From: Fabio M. De Francesco <fmdefrancesco@gmail.com>
Date: Tue, 31 May 2022 14:53:33 +0000 (+0200)
Subject: btrfs: replace kmap() with kmap_local_page() in inode.c
X-Git-Tag: baikal/mips/sdk6.1~5160^2~110
X-Git-Url: https://git.baikalelectronics.ru/sdk/?a=commitdiff_plain;h=ceb419860e8cc6a0a77a9ba9d8ab32031039255f;p=kernel.git

btrfs: replace kmap() with kmap_local_page() in inode.c

The use of kmap() is being deprecated in favor of kmap_local_page() where
it is feasible. With kmap_local_page(), the mapping is per thread, CPU
local and not globally visible.

Therefore, use kmap_local_page() / kunmap_local() in inode.c wherever the
mappings are per thread and not globally visible.

Tested on QEMU + KVM 32 bits VM with 4GB of RAM and HIGHMEM64G enabled.

Suggested-by: Ira Weiny <ira.weiny@intel.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Fabio M. De Francesco <fmdefrancesco@gmail.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
---

diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 9cce0a3228f83..92dca0e0d2073 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -10760,15 +10760,15 @@ ssize_t btrfs_do_encoded_write(struct kiocb *iocb, struct iov_iter *from,
 			ret = -ENOMEM;
 			goto out_pages;
 		}
-		kaddr = kmap(pages[i]);
+		kaddr = kmap_local_page(pages[i]);
 		if (copy_from_iter(kaddr, bytes, from) != bytes) {
-			kunmap(pages[i]);
+			kunmap_local(kaddr);
 			ret = -EFAULT;
 			goto out_pages;
 		}
 		if (bytes < PAGE_SIZE)
 			memset(kaddr + bytes, 0, PAGE_SIZE - bytes);
-		kunmap(pages[i]);
+		kunmap_local(kaddr);
 	}
 
 	for (;;) {