From aaac91468f5b6757f72f30464bcf4489a75846e6 Mon Sep 17 00:00:00 2001 From: "Fabio M. De Francesco" Date: Sun, 17 Jul 2022 10:36:13 +0200 Subject: [PATCH] f2fs: Delete f2fs_copy_page() and replace with memcpy_page() MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit [ Upstream commit 1dd55358efc4f74e49fa9e1e97a03804852a4c20 ] f2fs_copy_page() is a wrapper around two kmap() + one memcpy() from/to the mapped pages. It unnecessarily duplicates a kernel API and it makes use of kmap(), which is being deprecated in favor of kmap_local_page(). Two main problems with kmap(): (1) It comes with an overhead as mapping space is restricted and protected by a global lock for synchronization and (2) it also requires global TLB invalidation when the kmap’s pool wraps and it might block when the mapping space is fully utilized until a slot becomes available. With kmap_local_page() the mappings are per thread, CPU local, can take page faults, and can be called from any context (including interrupts). It is faster than kmap() in kernels with HIGHMEM enabled. Therefore, its use in __clone_blkaddrs() is safe and should be preferred. Delete f2fs_copy_page() and use a plain memcpy_page() in the only one site calling the removed function. memcpy_page() avoids open coding two kmap_local_page() + one memcpy() between the two kernel virtual addresses. Suggested-by: Christoph Hellwig Suggested-by: Ira Weiny Signed-off-by: Fabio M. De Francesco Reviewed-by: Christoph Hellwig Reviewed-by: Chao Yu Signed-off-by: Jaegeuk Kim Stable-dep-of: d3876e34e7e7 ("f2fs: fix to wait on page writeback in __clone_blkaddrs()") Signed-off-by: Sasha Levin --- fs/f2fs/f2fs.h | 10 ---------- fs/f2fs/file.c | 2 +- 2 files changed, 1 insertion(+), 11 deletions(-) diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h index 647d53df6a3d..e49fca9daf2d 100644 --- a/fs/f2fs/f2fs.h +++ b/fs/f2fs/f2fs.h @@ -2587,16 +2587,6 @@ static inline struct page *f2fs_pagecache_get_page( return pagecache_get_page(mapping, index, fgp_flags, gfp_mask); } -static inline void f2fs_copy_page(struct page *src, struct page *dst) -{ - char *src_kaddr = kmap(src); - char *dst_kaddr = kmap(dst); - - memcpy(dst_kaddr, src_kaddr, PAGE_SIZE); - kunmap(dst); - kunmap(src); -} - static inline void f2fs_put_page(struct page *page, int unlock) { if (!page) diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c index 378ab6bd1b8d..9b7ecbb97425 100644 --- a/fs/f2fs/file.c +++ b/fs/f2fs/file.c @@ -1276,7 +1276,7 @@ static int __clone_blkaddrs(struct inode *src_inode, struct inode *dst_inode, f2fs_put_page(psrc, 1); return PTR_ERR(pdst); } - f2fs_copy_page(psrc, pdst); + memcpy_page(pdst, 0, psrc, 0, PAGE_SIZE); set_page_dirty(pdst); set_page_private_gcing(pdst); f2fs_put_page(pdst, 1);