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Commit 4f024f37 authored by Kent Overstreet's avatar Kent Overstreet
Browse files

block: Abstract out bvec iterator 



Immutable biovecs are going to require an explicit iterator. To
implement immutable bvecs, a later patch is going to add a bi_bvec_done
member to this struct; for now, this patch effectively just renames
things.

Signed-off-by: default avatarKent Overstreet <kmo@daterainc.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: "Ed L. Cashin" <ecashin@coraid.com>
Cc: Nick Piggin <npiggin@kernel.dk>
Cc: Lars Ellenberg <drbd-dev@lists.linbit.com>
Cc: Jiri Kosina <jkosina@suse.cz>
Cc: Matthew Wilcox <willy@linux.intel.com>
Cc: Geoff Levand <geoff@infradead.org>
Cc: Yehuda Sadeh <yehuda@inktank.com>
Cc: Sage Weil <sage@inktank.com>
Cc: Alex Elder <elder@inktank.com>
Cc: ceph-devel@vger.kernel.org
Cc: Joshua Morris <josh.h.morris@us.ibm.com>
Cc: Philip Kelleher <pjk1939@linux.vnet.ibm.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>
Cc: Neil Brown <neilb@suse.de>
Cc: Alasdair Kergon <agk@redhat.com>
Cc: Mike Snitzer <snitzer@redhat.com>
Cc: dm-devel@redhat.com
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: linux390@de.ibm.com
Cc: Boaz Harrosh <bharrosh@panasas.com>
Cc: Benny Halevy <bhalevy@tonian.com>
Cc: "James E.J. Bottomley" <JBottomley@parallels.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: "Nicholas A. Bellinger" <nab@linux-iscsi.org>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Chris Mason <chris.mason@fusionio.com>
Cc: "Theodore Ts'o" <tytso@mit.edu>
Cc: Andreas Dilger <adilger.kernel@dilger.ca>
Cc: Jaegeuk Kim <jaegeuk.kim@samsung.com>
Cc: Steven Whitehouse <swhiteho@redhat.com>
Cc: Dave Kleikamp <shaggy@kernel.org>
Cc: Joern Engel <joern@logfs.org>
Cc: Prasad Joshi <prasadjoshi.linux@gmail.com>
Cc: Trond Myklebust <Trond.Myklebust@netapp.com>
Cc: KONISHI Ryusuke <konishi.ryusuke@lab.ntt.co.jp>
Cc: Mark Fasheh <mfasheh@suse.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Ben Myers <bpm@sgi.com>
Cc: xfs@oss.sgi.com
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Len Brown <len.brown@intel.com>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Cc: Herton Ronaldo Krzesinski <herton.krzesinski@canonical.com>
Cc: Ben Hutchings <ben@decadent.org.uk>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Guo Chao <yan@linux.vnet.ibm.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Asai Thambi S P <asamymuthupa@micron.com>
Cc: Selvan Mani <smani@micron.com>
Cc: Sam Bradshaw <sbradshaw@micron.com>
Cc: Wei Yongjun <yongjun_wei@trendmicro.com.cn>
Cc: "Roger Pau Monné" <roger.pau@citrix.com>
Cc: Jan Beulich <jbeulich@suse.com>
Cc: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Cc: Ian Campbell <Ian.Campbell@citrix.com>
Cc: Sebastian Ott <sebott@linux.vnet.ibm.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Jiang Liu <jiang.liu@huawei.com>
Cc: Nitin Gupta <ngupta@vflare.org>
Cc: Jerome Marchand <jmarchand@redhat.com>
Cc: Joe Perches <joe@perches.com>
Cc: Peng Tao <tao.peng@emc.com>
Cc: Andy Adamson <andros@netapp.com>
Cc: fanchaoting <fanchaoting@cn.fujitsu.com>
Cc: Jie Liu <jeff.liu@oracle.com>
Cc: Sunil Mushran <sunil.mushran@gmail.com>
Cc: "Martin K. Petersen" <martin.petersen@oracle.com>
Cc: Namjae Jeon <namjae.jeon@samsung.com>
Cc: Pankaj Kumar <pankaj.km@samsung.com>
Cc: Dan Magenheimer <dan.magenheimer@oracle.com>
Cc: Mel Gorman <mgorman@suse.de>6
parent ed9c47be

Documentation/block/biodoc.txt

+3 −4
Original line number Diff line number Diff line
@@ -447,14 +447,13 @@ struct bio_vec { 
 * main unit of I/O for the block layer and lower layers (ie drivers)

 */

struct bio {

       sector_t            bi_sector;

       struct bio          *bi_next;    /* request queue link */

       struct block_device *bi_bdev;	/* target device */

       unsigned long       bi_flags;    /* status, command, etc */

       unsigned long       bi_rw;       /* low bits: r/w, high: priority */



       unsigned int	bi_vcnt;     /* how may bio_vec's */

       unsigned int	bi_idx;		/* current index into bio_vec array */

       struct bvec_iter	bi_iter;	/* current index into bio_vec array */



       unsigned int	bi_size;     /* total size in bytes */

       unsigned short 	bi_phys_segments; /* segments after physaddr coalesce*/
@@ -480,7 +479,7 @@ With this multipage bio design: 
- Code that traverses the req list can find all the segments of a bio

  by using rq_for_each_segment.  This handles the fact that a request

  has multiple bios, each of which can have multiple segments.

- Drivers which can't process a large bio in one shot can use the bi_idx

- Drivers which can't process a large bio in one shot can use the bi_iter

  field to keep track of the next bio_vec entry to process.

  (e.g a 1MB bio_vec needs to be handled in max 128kB chunks for IDE)

  [TBD: Should preferably also have a bi_voffset and bi_vlen to avoid modifying
@@ -589,7 +588,7 @@ driver should not modify these values. The block layer sets up the 
nr_sectors and current_nr_sectors fields (based on the corresponding

hard_xxx values and the number of bytes transferred) and updates it on

every transfer that invokes end_that_request_first. It does the same for the

buffer, bio, bio->bi_idx fields too.

buffer, bio, bio->bi_iter fields too.



The buffer field is just a virtual address mapping of the current segment

of the i/o buffer in cases where the buffer resides in low-memory. For high

arch/m68k/emu/nfblock.c

+1 −1
Original line number Diff line number Diff line
@@ -64,7 +64,7 @@ static void nfhd_make_request(struct request_queue *queue, struct bio *bio) 
	struct nfhd_device *dev = queue->queuedata;

	struct bio_vec *bvec;

	int i, dir, len, shift;

	sector_t sec = bio->bi_sector;

	sector_t sec = bio->bi_iter.bi_sector;



	dir = bio_data_dir(bio);

	shift = dev->bshift;

arch/powerpc/sysdev/axonram.c

+2 −1
Original line number Diff line number Diff line
@@ -113,7 +113,8 @@ axon_ram_make_request(struct request_queue *queue, struct bio *bio) 
	unsigned int transfered;

	unsigned short idx;



	phys_mem = bank->io_addr + (bio->bi_sector << AXON_RAM_SECTOR_SHIFT);

	phys_mem = bank->io_addr + (bio->bi_iter.bi_sector <<

				    AXON_RAM_SECTOR_SHIFT);

	phys_end = bank->io_addr + bank->size;

	transfered = 0;

	bio_for_each_segment(vec, bio, idx) {

block/blk-core.c

+18 −18
Original line number Diff line number Diff line
@@ -130,7 +130,7 @@ static void req_bio_endio(struct request *rq, struct bio *bio, 
	bio_advance(bio, nbytes);



	/* don't actually finish bio if it's part of flush sequence */

	if (bio->bi_size == 0 && !(rq->cmd_flags & REQ_FLUSH_SEQ))

	if (bio->bi_iter.bi_size == 0 && !(rq->cmd_flags & REQ_FLUSH_SEQ))

		bio_endio(bio, error);

}
@@ -1326,7 +1326,7 @@ void blk_add_request_payload(struct request *rq, struct page *page, 
	bio->bi_io_vec->bv_offset = 0;

	bio->bi_io_vec->bv_len = len;



	bio->bi_size = len;

	bio->bi_iter.bi_size = len;

	bio->bi_vcnt = 1;

	bio->bi_phys_segments = 1;
@@ -1351,7 +1351,7 @@ bool bio_attempt_back_merge(struct request_queue *q, struct request *req, 


	req->biotail->bi_next = bio;

	req->biotail = bio;

	req->__data_len += bio->bi_size;

	req->__data_len += bio->bi_iter.bi_size;

	req->ioprio = ioprio_best(req->ioprio, bio_prio(bio));



	blk_account_io_start(req, false);
@@ -1380,8 +1380,8 @@ bool bio_attempt_front_merge(struct request_queue *q, struct request *req, 
	 * not touch req->buffer either...

	 */

	req->buffer = bio_data(bio);

	req->__sector = bio->bi_sector;

	req->__data_len += bio->bi_size;

	req->__sector = bio->bi_iter.bi_sector;

	req->__data_len += bio->bi_iter.bi_size;

	req->ioprio = ioprio_best(req->ioprio, bio_prio(bio));



	blk_account_io_start(req, false);
@@ -1459,7 +1459,7 @@ void init_request_from_bio(struct request *req, struct bio *bio) 
		req->cmd_flags |= REQ_FAILFAST_MASK;



	req->errors = 0;

	req->__sector = bio->bi_sector;

	req->__sector = bio->bi_iter.bi_sector;

	req->ioprio = bio_prio(bio);

	blk_rq_bio_prep(req->q, req, bio);

}
@@ -1583,12 +1583,12 @@ static inline void blk_partition_remap(struct bio *bio) 
	if (bio_sectors(bio) && bdev != bdev->bd_contains) {

		struct hd_struct *p = bdev->bd_part;



		bio->bi_sector += p->start_sect;

		bio->bi_iter.bi_sector += p->start_sect;

		bio->bi_bdev = bdev->bd_contains;



		trace_block_bio_remap(bdev_get_queue(bio->bi_bdev), bio,

				      bdev->bd_dev,

				      bio->bi_sector - p->start_sect);

				      bio->bi_iter.bi_sector - p->start_sect);

	}

}
@@ -1654,7 +1654,7 @@ static inline int bio_check_eod(struct bio *bio, unsigned int nr_sectors) 
	/* Test device or partition size, when known. */

	maxsector = i_size_read(bio->bi_bdev->bd_inode) >> 9;

	if (maxsector) {

		sector_t sector = bio->bi_sector;

		sector_t sector = bio->bi_iter.bi_sector;



		if (maxsector < nr_sectors || maxsector - nr_sectors < sector) {

			/*
@@ -1690,7 +1690,7 @@ generic_make_request_checks(struct bio *bio) 
		       "generic_make_request: Trying to access "

			"nonexistent block-device %s (%Lu)\n",

			bdevname(bio->bi_bdev, b),

			(long long) bio->bi_sector);

			(long long) bio->bi_iter.bi_sector);

		goto end_io;

	}
@@ -1704,9 +1704,9 @@ generic_make_request_checks(struct bio *bio) 
	}



	part = bio->bi_bdev->bd_part;

	if (should_fail_request(part, bio->bi_size) ||

	if (should_fail_request(part, bio->bi_iter.bi_size) ||

	    should_fail_request(&part_to_disk(part)->part0,

				bio->bi_size))

				bio->bi_iter.bi_size))

		goto end_io;



	/*
@@ -1865,7 +1865,7 @@ void submit_bio(int rw, struct bio *bio) 
		if (rw & WRITE) {

			count_vm_events(PGPGOUT, count);

		} else {

			task_io_account_read(bio->bi_size);

			task_io_account_read(bio->bi_iter.bi_size);

			count_vm_events(PGPGIN, count);

		}
@@ -1874,7 +1874,7 @@ void submit_bio(int rw, struct bio *bio) 
			printk(KERN_DEBUG "%s(%d): %s block %Lu on %s (%u sectors)\n",

			current->comm, task_pid_nr(current),

				(rw & WRITE) ? "WRITE" : "READ",

				(unsigned long long)bio->bi_sector,

				(unsigned long long)bio->bi_iter.bi_sector,

				bdevname(bio->bi_bdev, b),

				count);

		}
@@ -2007,7 +2007,7 @@ unsigned int blk_rq_err_bytes(const struct request *rq) 
	for (bio = rq->bio; bio; bio = bio->bi_next) {

		if ((bio->bi_rw & ff) != ff)

			break;

		bytes += bio->bi_size;

		bytes += bio->bi_iter.bi_size;

	}



	/* this could lead to infinite loop */
@@ -2378,9 +2378,9 @@ bool blk_update_request(struct request *req, int error, unsigned int nr_bytes) 
	total_bytes = 0;

	while (req->bio) {

		struct bio *bio = req->bio;

		unsigned bio_bytes = min(bio->bi_size, nr_bytes);

		unsigned bio_bytes = min(bio->bi_iter.bi_size, nr_bytes);



		if (bio_bytes == bio->bi_size)

		if (bio_bytes == bio->bi_iter.bi_size)

			req->bio = bio->bi_next;



		req_bio_endio(req, bio, bio_bytes, error);
@@ -2728,7 +2728,7 @@ void blk_rq_bio_prep(struct request_queue *q, struct request *rq, 
		rq->nr_phys_segments = bio_phys_segments(q, bio);

		rq->buffer = bio_data(bio);

	}

	rq->__data_len = bio->bi_size;

	rq->__data_len = bio->bi_iter.bi_size;

	rq->bio = rq->biotail = bio;



	if (bio->bi_bdev)

block/blk-flush.c

+1 −1
Original line number Diff line number Diff line
@@ -548,7 +548,7 @@ int blkdev_issue_flush(struct block_device *bdev, gfp_t gfp_mask, 
	 * copied from blk_rq_pos(rq).

	 */

	if (error_sector)

		*error_sector = bio->bi_sector;

		*error_sector = bio->bi_iter.bi_sector;



	bio_put(bio);

	return ret;