| /* |
| * 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 |
| #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); |
| 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); |
| } |
| |
| 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); |
| 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) { |
| abd_ksp->ks_data = &abd_stats; |
| kstat_install(abd_ksp); |
| |
| 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; |
| } |
| } |
| } |
| |
| 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); |
| } |
| |
| #ifndef HAVE_1ARG_KMAP_ATOMIC |
| #define NR_KM_TYPE (6) |
| #ifdef _KERNEL |
| int km_table[NR_KM_TYPE] = { |
| KM_USER0, |
| KM_USER1, |
| KM_BIO_SRC_IRQ, |
| KM_BIO_DST_IRQ, |
| KM_PTE0, |
| KM_PTE1, |
| }; |
| #endif |
| #endif |
| |
| 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 */ |
| #ifndef HAVE_1ARG_KMAP_ATOMIC |
| int iter_km; /* KM_* for kmap_atomic */ |
| #endif |
| }; |
| |
| /* |
| * 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; |
| } |
| #ifndef HAVE_1ARG_KMAP_ATOMIC |
| ASSERT3U(km_type, <, NR_KM_TYPE); |
| aiter->iter_km = km_type; |
| #endif |
| } |
| |
| /* |
| * 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 |