8 files changed, 44 insertions, 217 deletions

diff --git a/block/bdev.c b/block/bdev.c
index edc110d90df4..1795c7d4b99e 100644
--- a/block/bdev.c
+++ b/block/bdev.c
@@ -304,84 +304,6 @@ out:
 }
 EXPORT_SYMBOL(thaw_bdev);
 
-/**
- * bdev_read_page() - Start reading a page from a block device
- * @bdev: The device to read the page from
- * @sector: The offset on the device to read the page to (need not be aligned)
- * @page: The page to read
- *
- * On entry, the page should be locked.  It will be unlocked when the page
- * has been read.  If the block driver implements rw_page synchronously,
- * that will be true on exit from this function, but it need not be.
- *
- * Errors returned by this function are usually "soft", eg out of memory, or
- * queue full; callers should try a different route to read this page rather
- * than propagate an error back up the stack.
- *
- * Return: negative errno if an error occurs, 0 if submission was successful.
- */
-int bdev_read_page(struct block_device *bdev, sector_t sector,
-			struct page *page)
-{
-	const struct block_device_operations *ops = bdev->bd_disk->fops;
-	int result = -EOPNOTSUPP;
-
-	if (!ops->rw_page || bdev_get_integrity(bdev))
-		return result;
-
-	result = blk_queue_enter(bdev_get_queue(bdev), 0);
-	if (result)
-		return result;
-	result = ops->rw_page(bdev, sector + get_start_sect(bdev), page,
-			      REQ_OP_READ);
-	blk_queue_exit(bdev_get_queue(bdev));
-	return result;
-}
-
-/**
- * bdev_write_page() - Start writing a page to a block device
- * @bdev: The device to write the page to
- * @sector: The offset on the device to write the page to (need not be aligned)
- * @page: The page to write
- * @wbc: The writeback_control for the write
- *
- * On entry, the page should be locked and not currently under writeback.
- * On exit, if the write started successfully, the page will be unlocked and
- * under writeback.  If the write failed already (eg the driver failed to
- * queue the page to the device), the page will still be locked.  If the
- * caller is a ->writepage implementation, it will need to unlock the page.
- *
- * Errors returned by this function are usually "soft", eg out of memory, or
- * queue full; callers should try a different route to write this page rather
- * than propagate an error back up the stack.
- *
- * Return: negative errno if an error occurs, 0 if submission was successful.
- */
-int bdev_write_page(struct block_device *bdev, sector_t sector,
-			struct page *page, struct writeback_control *wbc)
-{
-	int result;
-	const struct block_device_operations *ops = bdev->bd_disk->fops;
-
-	if (!ops->rw_page || bdev_get_integrity(bdev))
-		return -EOPNOTSUPP;
-	result = blk_queue_enter(bdev_get_queue(bdev), 0);
-	if (result)
-		return result;
-
-	set_page_writeback(page);
-	result = ops->rw_page(bdev, sector + get_start_sect(bdev), page,
-			      REQ_OP_WRITE);
-	if (result) {
-		end_page_writeback(page);
-	} else {
-		clean_page_buffers(page);
-		unlock_page(page);
-	}
-	blk_queue_exit(bdev_get_queue(bdev));
-	return result;
-}
-
 /*
  * pseudo-fs
  */
diff --git a/drivers/block/brd.c b/drivers/block/brd.c
index 20acc4a1fd6d..37dce184eb56 100644
--- a/drivers/block/brd.c
+++ b/drivers/block/brd.c
@@ -309,23 +309,9 @@ static void brd_submit_bio(struct bio *bio)
 	bio_endio(bio);
 }
 
-static int brd_rw_page(struct block_device *bdev, sector_t sector,
-		       struct page *page, enum req_op op)
-{
-	struct brd_device *brd = bdev->bd_disk->private_data;
-	int err;
-
-	if (PageTransHuge(page))
-		return -ENOTSUPP;
-	err = brd_do_bvec(brd, page, PAGE_SIZE, 0, op, sector);
-	page_endio(page, op_is_write(op), err);
-	return err;
-}
-
 static const struct block_device_operations brd_fops = {
 	.owner =		THIS_MODULE,
 	.submit_bio =		brd_submit_bio,
-	.rw_page =		brd_rw_page,
 };
 
 /*
@@ -411,6 +397,7 @@ static int brd_alloc(int i)
 
 	/* Tell the block layer that this is not a rotational device */
 	blk_queue_flag_set(QUEUE_FLAG_NONROT, disk->queue);
+	blk_queue_flag_set(QUEUE_FLAG_SYNCHRONOUS, disk->queue);
 	blk_queue_flag_clear(QUEUE_FLAG_ADD_RANDOM, disk->queue);
 	err = add_disk(disk);
 	if (err)
diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
index 5d1088a645e3..25526707f607 100644
--- a/drivers/block/zram/zram_drv.c
+++ b/drivers/block/zram/zram_drv.c
@@ -1453,10 +1453,6 @@ static int __zram_bvec_read(struct zram *zram, struct page *page, u32 index,
 		/* Slot should be unlocked before the function call */
 		zram_slot_unlock(zram, index);
 
-		/* A null bio means rw_page was used, we must fallback to bio */
-		if (!bio)
-			return -EOPNOTSUPP;
-
 		ret = zram_bvec_read_from_bdev(zram, page, index, bio,
 					       partial_io);
 	}
@@ -2081,61 +2077,6 @@ static void zram_slot_free_notify(struct block_device *bdev,
 	zram_slot_unlock(zram, index);
 }
 
-static int zram_rw_page(struct block_device *bdev, sector_t sector,
-		       struct page *page, enum req_op op)
-{
-	int offset, ret;
-	u32 index;
-	struct zram *zram;
-	struct bio_vec bv;
-	unsigned long start_time;
-
-	if (PageTransHuge(page))
-		return -ENOTSUPP;
-	zram = bdev->bd_disk->private_data;
-
-	if (!valid_io_request(zram, sector, PAGE_SIZE)) {
-		atomic64_inc(&zram->stats.invalid_io);
-		ret = -EINVAL;
-		goto out;
-	}
-
-	index = sector >> SECTORS_PER_PAGE_SHIFT;
-	offset = (sector & (SECTORS_PER_PAGE - 1)) << SECTOR_SHIFT;
-
-	bv.bv_page = page;
-	bv.bv_len = PAGE_SIZE;
-	bv.bv_offset = 0;
-
-	start_time = bdev_start_io_acct(bdev->bd_disk->part0,
-			SECTORS_PER_PAGE, op, jiffies);
-	ret = zram_bvec_rw(zram, &bv, index, offset, op, NULL);
-	bdev_end_io_acct(bdev->bd_disk->part0, op, start_time);
-out:
-	/*
-	 * If I/O fails, just return error(ie, non-zero) without
-	 * calling page_endio.
-	 * It causes resubmit the I/O with bio request by upper functions
-	 * of rw_page(e.g., swap_readpage, __swap_writepage) and
-	 * bio->bi_end_io does things to handle the error
-	 * (e.g., SetPageError, set_page_dirty and extra works).
-	 */
-	if (unlikely(ret < 0))
-		return ret;
-
-	switch (ret) {
-	case 0:
-		page_endio(page, op_is_write(op), 0);
-		break;
-	case 1:
-		ret = 0;
-		break;
-	default:
-		WARN_ON(1);
-	}
-	return ret;
-}
-
 static void zram_destroy_comps(struct zram *zram)
 {
 	u32 prio;
@@ -2290,7 +2231,6 @@ static const struct block_device_operations zram_devops = {
 	.open = zram_open,
 	.submit_bio = zram_submit_bio,
 	.swap_slot_free_notify = zram_slot_free_notify,
-	.rw_page = zram_rw_page,
 	.owner = THIS_MODULE
 };
 
@@ -2389,6 +2329,7 @@ static int zram_add(void)
 	set_capacity(zram->disk, 0);
 	/* zram devices sort of resembles non-rotational disks */
 	blk_queue_flag_set(QUEUE_FLAG_NONROT, zram->disk->queue);
+	blk_queue_flag_set(QUEUE_FLAG_SYNCHRONOUS, zram->disk->queue);
 	blk_queue_flag_clear(QUEUE_FLAG_ADD_RANDOM, zram->disk->queue);
 
 	/*
diff --git a/drivers/nvdimm/btt.c b/drivers/nvdimm/btt.c
index 0297b7882e33..d5593b0dc700 100644
--- a/drivers/nvdimm/btt.c
+++ b/drivers/nvdimm/btt.c
@@ -1482,20 +1482,6 @@ static void btt_submit_bio(struct bio *bio)
 	bio_endio(bio);
 }
 
-static int btt_rw_page(struct block_device *bdev, sector_t sector,
-		struct page *page, enum req_op op)
-{
-	struct btt *btt = bdev->bd_disk->private_data;
-	int rc;
-
-	rc = btt_do_bvec(btt, NULL, page, thp_size(page), 0, op, sector);
-	if (rc == 0)
-		page_endio(page, op_is_write(op), 0);
-
-	return rc;
-}
-
-
 static int btt_getgeo(struct block_device *bd, struct hd_geometry *geo)
 {
 	/* some standard values */
@@ -1508,7 +1494,6 @@ static int btt_getgeo(struct block_device *bd, struct hd_geometry *geo)
 static const struct block_device_operations btt_fops = {
 	.owner =		THIS_MODULE,
 	.submit_bio =		btt_submit_bio,
-	.rw_page =		btt_rw_page,
 	.getgeo =		btt_getgeo,
 };
 
@@ -1530,6 +1515,7 @@ static int btt_blk_init(struct btt *btt)
 	blk_queue_logical_block_size(btt->btt_disk->queue, btt->sector_size);
 	blk_queue_max_hw_sectors(btt->btt_disk->queue, UINT_MAX);
 	blk_queue_flag_set(QUEUE_FLAG_NONROT, btt->btt_disk->queue);
+	blk_queue_flag_set(QUEUE_FLAG_SYNCHRONOUS, btt->btt_disk->queue);
 
 	if (btt_meta_size(btt)) {
 		rc = nd_integrity_init(btt->btt_disk, btt_meta_size(btt));
diff --git a/drivers/nvdimm/pmem.c b/drivers/nvdimm/pmem.c
index 96e6e9a5f235..ceea55f621cc 100644
--- a/drivers/nvdimm/pmem.c
+++ b/drivers/nvdimm/pmem.c
@@ -238,28 +238,6 @@ static void pmem_submit_bio(struct bio *bio)
 	bio_endio(bio);
 }
 
-static int pmem_rw_page(struct block_device *bdev, sector_t sector,
-		       struct page *page, enum req_op op)
-{
-	struct pmem_device *pmem = bdev->bd_disk->private_data;
-	blk_status_t rc;
-
-	if (op_is_write(op))
-		rc = pmem_do_write(pmem, page, 0, sector, thp_size(page));
-	else
-		rc = pmem_do_read(pmem, page, 0, sector, thp_size(page));
-	/*
-	 * The ->rw_page interface is subtle and tricky.  The core
-	 * retries on any error, so we can only invoke page_endio() in
-	 * the successful completion case.  Otherwise, we'll see crashes
-	 * caused by double completion.
-	 */
-	if (rc == 0)
-		page_endio(page, op_is_write(op), 0);
-
-	return blk_status_to_errno(rc);
-}
-
 /* see "strong" declaration in tools/testing/nvdimm/pmem-dax.c */
 __weak long __pmem_direct_access(struct pmem_device *pmem, pgoff_t pgoff,
 		long nr_pages, enum dax_access_mode mode, void **kaddr,
@@ -310,7 +288,6 @@ __weak long __pmem_direct_access(struct pmem_device *pmem, pgoff_t pgoff,
 static const struct block_device_operations pmem_fops = {
 	.owner =		THIS_MODULE,
 	.submit_bio =		pmem_submit_bio,
-	.rw_page =		pmem_rw_page,
 };
 
 static int pmem_dax_zero_page_range(struct dax_device *dax_dev, pgoff_t pgoff,
@@ -565,6 +542,7 @@ static int pmem_attach_disk(struct device *dev,
 	blk_queue_logical_block_size(q, pmem_sector_size(ndns));
 	blk_queue_max_hw_sectors(q, UINT_MAX);
 	blk_queue_flag_set(QUEUE_FLAG_NONROT, q);
+	blk_queue_flag_set(QUEUE_FLAG_SYNCHRONOUS, q);
 	if (pmem->pfn_flags & PFN_MAP)
 		blk_queue_flag_set(QUEUE_FLAG_DAX, q);
 
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 43d4e073b111..c5e59965b145 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -554,6 +554,7 @@ struct request_queue {
 #define QUEUE_FLAG_IO_STAT	7	/* do disk/partitions IO accounting */
 #define QUEUE_FLAG_NOXMERGES	9	/* No extended merges */
 #define QUEUE_FLAG_ADD_RANDOM	10	/* Contributes to random pool */
+#define QUEUE_FLAG_SYNCHRONOUS	11	/* always completes in submit context */
 #define QUEUE_FLAG_SAME_FORCE	12	/* force complete on same CPU */
 #define QUEUE_FLAG_INIT_DONE	14	/* queue is initialized */
 #define QUEUE_FLAG_STABLE_WRITES 15	/* don't modify blks until WB is done */
@@ -1250,6 +1251,12 @@ static inline bool bdev_nonrot(struct block_device *bdev)
 	return blk_queue_nonrot(bdev_get_queue(bdev));
 }
 
+static inline bool bdev_synchronous(struct block_device *bdev)
+{
+	return test_bit(QUEUE_FLAG_SYNCHRONOUS,
+			&bdev_get_queue(bdev)->queue_flags);
+}
+
 static inline bool bdev_stable_writes(struct block_device *bdev)
 {
 	return test_bit(QUEUE_FLAG_STABLE_WRITES,
@@ -1382,7 +1389,6 @@ struct block_device_operations {
 			unsigned int flags);
 	int (*open) (struct block_device *, fmode_t);
 	void (*release) (struct gendisk *, fmode_t);
-	int (*rw_page)(struct block_device *, sector_t, struct page *, enum req_op);
 	int (*ioctl) (struct block_device *, fmode_t, unsigned, unsigned long);
 	int (*compat_ioctl) (struct block_device *, fmode_t, unsigned, unsigned long);
 	unsigned int (*check_events) (struct gendisk *disk,
@@ -1417,10 +1423,6 @@ extern int blkdev_compat_ptr_ioctl(struct block_device *, fmode_t,
 #define blkdev_compat_ptr_ioctl NULL
 #endif
 
-extern int bdev_read_page(struct block_device *, sector_t, struct page *);
-extern int bdev_write_page(struct block_device *, sector_t, struct page *,
-						struct writeback_control *);
-
 static inline void blk_wake_io_task(struct task_struct *waiter)
 {
 	/*
diff --git a/mm/page_io.c b/mm/page_io.c
index 0a1a3b831344..a805117f7fd7 100644
--- a/mm/page_io.c
+++ b/mm/page_io.c
@@ -27,7 +27,7 @@
 #include <linux/delayacct.h>
 #include "swap.h"
 
-static void end_swap_bio_write(struct bio *bio)
+static void __end_swap_bio_write(struct bio *bio)
 {
 	struct page *page = bio_first_page_all(bio);
 
@@ -48,6 +48,11 @@ static void end_swap_bio_write(struct bio *bio)
 		ClearPageReclaim(page);
 	}
 	end_page_writeback(page);
+}
+
+static void end_swap_bio_write(struct bio *bio)
+{
+	__end_swap_bio_write(bio);
 	bio_put(bio);
 }
 
@@ -326,15 +331,31 @@ static void swap_writepage_fs(struct page *page, struct writeback_control *wbc)
 		*wbc->swap_plug = sio;
 }
 
-static void swap_writepage_bdev(struct page *page,
+static void swap_writepage_bdev_sync(struct page *page,
 		struct writeback_control *wbc, struct swap_info_struct *sis)
 {
-	struct bio *bio;
+	struct bio_vec bv;
+	struct bio bio;
 
-	if (!bdev_write_page(sis->bdev, swap_page_sector(page), page, wbc)) {
-		count_swpout_vm_event(page);
-		return;
-	}
+	bio_init(&bio, sis->bdev, &bv, 1,
+		 REQ_OP_WRITE | REQ_SWAP | wbc_to_write_flags(wbc));
+	bio.bi_iter.bi_sector = swap_page_sector(page);
+	bio_add_page(&bio, page, thp_size(page), 0);
+
+	bio_associate_blkg_from_page(&bio, page);
+	count_swpout_vm_event(page);
+
+	set_page_writeback(page);
+	unlock_page(page);
+
+	submit_bio_wait(&bio);
+	__end_swap_bio_write(&bio);
+}
+
+static void swap_writepage_bdev_async(struct page *page,
+		struct writeback_control *wbc, struct swap_info_struct *sis)
+{
+	struct bio *bio;
 
 	bio = bio_alloc(sis->bdev, 1,
 			REQ_OP_WRITE | REQ_SWAP | wbc_to_write_flags(wbc),
@@ -362,8 +383,10 @@ void __swap_writepage(struct page *page, struct writeback_control *wbc)
 	 */
 	if (data_race(sis->flags & SWP_FS_OPS))
 		swap_writepage_fs(page, wbc);
+	else if (sis->flags & SWP_SYNCHRONOUS_IO)
+		swap_writepage_bdev_sync(page, wbc, sis);
 	else
-		swap_writepage_bdev(page, wbc, sis);
+		swap_writepage_bdev_async(page, wbc, sis);
 }
 
 void swap_write_unplug(struct swap_iocb *sio)
@@ -447,12 +470,6 @@ static void swap_readpage_bdev_sync(struct page *page,
 	struct bio_vec bv;
 	struct bio bio;
 
-	if ((sis->flags & SWP_SYNCHRONOUS_IO) &&
-	    !bdev_read_page(sis->bdev, swap_page_sector(page), page)) {
-		count_vm_event(PSWPIN);
-		return;
-	}
-
 	bio_init(&bio, sis->bdev, &bv, 1, REQ_OP_READ);
 	bio.bi_iter.bi_sector = swap_page_sector(page);
 	bio_add_page(&bio, page, thp_size(page), 0);
@@ -472,12 +489,6 @@ static void swap_readpage_bdev_async(struct page *page,
 {
 	struct bio *bio;
 
-	if ((sis->flags & SWP_SYNCHRONOUS_IO) &&
-	    !bdev_read_page(sis->bdev, swap_page_sector(page), page)) {
-		count_vm_event(PSWPIN);
-		return;
-	}
-
 	bio = bio_alloc(sis->bdev, 1, REQ_OP_READ, GFP_KERNEL);
 	bio->bi_iter.bi_sector = swap_page_sector(page);
 	bio->bi_end_io = end_swap_bio_read;
@@ -513,7 +524,7 @@ void swap_readpage(struct page *page, bool synchronous, struct swap_iocb **plug)
 		unlock_page(page);
 	} else if (data_race(sis->flags & SWP_FS_OPS)) {
 		swap_readpage_fs(page, plug);
-	} else if (synchronous) {
+	} else if (synchronous || (sis->flags & SWP_SYNCHRONOUS_IO)) {
 		swap_readpage_bdev_sync(page, sis);
 	} else {
 		swap_readpage_bdev_async(page, sis);
diff --git a/mm/swapfile.c b/mm/swapfile.c
index af151679d13a..888aed774fb6 100644
--- a/mm/swapfile.c
+++ b/mm/swapfile.c
@@ -3071,7 +3071,7 @@ SYSCALL_DEFINE2(swapon, const char __user *, specialfile, int, swap_flags)
 	if (p->bdev && bdev_stable_writes(p->bdev))
 		p->flags |= SWP_STABLE_WRITES;
 
-	if (p->bdev && p->bdev->bd_disk->fops->rw_page)
+	if (p->bdev && bdev_synchronous(p->bdev))
 		p->flags |= SWP_SYNCHRONOUS_IO;
 
 	if (p->bdev && bdev_nonrot(p->bdev)) {