btrfs: factor out a btrfs_add_compressed_bio_pages helper

Factor out a common helper to add the compressed_bio pages to the
bio that is shared by the compressed read and write path.

Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

diff --git a/fs/btrfs/compression.c b/fs/btrfs/compression.c
index 6a6a605..89c9b39 100644 (file)
--- a/fs/btrfs/compression.c
+++ b/fs/btrfs/compression.c
@@ -280,6 +280,42 @@ static void end_compressed_bio_write(struct btrfs_bio *bbio)
        queue_work(fs_info->compressed_write_workers, &cb->write_end_work);
 }
 
+static void btrfs_add_compressed_bio_pages(struct compressed_bio *cb,
+                                          u64 disk_bytenr)
+{
+       struct btrfs_fs_info *fs_info = cb->bbio.inode->root->fs_info;
+       struct bio *bio = &cb->bbio.bio;
+       u64 cur_disk_byte = disk_bytenr;
+
+       bio->bi_iter.bi_sector = disk_bytenr >> SECTOR_SHIFT;
+       while (cur_disk_byte < disk_bytenr + cb->compressed_len) {
+               u64 offset = cur_disk_byte - disk_bytenr;
+               unsigned int index = offset >> PAGE_SHIFT;
+               unsigned int real_size;
+               unsigned int added;
+               struct page *page = cb->compressed_pages[index];
+
+               /*
+                * We have various limit on the real read size:
+                * - page boundary
+                * - compressed length boundary
+                */
+               real_size = min_t(u64, U32_MAX, PAGE_SIZE - offset_in_page(offset));
+               real_size = min_t(u64, real_size, cb->compressed_len - offset);
+               ASSERT(IS_ALIGNED(real_size, fs_info->sectorsize));
+
+               added = bio_add_page(bio, page, real_size, offset_in_page(offset));
+               /*
+                * Maximum compressed extent is smaller than bio size limit,
+                * thus bio_add_page() should always success.
+                */
+               ASSERT(added == real_size);
+               cur_disk_byte += added;
+       }
+
+       ASSERT(bio->bi_iter.bi_size);
+}
+
 /*
  * worker function to build and submit bios for previously compressed pages.
  * The corresponding pages in the inode should be marked for writeback
@@ -299,9 +335,7 @@ void btrfs_submit_compressed_write(struct btrfs_inode *inode, u64 start,
                                 bool writeback)
 {
        struct btrfs_fs_info *fs_info = inode->root->fs_info;
-       struct bio *bio;
        struct compressed_bio *cb;
-       u64 cur_disk_bytenr = disk_start;
 
        ASSERT(IS_ALIGNED(start, fs_info->sectorsize) &&
               IS_ALIGNED(len, fs_info->sectorsize));
@@ -322,37 +356,9 @@ void btrfs_submit_compressed_write(struct btrfs_inode *inode, u64 start,
        INIT_WORK(&cb->write_end_work, btrfs_finish_compressed_write_work);
        cb->nr_pages = nr_pages;
 
-       bio = &cb->bbio.bio;
-       bio->bi_iter.bi_sector = disk_start >> SECTOR_SHIFT;
-
-       while (cur_disk_bytenr < disk_start + compressed_len) {
-               u64 offset = cur_disk_bytenr - disk_start;
-               unsigned int index = offset >> PAGE_SHIFT;
-               unsigned int real_size;
-               unsigned int added;
-               struct page *page = compressed_pages[index];
-
-               /*
-                * We have various limits on the real read size:
-                * - page boundary
-                * - compressed length boundary
-                */
-               real_size = min_t(u64, U32_MAX, PAGE_SIZE - offset_in_page(offset));
-               real_size = min_t(u64, real_size, compressed_len - offset);
-               ASSERT(IS_ALIGNED(real_size, fs_info->sectorsize));
-
-               added = bio_add_page(bio, page, real_size, offset_in_page(offset));
-               /*
-                * Maximum compressed extent is smaller than bio size limit,
-                * thus bio_add_page() should always success.
-                */
-               ASSERT(added == real_size);
-               cur_disk_bytenr += added;
-       }
+       btrfs_add_compressed_bio_pages(cb, disk_start);
+       btrfs_submit_bio(&cb->bbio.bio, 0);
 
-       /* Finished the range. */
-       ASSERT(bio->bi_iter.bi_size);
-       btrfs_submit_bio(bio, 0);
        if (blkcg_css)
                kthread_associate_blkcg(NULL);
 }
@@ -523,9 +529,7 @@ void btrfs_submit_compressed_read(struct bio *bio, int mirror_num)
        struct extent_map_tree *em_tree = &inode->extent_tree;
        struct compressed_bio *cb;
        unsigned int compressed_len;
-       struct bio *comp_bio;
        const u64 disk_bytenr = bio->bi_iter.bi_sector << SECTOR_SHIFT;
-       u64 cur_disk_byte = disk_bytenr;
        u64 file_offset = btrfs_bio(bio)->file_offset;
        u64 em_len;
        u64 em_start;
@@ -549,8 +553,6 @@ void btrfs_submit_compressed_read(struct bio *bio, int mirror_num)
 
        cb = alloc_compressed_bio(inode, file_offset, REQ_OP_READ,
                                  end_compressed_bio_read);
-       comp_bio = &cb->bbio.bio;
-       comp_bio->bi_iter.bi_sector = cur_disk_byte >> SECTOR_SHIFT;
 
        cb->start = em->orig_start;
        em_len = em->len;
@@ -582,42 +584,18 @@ void btrfs_submit_compressed_read(struct bio *bio, int mirror_num)
        /* include any pages we added in add_ra-bio_pages */
        cb->len = bio->bi_iter.bi_size;
 
-       while (cur_disk_byte < disk_bytenr + compressed_len) {
-               u64 offset = cur_disk_byte - disk_bytenr;
-               unsigned int index = offset >> PAGE_SHIFT;
-               unsigned int real_size;
-               unsigned int added;
-               struct page *page = cb->compressed_pages[index];
-
-               /*
-                * We have various limit on the real read size:
-                * - page boundary
-                * - compressed length boundary
-                */
-               real_size = min_t(u64, U32_MAX, PAGE_SIZE - offset_in_page(offset));
-               real_size = min_t(u64, real_size, compressed_len - offset);
-               ASSERT(IS_ALIGNED(real_size, fs_info->sectorsize));
-
-               added = bio_add_page(comp_bio, page, real_size, offset_in_page(offset));
-               /*
-                * Maximum compressed extent is smaller than bio size limit,
-                * thus bio_add_page() should always success.
-                */
-               ASSERT(added == real_size);
-               cur_disk_byte += added;
-       }
+       btrfs_add_compressed_bio_pages(cb, disk_bytenr);
 
        if (memstall)
                psi_memstall_leave(&pflags);
 
-       ASSERT(comp_bio->bi_iter.bi_size);
-       btrfs_submit_bio(comp_bio, mirror_num);
+       btrfs_submit_bio(&cb->bbio.bio, mirror_num);
        return;
 
 out_free_compressed_pages:
        kfree(cb->compressed_pages);
 out_free_bio:
-       bio_put(comp_bio);
+       bio_put(&cb->bbio.bio);
 out:
        btrfs_bio_end_io(btrfs_bio(bio), ret);
 }