From a8b3a89074f8677533cdb3843da121d697c1938c Mon Sep 17 00:00:00 2001 From: David Sterba Date: Fri, 29 May 2020 15:26:07 +0200 Subject: [PATCH] btrfs: scrub: remove kmap/kunmap of pages All pages that scrub uses in the scrub_block::pagev array are allocated with GFP_KERNEL and never part of any mapping, so kmap is not necessary, we only need to know the page address. In scrub_write_page_to_dev_replace we don't even need to call flush_dcache_page because of the same reason as above. Signed-off-by: David Sterba --- fs/btrfs/scrub.c | 23 ++++++++--------------- 1 file changed, 8 insertions(+), 15 deletions(-) diff --git a/fs/btrfs/scrub.c b/fs/btrfs/scrub.c index 016a025e36c7..368791b17bac 100644 --- a/fs/btrfs/scrub.c +++ b/fs/btrfs/scrub.c @@ -1616,13 +1616,9 @@ static int scrub_write_page_to_dev_replace(struct scrub_block *sblock, struct scrub_page *spage = sblock->pagev[page_num]; BUG_ON(spage->page == NULL); - if (spage->io_error) { - void *mapped_buffer = kmap_atomic(spage->page); + if (spage->io_error) + clear_page(page_address(spage->page)); - clear_page(mapped_buffer); - flush_dcache_page(spage->page); - kunmap_atomic(mapped_buffer); - } return scrub_add_page_to_wr_bio(sblock->sctx, spage); } @@ -1805,7 +1801,7 @@ static int scrub_checksum_data(struct scrub_block *sblock) on_disk_csum = sblock->pagev[0]->csum; page = sblock->pagev[0]->page; - buffer = kmap_atomic(page); + buffer = page_address(page); len = sctx->fs_info->sectorsize; index = 0; @@ -1813,7 +1809,6 @@ static int scrub_checksum_data(struct scrub_block *sblock) u64 l = min_t(u64, len, PAGE_SIZE); crypto_shash_update(shash, buffer, l); - kunmap_atomic(buffer); len -= l; if (len == 0) break; @@ -1821,7 +1816,7 @@ static int scrub_checksum_data(struct scrub_block *sblock) BUG_ON(index >= sblock->page_count); BUG_ON(!sblock->pagev[index]->page); page = sblock->pagev[index]->page; - buffer = kmap_atomic(page); + buffer = page_address(page); } crypto_shash_final(shash, csum); @@ -1851,7 +1846,7 @@ static int scrub_checksum_tree_block(struct scrub_block *sblock) BUG_ON(sblock->page_count < 1); page = sblock->pagev[0]->page; - mapped_buffer = kmap_atomic(page); + mapped_buffer = page_address(page); h = (struct btrfs_header *)mapped_buffer; memcpy(on_disk_csum, h->csum, sctx->csum_size); @@ -1883,7 +1878,6 @@ static int scrub_checksum_tree_block(struct scrub_block *sblock) u64 l = min_t(u64, len, mapped_size); crypto_shash_update(shash, p, l); - kunmap_atomic(mapped_buffer); len -= l; if (len == 0) break; @@ -1891,7 +1885,7 @@ static int scrub_checksum_tree_block(struct scrub_block *sblock) BUG_ON(index >= sblock->page_count); BUG_ON(!sblock->pagev[index]->page); page = sblock->pagev[index]->page; - mapped_buffer = kmap_atomic(page); + mapped_buffer = page_address(page); mapped_size = PAGE_SIZE; p = mapped_buffer; } @@ -1925,7 +1919,7 @@ static int scrub_checksum_super(struct scrub_block *sblock) BUG_ON(sblock->page_count < 1); page = sblock->pagev[0]->page; - mapped_buffer = kmap_atomic(page); + mapped_buffer = page_address(page); s = (struct btrfs_super_block *)mapped_buffer; memcpy(on_disk_csum, s->csum, sctx->csum_size); @@ -1946,7 +1940,6 @@ static int scrub_checksum_super(struct scrub_block *sblock) u64 l = min_t(u64, len, mapped_size); crypto_shash_update(shash, p, l); - kunmap_atomic(mapped_buffer); len -= l; if (len == 0) break; @@ -1954,7 +1947,7 @@ static int scrub_checksum_super(struct scrub_block *sblock) BUG_ON(index >= sblock->page_count); BUG_ON(!sblock->pagev[index]->page); page = sblock->pagev[index]->page; - mapped_buffer = kmap_atomic(page); + mapped_buffer = page_address(page); mapped_size = PAGE_SIZE; p = mapped_buffer; }