md: Move sb writer loop to its own function

Preparatory patch for optimal I/O size calculation. Move the sb writer
loop routine into its own function for clarity.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jon Derrick <jonathan.derrick@linux.dev>
Signed-off-by: Song Liu <song@kernel.org>
Link: https://lore.kernel.org/r/20230224183323.638-2-jonathan.derrick@linux.dev

diff --git a/drivers/md/md-bitmap.c b/drivers/md/md-bitmap.c
index e7cc6ba..cdc61e6 100644 (file)
--- a/drivers/md/md-bitmap.c
+++ b/drivers/md/md-bitmap.c
@@ -209,76 +209,81 @@ static struct md_rdev *next_active_rdev(struct md_rdev *rdev, struct mddev *mdde
        return NULL;
 }
 
-static int write_sb_page(struct bitmap *bitmap, struct page *page, int wait)
+static int __write_sb_page(struct md_rdev *rdev, struct bitmap *bitmap,
+                          struct page *page)
 {
-       struct md_rdev *rdev;
        struct block_device *bdev;
        struct mddev *mddev = bitmap->mddev;
        struct bitmap_storage *store = &bitmap->storage;
+       loff_t offset = mddev->bitmap_info.offset;
+       int size = PAGE_SIZE;
+
+       bdev = (rdev->meta_bdev) ? rdev->meta_bdev : rdev->bdev;
+       if (page->index == store->file_pages - 1) {
+               int last_page_size = store->bytes & (PAGE_SIZE - 1);
+
+               if (last_page_size == 0)
+                       last_page_size = PAGE_SIZE;
+               size = roundup(last_page_size,
+                              bdev_logical_block_size(bdev));
+       }
+
+       /* Just make sure we aren't corrupting data or metadata */
+       if (mddev->external) {
+               /* Bitmap could be anywhere. */
+               if (rdev->sb_start + offset
+                   + (page->index * (PAGE_SIZE / SECTOR_SIZE))
+                   > rdev->data_offset &&
+                   rdev->sb_start + offset
+                   < (rdev->data_offset + mddev->dev_sectors
+                    + (PAGE_SIZE / SECTOR_SIZE)))
+                       return -EINVAL;
+       } else if (offset < 0) {
+               /* DATA  BITMAP METADATA  */
+               if (offset
+                   + (long)(page->index * (PAGE_SIZE / SECTOR_SIZE))
+                   + size / SECTOR_SIZE > 0)
+                       /* bitmap runs in to metadata */
+                       return -EINVAL;
+
+               if (rdev->data_offset + mddev->dev_sectors
+                   > rdev->sb_start + offset)
+                       /* data runs in to bitmap */
+                       return -EINVAL;
+       } else if (rdev->sb_start < rdev->data_offset) {
+               /* METADATA BITMAP DATA */
+               if (rdev->sb_start + offset
+                   + page->index * (PAGE_SIZE / SECTOR_SIZE)
+                   + size / SECTOR_SIZE > rdev->data_offset)
+                       /* bitmap runs in to data */
+                       return -EINVAL;
+       } else {
+               /* DATA METADATA BITMAP - no problems */
+       }
 
-restart:
-       rdev = NULL;
-       while ((rdev = next_active_rdev(rdev, mddev)) != NULL) {
-               int size = PAGE_SIZE;
-               loff_t offset = mddev->bitmap_info.offset;
+       md_super_write(mddev, rdev,
+                      rdev->sb_start + offset
+                      + page->index * (PAGE_SIZE / SECTOR_SIZE),
+                      size, page);
+       return 0;
+}
 
-               bdev = (rdev->meta_bdev) ? rdev->meta_bdev : rdev->bdev;
+static int write_sb_page(struct bitmap *bitmap, struct page *page, int wait)
+{
+       struct md_rdev *rdev;
+       struct mddev *mddev = bitmap->mddev;
+       int ret;
 
-               if (page->index == store->file_pages-1) {
-                       int last_page_size = store->bytes & (PAGE_SIZE-1);
-                       if (last_page_size == 0)
-                               last_page_size = PAGE_SIZE;
-                       size = roundup(last_page_size,
-                                      bdev_logical_block_size(bdev));
-               }
-               /* Just make sure we aren't corrupting data or
-                * metadata
-                */
-               if (mddev->external) {
-                       /* Bitmap could be anywhere. */
-                       if (rdev->sb_start + offset + (page->index
-                                                      * (PAGE_SIZE/512))
-                           > rdev->data_offset
-                           &&
-                           rdev->sb_start + offset
-                           < (rdev->data_offset + mddev->dev_sectors
-                            + (PAGE_SIZE/512)))
-                               goto bad_alignment;
-               } else if (offset < 0) {
-                       /* DATA  BITMAP METADATA  */
-                       if (offset
-                           + (long)(page->index * (PAGE_SIZE/512))
-                           + size/512 > 0)
-                               /* bitmap runs in to metadata */
-                               goto bad_alignment;
-                       if (rdev->data_offset + mddev->dev_sectors
-                           > rdev->sb_start + offset)
-                               /* data runs in to bitmap */
-                               goto bad_alignment;
-               } else if (rdev->sb_start < rdev->data_offset) {
-                       /* METADATA BITMAP DATA */
-                       if (rdev->sb_start
-                           + offset
-                           + page->index*(PAGE_SIZE/512) + size/512
-                           > rdev->data_offset)
-                               /* bitmap runs in to data */
-                               goto bad_alignment;
-               } else {
-                       /* DATA METADATA BITMAP - no problems */
+       do {
+               rdev = NULL;
+               while ((rdev = next_active_rdev(rdev, mddev)) != NULL) {
+                       ret = __write_sb_page(rdev, bitmap, page);
+                       if (ret)
+                               return ret;
                }
-               md_super_write(mddev, rdev,
-                              rdev->sb_start + offset
-                              + page->index * (PAGE_SIZE/512),
-                              size,
-                              page);
-       }
+       } while (wait && md_super_wait(mddev) < 0);
 
-       if (wait && md_super_wait(mddev) < 0)
-               goto restart;
        return 0;
-
- bad_alignment:
-       return -EINVAL;
 }
 
 static void md_bitmap_file_kick(struct bitmap *bitmap);