On 08/05/2016 07:52 AM, Jens Axboe wrote:

On 08/05/2016 01:57 AM, Christoph Hellwig wrote:

quoted

quoted

The rw_page users were not converted to use bio/req ops. As a result
bdev_write_page is not passing down REQ_OP_WRITE and the IOs will
be sent down as reads.

Can we just get rid of REQ_OP_WRITE enum for the ->rw_page interface
and pass a 'bool write'?  If not I'd prefer to avoid using op_is_write
as much as possible - it's a confusing interface if we really want
to do a switch on read vs write vs invalid.

That's a really good point, especially since the op_flags was dropped as
well. I'll cook that up.

How about something like this? We don't bleed into the non-core bits
anymore, so we can move those back under CONFIG_BLOCK too.

diff --git a/drivers/block/brd.c b/drivers/block/brd.c
index 3439b28cce8b..0c76d4016eeb 100644
--- a/drivers/block/brd.c
+++ b/drivers/block/brd.c

@@ -300,20 +300,20 @@ static void copy_from_brd(void *dst, struct 

brd_device *brd,
   * Process a single bvec of a bio.
   */
  static int brd_do_bvec(struct brd_device *brd, struct page *page,
-			unsigned int len, unsigned int off, int op,
+			unsigned int len, unsigned int off, bool is_write,
  			sector_t sector)
  {
  	void *mem;
  	int err = 0;

-	if (op_is_write(op)) {
+	if (is_write) {
  		err = copy_to_brd_setup(brd, sector, len);
  		if (err)
  			goto out;
  	}

  	mem = kmap_atomic(page);
-	if (!op_is_write(op)) {
+	if (!is_write) {
  		copy_from_brd(mem + off, brd, sector, len);
  		flush_dcache_page(page);
  	} else {

@@ -350,8 +350,8 @@ static blk_qc_t brd_make_request(struct 

request_queue *q, struct bio *bio)
  		unsigned int len = bvec.bv_len;
  		int err;

-		err = brd_do_bvec(brd, bvec.bv_page, len,
-					bvec.bv_offset, bio_op(bio), sector);
+		err = brd_do_bvec(brd, bvec.bv_page, len, bvec.bv_offset,
+					op_is_write(bio_op(bio)), sector);
  		if (err)
  			goto io_error;
  		sector += len >> SECTOR_SHIFT;

@@ -366,11 +366,11 @@ io_error:
  }

  static int brd_rw_page(struct block_device *bdev, sector_t sector,
-		       struct page *page, int op)
+		       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, op, sector);
-	page_endio(page, op, err);
+	int err = brd_do_bvec(brd, page, PAGE_SIZE, 0, is_write, sector);
+	page_endio(page, is_write, err);
  	return err;
  }

diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
index ca29649c4b08..04365b17ee67 100644
--- a/drivers/block/zram/zram_drv.c
+++ b/drivers/block/zram/zram_drv.c

@@ -843,15 +843,16 @@ static void zram_bio_discard(struct zram *zram, 

u32 index,
  }

  static int zram_bvec_rw(struct zram *zram, struct bio_vec *bvec, u32 
index,
-			int offset, int op)
+			int offset, bool is_write)
  {
  	unsigned long start_time = jiffies;
+	int rw_acct = is_write ? REQ_OP_WRITE : REQ_OP_READ;
  	int ret;

-	generic_start_io_acct(op, bvec->bv_len >> SECTOR_SHIFT,
+	generic_start_io_acct(rw_acct, bvec->bv_len >> SECTOR_SHIFT,
  			&zram->disk->part0);

-	if (!op_is_write(op)) {
+	if (!is_write) {
  		atomic64_inc(&zram->stats.num_reads);
  		ret = zram_bvec_read(zram, bvec, index, offset);
  	} else {

@@ -859,10 +860,10 @@ static int zram_bvec_rw(struct zram *zram, struct 

bio_vec *bvec, u32 index,
  		ret = zram_bvec_write(zram, bvec, index, offset);
  	}

-	generic_end_io_acct(op, &zram->disk->part0, start_time);
+	generic_end_io_acct(rw_acct, &zram->disk->part0, start_time);

  	if (unlikely(ret)) {
-		if (!op_is_write(op))
+		if (!is_write)
  			atomic64_inc(&zram->stats.failed_reads);
  		else
  			atomic64_inc(&zram->stats.failed_writes);

@@ -903,17 +904,17 @@ static void __zram_make_request(struct zram *zram, 

struct bio *bio)
  			bv.bv_offset = bvec.bv_offset;

  			if (zram_bvec_rw(zram, &bv, index, offset,
-					 bio_op(bio)) < 0)
+					 op_is_write(bio_op(bio))) < 0)
  				goto out;

  			bv.bv_len = bvec.bv_len - max_transfer_size;
  			bv.bv_offset += max_transfer_size;
  			if (zram_bvec_rw(zram, &bv, index + 1, 0,
-					 bio_op(bio)) < 0)
+					 op_is_write(bio_op(bio))) < 0)
  				goto out;
  		} else
  			if (zram_bvec_rw(zram, &bvec, index, offset,
-					 bio_op(bio)) < 0)
+					 op_is_write(bio_op(bio))) < 0)
  				goto out;

  		update_position(&index, &offset, &bvec);

@@ -970,7 +971,7 @@ static void zram_slot_free_notify(struct 

block_device *bdev,
  }

  static int zram_rw_page(struct block_device *bdev, sector_t sector,
-		       struct page *page, int op)
+		       struct page *page, bool is_write)
  {
  	int offset, err = -EIO;
  	u32 index;

@@ -994,7 +995,7 @@ static int zram_rw_page(struct block_device *bdev, 

sector_t sector,
  	bv.bv_len = PAGE_SIZE;
  	bv.bv_offset = 0;

-	err = zram_bvec_rw(zram, &bv, index, offset, op);
+	err = zram_bvec_rw(zram, &bv, index, offset, is_write);
  put_zram:
  	zram_meta_put(zram);
  out:

@@ -1007,7 +1008,7 @@ out:
  	 * (e.g., SetPageError, set_page_dirty and extra works).
  	 */
  	if (err == 0)
-		page_endio(page, op, 0);
+		page_endio(page, is_write, 0);
  	return err;
  }

diff --git a/drivers/nvdimm/btt.c b/drivers/nvdimm/btt.c
index 7cf3bdfaf809..88e91666f145 100644
--- a/drivers/nvdimm/btt.c
+++ b/drivers/nvdimm/btt.c

@@ -1133,11 +1133,11 @@ static int btt_write_pg(struct btt *btt, struct 

bio_integrity_payload *bip,

  static int btt_do_bvec(struct btt *btt, struct bio_integrity_payload *bip,
  			struct page *page, unsigned int len, unsigned int off,
-			int op, sector_t sector)
+			bool is_write, sector_t sector)
  {
  	int ret;

-	if (!op_is_write(op)) {
+	if (!is_write) {
  		ret = btt_read_pg(btt, bip, page, off, sector, len);
  		flush_dcache_page(page);
  	} else {

@@ -1180,7 +1180,7 @@ static blk_qc_t btt_make_request(struct 

request_queue *q, struct bio *bio)
  		BUG_ON(len % btt->sector_size);

  		err = btt_do_bvec(btt, bip, bvec.bv_page, len, bvec.bv_offset,
-				  bio_op(bio), iter.bi_sector);
+				  op_is_write(bio_op(bio)), iter.bi_sector);
  		if (err) {
  			dev_info(&btt->nd_btt->dev,
  					"io error in %s sector %lld, len %d,\n",

@@ -1200,12 +1200,12 @@ out:
  }

  static int btt_rw_page(struct block_device *bdev, sector_t sector,
-		struct page *page, int op)
+		struct page *page, bool is_write)
  {
  	struct btt *btt = bdev->bd_disk->private_data;

-	btt_do_bvec(btt, NULL, page, PAGE_SIZE, 0, op, sector);
-	page_endio(page, op, 0);
+	btt_do_bvec(btt, NULL, page, PAGE_SIZE, 0, is_write, sector);
+	page_endio(page, is_write, 0);
  	return 0;
  }

diff --git a/drivers/nvdimm/pmem.c b/drivers/nvdimm/pmem.c
index d64d92481c1d..20bae50c231d 100644
--- a/drivers/nvdimm/pmem.c
+++ b/drivers/nvdimm/pmem.c

@@ -67,7 +67,7 @@ static void pmem_clear_poison(struct pmem_device 

*pmem, phys_addr_t offset,
  }

  static int pmem_do_bvec(struct pmem_device *pmem, struct page *page,
-			unsigned int len, unsigned int off, int op,
+			unsigned int len, unsigned int off, bool is_write,
  			sector_t sector)
  {
  	int rc = 0;

@@ -79,7 +79,7 @@ static int pmem_do_bvec(struct pmem_device *pmem, 

struct page *page,
  	if (unlikely(is_bad_pmem(&pmem->bb, sector, len)))
  		bad_pmem = true;

-	if (!op_is_write(op)) {
+	if (!is_write) {
  		if (unlikely(bad_pmem))
  			rc = -EIO;
  		else {

@@ -134,7 +134,7 @@ static blk_qc_t pmem_make_request(struct 

request_queue *q, struct bio *bio)
  	do_acct = nd_iostat_start(bio, &start);
  	bio_for_each_segment(bvec, bio, iter) {
  		rc = pmem_do_bvec(pmem, bvec.bv_page, bvec.bv_len,
-				bvec.bv_offset, bio_op(bio),
+				bvec.bv_offset, op_is_write(bio_op(bio)),
  				iter.bi_sector);
  		if (rc) {
  			bio->bi_error = rc;

@@ -152,12 +152,12 @@ static blk_qc_t pmem_make_request(struct 

request_queue *q, struct bio *bio)
  }

  static int pmem_rw_page(struct block_device *bdev, sector_t sector,
-		       struct page *page, int op)
+		       struct page *page, bool is_write)
  {
  	struct pmem_device *pmem = bdev->bd_queue->queuedata;
  	int rc;

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

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

@@ -166,7 +166,7 @@ static int pmem_rw_page(struct block_device *bdev, 

sector_t sector,
  	 * caused by double completion.
  	 */
  	if (rc == 0)
-		page_endio(page, op, 0);
+		page_endio(page, is_write, 0);

  	return rc;
  }

diff --git a/fs/block_dev.c b/fs/block_dev.c
index d402899ba135..c3cdde87cc8c 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c

@@ -416,8 +416,7 @@ int bdev_read_page(struct block_device *bdev, 

sector_t sector,
  	result = blk_queue_enter(bdev->bd_queue, false);
  	if (result)
  		return result;
-	result = ops->rw_page(bdev, sector + get_start_sect(bdev), page,
-			      REQ_OP_READ);
+	result = ops->rw_page(bdev, sector + get_start_sect(bdev), page, false);
  	blk_queue_exit(bdev->bd_queue);
  	return result;
  }

@@ -455,8 +454,7 @@ int bdev_write_page(struct block_device *bdev, 

sector_t sector,
  		return result;

  	set_page_writeback(page);
-	result = ops->rw_page(bdev, sector + get_start_sect(bdev), page,
-			      REQ_OP_WRITE);
+	result = ops->rw_page(bdev, sector + get_start_sect(bdev), page, true);
  	if (result)
  		end_page_writeback(page);
  	else

diff --git a/fs/mpage.c b/fs/mpage.c
index 7a09c55b4bd0..d2413af0823a 100644
--- a/fs/mpage.c
+++ b/fs/mpage.c

@@ -50,7 +50,7 @@ static void mpage_end_io(struct bio *bio)

  	bio_for_each_segment_all(bv, bio, i) {
  		struct page *page = bv->bv_page;
-		page_endio(page, bio_op(bio), bio->bi_error);
+		page_endio(page, op_is_write(bio_op(bio)), bio->bi_error);
  	}

  	bio_put(bio);

diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h
index 14b28ff2caf8..f254eb264924 100644
--- a/include/linux/blk_types.h
+++ b/include/linux/blk_types.h

@@ -18,17 +18,6 @@ struct cgroup_subsys_state;
  typedef void (bio_end_io_t) (struct bio *);
  typedef void (bio_destructor_t) (struct bio *);

-enum req_op {
-	REQ_OP_READ,
-	REQ_OP_WRITE,
-	REQ_OP_DISCARD,		/* request to discard sectors */
-	REQ_OP_SECURE_ERASE,	/* request to securely erase sectors */
-	REQ_OP_WRITE_SAME,	/* write same block many times */
-	REQ_OP_FLUSH,		/* request for cache flush */
-};
-
-#define REQ_OP_BITS 3
-
  #ifdef CONFIG_BLOCK
  /*
   * main unit of I/O for the block layer and lower layers (ie drivers and

@@ -239,6 +228,17 @@ enum rq_flag_bits {
  #define REQ_HASHED		(1ULL << __REQ_HASHED)
  #define REQ_MQ_INFLIGHT		(1ULL << __REQ_MQ_INFLIGHT)

+enum req_op {
+	REQ_OP_READ,
+	REQ_OP_WRITE,
+	REQ_OP_DISCARD,		/* request to discard sectors */
+	REQ_OP_SECURE_ERASE,	/* request to securely erase sectors */
+	REQ_OP_WRITE_SAME,	/* write same block many times */
+	REQ_OP_FLUSH,		/* request for cache flush */
+};
+
+#define REQ_OP_BITS 3
+
  typedef unsigned int blk_qc_t;
  #define BLK_QC_T_NONE	-1U
  #define BLK_QC_T_SHIFT	16

diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index ccd68c0d01de..2c210b6a7bcf 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h

@@ -1672,7 +1672,7 @@ struct blk_dax_ctl {
  struct block_device_operations {
  	int (*open) (struct block_device *, fmode_t);
  	void (*release) (struct gendisk *, fmode_t);
-	int (*rw_page)(struct block_device *, sector_t, struct page *, int op);
+	int (*rw_page)(struct block_device *, sector_t, struct page *, bool);
  	int (*ioctl) (struct block_device *, fmode_t, unsigned, unsigned long);
  	int (*compat_ioctl) (struct block_device *, fmode_t, unsigned, 

unsigned long);
  	long (*direct_access)(struct block_device *, sector_t, void **, pfn_t *,

diff --git a/include/linux/fs.h b/include/linux/fs.h
index 498255e6914e..f3f0b4c8e8ac 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h

@@ -2480,13 +2480,12 @@ extern void init_special_inode(struct inode *, 

umode_t, dev_t);
  extern void make_bad_inode(struct inode *);
  extern bool is_bad_inode(struct inode *);

+#ifdef CONFIG_BLOCK
  static inline bool op_is_write(unsigned int op)
  {
  	return op == REQ_OP_READ ? false : true;
  }

-#ifdef CONFIG_BLOCK
-
  /*
   * return data direction, READ or WRITE
   */

diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h
index 45786374abbd..66a1260b33de 100644
--- a/include/linux/pagemap.h
+++ b/include/linux/pagemap.h

@@ -510,7 +510,7 @@ static inline void wait_on_page_writeback(struct 

page *page)
  extern void end_page_writeback(struct page *page);
  void wait_for_stable_page(struct page *page);

-void page_endio(struct page *page, int op, int err);
+void page_endio(struct page *page, bool is_write, int err);

  /*
   * Add an arbitrary waiter to a page's wait queue

diff --git a/mm/filemap.c b/mm/filemap.c
index daef091d4c50..8a287dfc5372 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c

@@ -887,9 +887,9 @@ EXPORT_SYMBOL(end_page_writeback);
   * After completing I/O on a page, call this routine to update the page
   * flags appropriately
   */
-void page_endio(struct page *page, int op, int err)
+void page_endio(struct page *page, bool is_write, int err)
  {
-	if (!op_is_write(op)) {
+	if (!is_write) {
  		if (!err) {
  			SetPageUptodate(page);
  		} else {

-- 
Jens Axboe