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 9cce0a3228f831ae065e57aee353da3841534db5..92dca0e0d20731dc392201cffabe0e891635e086 100644 (file)
--- 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 (;;) {