From: Qu Wenruo <wqu@suse.com>
Date: Tue, 20 Jan 2026 00:00:10 +0000 (+1030)
Subject: btrfs: zstd: use folio_iter to handle zstd_decompress_bio()
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=1914b94231e98280de4ec3a7f10e7abfd928c649;p=thirdparty%2Fkernel%2Flinux.git

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 c9cddcfa337b9..7fad1e299c7ae 100644
--- 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);
 		}