btrfs: zstd: use folio_iter to handle zstd_decompress_bio()

Currently zstd_decompress_bio() is using
compressed_bio->compressed_folios[] array to grab each compressed folio.

However cb->compressed_folios[] is just a pointer to each folio of the
compressed bio, meaning we can just replace the compressed_folios[]
array by just grabbing the folio inside the compressed bio.

Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

diff --git a/fs/btrfs/zstd.c b/fs/btrfs/zstd.c
index c9cddcfa337b912a973cf1e2df500fe85ba0b04e..7fad1e299c7ae6821a102fd3fe653bc50c6dfa9c 100644 (file)
--- a/fs/btrfs/zstd.c
+++ b/fs/btrfs/zstd.c
@@ -589,7 +589,7 @@ int zstd_decompress_bio(struct list_head *ws, struct compressed_bio *cb)
 {
        struct btrfs_fs_info *fs_info = cb_to_fs_info(cb);
        struct workspace *workspace = list_entry(ws, struct workspace, list);
-       struct folio **folios_in = cb->compressed_folios;
+       struct folio_iter fi;
        size_t srclen = cb->compressed_len;
        zstd_dstream *stream;
        int ret = 0;
@@ -600,6 +600,11 @@ int zstd_decompress_bio(struct list_head *ws, struct compressed_bio *cb)
        unsigned long buf_start;
        unsigned long total_out = 0;
 
+       bio_first_folio(&fi, &cb->bbio.bio, 0);
+       if (unlikely(!fi.folio))
+               return -EINVAL;
+       ASSERT(folio_size(fi.folio) == blocksize);
+
        stream = zstd_init_dstream(
                        ZSTD_BTRFS_MAX_INPUT, workspace->mem, workspace->size);
        if (unlikely(!stream)) {
@@ -612,7 +617,7 @@ int zstd_decompress_bio(struct list_head *ws, struct compressed_bio *cb)
                goto done;
        }
 
-       workspace->in_buf.src = kmap_local_folio(folios_in[folio_in_index], 0);
+       workspace->in_buf.src = kmap_local_folio(fi.folio, 0);
        workspace->in_buf.pos = 0;
        workspace->in_buf.size = min_t(size_t, srclen, min_folio_size);
 
@@ -660,8 +665,9 @@ int zstd_decompress_bio(struct list_head *ws, struct compressed_bio *cb)
                                goto done;
                        }
                        srclen -= min_folio_size;
-                       workspace->in_buf.src =
-                               kmap_local_folio(folios_in[folio_in_index], 0);
+                       bio_next_folio(&fi, &cb->bbio.bio);
+                       ASSERT(fi.folio);
+                       workspace->in_buf.src = kmap_local_folio(fi.folio, 0);
                        workspace->in_buf.pos = 0;
                        workspace->in_buf.size = min_t(size_t, srclen, min_folio_size);
                }