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Commit 98cc093c authored by Huang Ying's avatar Huang Ying Committed by Linus Torvalds
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block, THP: make block_device_operations.rw_page support THP 

The .rw_page in struct block_device_operations is used by the swap
subsystem to read/write the page contents from/into the corresponding
swap slot in the swap device.  To support the THP (Transparent Huge
Page) swap optimization, the .rw_page is enhanced to support to
read/write THP if possible.

Link: http://lkml.kernel.org/r/20170724051840.2309-6-ying.huang@intel.com


Signed-off-by: default avatar"Huang, Ying" <ying.huang@intel.com>
Reviewed-by: Ross Zwisler <ross.zwisler@intel.com> [for brd.c, zram_drv.c, pmem.c]
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Vishal L Verma <vishal.l.verma@intel.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: "Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Shaohua Li <shli@kernel.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent f0eea189

drivers/block/brd.c

+5 −1
Original line number Diff line number Diff line
@@ -326,7 +326,11 @@ static int brd_rw_page(struct block_device *bdev, sector_t sector, 
		       struct page *page, bool is_write)

{

	struct brd_device *brd = bdev->bd_disk->private_data;

	int err = brd_do_bvec(brd, page, PAGE_SIZE, 0, is_write, sector);

	int err;



	if (PageTransHuge(page))

		return -ENOTSUPP;

	err = brd_do_bvec(brd, page, PAGE_SIZE, 0, is_write, sector);

	page_endio(page, is_write, err);

	return err;

}

drivers/block/zram/zram_drv.c

+2 −0
Original line number Diff line number Diff line
@@ -1285,6 +1285,8 @@ static int zram_rw_page(struct block_device *bdev, sector_t sector, 
	struct zram *zram;

	struct bio_vec bv;



	if (PageTransHuge(page))

		return -ENOTSUPP;

	zram = bdev->bd_disk->private_data;



	if (!valid_io_request(zram, sector, PAGE_SIZE)) {

drivers/nvdimm/btt.c

+3 −1
Original line number Diff line number Diff line
@@ -1241,8 +1241,10 @@ static int btt_rw_page(struct block_device *bdev, sector_t sector, 
{

	struct btt *btt = bdev->bd_disk->private_data;

	int rc;

	unsigned int len;



	rc = btt_do_bvec(btt, NULL, page, PAGE_SIZE, 0, is_write, sector);

	len = hpage_nr_pages(page) * PAGE_SIZE;

	rc = btt_do_bvec(btt, NULL, page, len, 0, is_write, sector);

	if (rc == 0)

		page_endio(page, is_write, 0);

drivers/nvdimm/pmem.c

+30 −11
Original line number Diff line number Diff line
@@ -80,22 +80,40 @@ static blk_status_t pmem_clear_poison(struct pmem_device *pmem, 
static void write_pmem(void *pmem_addr, struct page *page,

		unsigned int off, unsigned int len)

{

	void *mem = kmap_atomic(page);

	unsigned int chunk;

	void *mem;



	memcpy_flushcache(pmem_addr, mem + off, len);

	while (len) {

		mem = kmap_atomic(page);

		chunk = min_t(unsigned int, len, PAGE_SIZE);

		memcpy_flushcache(pmem_addr, mem + off, chunk);

		kunmap_atomic(mem);

		len -= chunk;

		off = 0;

		page++;

		pmem_addr += PAGE_SIZE;

	}

}



static blk_status_t read_pmem(struct page *page, unsigned int off,

		void *pmem_addr, unsigned int len)

{

	unsigned int chunk;

	int rc;

	void *mem = kmap_atomic(page);

	void *mem;



	rc = memcpy_mcsafe(mem + off, pmem_addr, len);

	while (len) {

		mem = kmap_atomic(page);

		chunk = min_t(unsigned int, len, PAGE_SIZE);

		rc = memcpy_mcsafe(mem + off, pmem_addr, chunk);

		kunmap_atomic(mem);

		if (rc)

			return BLK_STS_IOERR;

		len -= chunk;

		off = 0;

		page++;

		pmem_addr += PAGE_SIZE;

	}

	return BLK_STS_OK;

}
@@ -188,7 +206,8 @@ static int pmem_rw_page(struct block_device *bdev, sector_t sector, 
	struct pmem_device *pmem = bdev->bd_queue->queuedata;

	blk_status_t rc;



	rc = pmem_do_bvec(pmem, page, PAGE_SIZE, 0, is_write, sector);

	rc = pmem_do_bvec(pmem, page, hpage_nr_pages(page) * PAGE_SIZE,

			  0, is_write, sector);



	/*

	 * The ->rw_page interface is subtle and tricky.  The core