Commit 70826b6b authored by Fabio M. De Francesco's avatar Fabio M. De Francesco Committed by David Sterba
Browse files

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: default avatarIra Weiny <ira.weiny@intel.com>
Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
Signed-off-by: default avatarFabio M. De Francesco <fmdefrancesco@gmail.com>
Reviewed-by: default avatarDavid Sterba <dsterba@suse.com>
Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
parent 9ff7ddd3

fs/btrfs/inode.c

+3 −3
Original line number Diff line number Diff line
@@ -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 (;;) {