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alistair23-linux
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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 <dsterba@suse.com>
zero-sugar-mainline-defconfig
David Sterba 2020-05-29 15:26:07 +02:00
parent 74ef00185e
commit a8b3a89074
1 changed files with 8 additions and 15 deletions
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23
fs/btrfs/scrub.c
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@ -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;
}