f2fs: don't put dentry page in pagecache into highmem

Previous dentry page uses highmem, which will cause panic in platforms
using highmem (such as arm), since the address space of dentry pages
from highmem directly goes into the decryption path via the function
fscrypt_fname_disk_to_usr. But sg_init_one assumes the address is not
from highmem, and then cause panic since it doesn't call kmap_high but
kunmap_high is triggered at the end. To fix this problem in a simple
way, this patch avoids to put dentry page in pagecache into highmem.

Signed-off-by: Yunlong Song <yunlong.song@huawei.com>
Reviewed-by: Chao Yu <yuchao0@huawei.com>
[Jaegeuk Kim: fix coding style]
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

1 files changed, 5 insertions, 18 deletions

diff --git a/fs/f2fs/dir.c b/fs/f2fs/dir.c
index f00b5ed8c011..797eb05cb538 100644
--- a/fs/f2fs/dir.c
+++ b/fs/f2fs/dir.c
@@ -94,14 +94,12 @@ static struct f2fs_dir_entry *find_in_block(struct page *dentry_page,
 	struct f2fs_dir_entry *de;
 	struct f2fs_dentry_ptr d;
 
-	dentry_blk = (struct f2fs_dentry_block *)kmap(dentry_page);
+	dentry_blk = (struct f2fs_dentry_block *)page_address(dentry_page);
 
 	make_dentry_ptr_block(NULL, &d, dentry_blk);
 	de = find_target_dentry(fname, namehash, max_slots, &d);
 	if (de)
 		*res_page = dentry_page;
-	else
-		kunmap(dentry_page);
 
 	return de;
 }
@@ -287,7 +285,6 @@ ino_t f2fs_inode_by_name(struct inode *dir, const struct qstr *qstr,
 	de = f2fs_find_entry(dir, qstr, page);
 	if (de) {
 		res = le32_to_cpu(de->ino);
-		f2fs_dentry_kunmap(dir, *page);
 		f2fs_put_page(*page, 0);
 	}
 
@@ -302,7 +299,6 @@ void f2fs_set_link(struct inode *dir, struct f2fs_dir_entry *de,
 	f2fs_wait_on_page_writeback(page, type, true);
 	de->ino = cpu_to_le32(inode->i_ino);
 	set_de_type(de, inode->i_mode);
-	f2fs_dentry_kunmap(dir, page);
 	set_page_dirty(page);
 
 	dir->i_mtime = dir->i_ctime = current_time(dir);
@@ -350,13 +346,11 @@ static int make_empty_dir(struct inode *inode,
 	if (IS_ERR(dentry_page))
 		return PTR_ERR(dentry_page);
 
-	dentry_blk = kmap_atomic(dentry_page);
+	dentry_blk = page_address(dentry_page);
 
 	make_dentry_ptr_block(NULL, &d, dentry_blk);
 	do_make_empty_dir(inode, parent, &d);
 
-	kunmap_atomic(dentry_blk);
-
 	set_page_dirty(dentry_page);
 	f2fs_put_page(dentry_page, 1);
 	return 0;
@@ -547,13 +541,12 @@ start:
 		if (IS_ERR(dentry_page))
 			return PTR_ERR(dentry_page);
 
-		dentry_blk = kmap(dentry_page);
+		dentry_blk = page_address(dentry_page);
 		bit_pos = room_for_filename(&dentry_blk->dentry_bitmap,
 						slots, NR_DENTRY_IN_BLOCK);
 		if (bit_pos < NR_DENTRY_IN_BLOCK)
 			goto add_dentry;
 
-		kunmap(dentry_page);
 		f2fs_put_page(dentry_page, 1);
 	}
 
@@ -588,7 +581,6 @@ fail:
 	if (inode)
 		up_write(&F2FS_I(inode)->i_sem);
 
-	kunmap(dentry_page);
 	f2fs_put_page(dentry_page, 1);
 
 	return err;
@@ -642,7 +634,6 @@ int __f2fs_add_link(struct inode *dir, const struct qstr *name,
 		F2FS_I(dir)->task = NULL;
 	}
 	if (de) {
-		f2fs_dentry_kunmap(dir, page);
 		f2fs_put_page(page, 0);
 		err = -EEXIST;
 	} else if (IS_ERR(page)) {
@@ -730,7 +721,6 @@ void f2fs_delete_entry(struct f2fs_dir_entry *dentry, struct page *page,
 	bit_pos = find_next_bit_le(&dentry_blk->dentry_bitmap,
 			NR_DENTRY_IN_BLOCK,
 			0);
-	kunmap(page); /* kunmap - pair of f2fs_find_entry */
 	set_page_dirty(page);
 
 	dir->i_ctime = dir->i_mtime = current_time(dir);
@@ -775,7 +765,7 @@ bool f2fs_empty_dir(struct inode *dir)
 				return false;
 		}
 
-		dentry_blk = kmap_atomic(dentry_page);
+		dentry_blk = page_address(dentry_page);
 		if (bidx == 0)
 			bit_pos = 2;
 		else
@@ -783,7 +773,6 @@ bool f2fs_empty_dir(struct inode *dir)
 		bit_pos = find_next_bit_le(&dentry_blk->dentry_bitmap,
 						NR_DENTRY_IN_BLOCK,
 						bit_pos);
-		kunmap_atomic(dentry_blk);
 
 		f2fs_put_page(dentry_page, 1);
 
@@ -901,19 +890,17 @@ static int f2fs_readdir(struct file *file, struct dir_context *ctx)
 			}
 		}
 
-		dentry_blk = kmap(dentry_page);
+		dentry_blk = page_address(dentry_page);
 
 		make_dentry_ptr_block(inode, &d, dentry_blk);
 
 		err = f2fs_fill_dentries(ctx, &d,
 				n * NR_DENTRY_IN_BLOCK, &fstr);
 		if (err) {
-			kunmap(dentry_page);
 			f2fs_put_page(dentry_page, 1);
 			break;
 		}
 
-		kunmap(dentry_page);
 		f2fs_put_page(dentry_page, 1);
 	}
 out_free: