[PATCHv6 12/37] brd: make it handle huge pages
From: Kirill A. Shutemov <hidden>
Date: 2017-01-26 11:57:54
Also in:
linux-ext4, linux-fsdevel, linux-mm, lkml
Subsystem:
block layer, ramdisk ram block device driver, the rest · Maintainers:
Jens Axboe, Linus Torvalds
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 <redacted> --- 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