From: David Sterba <dsterba@suse.com>
Date: Wed, 27 Oct 2021 10:39:03 +0200
Subject: [PATCH 129/132] Revert "btrfs: compression: drop kmap/kunmap from
 generic helpers"
Git-commit: 3a60f6537c9adf0828bf1dd868c59f659395257e
Patch-mainline: 5.15
References: bsc#1193852

This reverts commit 4c2bf276b56d8d27ddbafcdf056ef3fc60ae50b0.

The kmaps in compression code are still needed and cause crashes on
32bit machines (ARM, x86). Reproducible eg. by running fstest btrfs/004
with enabled LZO or ZSTD compression.

Link: https://lore.kernel.org/all/CAJCQCtT+OuemovPO7GZk8Y8=qtOObr0XTDp8jh4OHD6y84AFxw@mail.gmail.com/
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=214839
Signed-off-by: David Sterba <dsterba@suse.com>
---
 fs/btrfs/compression.c | 3 ++-
 fs/btrfs/inode.c       | 3 ++-
 2 files changed, 4 insertions(+), 2 deletions(-)

diff --git a/fs/btrfs/compression.c b/fs/btrfs/compression.c
index 7869ad12bc6e..0913ee50e6c3 100644
--- a/fs/btrfs/compression.c
+++ b/fs/btrfs/compression.c
@@ -172,9 +172,10 @@ static int check_compressed_csum(struct btrfs_inode *inode, struct bio *bio,
 		/* Hash through the page sector by sector */
 		for (pg_offset = 0; pg_offset < bytes_left;
 		     pg_offset += sectorsize) {
-			kaddr = page_address(page);
+			kaddr = kmap_atomic(page);
 			crypto_shash_digest(shash, kaddr + pg_offset,
 					    sectorsize, csum);
+			kunmap_atomic(kaddr);
 
 			if (memcmp(&csum, cb_sum, csum_size) != 0) {
 				btrfs_print_data_csum_error(inode, disk_start,
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 2aa9646bce56..e6772f55943e 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -287,8 +287,9 @@ static int insert_inline_extent(struct btrfs_trans_handle *trans,
 			cur_size = min_t(unsigned long, compressed_size,
 				       PAGE_SIZE);
 
-			kaddr = page_address(cpage);
+			kaddr = kmap_atomic(cpage);
 			write_extent_buffer(leaf, kaddr, ptr, cur_size);
+			kunmap_atomic(kaddr);
 
 			i++;
 			ptr += cur_size;
-- 
2.33.0