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Groups > linux.kernel > #1567376

[PATCHv6 12/37] brd: make it handle huge pages

From "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Newsgroups linux.kernel
Subject [PATCHv6 12/37] brd: make it handle huge pages
Date 2017-01-26 13:10 +0100
Message-ID <t3R2i-79n-19@gated-at.bofh.it> (permalink)
References <t3QSB-6QS-5@gated-at.bofh.it>
Organization linux.* mail to news gateway

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Do not assume length of bio segment is never larger than PAGE_SIZE.
With huge pages it's HPAGE_PMD_SIZE (2M on x86-64).

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
---
 drivers/block/brd.c | 17 ++++++++++++-----
 1 file changed, 12 insertions(+), 5 deletions(-)

diff --git a/drivers/block/brd.c b/drivers/block/brd.c
index 3adc32a3153b..d2f7dc87b545 100644
--- a/drivers/block/brd.c
+++ b/drivers/block/brd.c
@@ -202,12 +202,15 @@ static int copy_to_brd_setup(struct brd_device *brd, sector_t sector, size_t n)
 	size_t copy;
 
 	copy = min_t(size_t, n, PAGE_SIZE - offset);
+	n -= copy;
 	if (!brd_insert_page(brd, sector))
 		return -ENOSPC;
-	if (copy < n) {
+	while (n) {
 		sector += copy >> SECTOR_SHIFT;
 		if (!brd_insert_page(brd, sector))
 			return -ENOSPC;
+		copy = min_t(size_t, n, PAGE_SIZE);
+		n -= copy;
 	}
 	return 0;
 }
@@ -242,6 +245,7 @@ static void copy_to_brd(struct brd_device *brd, const void *src,
 	size_t copy;
 
 	copy = min_t(size_t, n, PAGE_SIZE - offset);
+	n -= copy;
 	page = brd_lookup_page(brd, sector);
 	BUG_ON(!page);
 
@@ -249,10 +253,11 @@ static void copy_to_brd(struct brd_device *brd, const void *src,
 	memcpy(dst + offset, src, copy);
 	kunmap_atomic(dst);
 
-	if (copy < n) {
+	while (n) {
 		src += copy;
 		sector += copy >> SECTOR_SHIFT;
-		copy = n - copy;
+		copy = min_t(size_t, n, PAGE_SIZE);
+		n -= copy;
 		page = brd_lookup_page(brd, sector);
 		BUG_ON(!page);
 
@@ -274,6 +279,7 @@ static void copy_from_brd(void *dst, struct brd_device *brd,
 	size_t copy;
 
 	copy = min_t(size_t, n, PAGE_SIZE - offset);
+	n -= copy;
 	page = brd_lookup_page(brd, sector);
 	if (page) {
 		src = kmap_atomic(page);
@@ -282,10 +288,11 @@ static void copy_from_brd(void *dst, struct brd_device *brd,
 	} else
 		memset(dst, 0, copy);
 
-	if (copy < n) {
+	while (n) {
 		dst += copy;
 		sector += copy >> SECTOR_SHIFT;
-		copy = n - copy;
+		copy = min_t(size_t, n, PAGE_SIZE);
+		n -= copy;
 		page = brd_lookup_page(brd, sector);
 		if (page) {
 			src = kmap_atomic(page);
-- 
2.11.0

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Thread

[PATCHv6 00/37] ext4: support of huge pages "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> - 2017-01-26 13:00 +0100
  [PATCHv6 03/37] page-flags: relax page flag policy for few flags "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> - 2017-01-26 13:00 +0100
  [PATCHv6 36/37] mm, fs, ext4: expand use of page_mapping() and page_to_pgoff() "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> - 2017-01-26 13:00 +0100
  [PATCHv6 06/37] thp: handle write-protection faults for file THP "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> - 2017-01-26 13:00 +0100
    Re: [PATCHv6 06/37] thp: handle write-protection faults for file THP Matthew Wilcox <willy@infradead.org> - 2017-01-26 16:50 +0100
      Re: [PATCHv6 06/37] thp: handle write-protection faults for file THP "Kirill A. Shutemov" <kirill@shutemov.name> - 2017-01-26 17:00 +0100
  [PATCHv6 09/37] filemap: allocate huge page in pagecache_get_page(), if allowed "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> - 2017-01-26 13:00 +0100
  [PATCHv6 34/37] ext4: make fallocate() operations work with huge pages "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> - 2017-01-26 13:00 +0100
  [PATCHv6 31/37] ext4: handle writeback with huge pages "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> - 2017-01-26 13:00 +0100
  [PATCHv6 10/37] filemap: handle huge pages in filemap_fdatawait_range() "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> - 2017-01-26 13:10 +0100
  [PATCHv6 15/37] thp: do not threat slab pages as huge in hpage_{nr_pages,size,mask} "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> - 2017-01-26 13:10 +0100
  [PATCHv6 20/37] truncate: make truncate_inode_pages_range() aware about huge pages "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> - 2017-01-26 13:10 +0100
  [PATCHv6 13/37] mm: make write_cache_pages() work on huge pages "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> - 2017-01-26 13:10 +0100
  [PATCHv6 18/37] fs: make block_write_{begin,end}() be able to handle huge pages "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> - 2017-01-26 13:10 +0100
  [PATCHv6 32/37] ext4: make EXT4_IOC_MOVE_EXT work with huge pages "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> - 2017-01-26 13:10 +0100
  [PATCHv6 37/37] ext4, vfs: add huge= mount option "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> - 2017-01-26 13:10 +0100
  [PATCHv6 19/37] fs: make block_page_mkwrite() aware about huge pages "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> - 2017-01-26 13:10 +0100
  [PATCHv6 14/37] thp: introduce hpage_size() and hpage_mask() "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> - 2017-01-26 13:10 +0100
  [PATCHv6 02/37] Revert "radix-tree: implement radix_tree_maybe_preload_order()" "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> - 2017-01-26 13:10 +0100
    Re: [PATCHv6 02/37] Revert "radix-tree: implement  radix_tree_maybe_preload_order()" Matthew Wilcox <willy@infradead.org> - 2017-01-26 16:40 +0100
  [PATCHv6 26/37] ext4: handle huge pages in ext4_page_mkwrite() "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> - 2017-01-26 13:10 +0100
  [PATCHv6 12/37] brd: make it handle huge pages "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> - 2017-01-26 13:10 +0100
  [PATCHv6 27/37] ext4: handle huge pages in __ext4_block_zero_page_range() "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> - 2017-01-26 13:10 +0100
  [PATCHv6 29/37] ext4: handle huge pages in ext4_da_write_end() "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> - 2017-01-26 13:10 +0100
  [PATCHv6 11/37] HACK: readahead: alloc huge pages, if allowed "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> - 2017-01-26 13:10 +0100
  [PATCHv6 33/37] ext4: fix SEEK_DATA/SEEK_HOLE for huge pages "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> - 2017-01-26 13:10 +0100
  [PATCHv6 24/37] ext4: make ext4_mpage_readpages() hugepage-aware "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> - 2017-01-26 13:10 +0100
  [PATCHv6 17/37] fs: make block_read_full_page() be able to read huge page "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> - 2017-01-26 13:10 +0100
  [PATCHv6 35/37] ext4: reserve larger jounral transaction for huge pages "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> - 2017-01-26 13:10 +0100
  [PATCHv6 07/37] filemap: allocate huge page in page_cache_read(), if allowed "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> - 2017-01-26 13:10 +0100
  [PATCHv6 23/37] mm: account huge pages to dirty, writaback, reclaimable, etc. "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> - 2017-01-26 13:10 +0100
  [PATCHv6 01/37] mm, shmem: swich huge tmpfs to multi-order radix-tree entries "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> - 2017-01-26 13:10 +0100
  [PATCHv6 04/37] mm, rmap: account file thp pages "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> - 2017-01-26 13:10 +0100
  [PATCHv6 22/37] mm, hugetlb: switch hugetlbfs to multi-order radix-tree entries "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> - 2017-01-26 13:10 +0100
  [PATCHv6 05/37] thp: try to free page's buffers before attempt split "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> - 2017-01-26 13:10 +0100
  [PATCHv6 28/37] ext4: make ext4_block_write_begin() aware about huge pages "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> - 2017-01-26 13:10 +0100
  [PATCHv6 08/37] filemap: handle huge pages in do_generic_file_read() "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> - 2017-01-26 13:10 +0100
  [PATCHv6 16/37] thp: make thp_get_unmapped_area() respect S_HUGE_MODE "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> - 2017-01-26 13:10 +0100
  [PATCHv6 21/37] truncate: make invalidate_inode_pages2_range() aware about huge pages "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> - 2017-01-26 13:10 +0100
  [PATCHv6 25/37] ext4: make ext4_writepage() work on huge pages "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> - 2017-01-26 13:10 +0100

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