release_swap_writer(struct swap_map_handle *handle)
 
 static int get_swap_writer(struct swap_map_handle *handle)
 {
+        int ret;
+
+        ret = swsusp_swap_check();
+        if (ret) {
+                if (ret != -ENOSPC)
+                        printk(KERN_ERR "PM: Cannot find swap device, try "
+                                        "swapon -a.\n");
+                return ret;
+        }
         handle->cur = (struct swap_map_page *)get_zeroed_page(GFP_KERNEL);
-        if (!handle->cur)
-                return -ENOMEM;
+        if (!handle->cur) {
+                ret = -ENOMEM;
+                goto err_close;
+        }
         handle->cur_swap = alloc_swapdev_block(root_swap);
         if (!handle->cur_swap) {
-                release_swap_writer(handle);
-                return -ENOSPC;
+                ret = -ENOSPC;
+                goto err_rel;
         }
         handle->k = 0;
         handle->first_sector = handle->cur_swap;
         return 0;
+err_rel:
+        release_swap_writer(handle);
+err_close:
+        swsusp_close(FMODE_WRITE);
+        return ret;
 }
 
 static int swap_write_page(struct swap_map_handle *handle, void *buf,
@@ -322,6 +339,24 @@ static int flush_swap_writer(struct swap_map_handle *handle)
                 return -EINVAL;
 }
 
+static int swap_writer_finish(struct swap_map_handle *handle,
+                unsigned int flags, int error)
+{
+        if (!error) {
+                flush_swap_writer(handle);
+                printk(KERN_INFO "PM: S");
+                error = mark_swapfiles(handle, flags);
+                printk("|\n");
+        }
+
+        if (error)
+                free_all_swap_pages(root_swap);
+        release_swap_writer(handle);
+        swsusp_close(FMODE_WRITE);
+
+        return error;
+}
+
 /**
  *      save_image - save the suspend image data
  */
@@ -399,48 +434,34 @@ int swsusp_write(unsigned int flags)
         struct swap_map_handle handle;
         struct snapshot_handle snapshot;
         struct swsusp_info *header;
+        unsigned long pages;
         int error;
 
-        error = swsusp_swap_check();
+        pages = snapshot_get_image_size();
+        error = get_swap_writer(&handle);
         if (error) {
-                printk(KERN_ERR "PM: Cannot find swap device, try "
-                                "swapon -a.\n");
+                printk(KERN_ERR "PM: Cannot get swap writer\n");
                 return error;
         }
+        if (!enough_swap(pages)) {
+                printk(KERN_ERR "PM: Not enough free swap\n");
+                error = -ENOSPC;
+                goto out_finish;
+        }
         memset(&snapshot, 0, sizeof(struct snapshot_handle));
         error = snapshot_read_next(&snapshot);
         if (error < PAGE_SIZE) {
                 if (error >= 0)
                         error = -EFAULT;
 
-                goto out;
+                goto out_finish;
         }
         header = (struct swsusp_info *)data_of(snapshot);
-        if (!enough_swap(header->pages)) {
-                printk(KERN_ERR "PM: Not enough free swap\n");
-                error = -ENOSPC;
-                goto out;
-        }
-        error = get_swap_writer(&handle);
-        if (!error) {
-                error = swap_write_page(&handle, header, NULL);
-                if (!error)
-                        error = save_image(&handle, &snapshot,
-                                        header->pages - 1);
-
-                if (!error) {
-                        flush_swap_writer(&handle);
-                        printk(KERN_INFO "PM: S");
-                        error = mark_swapfiles(&handle, flags);
-                        printk("|\n");
-                }
-        }
-        if (error)
-                free_all_swap_pages(root_swap);
-
-        release_swap_writer(&handle);
- out:
-        swsusp_close(FMODE_WRITE);
+        error = swap_write_page(&handle, header, NULL);
+        if (!error)
+                error = save_image(&handle, &snapshot, pages - 1);
+out_finish:
+        error = swap_writer_finish(&handle, flags, error);
         return error;
 }
 
@@ -456,18 +477,21 @@ static void release_swap_reader(struct swap_map_handle *handle)
         handle->cur = NULL;
 }
 
-static int get_swap_reader(struct swap_map_handle *handle, sector_t start)
+static int get_swap_reader(struct swap_map_handle *handle,
+                unsigned int *flags_p)
 {
         int error;
 
-        if (!start)
+        *flags_p = swsusp_header->flags;
+
+        if (!swsusp_header->image) /* how can this happen? */
                 return -EINVAL;
 
         handle->cur = (struct swap_map_page *)get_zeroed_page(__GFP_WAIT | __GFP_HIGH);
         if (!handle->cur)
                 return -ENOMEM;
 
-        error = hib_bio_read_page(start, handle->cur, NULL);
+        error = hib_bio_read_page(swsusp_header->image, handle->cur, NULL);
         if (error) {
                 release_swap_reader(handle);
                 return error;
@@ -502,6 +526,13 @@ static int swap_read_page(struct swap_map_handle *handle, void *buf,
         return error;
 }
 
+static int swap_reader_finish(struct swap_map_handle *handle)
+{
+        release_swap_reader(handle);
+
+        return 0;
+}
+
 /**
  *      load_image - load the image using the swap map handle
  *      @handle and the snapshot handle @snapshot
@@ -571,20 +602,20 @@ int swsusp_read(unsigned int *flags_p)
         struct snapshot_handle snapshot;
         struct swsusp_info *header;
 
-        *flags_p = swsusp_header->flags;
-
         memset(&snapshot, 0, sizeof(struct snapshot_handle));
         error = snapshot_write_next(&snapshot);
         if (error < PAGE_SIZE)
                 return error < 0 ? error : -EFAULT;
         header = (struct swsusp_info *)data_of(snapshot);
-        error = get_swap_reader(&handle, swsusp_header->image);
+        error = get_swap_reader(&handle, flags_p);
+        if (error)
+                goto end;
         if (!error)
                 error = swap_read_page(&handle, header, NULL);
         if (!error)
                 error = load_image(&handle, &snapshot, header->pages - 1);
-        release_swap_reader(&handle);
-
+        swap_reader_finish(&handle);
+end:
         if (!error)
                 pr_debug("PM: Image successfully loaded\n");
         else