| /* |
| * Copyright (C) 2003 Sistina Software |
| * Copyright (C) 2006 Red Hat GmbH |
| * |
| * This file is released under the GPL. |
| */ |
| |
| #include "dm-core.h" |
| |
| #include <linux/device-mapper.h> |
| |
| #include <linux/bio.h> |
| #include <linux/completion.h> |
| #include <linux/mempool.h> |
| #include <linux/module.h> |
| #include <linux/sched.h> |
| #include <linux/slab.h> |
| #include <linux/dm-io.h> |
| |
| #define DM_MSG_PREFIX "io" |
| |
| #define DM_IO_MAX_REGIONS BITS_PER_LONG |
| |
| struct dm_io_client { |
| mempool_t pool; |
| struct bio_set bios; |
| }; |
| |
| /* |
| * Aligning 'struct io' reduces the number of bits required to store |
| * its address. Refer to store_io_and_region_in_bio() below. |
| */ |
| struct io { |
| unsigned long error_bits; |
| atomic_t count; |
| struct dm_io_client *client; |
| io_notify_fn callback; |
| void *context; |
| void *vma_invalidate_address; |
| unsigned long vma_invalidate_size; |
| } __attribute__((aligned(DM_IO_MAX_REGIONS))); |
| |
| static struct kmem_cache *_dm_io_cache; |
| |
| /* |
| * Create a client with mempool and bioset. |
| */ |
| struct dm_io_client *dm_io_client_create(void) |
| { |
| struct dm_io_client *client; |
| unsigned min_ios = dm_get_reserved_bio_based_ios(); |
| int ret; |
| |
| client = kzalloc(sizeof(*client), GFP_KERNEL); |
| if (!client) |
| return ERR_PTR(-ENOMEM); |
| |
| ret = mempool_init_slab_pool(&client->pool, min_ios, _dm_io_cache); |
| if (ret) |
| goto bad; |
| |
| ret = bioset_init(&client->bios, min_ios, 0, BIOSET_NEED_BVECS); |
| if (ret) |
| goto bad; |
| |
| return client; |
| |
| bad: |
| mempool_exit(&client->pool); |
| kfree(client); |
| return ERR_PTR(ret); |
| } |
| EXPORT_SYMBOL(dm_io_client_create); |
| |
| void dm_io_client_destroy(struct dm_io_client *client) |
| { |
| mempool_exit(&client->pool); |
| bioset_exit(&client->bios); |
| kfree(client); |
| } |
| EXPORT_SYMBOL(dm_io_client_destroy); |
| |
| /*----------------------------------------------------------------- |
| * We need to keep track of which region a bio is doing io for. |
| * To avoid a memory allocation to store just 5 or 6 bits, we |
| * ensure the 'struct io' pointer is aligned so enough low bits are |
| * always zero and then combine it with the region number directly in |
| * bi_private. |
| *---------------------------------------------------------------*/ |
| static void store_io_and_region_in_bio(struct bio *bio, struct io *io, |
| unsigned region) |
| { |
| if (unlikely(!IS_ALIGNED((unsigned long)io, DM_IO_MAX_REGIONS))) { |
| DMCRIT("Unaligned struct io pointer %p", io); |
| BUG(); |
| } |
| |
| bio->bi_private = (void *)((unsigned long)io | region); |
| } |
| |
| static void retrieve_io_and_region_from_bio(struct bio *bio, struct io **io, |
| unsigned *region) |
| { |
| unsigned long val = (unsigned long)bio->bi_private; |
| |
| *io = (void *)(val & -(unsigned long)DM_IO_MAX_REGIONS); |
| *region = val & (DM_IO_MAX_REGIONS - 1); |
| } |
| |
| /*----------------------------------------------------------------- |
| * We need an io object to keep track of the number of bios that |
| * have been dispatched for a particular io. |
| *---------------------------------------------------------------*/ |
| static void complete_io(struct io *io) |
| { |
| unsigned long error_bits = io->error_bits; |
| io_notify_fn fn = io->callback; |
| void *context = io->context; |
| |
| if (io->vma_invalidate_size) |
| invalidate_kernel_vmap_range(io->vma_invalidate_address, |
| io->vma_invalidate_size); |
| |
| mempool_free(io, &io->client->pool); |
| fn(error_bits, context); |
| } |
| |
| static void dec_count(struct io *io, unsigned int region, blk_status_t error) |
| { |
| if (error) |
| set_bit(region, &io->error_bits); |
| |
| if (atomic_dec_and_test(&io->count)) |
| complete_io(io); |
| } |
| |
| static void endio(struct bio *bio) |
| { |
| struct io *io; |
| unsigned region; |
| blk_status_t error; |
| |
| if (bio->bi_status && bio_data_dir(bio) == READ) |
| zero_fill_bio(bio); |
| |
| /* |
| * The bio destructor in bio_put() may use the io object. |
| */ |
| retrieve_io_and_region_from_bio(bio, &io, ®ion); |
| |
| error = bio->bi_status; |
| bio_put(bio); |
| |
| dec_count(io, region, error); |
| } |
| |
| /*----------------------------------------------------------------- |
| * These little objects provide an abstraction for getting a new |
| * destination page for io. |
| *---------------------------------------------------------------*/ |
| struct dpages { |
| void (*get_page)(struct dpages *dp, |
| struct page **p, unsigned long *len, unsigned *offset); |
| void (*next_page)(struct dpages *dp); |
| |
| union { |
| unsigned context_u; |
| struct bvec_iter context_bi; |
| }; |
| void *context_ptr; |
| |
| void *vma_invalidate_address; |
| unsigned long vma_invalidate_size; |
| }; |
| |
| /* |
| * Functions for getting the pages from a list. |
| */ |
| static void list_get_page(struct dpages *dp, |
| struct page **p, unsigned long *len, unsigned *offset) |
| { |
| unsigned o = dp->context_u; |
| struct page_list *pl = (struct page_list *) dp->context_ptr; |
| |
| *p = pl->page; |
| *len = PAGE_SIZE - o; |
| *offset = o; |
| } |
| |
| static void list_next_page(struct dpages *dp) |
| { |
| struct page_list *pl = (struct page_list *) dp->context_ptr; |
| dp->context_ptr = pl->next; |
| dp->context_u = 0; |
| } |
| |
| static void list_dp_init(struct dpages *dp, struct page_list *pl, unsigned offset) |
| { |
| dp->get_page = list_get_page; |
| dp->next_page = list_next_page; |
| dp->context_u = offset; |
| dp->context_ptr = pl; |
| } |
| |
| /* |
| * Functions for getting the pages from a bvec. |
| */ |
| static void bio_get_page(struct dpages *dp, struct page **p, |
| unsigned long *len, unsigned *offset) |
| { |
| struct bio_vec bvec = bvec_iter_bvec((struct bio_vec *)dp->context_ptr, |
| dp->context_bi); |
| |
| *p = bvec.bv_page; |
| *len = bvec.bv_len; |
| *offset = bvec.bv_offset; |
| |
| /* avoid figuring it out again in bio_next_page() */ |
| dp->context_bi.bi_sector = (sector_t)bvec.bv_len; |
| } |
| |
| static void bio_next_page(struct dpages *dp) |
| { |
| unsigned int len = (unsigned int)dp->context_bi.bi_sector; |
| |
| bvec_iter_advance((struct bio_vec *)dp->context_ptr, |
| &dp->context_bi, len); |
| } |
| |
| static void bio_dp_init(struct dpages *dp, struct bio *bio) |
| { |
| dp->get_page = bio_get_page; |
| dp->next_page = bio_next_page; |
| |
| /* |
| * We just use bvec iterator to retrieve pages, so it is ok to |
| * access the bvec table directly here |
| */ |
| dp->context_ptr = bio->bi_io_vec; |
| dp->context_bi = bio->bi_iter; |
| } |
| |
| /* |
| * Functions for getting the pages from a VMA. |
| */ |
| static void vm_get_page(struct dpages *dp, |
| struct page **p, unsigned long *len, unsigned *offset) |
| { |
| *p = vmalloc_to_page(dp->context_ptr); |
| *offset = dp->context_u; |
| *len = PAGE_SIZE - dp->context_u; |
| } |
| |
| static void vm_next_page(struct dpages *dp) |
| { |
| dp->context_ptr += PAGE_SIZE - dp->context_u; |
| dp->context_u = 0; |
| } |
| |
| static void vm_dp_init(struct dpages *dp, void *data) |
| { |
| dp->get_page = vm_get_page; |
| dp->next_page = vm_next_page; |
| dp->context_u = offset_in_page(data); |
| dp->context_ptr = data; |
| } |
| |
| /* |
| * Functions for getting the pages from kernel memory. |
| */ |
| static void km_get_page(struct dpages *dp, struct page **p, unsigned long *len, |
| unsigned *offset) |
| { |
| *p = virt_to_page(dp->context_ptr); |
| *offset = dp->context_u; |
| *len = PAGE_SIZE - dp->context_u; |
| } |
| |
| static void km_next_page(struct dpages *dp) |
| { |
| dp->context_ptr += PAGE_SIZE - dp->context_u; |
| dp->context_u = 0; |
| } |
| |
| static void km_dp_init(struct dpages *dp, void *data) |
| { |
| dp->get_page = km_get_page; |
| dp->next_page = km_next_page; |
| dp->context_u = offset_in_page(data); |
| dp->context_ptr = data; |
| } |
| |
| /*----------------------------------------------------------------- |
| * IO routines that accept a list of pages. |
| *---------------------------------------------------------------*/ |
| static void do_region(int op, int op_flags, unsigned region, |
| struct dm_io_region *where, struct dpages *dp, |
| struct io *io) |
| { |
| struct bio *bio; |
| struct page *page; |
| unsigned long len; |
| unsigned offset; |
| unsigned num_bvecs; |
| sector_t remaining = where->count; |
| struct request_queue *q = bdev_get_queue(where->bdev); |
| sector_t num_sectors; |
| unsigned int special_cmd_max_sectors; |
| |
| /* |
| * Reject unsupported discard and write same requests. |
| */ |
| if (op == REQ_OP_DISCARD) |
| special_cmd_max_sectors = bdev_max_discard_sectors(where->bdev); |
| else if (op == REQ_OP_WRITE_ZEROES) |
| special_cmd_max_sectors = q->limits.max_write_zeroes_sectors; |
| if ((op == REQ_OP_DISCARD || op == REQ_OP_WRITE_ZEROES) && |
| special_cmd_max_sectors == 0) { |
| atomic_inc(&io->count); |
| dec_count(io, region, BLK_STS_NOTSUPP); |
| return; |
| } |
| |
| /* |
| * where->count may be zero if op holds a flush and we need to |
| * send a zero-sized flush. |
| */ |
| do { |
| /* |
| * Allocate a suitably sized-bio. |
| */ |
| switch (op) { |
| case REQ_OP_DISCARD: |
| case REQ_OP_WRITE_ZEROES: |
| num_bvecs = 0; |
| break; |
| default: |
| num_bvecs = bio_max_segs(dm_sector_div_up(remaining, |
| (PAGE_SIZE >> SECTOR_SHIFT))); |
| } |
| |
| bio = bio_alloc_bioset(where->bdev, num_bvecs, op | op_flags, |
| GFP_NOIO, &io->client->bios); |
| bio->bi_iter.bi_sector = where->sector + (where->count - remaining); |
| bio->bi_end_io = endio; |
| store_io_and_region_in_bio(bio, io, region); |
| |
| if (op == REQ_OP_DISCARD || op == REQ_OP_WRITE_ZEROES) { |
| num_sectors = min_t(sector_t, special_cmd_max_sectors, remaining); |
| bio->bi_iter.bi_size = num_sectors << SECTOR_SHIFT; |
| remaining -= num_sectors; |
| } else while (remaining) { |
| /* |
| * Try and add as many pages as possible. |
| */ |
| dp->get_page(dp, &page, &len, &offset); |
| len = min(len, to_bytes(remaining)); |
| if (!bio_add_page(bio, page, len, offset)) |
| break; |
| |
| offset = 0; |
| remaining -= to_sector(len); |
| dp->next_page(dp); |
| } |
| |
| atomic_inc(&io->count); |
| submit_bio(bio); |
| } while (remaining); |
| } |
| |
| static void dispatch_io(int op, int op_flags, unsigned int num_regions, |
| struct dm_io_region *where, struct dpages *dp, |
| struct io *io, int sync) |
| { |
| int i; |
| struct dpages old_pages = *dp; |
| |
| BUG_ON(num_regions > DM_IO_MAX_REGIONS); |
| |
| if (sync) |
| op_flags |= REQ_SYNC; |
| |
| /* |
| * For multiple regions we need to be careful to rewind |
| * the dp object for each call to do_region. |
| */ |
| for (i = 0; i < num_regions; i++) { |
| *dp = old_pages; |
| if (where[i].count || (op_flags & REQ_PREFLUSH)) |
| do_region(op, op_flags, i, where + i, dp, io); |
| } |
| |
| /* |
| * Drop the extra reference that we were holding to avoid |
| * the io being completed too early. |
| */ |
| dec_count(io, 0, 0); |
| } |
| |
| struct sync_io { |
| unsigned long error_bits; |
| struct completion wait; |
| }; |
| |
| static void sync_io_complete(unsigned long error, void *context) |
| { |
| struct sync_io *sio = context; |
| |
| sio->error_bits = error; |
| complete(&sio->wait); |
| } |
| |
| static int sync_io(struct dm_io_client *client, unsigned int num_regions, |
| struct dm_io_region *where, int op, int op_flags, |
| struct dpages *dp, unsigned long *error_bits) |
| { |
| struct io *io; |
| struct sync_io sio; |
| |
| if (num_regions > 1 && !op_is_write(op)) { |
| WARN_ON(1); |
| return -EIO; |
| } |
| |
| init_completion(&sio.wait); |
| |
| io = mempool_alloc(&client->pool, GFP_NOIO); |
| io->error_bits = 0; |
| atomic_set(&io->count, 1); /* see dispatch_io() */ |
| io->client = client; |
| io->callback = sync_io_complete; |
| io->context = &sio; |
| |
| io->vma_invalidate_address = dp->vma_invalidate_address; |
| io->vma_invalidate_size = dp->vma_invalidate_size; |
| |
| dispatch_io(op, op_flags, num_regions, where, dp, io, 1); |
| |
| wait_for_completion_io(&sio.wait); |
| |
| if (error_bits) |
| *error_bits = sio.error_bits; |
| |
| return sio.error_bits ? -EIO : 0; |
| } |
| |
| static int async_io(struct dm_io_client *client, unsigned int num_regions, |
| struct dm_io_region *where, int op, int op_flags, |
| struct dpages *dp, io_notify_fn fn, void *context) |
| { |
| struct io *io; |
| |
| if (num_regions > 1 && !op_is_write(op)) { |
| 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->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(op, op_flags, 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_BIO: |
| bio_dp_init(dp, io_req->mem.ptr.bio); |
| break; |
| |
| case DM_IO_VMA: |
| flush_kernel_vmap_range(io_req->mem.ptr.vma, size); |
| if (io_req->bi_op == REQ_OP_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; |
| } |
| |
| 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_op, io_req->bi_op_flags, &dp, |
| sync_error_bits); |
| |
| return async_io(io_req->client, num_regions, where, io_req->bi_op, |
| io_req->bi_op_flags, &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; |
| } |