Commit a8b3a890 authored by David Sterba's avatar David Sterba
Browse files

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: default avatarDavid Sterba <dsterba@suse.com>
parent 74ef0018

fs/btrfs/scrub.c

+8 −15
Original line number Diff line number Diff line
@@ -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;

	}