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Message-ID: <57A4D54F.4080307@redhat.com>
Date: Fri, 5 Aug 2016 13:05:03 -0500
From: Mike Christie <mchristi@...hat.com>
To: Jens Axboe <axboe@...nel.dk>, Christoph Hellwig <hch@...radead.org>
Cc: ross.zwisler@...ux.intel.com, linux-ext4@...r.kernel.org,
linux-block@...r.kernel.org, linux-fsdevel@...r.kernel.org,
david@...morbit.com, minchan@...nel.org, ngupta@...are.org,
vishal.l.verma@...el.com
Subject: Re: [PATCH 1/1] mm/block: convert rw_page users to bio op use
On 08/05/2016 09:09 AM, Jens Axboe wrote:
> On 08/05/2016 07:52 AM, Jens Axboe wrote:
>> On 08/05/2016 01:57 AM, Christoph Hellwig wrote:
>>>>
>>>> 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 {
>
Looks ok to me. Also tested all the patches in the linus2 branch
and verified it fixed the rw_page related hang for me.
Reviewed-by: Mike Christie <mchristi@...hat.com>
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