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Diffstat (limited to 'module/os/linux/zfs/abd.c')
| -rw-r--r-- | module/os/linux/zfs/abd.c | 1616 |
1 files changed, 0 insertions, 1616 deletions
diff --git a/module/os/linux/zfs/abd.c b/module/os/linux/zfs/abd.c deleted file mode 100644 index bc6f81000..000000000 --- a/module/os/linux/zfs/abd.c +++ /dev/null @@ -1,1616 +0,0 @@ -/* - * CDDL HEADER START - * - * The contents of this file are subject to the terms of the - * Common Development and Distribution License (the "License"). - * You may not use this file except in compliance with the License. - * - * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE - * or http://www.opensolaris.org/os/licensing. - * See the License for the specific language governing permissions - * and limitations under the License. - * - * When distributing Covered Code, include this CDDL HEADER in each - * file and include the License file at usr/src/OPENSOLARIS.LICENSE. - * If applicable, add the following below this CDDL HEADER, with the - * fields enclosed by brackets "[]" replaced with your own identifying - * information: Portions Copyright [yyyy] [name of copyright owner] - * - * CDDL HEADER END - */ -/* - * Copyright (c) 2014 by Chunwei Chen. All rights reserved. - * Copyright (c) 2019 by Delphix. All rights reserved. - */ - -/* - * ARC buffer data (ABD). - * - * ABDs are an abstract data structure for the ARC which can use two - * different ways of storing the underlying data: - * - * (a) Linear buffer. In this case, all the data in the ABD is stored in one - * contiguous buffer in memory (from a zio_[data_]buf_* kmem cache). - * - * +-------------------+ - * | ABD (linear) | - * | abd_flags = ... | - * | abd_size = ... | +--------------------------------+ - * | abd_buf ------------->| raw buffer of size abd_size | - * +-------------------+ +--------------------------------+ - * no abd_chunks - * - * (b) Scattered buffer. In this case, the data in the ABD is split into - * equal-sized chunks (from the abd_chunk_cache kmem_cache), with pointers - * to the chunks recorded in an array at the end of the ABD structure. - * - * +-------------------+ - * | ABD (scattered) | - * | abd_flags = ... | - * | abd_size = ... | - * | abd_offset = 0 | +-----------+ - * | abd_chunks[0] ----------------------------->| chunk 0 | - * | abd_chunks[1] ---------------------+ +-----------+ - * | ... | | +-----------+ - * | abd_chunks[N-1] ---------+ +------->| chunk 1 | - * +-------------------+ | +-----------+ - * | ... - * | +-----------+ - * +----------------->| chunk N-1 | - * +-----------+ - * - * Linear buffers act exactly like normal buffers and are always mapped into the - * kernel's virtual memory space, while scattered ABD data chunks are allocated - * as physical pages and then mapped in only while they are actually being - * accessed through one of the abd_* library functions. Using scattered ABDs - * provides several benefits: - * - * (1) They avoid use of kmem_*, preventing performance problems where running - * kmem_reap on very large memory systems never finishes and causes - * constant TLB shootdowns. - * - * (2) Fragmentation is less of an issue since when we are at the limit of - * allocatable space, we won't have to search around for a long free - * hole in the VA space for large ARC allocations. Each chunk is mapped in - * individually, so even if we are using HIGHMEM (see next point) we - * wouldn't need to worry about finding a contiguous address range. - * - * (3) If we are not using HIGHMEM, then all physical memory is always - * mapped into the kernel's address space, so we also avoid the map / - * unmap costs on each ABD access. - * - * If we are not using HIGHMEM, scattered buffers which have only one chunk - * can be treated as linear buffers, because they are contiguous in the - * kernel's virtual address space. See abd_alloc_pages() for details. - * - * It is possible to make all ABDs linear by setting zfs_abd_scatter_enabled to - * B_FALSE. - * - * In addition to directly allocating a linear or scattered ABD, it is also - * possible to create an ABD by requesting the "sub-ABD" starting at an offset - * within an existing ABD. In linear buffers this is simple (set abd_buf of - * the new ABD to the starting point within the original raw buffer), but - * scattered ABDs are a little more complex. The new ABD makes a copy of the - * relevant abd_chunks pointers (but not the underlying data). However, to - * provide arbitrary rather than only chunk-aligned starting offsets, it also - * tracks an abd_offset field which represents the starting point of the data - * within the first chunk in abd_chunks. For both linear and scattered ABDs, - * creating an offset ABD marks the original ABD as the offset's parent, and the - * original ABD's abd_children refcount is incremented. This data allows us to - * ensure the root ABD isn't deleted before its children. - * - * Most consumers should never need to know what type of ABD they're using -- - * the ABD public API ensures that it's possible to transparently switch from - * using a linear ABD to a scattered one when doing so would be beneficial. - * - * If you need to use the data within an ABD directly, if you know it's linear - * (because you allocated it) you can use abd_to_buf() to access the underlying - * raw buffer. Otherwise, you should use one of the abd_borrow_buf* functions - * which will allocate a raw buffer if necessary. Use the abd_return_buf* - * functions to return any raw buffers that are no longer necessary when you're - * done using them. - * - * There are a variety of ABD APIs that implement basic buffer operations: - * compare, copy, read, write, and fill with zeroes. If you need a custom - * function which progressively accesses the whole ABD, use the abd_iterate_* - * functions. - */ - -#include <sys/abd.h> -#include <sys/param.h> -#include <sys/zio.h> -#include <sys/zfs_context.h> -#include <sys/zfs_znode.h> -#ifdef _KERNEL -#include <linux/scatterlist.h> -#include <linux/kmap_compat.h> -#else -#define MAX_ORDER 1 -#endif - -typedef struct abd_stats { - kstat_named_t abdstat_struct_size; - kstat_named_t abdstat_linear_cnt; - kstat_named_t abdstat_linear_data_size; - kstat_named_t abdstat_scatter_cnt; - kstat_named_t abdstat_scatter_data_size; - kstat_named_t abdstat_scatter_chunk_waste; - kstat_named_t abdstat_scatter_orders[MAX_ORDER]; - kstat_named_t abdstat_scatter_page_multi_chunk; - kstat_named_t abdstat_scatter_page_multi_zone; - kstat_named_t abdstat_scatter_page_alloc_retry; - kstat_named_t abdstat_scatter_sg_table_retry; -} abd_stats_t; - -static abd_stats_t abd_stats = { - /* Amount of memory occupied by all of the abd_t struct allocations */ - { "struct_size", KSTAT_DATA_UINT64 }, - /* - * The number of linear ABDs which are currently allocated, excluding - * ABDs which don't own their data (for instance the ones which were - * allocated through abd_get_offset() and abd_get_from_buf()). If an - * ABD takes ownership of its buf then it will become tracked. - */ - { "linear_cnt", KSTAT_DATA_UINT64 }, - /* Amount of data stored in all linear ABDs tracked by linear_cnt */ - { "linear_data_size", KSTAT_DATA_UINT64 }, - /* - * The number of scatter ABDs which are currently allocated, excluding - * ABDs which don't own their data (for instance the ones which were - * allocated through abd_get_offset()). - */ - { "scatter_cnt", KSTAT_DATA_UINT64 }, - /* Amount of data stored in all scatter ABDs tracked by scatter_cnt */ - { "scatter_data_size", KSTAT_DATA_UINT64 }, - /* - * The amount of space wasted at the end of the last chunk across all - * scatter ABDs tracked by scatter_cnt. - */ - { "scatter_chunk_waste", KSTAT_DATA_UINT64 }, - /* - * The number of compound allocations of a given order. These - * allocations are spread over all currently allocated ABDs, and - * act as a measure of memory fragmentation. - */ - { { "scatter_order_N", KSTAT_DATA_UINT64 } }, - /* - * The number of scatter ABDs which contain multiple chunks. - * ABDs are preferentially allocated from the minimum number of - * contiguous multi-page chunks, a single chunk is optimal. - */ - { "scatter_page_multi_chunk", KSTAT_DATA_UINT64 }, - /* - * The number of scatter ABDs which are split across memory zones. - * ABDs are preferentially allocated using pages from a single zone. - */ - { "scatter_page_multi_zone", KSTAT_DATA_UINT64 }, - /* - * The total number of retries encountered when attempting to - * allocate the pages to populate the scatter ABD. - */ - { "scatter_page_alloc_retry", KSTAT_DATA_UINT64 }, - /* - * The total number of retries encountered when attempting to - * allocate the sg table for an ABD. - */ - { "scatter_sg_table_retry", KSTAT_DATA_UINT64 }, -}; - -#define ABDSTAT(stat) (abd_stats.stat.value.ui64) -#define ABDSTAT_INCR(stat, val) \ - atomic_add_64(&abd_stats.stat.value.ui64, (val)) -#define ABDSTAT_BUMP(stat) ABDSTAT_INCR(stat, 1) -#define ABDSTAT_BUMPDOWN(stat) ABDSTAT_INCR(stat, -1) - -#define ABD_SCATTER(abd) (abd->abd_u.abd_scatter) -#define ABD_BUF(abd) (abd->abd_u.abd_linear.abd_buf) -#define abd_for_each_sg(abd, sg, n, i) \ - for_each_sg(ABD_SCATTER(abd).abd_sgl, sg, n, i) - -/* see block comment above for description */ -int zfs_abd_scatter_enabled = B_TRUE; -unsigned zfs_abd_scatter_max_order = MAX_ORDER - 1; - -/* - * zfs_abd_scatter_min_size is the minimum allocation size to use scatter - * ABD's. Smaller allocations will use linear ABD's which uses - * zio_[data_]buf_alloc(). - * - * Scatter ABD's use at least one page each, so sub-page allocations waste - * some space when allocated as scatter (e.g. 2KB scatter allocation wastes - * half of each page). Using linear ABD's for small allocations means that - * they will be put on slabs which contain many allocations. This can - * improve memory efficiency, but it also makes it much harder for ARC - * evictions to actually free pages, because all the buffers on one slab need - * to be freed in order for the slab (and underlying pages) to be freed. - * Typically, 512B and 1KB kmem caches have 16 buffers per slab, so it's - * possible for them to actually waste more memory than scatter (one page per - * buf = wasting 3/4 or 7/8th; one buf per slab = wasting 15/16th). - * - * Spill blocks are typically 512B and are heavily used on systems running - * selinux with the default dnode size and the `xattr=sa` property set. - * - * By default we use linear allocations for 512B and 1KB, and scatter - * allocations for larger (1.5KB and up). - */ -int zfs_abd_scatter_min_size = 512 * 3; - -static kmem_cache_t *abd_cache = NULL; -static kstat_t *abd_ksp; - -static inline size_t -abd_chunkcnt_for_bytes(size_t size) -{ - return (P2ROUNDUP(size, PAGESIZE) / PAGESIZE); -} - -#ifdef _KERNEL -/* - * Mark zfs data pages so they can be excluded from kernel crash dumps - */ -#ifdef _LP64 -#define ABD_FILE_CACHE_PAGE 0x2F5ABDF11ECAC4E - -static inline void -abd_mark_zfs_page(struct page *page) -{ - get_page(page); - SetPagePrivate(page); - set_page_private(page, ABD_FILE_CACHE_PAGE); -} - -static inline void -abd_unmark_zfs_page(struct page *page) -{ - set_page_private(page, 0UL); - ClearPagePrivate(page); - put_page(page); -} -#else -#define abd_mark_zfs_page(page) -#define abd_unmark_zfs_page(page) -#endif /* _LP64 */ - -#ifndef CONFIG_HIGHMEM - -#ifndef __GFP_RECLAIM -#define __GFP_RECLAIM __GFP_WAIT -#endif - -/* - * The goal is to minimize fragmentation by preferentially populating ABDs - * with higher order compound pages from a single zone. Allocation size is - * progressively decreased until it can be satisfied without performing - * reclaim or compaction. When necessary this function will degenerate to - * allocating individual pages and allowing reclaim to satisfy allocations. - */ -static void -abd_alloc_pages(abd_t *abd, size_t size) -{ - struct list_head pages; - struct sg_table table; - struct scatterlist *sg; - struct page *page, *tmp_page = NULL; - gfp_t gfp = __GFP_NOWARN | GFP_NOIO; - gfp_t gfp_comp = (gfp | __GFP_NORETRY | __GFP_COMP) & ~__GFP_RECLAIM; - int max_order = MIN(zfs_abd_scatter_max_order, MAX_ORDER - 1); - int nr_pages = abd_chunkcnt_for_bytes(size); - int chunks = 0, zones = 0; - size_t remaining_size; - int nid = NUMA_NO_NODE; - int alloc_pages = 0; - - INIT_LIST_HEAD(&pages); - - while (alloc_pages < nr_pages) { - unsigned chunk_pages; - int order; - - order = MIN(highbit64(nr_pages - alloc_pages) - 1, max_order); - chunk_pages = (1U << order); - - page = alloc_pages_node(nid, order ? gfp_comp : gfp, order); - if (page == NULL) { - if (order == 0) { - ABDSTAT_BUMP(abdstat_scatter_page_alloc_retry); - schedule_timeout_interruptible(1); - } else { - max_order = MAX(0, order - 1); - } - continue; - } - - list_add_tail(&page->lru, &pages); - - if ((nid != NUMA_NO_NODE) && (page_to_nid(page) != nid)) - zones++; - - nid = page_to_nid(page); - ABDSTAT_BUMP(abdstat_scatter_orders[order]); - chunks++; - alloc_pages += chunk_pages; - } - - ASSERT3S(alloc_pages, ==, nr_pages); - - while (sg_alloc_table(&table, chunks, gfp)) { - ABDSTAT_BUMP(abdstat_scatter_sg_table_retry); - schedule_timeout_interruptible(1); - } - - sg = table.sgl; - remaining_size = size; - list_for_each_entry_safe(page, tmp_page, &pages, lru) { - size_t sg_size = MIN(PAGESIZE << compound_order(page), - remaining_size); - sg_set_page(sg, page, sg_size, 0); - abd_mark_zfs_page(page); - remaining_size -= sg_size; - - sg = sg_next(sg); - list_del(&page->lru); - } - - /* - * These conditions ensure that a possible transformation to a linear - * ABD would be valid. - */ - ASSERT(!PageHighMem(sg_page(table.sgl))); - ASSERT0(ABD_SCATTER(abd).abd_offset); - - if (table.nents == 1) { - /* - * Since there is only one entry, this ABD can be represented - * as a linear buffer. All single-page (4K) ABD's can be - * represented this way. Some multi-page ABD's can also be - * represented this way, if we were able to allocate a single - * "chunk" (higher-order "page" which represents a power-of-2 - * series of physically-contiguous pages). This is often the - * case for 2-page (8K) ABD's. - * - * Representing a single-entry scatter ABD as a linear ABD - * has the performance advantage of avoiding the copy (and - * allocation) in abd_borrow_buf_copy / abd_return_buf_copy. - * A performance increase of around 5% has been observed for - * ARC-cached reads (of small blocks which can take advantage - * of this). - * - * Note that this optimization is only possible because the - * pages are always mapped into the kernel's address space. - * This is not the case for highmem pages, so the - * optimization can not be made there. - */ - abd->abd_flags |= ABD_FLAG_LINEAR; - abd->abd_flags |= ABD_FLAG_LINEAR_PAGE; - abd->abd_u.abd_linear.abd_sgl = table.sgl; - abd->abd_u.abd_linear.abd_buf = - page_address(sg_page(table.sgl)); - } else if (table.nents > 1) { - ABDSTAT_BUMP(abdstat_scatter_page_multi_chunk); - abd->abd_flags |= ABD_FLAG_MULTI_CHUNK; - - if (zones) { - ABDSTAT_BUMP(abdstat_scatter_page_multi_zone); - abd->abd_flags |= ABD_FLAG_MULTI_ZONE; - } - - ABD_SCATTER(abd).abd_sgl = table.sgl; - ABD_SCATTER(abd).abd_nents = table.nents; - } -} -#else -/* - * Allocate N individual pages to construct a scatter ABD. This function - * makes no attempt to request contiguous pages and requires the minimal - * number of kernel interfaces. It's designed for maximum compatibility. - */ -static void -abd_alloc_pages(abd_t *abd, size_t size) -{ - struct scatterlist *sg = NULL; - struct sg_table table; - struct page *page; - gfp_t gfp = __GFP_NOWARN | GFP_NOIO; - int nr_pages = abd_chunkcnt_for_bytes(size); - int i = 0; - - while (sg_alloc_table(&table, nr_pages, gfp)) { - ABDSTAT_BUMP(abdstat_scatter_sg_table_retry); - schedule_timeout_interruptible(1); - } - - ASSERT3U(table.nents, ==, nr_pages); - ABD_SCATTER(abd).abd_sgl = table.sgl; - ABD_SCATTER(abd).abd_nents = nr_pages; - - abd_for_each_sg(abd, sg, nr_pages, i) { - while ((page = __page_cache_alloc(gfp)) == NULL) { - ABDSTAT_BUMP(abdstat_scatter_page_alloc_retry); - schedule_timeout_interruptible(1); - } - - ABDSTAT_BUMP(abdstat_scatter_orders[0]); - sg_set_page(sg, page, PAGESIZE, 0); - abd_mark_zfs_page(page); - } - - if (nr_pages > 1) { - ABDSTAT_BUMP(abdstat_scatter_page_multi_chunk); - abd->abd_flags |= ABD_FLAG_MULTI_CHUNK; - } -} -#endif /* !CONFIG_HIGHMEM */ - -static void -abd_free_pages(abd_t *abd) -{ - struct scatterlist *sg = NULL; - struct sg_table table; - struct page *page; - int nr_pages = ABD_SCATTER(abd).abd_nents; - int order, i = 0; - - if (abd->abd_flags & ABD_FLAG_MULTI_ZONE) - ABDSTAT_BUMPDOWN(abdstat_scatter_page_multi_zone); - - if (abd->abd_flags & ABD_FLAG_MULTI_CHUNK) - ABDSTAT_BUMPDOWN(abdstat_scatter_page_multi_chunk); - - abd_for_each_sg(abd, sg, nr_pages, i) { - page = sg_page(sg); - abd_unmark_zfs_page(page); - order = compound_order(page); - __free_pages(page, order); - ASSERT3U(sg->length, <=, PAGE_SIZE << order); - ABDSTAT_BUMPDOWN(abdstat_scatter_orders[order]); - } - - table.sgl = ABD_SCATTER(abd).abd_sgl; - table.nents = table.orig_nents = nr_pages; - sg_free_table(&table); -} - -#else /* _KERNEL */ - -#ifndef PAGE_SHIFT -#define PAGE_SHIFT (highbit64(PAGESIZE)-1) -#endif - -struct page; - -#define zfs_kmap_atomic(chunk, km) ((void *)chunk) -#define zfs_kunmap_atomic(addr, km) do { (void)(addr); } while (0) -#define local_irq_save(flags) do { (void)(flags); } while (0) -#define local_irq_restore(flags) do { (void)(flags); } while (0) -#define nth_page(pg, i) \ - ((struct page *)((void *)(pg) + (i) * PAGESIZE)) - -struct scatterlist { - struct page *page; - int length; - int end; -}; - -static void -sg_init_table(struct scatterlist *sg, int nr) -{ - memset(sg, 0, nr * sizeof (struct scatterlist)); - sg[nr - 1].end = 1; -} - -#define for_each_sg(sgl, sg, nr, i) \ - for ((i) = 0, (sg) = (sgl); (i) < (nr); (i)++, (sg) = sg_next(sg)) - -static inline void -sg_set_page(struct scatterlist *sg, struct page *page, unsigned int len, - unsigned int offset) -{ - /* currently we don't use offset */ - ASSERT(offset == 0); - sg->page = page; - sg->length = len; -} - -static inline struct page * -sg_page(struct scatterlist *sg) -{ - return (sg->page); -} - -static inline struct scatterlist * -sg_next(struct scatterlist *sg) -{ - if (sg->end) - return (NULL); - - return (sg + 1); -} - -static void -abd_alloc_pages(abd_t *abd, size_t size) -{ - unsigned nr_pages = abd_chunkcnt_for_bytes(size); - struct scatterlist *sg; - int i; - - ABD_SCATTER(abd).abd_sgl = vmem_alloc(nr_pages * - sizeof (struct scatterlist), KM_SLEEP); - sg_init_table(ABD_SCATTER(abd).abd_sgl, nr_pages); - - abd_for_each_sg(abd, sg, nr_pages, i) { - struct page *p = umem_alloc_aligned(PAGESIZE, 64, KM_SLEEP); - sg_set_page(sg, p, PAGESIZE, 0); - } - ABD_SCATTER(abd).abd_nents = nr_pages; -} - -static void -abd_free_pages(abd_t *abd) -{ - int i, n = ABD_SCATTER(abd).abd_nents; - struct scatterlist *sg; - - abd_for_each_sg(abd, sg, n, i) { - for (int j = 0; j < sg->length; j += PAGESIZE) { - struct page *p = nth_page(sg_page(sg), j >> PAGE_SHIFT); - umem_free(p, PAGESIZE); - } - } - - vmem_free(ABD_SCATTER(abd).abd_sgl, n * sizeof (struct scatterlist)); -} - -#endif /* _KERNEL */ - -void -abd_init(void) -{ - int i; - - abd_cache = kmem_cache_create("abd_t", sizeof (abd_t), - 0, NULL, NULL, NULL, NULL, NULL, 0); - - abd_ksp = kstat_create("zfs", 0, "abdstats", "misc", KSTAT_TYPE_NAMED, - sizeof (abd_stats) / sizeof (kstat_named_t), KSTAT_FLAG_VIRTUAL); - if (abd_ksp != NULL) { - for (i = 0; i < MAX_ORDER; i++) { - snprintf(abd_stats.abdstat_scatter_orders[i].name, - KSTAT_STRLEN, "scatter_order_%d", i); - abd_stats.abdstat_scatter_orders[i].data_type = - KSTAT_DATA_UINT64; - } - abd_ksp->ks_data = &abd_stats; - kstat_install(abd_ksp); - } -} - -void -abd_fini(void) -{ - if (abd_ksp != NULL) { - kstat_delete(abd_ksp); - abd_ksp = NULL; - } - - if (abd_cache) { - kmem_cache_destroy(abd_cache); - abd_cache = NULL; - } -} - -static inline void -abd_verify(abd_t *abd) -{ - ASSERT3U(abd->abd_size, >, 0); - ASSERT3U(abd->abd_size, <=, SPA_MAXBLOCKSIZE); - ASSERT3U(abd->abd_flags, ==, abd->abd_flags & (ABD_FLAG_LINEAR | - ABD_FLAG_OWNER | ABD_FLAG_META | ABD_FLAG_MULTI_ZONE | - ABD_FLAG_MULTI_CHUNK | ABD_FLAG_LINEAR_PAGE)); - IMPLY(abd->abd_parent != NULL, !(abd->abd_flags & ABD_FLAG_OWNER)); - IMPLY(abd->abd_flags & ABD_FLAG_META, abd->abd_flags & ABD_FLAG_OWNER); - if (abd_is_linear(abd)) { - ASSERT3P(abd->abd_u.abd_linear.abd_buf, !=, NULL); - } else { - size_t n; - int i = 0; - struct scatterlist *sg = NULL; - - ASSERT3U(ABD_SCATTER(abd).abd_nents, >, 0); - ASSERT3U(ABD_SCATTER(abd).abd_offset, <, - ABD_SCATTER(abd).abd_sgl->length); - n = ABD_SCATTER(abd).abd_nents; - abd_for_each_sg(abd, sg, n, i) { - ASSERT3P(sg_page(sg), !=, NULL); - } - } -} - -static inline abd_t * -abd_alloc_struct(void) -{ - abd_t *abd = kmem_cache_alloc(abd_cache, KM_PUSHPAGE); - - ASSERT3P(abd, !=, NULL); - ABDSTAT_INCR(abdstat_struct_size, sizeof (abd_t)); - - return (abd); -} - -static inline void -abd_free_struct(abd_t *abd) -{ - kmem_cache_free(abd_cache, abd); - ABDSTAT_INCR(abdstat_struct_size, -(int)sizeof (abd_t)); -} - -/* - * Allocate an ABD, along with its own underlying data buffers. Use this if you - * don't care whether the ABD is linear or not. - */ -abd_t * -abd_alloc(size_t size, boolean_t is_metadata) -{ - /* see the comment above zfs_abd_scatter_min_size */ - if (!zfs_abd_scatter_enabled || size < zfs_abd_scatter_min_size) - return (abd_alloc_linear(size, is_metadata)); - - VERIFY3U(size, <=, SPA_MAXBLOCKSIZE); - - abd_t *abd = abd_alloc_struct(); - abd->abd_flags = ABD_FLAG_OWNER; - abd->abd_u.abd_scatter.abd_offset = 0; - abd_alloc_pages(abd, size); - - if (is_metadata) { - abd->abd_flags |= ABD_FLAG_META; - } - abd->abd_size = size; - abd->abd_parent = NULL; - zfs_refcount_create(&abd->abd_children); - - ABDSTAT_BUMP(abdstat_scatter_cnt); - ABDSTAT_INCR(abdstat_scatter_data_size, size); - ABDSTAT_INCR(abdstat_scatter_chunk_waste, - P2ROUNDUP(size, PAGESIZE) - size); - - return (abd); -} - -static void -abd_free_scatter(abd_t *abd) -{ - abd_free_pages(abd); - - zfs_refcount_destroy(&abd->abd_children); - ABDSTAT_BUMPDOWN(abdstat_scatter_cnt); - ABDSTAT_INCR(abdstat_scatter_data_size, -(int)abd->abd_size); - ABDSTAT_INCR(abdstat_scatter_chunk_waste, - (int)abd->abd_size - (int)P2ROUNDUP(abd->abd_size, PAGESIZE)); - - abd_free_struct(abd); -} - -/* - * Allocate an ABD that must be linear, along with its own underlying data - * buffer. Only use this when it would be very annoying to write your ABD - * consumer with a scattered ABD. - */ -abd_t * -abd_alloc_linear(size_t size, boolean_t is_metadata) -{ - abd_t *abd = abd_alloc_struct(); - - VERIFY3U(size, <=, SPA_MAXBLOCKSIZE); - - abd->abd_flags = ABD_FLAG_LINEAR | ABD_FLAG_OWNER; - if (is_metadata) { - abd->abd_flags |= ABD_FLAG_META; - } - abd->abd_size = size; - abd->abd_parent = NULL; - zfs_refcount_create(&abd->abd_children); - - if (is_metadata) { - abd->abd_u.abd_linear.abd_buf = zio_buf_alloc(size); - } else { - abd->abd_u.abd_linear.abd_buf = zio_data_buf_alloc(size); - } - - ABDSTAT_BUMP(abdstat_linear_cnt); - ABDSTAT_INCR(abdstat_linear_data_size, size); - - return (abd); -} - -static void -abd_free_linear(abd_t *abd) -{ - if (abd_is_linear_page(abd)) { - /* Transform it back into a scatter ABD for freeing */ - struct scatterlist *sg = abd->abd_u.abd_linear.abd_sgl; - abd->abd_flags &= ~ABD_FLAG_LINEAR; - abd->abd_flags &= ~ABD_FLAG_LINEAR_PAGE; - ABD_SCATTER(abd).abd_nents = 1; - ABD_SCATTER(abd).abd_offset = 0; - ABD_SCATTER(abd).abd_sgl = sg; - abd_free_scatter(abd); - return; - } - if (abd->abd_flags & ABD_FLAG_META) { - zio_buf_free(abd->abd_u.abd_linear.abd_buf, abd->abd_size); - } else { - zio_data_buf_free(abd->abd_u.abd_linear.abd_buf, abd->abd_size); - } - - zfs_refcount_destroy(&abd->abd_children); - ABDSTAT_BUMPDOWN(abdstat_linear_cnt); - ABDSTAT_INCR(abdstat_linear_data_size, -(int)abd->abd_size); - - abd_free_struct(abd); -} - -/* - * Free an ABD. Only use this on ABDs allocated with abd_alloc() or - * abd_alloc_linear(). - */ -void -abd_free(abd_t *abd) -{ - abd_verify(abd); - ASSERT3P(abd->abd_parent, ==, NULL); - ASSERT(abd->abd_flags & ABD_FLAG_OWNER); - if (abd_is_linear(abd)) - abd_free_linear(abd); - else - abd_free_scatter(abd); -} - -/* - * Allocate an ABD of the same format (same metadata flag, same scatterize - * setting) as another ABD. - */ -abd_t * -abd_alloc_sametype(abd_t *sabd, size_t size) -{ - boolean_t is_metadata = (sabd->abd_flags & ABD_FLAG_META) != 0; - if (abd_is_linear(sabd) && - !abd_is_linear_page(sabd)) { - return (abd_alloc_linear(size, is_metadata)); - } else { - return (abd_alloc(size, is_metadata)); - } -} - -/* - * If we're going to use this ABD for doing I/O using the block layer, the - * consumer of the ABD data doesn't care if it's scattered or not, and we don't - * plan to store this ABD in memory for a long period of time, we should - * allocate the ABD type that requires the least data copying to do the I/O. - * - * On Illumos this is linear ABDs, however if ldi_strategy() can ever issue I/Os - * using a scatter/gather list we should switch to that and replace this call - * with vanilla abd_alloc(). - * - * On Linux the optimal thing to do would be to use abd_get_offset() and - * construct a new ABD which shares the original pages thereby eliminating - * the copy. But for the moment a new linear ABD is allocated until this - * performance optimization can be implemented. - */ -abd_t * -abd_alloc_for_io(size_t size, boolean_t is_metadata) -{ - return (abd_alloc(size, is_metadata)); -} - -/* - * Allocate a new ABD to point to offset off of sabd. It shares the underlying - * buffer data with sabd. Use abd_put() to free. sabd must not be freed while - * any derived ABDs exist. - */ -static inline abd_t * -abd_get_offset_impl(abd_t *sabd, size_t off, size_t size) -{ - abd_t *abd; - - abd_verify(sabd); - ASSERT3U(off, <=, sabd->abd_size); - - if (abd_is_linear(sabd)) { - abd = abd_alloc_struct(); - - /* - * Even if this buf is filesystem metadata, we only track that - * if we own the underlying data buffer, which is not true in - * this case. Therefore, we don't ever use ABD_FLAG_META here. - */ - abd->abd_flags = ABD_FLAG_LINEAR; - - abd->abd_u.abd_linear.abd_buf = - (char *)sabd->abd_u.abd_linear.abd_buf + off; - } else { - int i = 0; - struct scatterlist *sg = NULL; - size_t new_offset = sabd->abd_u.abd_scatter.abd_offset + off; - - abd = abd_alloc_struct(); - - /* - * Even if this buf is filesystem metadata, we only track that - * if we own the underlying data buffer, which is not true in - * this case. Therefore, we don't ever use ABD_FLAG_META here. - */ - abd->abd_flags = 0; - - abd_for_each_sg(sabd, sg, ABD_SCATTER(sabd).abd_nents, i) { - if (new_offset < sg->length) - break; - new_offset -= sg->length; - } - - ABD_SCATTER(abd).abd_sgl = sg; - ABD_SCATTER(abd).abd_offset = new_offset; - ABD_SCATTER(abd).abd_nents = ABD_SCATTER(sabd).abd_nents - i; - } - - abd->abd_size = size; - abd->abd_parent = sabd; - zfs_refcount_create(&abd->abd_children); - (void) zfs_refcount_add_many(&sabd->abd_children, abd->abd_size, abd); - - return (abd); -} - -abd_t * -abd_get_offset(abd_t *sabd, size_t off) -{ - size_t size = sabd->abd_size > off ? sabd->abd_size - off : 0; - - VERIFY3U(size, >, 0); - - return (abd_get_offset_impl(sabd, off, size)); -} - -abd_t * -abd_get_offset_size(abd_t *sabd, size_t off, size_t size) -{ - ASSERT3U(off + size, <=, sabd->abd_size); - - return (abd_get_offset_impl(sabd, off, size)); -} - -/* - * Allocate a linear ABD structure for buf. You must free this with abd_put() - * since the resulting ABD doesn't own its own buffer. - */ -abd_t * -abd_get_from_buf(void *buf, size_t size) -{ - abd_t *abd = abd_alloc_struct(); - - VERIFY3U(size, <=, SPA_MAXBLOCKSIZE); - - /* - * Even if this buf is filesystem metadata, we only track that if we - * own the underlying data buffer, which is not true in this case. - * Therefore, we don't ever use ABD_FLAG_META here. - */ - abd->abd_flags = ABD_FLAG_LINEAR; - abd->abd_size = size; - abd->abd_parent = NULL; - zfs_refcount_create(&abd->abd_children); - - abd->abd_u.abd_linear.abd_buf = buf; - - return (abd); -} - -/* - * Free an ABD allocated from abd_get_offset() or abd_get_from_buf(). Will not - * free the underlying scatterlist or buffer. - */ -void -abd_put(abd_t *abd) -{ - abd_verify(abd); - ASSERT(!(abd->abd_flags & ABD_FLAG_OWNER)); - - if (abd->abd_parent != NULL) { - (void) zfs_refcount_remove_many(&abd->abd_parent->abd_children, - abd->abd_size, abd); - } - - zfs_refcount_destroy(&abd->abd_children); - abd_free_struct(abd); -} - -/* - * Get the raw buffer associated with a linear ABD. - */ -void * -abd_to_buf(abd_t *abd) -{ - ASSERT(abd_is_linear(abd)); - abd_verify(abd); - return (abd->abd_u.abd_linear.abd_buf); -} - -/* - * Borrow a raw buffer from an ABD without copying the contents of the ABD - * into the buffer. If the ABD is scattered, this will allocate a raw buffer - * whose contents are undefined. To copy over the existing data in the ABD, use - * abd_borrow_buf_copy() instead. - */ -void * -abd_borrow_buf(abd_t *abd, size_t n) -{ - void *buf; - abd_verify(abd); - ASSERT3U(abd->abd_size, >=, n); - if (abd_is_linear(abd)) { - buf = abd_to_buf(abd); - } else { - buf = zio_buf_alloc(n); - } - (void) zfs_refcount_add_many(&abd->abd_children, n, buf); - - return (buf); -} - -void * -abd_borrow_buf_copy(abd_t *abd, size_t n) -{ - void *buf = abd_borrow_buf(abd, n); - if (!abd_is_linear(abd)) { - abd_copy_to_buf(buf, abd, n); - } - return (buf); -} - -/* - * Return a borrowed raw buffer to an ABD. If the ABD is scattered, this will - * not change the contents of the ABD and will ASSERT that you didn't modify - * the buffer since it was borrowed. If you want any changes you made to buf to - * be copied back to abd, use abd_return_buf_copy() instead. - */ -void -abd_return_buf(abd_t *abd, void *buf, size_t n) -{ - abd_verify(abd); - ASSERT3U(abd->abd_size, >=, n); - if (abd_is_linear(abd)) { - ASSERT3P(buf, ==, abd_to_buf(abd)); - } else { - ASSERT0(abd_cmp_buf(abd, buf, n)); - zio_buf_free(buf, n); - } - (void) zfs_refcount_remove_many(&abd->abd_children, n, buf); -} - -void -abd_return_buf_copy(abd_t *abd, void *buf, size_t n) -{ - if (!abd_is_linear(abd)) { - abd_copy_from_buf(abd, buf, n); - } - abd_return_buf(abd, buf, n); -} - -/* - * Give this ABD ownership of the buffer that it's storing. Can only be used on - * linear ABDs which were allocated via abd_get_from_buf(), or ones allocated - * with abd_alloc_linear() which subsequently released ownership of their buf - * with abd_release_ownership_of_buf(). - */ -void -abd_take_ownership_of_buf(abd_t *abd, boolean_t is_metadata) -{ - ASSERT(abd_is_linear(abd)); - ASSERT(!(abd->abd_flags & ABD_FLAG_OWNER)); - abd_verify(abd); - - abd->abd_flags |= ABD_FLAG_OWNER; - if (is_metadata) { - abd->abd_flags |= ABD_FLAG_META; - } - - ABDSTAT_BUMP(abdstat_linear_cnt); - ABDSTAT_INCR(abdstat_linear_data_size, abd->abd_size); -} - -void -abd_release_ownership_of_buf(abd_t *abd) -{ - ASSERT(abd_is_linear(abd)); - ASSERT(abd->abd_flags & ABD_FLAG_OWNER); - - /* - * abd_free() needs to handle LINEAR_PAGE ABD's specially. - * Since that flag does not survive the - * abd_release_ownership_of_buf() -> abd_get_from_buf() -> - * abd_take_ownership_of_buf() sequence, we don't allow releasing - * these "linear but not zio_[data_]buf_alloc()'ed" ABD's. - */ - ASSERT(!abd_is_linear_page(abd)); - - abd_verify(abd); - - abd->abd_flags &= ~ABD_FLAG_OWNER; - /* Disable this flag since we no longer own the data buffer */ - abd->abd_flags &= ~ABD_FLAG_META; - - ABDSTAT_BUMPDOWN(abdstat_linear_cnt); - ABDSTAT_INCR(abdstat_linear_data_size, -(int)abd->abd_size); -} - -struct abd_iter { - /* public interface */ - void *iter_mapaddr; /* addr corresponding to iter_pos */ - size_t iter_mapsize; /* length of data valid at mapaddr */ - - /* private */ - abd_t *iter_abd; /* ABD being iterated through */ - size_t iter_pos; - size_t iter_offset; /* offset in current sg/abd_buf, */ - /* abd_offset included */ - struct scatterlist *iter_sg; /* current sg */ -}; - -/* - * Initialize the abd_iter. - */ -static void -abd_iter_init(struct abd_iter *aiter, abd_t *abd, int km_type) -{ - abd_verify(abd); - aiter->iter_abd = abd; - aiter->iter_mapaddr = NULL; - aiter->iter_mapsize = 0; - aiter->iter_pos = 0; - if (abd_is_linear(abd)) { - aiter->iter_offset = 0; - aiter->iter_sg = NULL; - } else { - aiter->iter_offset = ABD_SCATTER(abd).abd_offset; - aiter->iter_sg = ABD_SCATTER(abd).abd_sgl; - } -} - -/* - * Advance the iterator by a certain amount. Cannot be called when a chunk is - * in use. This can be safely called when the aiter has already exhausted, in - * which case this does nothing. - */ -static void -abd_iter_advance(struct abd_iter *aiter, size_t amount) -{ - ASSERT3P(aiter->iter_mapaddr, ==, NULL); - ASSERT0(aiter->iter_mapsize); - - /* There's nothing left to advance to, so do nothing */ - if (aiter->iter_pos == aiter->iter_abd->abd_size) - return; - - aiter->iter_pos += amount; - aiter->iter_offset += amount; - if (!abd_is_linear(aiter->iter_abd)) { - while (aiter->iter_offset >= aiter->iter_sg->length) { - aiter->iter_offset -= aiter->iter_sg->length; - aiter->iter_sg = sg_next(aiter->iter_sg); - if (aiter->iter_sg == NULL) { - ASSERT0(aiter->iter_offset); - break; - } - } - } -} - -/* - * Map the current chunk into aiter. This can be safely called when the aiter - * has already exhausted, in which case this does nothing. - */ -static void -abd_iter_map(struct abd_iter *aiter) -{ - void *paddr; - size_t offset = 0; - - ASSERT3P(aiter->iter_mapaddr, ==, NULL); - ASSERT0(aiter->iter_mapsize); - - /* There's nothing left to iterate over, so do nothing */ - if (aiter->iter_pos == aiter->iter_abd->abd_size) - return; - - if (abd_is_linear(aiter->iter_abd)) { - ASSERT3U(aiter->iter_pos, ==, aiter->iter_offset); - offset = aiter->iter_offset; - aiter->iter_mapsize = aiter->iter_abd->abd_size - offset; - paddr = aiter->iter_abd->abd_u.abd_linear.abd_buf; - } else { - offset = aiter->iter_offset; - aiter->iter_mapsize = MIN(aiter->iter_sg->length - offset, - aiter->iter_abd->abd_size - aiter->iter_pos); - - paddr = zfs_kmap_atomic(sg_page(aiter->iter_sg), - km_table[aiter->iter_km]); - } - - aiter->iter_mapaddr = (char *)paddr + offset; -} - -/* - * Unmap the current chunk from aiter. This can be safely called when the aiter - * has already exhausted, in which case this does nothing. - */ -static void -abd_iter_unmap(struct abd_iter *aiter) -{ - /* There's nothing left to unmap, so do nothing */ - if (aiter->iter_pos == aiter->iter_abd->abd_size) - return; - - if (!abd_is_linear(aiter->iter_abd)) { - /* LINTED E_FUNC_SET_NOT_USED */ - zfs_kunmap_atomic(aiter->iter_mapaddr - aiter->iter_offset, - km_table[aiter->iter_km]); - } - - ASSERT3P(aiter->iter_mapaddr, !=, NULL); - ASSERT3U(aiter->iter_mapsize, >, 0); - - aiter->iter_mapaddr = NULL; - aiter->iter_mapsize = 0; -} - -int -abd_iterate_func(abd_t *abd, size_t off, size_t size, - abd_iter_func_t *func, void *private) -{ - int ret = 0; - struct abd_iter aiter; - - abd_verify(abd); - ASSERT3U(off + size, <=, abd->abd_size); - - abd_iter_init(&aiter, abd, 0); - abd_iter_advance(&aiter, off); - - while (size > 0) { - abd_iter_map(&aiter); - - size_t len = MIN(aiter.iter_mapsize, size); - ASSERT3U(len, >, 0); - - ret = func(aiter.iter_mapaddr, len, private); - - abd_iter_unmap(&aiter); - - if (ret != 0) - break; - - size -= len; - abd_iter_advance(&aiter, len); - } - - return (ret); -} - -struct buf_arg { - void *arg_buf; -}; - -static int -abd_copy_to_buf_off_cb(void *buf, size_t size, void *private) -{ - struct buf_arg *ba_ptr = private; - - (void) memcpy(ba_ptr->arg_buf, buf, size); - ba_ptr->arg_buf = (char *)ba_ptr->arg_buf + size; - - return (0); -} - -/* - * Copy abd to buf. (off is the offset in abd.) - */ -void -abd_copy_to_buf_off(void *buf, abd_t *abd, size_t off, size_t size) -{ - struct buf_arg ba_ptr = { buf }; - - (void) abd_iterate_func(abd, off, size, abd_copy_to_buf_off_cb, - &ba_ptr); -} - -static int -abd_cmp_buf_off_cb(void *buf, size_t size, void *private) -{ - int ret; - struct buf_arg *ba_ptr = private; - - ret = memcmp(buf, ba_ptr->arg_buf, size); - ba_ptr->arg_buf = (char *)ba_ptr->arg_buf + size; - - return (ret); -} - -/* - * Compare the contents of abd to buf. (off is the offset in abd.) - */ -int -abd_cmp_buf_off(abd_t *abd, const void *buf, size_t off, size_t size) -{ - struct buf_arg ba_ptr = { (void *) buf }; - - return (abd_iterate_func(abd, off, size, abd_cmp_buf_off_cb, &ba_ptr)); -} - -static int -abd_copy_from_buf_off_cb(void *buf, size_t size, void *private) -{ - struct buf_arg *ba_ptr = private; - - (void) memcpy(buf, ba_ptr->arg_buf, size); - ba_ptr->arg_buf = (char *)ba_ptr->arg_buf + size; - - return (0); -} - -/* - * Copy from buf to abd. (off is the offset in abd.) - */ -void -abd_copy_from_buf_off(abd_t *abd, const void *buf, size_t off, size_t size) -{ - struct buf_arg ba_ptr = { (void *) buf }; - - (void) abd_iterate_func(abd, off, size, abd_copy_from_buf_off_cb, - &ba_ptr); -} - -/*ARGSUSED*/ -static int -abd_zero_off_cb(void *buf, size_t size, void *private) -{ - (void) memset(buf, 0, size); - return (0); -} - -/* - * Zero out the abd from a particular offset to the end. - */ -void -abd_zero_off(abd_t *abd, size_t off, size_t size) -{ - (void) abd_iterate_func(abd, off, size, abd_zero_off_cb, NULL); -} - -/* - * Iterate over two ABDs and call func incrementally on the two ABDs' data in - * equal-sized chunks (passed to func as raw buffers). func could be called many - * times during this iteration. - */ -int -abd_iterate_func2(abd_t *dabd, abd_t *sabd, size_t doff, size_t soff, - size_t size, abd_iter_func2_t *func, void *private) -{ - int ret = 0; - struct abd_iter daiter, saiter; - - abd_verify(dabd); - abd_verify(sabd); - - ASSERT3U(doff + size, <=, dabd->abd_size); - ASSERT3U(soff + size, <=, sabd->abd_size); - - abd_iter_init(&daiter, dabd, 0); - abd_iter_init(&saiter, sabd, 1); - abd_iter_advance(&daiter, doff); - abd_iter_advance(&saiter, soff); - - while (size > 0) { - abd_iter_map(&daiter); - abd_iter_map(&saiter); - - size_t dlen = MIN(daiter.iter_mapsize, size); - size_t slen = MIN(saiter.iter_mapsize, size); - size_t len = MIN(dlen, slen); - ASSERT(dlen > 0 || slen > 0); - - ret = func(daiter.iter_mapaddr, saiter.iter_mapaddr, len, - private); - - abd_iter_unmap(&saiter); - abd_iter_unmap(&daiter); - - if (ret != 0) - break; - - size -= len; - abd_iter_advance(&daiter, len); - abd_iter_advance(&saiter, len); - } - - return (ret); -} - -/*ARGSUSED*/ -static int -abd_copy_off_cb(void *dbuf, void *sbuf, size_t size, void *private) -{ - (void) memcpy(dbuf, sbuf, size); - return (0); -} - -/* - * Copy from sabd to dabd starting from soff and doff. - */ -void -abd_copy_off(abd_t *dabd, abd_t *sabd, size_t doff, size_t soff, size_t size) -{ - (void) abd_iterate_func2(dabd, sabd, doff, soff, size, - abd_copy_off_cb, NULL); -} - -/*ARGSUSED*/ -static int -abd_cmp_cb(void *bufa, void *bufb, size_t size, void *private) -{ - return (memcmp(bufa, bufb, size)); -} - -/* - * Compares the contents of two ABDs. - */ -int -abd_cmp(abd_t *dabd, abd_t *sabd) -{ - ASSERT3U(dabd->abd_size, ==, sabd->abd_size); - return (abd_iterate_func2(dabd, sabd, 0, 0, dabd->abd_size, - abd_cmp_cb, NULL)); -} - -/* - * Iterate over code ABDs and a data ABD and call @func_raidz_gen. - * - * @cabds parity ABDs, must have equal size - * @dabd data ABD. Can be NULL (in this case @dsize = 0) - * @func_raidz_gen should be implemented so that its behaviour - * is the same when taking linear and when taking scatter - */ -void -abd_raidz_gen_iterate(abd_t **cabds, abd_t *dabd, - ssize_t csize, ssize_t dsize, const unsigned parity, - void (*func_raidz_gen)(void **, const void *, size_t, size_t)) -{ - int i; - ssize_t len, dlen; - struct abd_iter caiters[3]; - struct abd_iter daiter = {0}; - void *caddrs[3]; - unsigned long flags; - - ASSERT3U(parity, <=, 3); - - for (i = 0; i < parity; i++) - abd_iter_init(&caiters[i], cabds[i], i); - - if (dabd) - abd_iter_init(&daiter, dabd, i); - - ASSERT3S(dsize, >=, 0); - - local_irq_save(flags); - while (csize > 0) { - len = csize; - - if (dabd && dsize > 0) - abd_iter_map(&daiter); - - for (i = 0; i < parity; i++) { - abd_iter_map(&caiters[i]); - caddrs[i] = caiters[i].iter_mapaddr; - } - - switch (parity) { - case 3: - len = MIN(caiters[2].iter_mapsize, len); - /* falls through */ - case 2: - len = MIN(caiters[1].iter_mapsize, len); - /* falls through */ - case 1: - len = MIN(caiters[0].iter_mapsize, len); - } - - /* must be progressive */ - ASSERT3S(len, >, 0); - - if (dabd && dsize > 0) { - /* this needs precise iter.length */ - len = MIN(daiter.iter_mapsize, len); - dlen = len; - } else - dlen = 0; - - /* must be progressive */ - ASSERT3S(len, >, 0); - /* - * The iterated function likely will not do well if each - * segment except the last one is not multiple of 512 (raidz). - */ - ASSERT3U(((uint64_t)len & 511ULL), ==, 0); - - func_raidz_gen(caddrs, daiter.iter_mapaddr, len, dlen); - - for (i = parity-1; i >= 0; i--) { - abd_iter_unmap(&caiters[i]); - abd_iter_advance(&caiters[i], len); - } - - if (dabd && dsize > 0) { - abd_iter_unmap(&daiter); - abd_iter_advance(&daiter, dlen); - dsize -= dlen; - } - - csize -= len; - - ASSERT3S(dsize, >=, 0); - ASSERT3S(csize, >=, 0); - } - local_irq_restore(flags); -} - -/* - * Iterate over code ABDs and data reconstruction target ABDs and call - * @func_raidz_rec. Function maps at most 6 pages atomically. - * - * @cabds parity ABDs, must have equal size - * @tabds rec target ABDs, at most 3 - * @tsize size of data target columns - * @func_raidz_rec expects syndrome data in target columns. Function - * reconstructs data and overwrites target columns. - */ -void -abd_raidz_rec_iterate(abd_t **cabds, abd_t **tabds, - ssize_t tsize, const unsigned parity, - void (*func_raidz_rec)(void **t, const size_t tsize, void **c, - const unsigned *mul), - const unsigned *mul) -{ - int i; - ssize_t len; - struct abd_iter citers[3]; - struct abd_iter xiters[3]; - void *caddrs[3], *xaddrs[3]; - unsigned long flags; - - ASSERT3U(parity, <=, 3); - - for (i = 0; i < parity; i++) { - abd_iter_init(&citers[i], cabds[i], 2*i); - abd_iter_init(&xiters[i], tabds[i], 2*i+1); - } - - local_irq_save(flags); - while (tsize > 0) { - - for (i = 0; i < parity; i++) { - abd_iter_map(&citers[i]); - abd_iter_map(&xiters[i]); - caddrs[i] = citers[i].iter_mapaddr; - xaddrs[i] = xiters[i].iter_mapaddr; - } - - len = tsize; - switch (parity) { - case 3: - len = MIN(xiters[2].iter_mapsize, len); - len = MIN(citers[2].iter_mapsize, len); - /* falls through */ - case 2: - len = MIN(xiters[1].iter_mapsize, len); - len = MIN(citers[1].iter_mapsize, len); - /* falls through */ - case 1: - len = MIN(xiters[0].iter_mapsize, len); - len = MIN(citers[0].iter_mapsize, len); - } - /* must be progressive */ - ASSERT3S(len, >, 0); - /* - * The iterated function likely will not do well if each - * segment except the last one is not multiple of 512 (raidz). - */ - ASSERT3U(((uint64_t)len & 511ULL), ==, 0); - - func_raidz_rec(xaddrs, len, caddrs, mul); - - for (i = parity-1; i >= 0; i--) { - abd_iter_unmap(&xiters[i]); - abd_iter_unmap(&citers[i]); - abd_iter_advance(&xiters[i], len); - abd_iter_advance(&citers[i], len); - } - - tsize -= len; - ASSERT3S(tsize, >=, 0); - } - local_irq_restore(flags); -} - -#if defined(_KERNEL) -/* - * bio_nr_pages for ABD. - * @off is the offset in @abd - */ -unsigned long -abd_nr_pages_off(abd_t *abd, unsigned int size, size_t off) -{ - unsigned long pos; - - if (abd_is_linear(abd)) - pos = (unsigned long)abd_to_buf(abd) + off; - else - pos = abd->abd_u.abd_scatter.abd_offset + off; - - return ((pos + size + PAGESIZE - 1) >> PAGE_SHIFT) - - (pos >> PAGE_SHIFT); -} - -/* - * bio_map for scatter ABD. - * @off is the offset in @abd - * Remaining IO size is returned - */ -unsigned int -abd_scatter_bio_map_off(struct bio *bio, abd_t *abd, - unsigned int io_size, size_t off) -{ - int i; - struct abd_iter aiter; - - ASSERT(!abd_is_linear(abd)); - ASSERT3U(io_size, <=, abd->abd_size - off); - - abd_iter_init(&aiter, abd, 0); - abd_iter_advance(&aiter, off); - - for (i = 0; i < bio->bi_max_vecs; i++) { - struct page *pg; - size_t len, sgoff, pgoff; - struct scatterlist *sg; - - if (io_size <= 0) - break; - - sg = aiter.iter_sg; - sgoff = aiter.iter_offset; - pgoff = sgoff & (PAGESIZE - 1); - len = MIN(io_size, PAGESIZE - pgoff); - ASSERT(len > 0); - - pg = nth_page(sg_page(sg), sgoff >> PAGE_SHIFT); - if (bio_add_page(bio, pg, len, pgoff) != len) - break; - - io_size -= len; - abd_iter_advance(&aiter, len); - } - - return (io_size); -} - -/* Tunable Parameters */ -module_param(zfs_abd_scatter_enabled, int, 0644); -MODULE_PARM_DESC(zfs_abd_scatter_enabled, - "Toggle whether ABD allocations must be linear."); -module_param(zfs_abd_scatter_min_size, int, 0644); -MODULE_PARM_DESC(zfs_abd_scatter_min_size, - "Minimum size of scatter allocations."); -/* CSTYLED */ -module_param(zfs_abd_scatter_max_order, uint, 0644); -MODULE_PARM_DESC(zfs_abd_scatter_max_order, - "Maximum order allocation used for a scatter ABD."); -#endif |