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![Kent Overstreet](/assets/img/avatar_default.png)
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: Kent 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
524 lines
13 KiB
C
524 lines
13 KiB
C
/*
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* Copyright (C) 2003 Sistina Software
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* Copyright (C) 2006 Red Hat GmbH
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*
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* This file is released under the GPL.
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*/
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#include "dm.h"
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#include <linux/device-mapper.h>
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#include <linux/bio.h>
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#include <linux/mempool.h>
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#include <linux/module.h>
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#include <linux/sched.h>
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#include <linux/slab.h>
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#include <linux/dm-io.h>
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#define DM_MSG_PREFIX "io"
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#define DM_IO_MAX_REGIONS BITS_PER_LONG
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struct dm_io_client {
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mempool_t *pool;
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struct bio_set *bios;
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};
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/*
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* Aligning 'struct io' reduces the number of bits required to store
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* its address. Refer to store_io_and_region_in_bio() below.
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*/
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struct io {
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unsigned long error_bits;
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atomic_t count;
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struct task_struct *sleeper;
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struct dm_io_client *client;
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io_notify_fn callback;
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void *context;
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void *vma_invalidate_address;
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unsigned long vma_invalidate_size;
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} __attribute__((aligned(DM_IO_MAX_REGIONS)));
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static struct kmem_cache *_dm_io_cache;
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/*
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* Create a client with mempool and bioset.
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*/
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struct dm_io_client *dm_io_client_create(void)
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{
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struct dm_io_client *client;
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unsigned min_ios = dm_get_reserved_bio_based_ios();
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client = kmalloc(sizeof(*client), GFP_KERNEL);
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if (!client)
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return ERR_PTR(-ENOMEM);
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client->pool = mempool_create_slab_pool(min_ios, _dm_io_cache);
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if (!client->pool)
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goto bad;
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client->bios = bioset_create(min_ios, 0);
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if (!client->bios)
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goto bad;
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return client;
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bad:
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if (client->pool)
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mempool_destroy(client->pool);
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kfree(client);
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return ERR_PTR(-ENOMEM);
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}
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EXPORT_SYMBOL(dm_io_client_create);
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void dm_io_client_destroy(struct dm_io_client *client)
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{
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mempool_destroy(client->pool);
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bioset_free(client->bios);
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kfree(client);
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}
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EXPORT_SYMBOL(dm_io_client_destroy);
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/*-----------------------------------------------------------------
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* We need to keep track of which region a bio is doing io for.
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* To avoid a memory allocation to store just 5 or 6 bits, we
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* ensure the 'struct io' pointer is aligned so enough low bits are
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* always zero and then combine it with the region number directly in
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* bi_private.
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*---------------------------------------------------------------*/
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static void store_io_and_region_in_bio(struct bio *bio, struct io *io,
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unsigned region)
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{
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if (unlikely(!IS_ALIGNED((unsigned long)io, DM_IO_MAX_REGIONS))) {
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DMCRIT("Unaligned struct io pointer %p", io);
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BUG();
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}
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bio->bi_private = (void *)((unsigned long)io | region);
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}
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static void retrieve_io_and_region_from_bio(struct bio *bio, struct io **io,
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unsigned *region)
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{
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unsigned long val = (unsigned long)bio->bi_private;
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*io = (void *)(val & -(unsigned long)DM_IO_MAX_REGIONS);
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*region = val & (DM_IO_MAX_REGIONS - 1);
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}
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/*-----------------------------------------------------------------
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* We need an io object to keep track of the number of bios that
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* have been dispatched for a particular io.
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*---------------------------------------------------------------*/
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static void dec_count(struct io *io, unsigned int region, int error)
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{
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if (error)
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set_bit(region, &io->error_bits);
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if (atomic_dec_and_test(&io->count)) {
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if (io->vma_invalidate_size)
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invalidate_kernel_vmap_range(io->vma_invalidate_address,
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io->vma_invalidate_size);
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if (io->sleeper)
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wake_up_process(io->sleeper);
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else {
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unsigned long r = io->error_bits;
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io_notify_fn fn = io->callback;
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void *context = io->context;
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mempool_free(io, io->client->pool);
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fn(r, context);
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}
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}
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}
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static void endio(struct bio *bio, int error)
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{
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struct io *io;
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unsigned region;
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if (error && bio_data_dir(bio) == READ)
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zero_fill_bio(bio);
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/*
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* The bio destructor in bio_put() may use the io object.
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*/
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retrieve_io_and_region_from_bio(bio, &io, ®ion);
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bio_put(bio);
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dec_count(io, region, error);
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}
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/*-----------------------------------------------------------------
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* These little objects provide an abstraction for getting a new
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* destination page for io.
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*---------------------------------------------------------------*/
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struct dpages {
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void (*get_page)(struct dpages *dp,
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struct page **p, unsigned long *len, unsigned *offset);
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void (*next_page)(struct dpages *dp);
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unsigned context_u;
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void *context_ptr;
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void *vma_invalidate_address;
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unsigned long vma_invalidate_size;
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};
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/*
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* Functions for getting the pages from a list.
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*/
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static void list_get_page(struct dpages *dp,
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struct page **p, unsigned long *len, unsigned *offset)
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{
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unsigned o = dp->context_u;
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struct page_list *pl = (struct page_list *) dp->context_ptr;
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*p = pl->page;
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*len = PAGE_SIZE - o;
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*offset = o;
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}
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static void list_next_page(struct dpages *dp)
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{
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struct page_list *pl = (struct page_list *) dp->context_ptr;
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dp->context_ptr = pl->next;
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dp->context_u = 0;
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}
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static void list_dp_init(struct dpages *dp, struct page_list *pl, unsigned offset)
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{
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dp->get_page = list_get_page;
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dp->next_page = list_next_page;
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dp->context_u = offset;
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dp->context_ptr = pl;
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}
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/*
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* Functions for getting the pages from a bvec.
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*/
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static void bvec_get_page(struct dpages *dp,
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struct page **p, unsigned long *len, unsigned *offset)
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{
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struct bio_vec *bvec = (struct bio_vec *) dp->context_ptr;
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*p = bvec->bv_page;
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*len = bvec->bv_len;
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*offset = bvec->bv_offset;
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}
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static void bvec_next_page(struct dpages *dp)
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{
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struct bio_vec *bvec = (struct bio_vec *) dp->context_ptr;
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dp->context_ptr = bvec + 1;
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}
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static void bvec_dp_init(struct dpages *dp, struct bio_vec *bvec)
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{
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dp->get_page = bvec_get_page;
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dp->next_page = bvec_next_page;
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dp->context_ptr = bvec;
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}
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/*
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* Functions for getting the pages from a VMA.
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*/
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static void vm_get_page(struct dpages *dp,
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struct page **p, unsigned long *len, unsigned *offset)
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{
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*p = vmalloc_to_page(dp->context_ptr);
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*offset = dp->context_u;
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*len = PAGE_SIZE - dp->context_u;
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}
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static void vm_next_page(struct dpages *dp)
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{
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dp->context_ptr += PAGE_SIZE - dp->context_u;
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dp->context_u = 0;
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}
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static void vm_dp_init(struct dpages *dp, void *data)
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{
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dp->get_page = vm_get_page;
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dp->next_page = vm_next_page;
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dp->context_u = ((unsigned long) data) & (PAGE_SIZE - 1);
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dp->context_ptr = data;
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}
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/*
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* Functions for getting the pages from kernel memory.
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*/
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static void km_get_page(struct dpages *dp, struct page **p, unsigned long *len,
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unsigned *offset)
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{
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*p = virt_to_page(dp->context_ptr);
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*offset = dp->context_u;
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*len = PAGE_SIZE - dp->context_u;
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}
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static void km_next_page(struct dpages *dp)
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{
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dp->context_ptr += PAGE_SIZE - dp->context_u;
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dp->context_u = 0;
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}
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static void km_dp_init(struct dpages *dp, void *data)
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{
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dp->get_page = km_get_page;
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dp->next_page = km_next_page;
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dp->context_u = ((unsigned long) data) & (PAGE_SIZE - 1);
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dp->context_ptr = data;
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}
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/*-----------------------------------------------------------------
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* IO routines that accept a list of pages.
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*---------------------------------------------------------------*/
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static void do_region(int rw, unsigned region, struct dm_io_region *where,
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struct dpages *dp, struct io *io)
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{
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struct bio *bio;
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struct page *page;
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unsigned long len;
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unsigned offset;
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unsigned num_bvecs;
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sector_t remaining = where->count;
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struct request_queue *q = bdev_get_queue(where->bdev);
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unsigned short logical_block_size = queue_logical_block_size(q);
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sector_t num_sectors;
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/*
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* where->count may be zero if rw holds a flush and we need to
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* send a zero-sized flush.
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*/
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do {
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/*
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* Allocate a suitably sized-bio.
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*/
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if ((rw & REQ_DISCARD) || (rw & REQ_WRITE_SAME))
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num_bvecs = 1;
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else
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num_bvecs = min_t(int, bio_get_nr_vecs(where->bdev),
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dm_sector_div_up(remaining, (PAGE_SIZE >> SECTOR_SHIFT)));
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bio = bio_alloc_bioset(GFP_NOIO, num_bvecs, io->client->bios);
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bio->bi_iter.bi_sector = where->sector + (where->count - remaining);
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bio->bi_bdev = where->bdev;
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bio->bi_end_io = endio;
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store_io_and_region_in_bio(bio, io, region);
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if (rw & REQ_DISCARD) {
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num_sectors = min_t(sector_t, q->limits.max_discard_sectors, remaining);
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bio->bi_iter.bi_size = num_sectors << SECTOR_SHIFT;
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remaining -= num_sectors;
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} else if (rw & REQ_WRITE_SAME) {
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/*
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* WRITE SAME only uses a single page.
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*/
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dp->get_page(dp, &page, &len, &offset);
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bio_add_page(bio, page, logical_block_size, offset);
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num_sectors = min_t(sector_t, q->limits.max_write_same_sectors, remaining);
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bio->bi_iter.bi_size = num_sectors << SECTOR_SHIFT;
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offset = 0;
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remaining -= num_sectors;
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dp->next_page(dp);
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} else while (remaining) {
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/*
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* Try and add as many pages as possible.
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*/
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dp->get_page(dp, &page, &len, &offset);
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len = min(len, to_bytes(remaining));
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if (!bio_add_page(bio, page, len, offset))
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break;
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offset = 0;
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remaining -= to_sector(len);
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dp->next_page(dp);
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}
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atomic_inc(&io->count);
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submit_bio(rw, bio);
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} while (remaining);
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}
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static void dispatch_io(int rw, unsigned int num_regions,
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struct dm_io_region *where, struct dpages *dp,
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struct io *io, int sync)
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{
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int i;
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struct dpages old_pages = *dp;
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BUG_ON(num_regions > DM_IO_MAX_REGIONS);
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if (sync)
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rw |= REQ_SYNC;
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/*
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* For multiple regions we need to be careful to rewind
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* the dp object for each call to do_region.
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*/
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for (i = 0; i < num_regions; i++) {
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*dp = old_pages;
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if (where[i].count || (rw & REQ_FLUSH))
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do_region(rw, i, where + i, dp, io);
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}
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/*
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* Drop the extra reference that we were holding to avoid
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* the io being completed too early.
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*/
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dec_count(io, 0, 0);
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}
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static int sync_io(struct dm_io_client *client, unsigned int num_regions,
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struct dm_io_region *where, int rw, struct dpages *dp,
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unsigned long *error_bits)
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{
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/*
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* gcc <= 4.3 can't do the alignment for stack variables, so we must
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* align it on our own.
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* volatile prevents the optimizer from removing or reusing
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* "io_" field from the stack frame (allowed in ANSI C).
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*/
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volatile char io_[sizeof(struct io) + __alignof__(struct io) - 1];
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struct io *io = (struct io *)PTR_ALIGN(&io_, __alignof__(struct io));
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if (num_regions > 1 && (rw & RW_MASK) != WRITE) {
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WARN_ON(1);
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return -EIO;
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}
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io->error_bits = 0;
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atomic_set(&io->count, 1); /* see dispatch_io() */
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io->sleeper = current;
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io->client = client;
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io->vma_invalidate_address = dp->vma_invalidate_address;
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io->vma_invalidate_size = dp->vma_invalidate_size;
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dispatch_io(rw, num_regions, where, dp, io, 1);
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while (1) {
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set_current_state(TASK_UNINTERRUPTIBLE);
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if (!atomic_read(&io->count))
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break;
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io_schedule();
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}
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set_current_state(TASK_RUNNING);
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if (error_bits)
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*error_bits = io->error_bits;
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return io->error_bits ? -EIO : 0;
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}
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static int async_io(struct dm_io_client *client, unsigned int num_regions,
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struct dm_io_region *where, int rw, struct dpages *dp,
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io_notify_fn fn, void *context)
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{
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struct io *io;
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if (num_regions > 1 && (rw & RW_MASK) != WRITE) {
|
|
WARN_ON(1);
|
|
fn(1, context);
|
|
return -EIO;
|
|
}
|
|
|
|
io = mempool_alloc(client->pool, GFP_NOIO);
|
|
io->error_bits = 0;
|
|
atomic_set(&io->count, 1); /* see dispatch_io() */
|
|
io->sleeper = NULL;
|
|
io->client = client;
|
|
io->callback = fn;
|
|
io->context = context;
|
|
|
|
io->vma_invalidate_address = dp->vma_invalidate_address;
|
|
io->vma_invalidate_size = dp->vma_invalidate_size;
|
|
|
|
dispatch_io(rw, num_regions, where, dp, io, 0);
|
|
return 0;
|
|
}
|
|
|
|
static int dp_init(struct dm_io_request *io_req, struct dpages *dp,
|
|
unsigned long size)
|
|
{
|
|
/* Set up dpages based on memory type */
|
|
|
|
dp->vma_invalidate_address = NULL;
|
|
dp->vma_invalidate_size = 0;
|
|
|
|
switch (io_req->mem.type) {
|
|
case DM_IO_PAGE_LIST:
|
|
list_dp_init(dp, io_req->mem.ptr.pl, io_req->mem.offset);
|
|
break;
|
|
|
|
case DM_IO_BVEC:
|
|
bvec_dp_init(dp, io_req->mem.ptr.bvec);
|
|
break;
|
|
|
|
case DM_IO_VMA:
|
|
flush_kernel_vmap_range(io_req->mem.ptr.vma, size);
|
|
if ((io_req->bi_rw & RW_MASK) == READ) {
|
|
dp->vma_invalidate_address = io_req->mem.ptr.vma;
|
|
dp->vma_invalidate_size = size;
|
|
}
|
|
vm_dp_init(dp, io_req->mem.ptr.vma);
|
|
break;
|
|
|
|
case DM_IO_KMEM:
|
|
km_dp_init(dp, io_req->mem.ptr.addr);
|
|
break;
|
|
|
|
default:
|
|
return -EINVAL;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* New collapsed (a)synchronous interface.
|
|
*
|
|
* If the IO is asynchronous (i.e. it has notify.fn), you must either unplug
|
|
* the queue with blk_unplug() some time later or set REQ_SYNC in
|
|
io_req->bi_rw. If you fail to do one of these, the IO will be submitted to
|
|
* the disk after q->unplug_delay, which defaults to 3ms in blk-settings.c.
|
|
*/
|
|
int dm_io(struct dm_io_request *io_req, unsigned num_regions,
|
|
struct dm_io_region *where, unsigned long *sync_error_bits)
|
|
{
|
|
int r;
|
|
struct dpages dp;
|
|
|
|
r = dp_init(io_req, &dp, (unsigned long)where->count << SECTOR_SHIFT);
|
|
if (r)
|
|
return r;
|
|
|
|
if (!io_req->notify.fn)
|
|
return sync_io(io_req->client, num_regions, where,
|
|
io_req->bi_rw, &dp, sync_error_bits);
|
|
|
|
return async_io(io_req->client, num_regions, where, io_req->bi_rw,
|
|
&dp, io_req->notify.fn, io_req->notify.context);
|
|
}
|
|
EXPORT_SYMBOL(dm_io);
|
|
|
|
int __init dm_io_init(void)
|
|
{
|
|
_dm_io_cache = KMEM_CACHE(io, 0);
|
|
if (!_dm_io_cache)
|
|
return -ENOMEM;
|
|
|
|
return 0;
|
|
}
|
|
|
|
void dm_io_exit(void)
|
|
{
|
|
kmem_cache_destroy(_dm_io_cache);
|
|
_dm_io_cache = NULL;
|
|
}
|