diff options
Diffstat (limited to 'drivers/infiniband/hw/hfi1/pin_system.c')
| -rw-r--r-- | drivers/infiniband/hw/hfi1/pin_system.c | 474 |
1 files changed, 474 insertions, 0 deletions
diff --git a/drivers/infiniband/hw/hfi1/pin_system.c b/drivers/infiniband/hw/hfi1/pin_system.c new file mode 100644 index 000000000000..384f722093e0 --- /dev/null +++ b/drivers/infiniband/hw/hfi1/pin_system.c @@ -0,0 +1,474 @@ +// SPDX-License-Identifier: GPL-2.0 or BSD-3-Clause +/* + * Copyright(c) 2023 - Cornelis Networks, Inc. + */ + +#include <linux/types.h> + +#include "hfi.h" +#include "common.h" +#include "device.h" +#include "pinning.h" +#include "mmu_rb.h" +#include "user_sdma.h" +#include "trace.h" + +struct sdma_mmu_node { + struct mmu_rb_node rb; + struct hfi1_user_sdma_pkt_q *pq; + struct page **pages; + unsigned int npages; +}; + +static bool sdma_rb_filter(struct mmu_rb_node *node, unsigned long addr, + unsigned long len); +static int sdma_rb_evict(void *arg, struct mmu_rb_node *mnode, void *arg2, + bool *stop); +static void sdma_rb_remove(void *arg, struct mmu_rb_node *mnode); + +static struct mmu_rb_ops sdma_rb_ops = { + .filter = sdma_rb_filter, + .evict = sdma_rb_evict, + .remove = sdma_rb_remove, +}; + +int hfi1_init_system_pinning(struct hfi1_user_sdma_pkt_q *pq) +{ + struct hfi1_devdata *dd = pq->dd; + int ret; + + ret = hfi1_mmu_rb_register(pq, &sdma_rb_ops, dd->pport->hfi1_wq, + &pq->handler); + if (ret) + dd_dev_err(dd, + "[%u:%u] Failed to register system memory DMA support with MMU: %d\n", + pq->ctxt, pq->subctxt, ret); + return ret; +} + +void hfi1_free_system_pinning(struct hfi1_user_sdma_pkt_q *pq) +{ + if (pq->handler) + hfi1_mmu_rb_unregister(pq->handler); +} + +static u32 sdma_cache_evict(struct hfi1_user_sdma_pkt_q *pq, u32 npages) +{ + struct evict_data evict_data; + + evict_data.cleared = 0; + evict_data.target = npages; + hfi1_mmu_rb_evict(pq->handler, &evict_data); + return evict_data.cleared; +} + +static void unpin_vector_pages(struct mm_struct *mm, struct page **pages, + unsigned int start, unsigned int npages) +{ + hfi1_release_user_pages(mm, pages + start, npages, false); + kfree(pages); +} + +static inline struct mm_struct *mm_from_sdma_node(struct sdma_mmu_node *node) +{ + return node->rb.handler->mn.mm; +} + +static void free_system_node(struct sdma_mmu_node *node) +{ + if (node->npages) { + unpin_vector_pages(mm_from_sdma_node(node), node->pages, 0, + node->npages); + atomic_sub(node->npages, &node->pq->n_locked); + } + kfree(node); +} + +/* + * kref_get()'s an additional kref on the returned rb_node to prevent rb_node + * from being released until after rb_node is assigned to an SDMA descriptor + * (struct sdma_desc) under add_system_iovec_to_sdma_packet(), even if the + * virtual address range for rb_node is invalidated between now and then. + */ +static struct sdma_mmu_node *find_system_node(struct mmu_rb_handler *handler, + unsigned long start, + unsigned long end) +{ + struct mmu_rb_node *rb_node; + unsigned long flags; + + spin_lock_irqsave(&handler->lock, flags); + rb_node = hfi1_mmu_rb_get_first(handler, start, (end - start)); + if (!rb_node) { + spin_unlock_irqrestore(&handler->lock, flags); + return NULL; + } + + /* "safety" kref to prevent release before add_system_iovec_to_sdma_packet() */ + kref_get(&rb_node->refcount); + spin_unlock_irqrestore(&handler->lock, flags); + + return container_of(rb_node, struct sdma_mmu_node, rb); +} + +static int pin_system_pages(struct user_sdma_request *req, + uintptr_t start_address, size_t length, + struct sdma_mmu_node *node, int npages) +{ + struct hfi1_user_sdma_pkt_q *pq = req->pq; + int pinned, cleared; + struct page **pages; + + pages = kcalloc(npages, sizeof(*pages), GFP_KERNEL); + if (!pages) + return -ENOMEM; + +retry: + if (!hfi1_can_pin_pages(pq->dd, current->mm, atomic_read(&pq->n_locked), + npages)) { + SDMA_DBG(req, "Evicting: nlocked %u npages %u", + atomic_read(&pq->n_locked), npages); + cleared = sdma_cache_evict(pq, npages); + if (cleared >= npages) + goto retry; + } + + SDMA_DBG(req, "Acquire user pages start_address %lx node->npages %u npages %u", + start_address, node->npages, npages); + pinned = hfi1_acquire_user_pages(current->mm, start_address, npages, 0, + pages); + + if (pinned < 0) { + kfree(pages); + SDMA_DBG(req, "pinned %d", pinned); + return pinned; + } + if (pinned != npages) { + unpin_vector_pages(current->mm, pages, node->npages, pinned); + SDMA_DBG(req, "npages %u pinned %d", npages, pinned); + return -EFAULT; + } + node->rb.addr = start_address; + node->rb.len = length; + node->pages = pages; + node->npages = npages; + atomic_add(pinned, &pq->n_locked); + SDMA_DBG(req, "done. pinned %d", pinned); + return 0; +} + +/* + * kref refcount on *node_p will be 2 on successful addition: one kref from + * kref_init() for mmu_rb_handler and one kref to prevent *node_p from being + * released until after *node_p is assigned to an SDMA descriptor (struct + * sdma_desc) under add_system_iovec_to_sdma_packet(), even if the virtual + * address range for *node_p is invalidated between now and then. + */ +static int add_system_pinning(struct user_sdma_request *req, + struct sdma_mmu_node **node_p, + unsigned long start, unsigned long len) + +{ + struct hfi1_user_sdma_pkt_q *pq = req->pq; + struct sdma_mmu_node *node; + int ret; + + node = kzalloc(sizeof(*node), GFP_KERNEL); + if (!node) + return -ENOMEM; + + /* First kref "moves" to mmu_rb_handler */ + kref_init(&node->rb.refcount); + + /* "safety" kref to prevent release before add_system_iovec_to_sdma_packet() */ + kref_get(&node->rb.refcount); + + node->pq = pq; + ret = pin_system_pages(req, start, len, node, PFN_DOWN(len)); + if (ret == 0) { + ret = hfi1_mmu_rb_insert(pq->handler, &node->rb); + if (ret) + free_system_node(node); + else + *node_p = node; + + return ret; + } + + kfree(node); + return ret; +} + +static int get_system_cache_entry(struct user_sdma_request *req, + struct sdma_mmu_node **node_p, + size_t req_start, size_t req_len) +{ + struct hfi1_user_sdma_pkt_q *pq = req->pq; + u64 start = ALIGN_DOWN(req_start, PAGE_SIZE); + u64 end = PFN_ALIGN(req_start + req_len); + int ret; + + if ((end - start) == 0) { + SDMA_DBG(req, + "Request for empty cache entry req_start %lx req_len %lx start %llx end %llx", + req_start, req_len, start, end); + return -EINVAL; + } + + SDMA_DBG(req, "req_start %lx req_len %lu", req_start, req_len); + + while (1) { + struct sdma_mmu_node *node = + find_system_node(pq->handler, start, end); + u64 prepend_len = 0; + + SDMA_DBG(req, "node %p start %llx end %llu", node, start, end); + if (!node) { + ret = add_system_pinning(req, node_p, start, + end - start); + if (ret == -EEXIST) { + /* + * Another execution context has inserted a + * conficting entry first. + */ + continue; + } + return ret; + } + + if (node->rb.addr <= start) { + /* + * This entry covers at least part of the region. If it doesn't extend + * to the end, then this will be called again for the next segment. + */ + *node_p = node; + return 0; + } + + SDMA_DBG(req, "prepend: node->rb.addr %lx, node->rb.refcount %d", + node->rb.addr, kref_read(&node->rb.refcount)); + prepend_len = node->rb.addr - start; + + /* + * This node will not be returned, instead a new node + * will be. So release the reference. + */ + kref_put(&node->rb.refcount, hfi1_mmu_rb_release); + + /* Prepend a node to cover the beginning of the allocation */ + ret = add_system_pinning(req, node_p, start, prepend_len); + if (ret == -EEXIST) { + /* Another execution context has inserted a conficting entry first. */ + continue; + } + return ret; + } +} + +static void sdma_mmu_rb_node_get(void *ctx) +{ + struct mmu_rb_node *node = ctx; + + kref_get(&node->refcount); +} + +static void sdma_mmu_rb_node_put(void *ctx) +{ + struct sdma_mmu_node *node = ctx; + + kref_put(&node->rb.refcount, hfi1_mmu_rb_release); +} + +static int add_mapping_to_sdma_packet(struct user_sdma_request *req, + struct user_sdma_txreq *tx, + struct sdma_mmu_node *cache_entry, + size_t start, + size_t from_this_cache_entry) +{ + struct hfi1_user_sdma_pkt_q *pq = req->pq; + unsigned int page_offset; + unsigned int from_this_page; + size_t page_index; + void *ctx; + int ret; + + /* + * Because the cache may be more fragmented than the memory that is being accessed, + * it's not strictly necessary to have a descriptor per cache entry. + */ + + while (from_this_cache_entry) { + page_index = PFN_DOWN(start - cache_entry->rb.addr); + + if (page_index >= cache_entry->npages) { + SDMA_DBG(req, + "Request for page_index %zu >= cache_entry->npages %u", + page_index, cache_entry->npages); + return -EINVAL; + } + + page_offset = start - ALIGN_DOWN(start, PAGE_SIZE); + from_this_page = PAGE_SIZE - page_offset; + + if (from_this_page < from_this_cache_entry) { + ctx = NULL; + } else { + /* + * In the case they are equal the next line has no practical effect, + * but it's better to do a register to register copy than a conditional + * branch. + */ + from_this_page = from_this_cache_entry; + ctx = cache_entry; + } + + ret = sdma_txadd_page(pq->dd, &tx->txreq, + cache_entry->pages[page_index], + page_offset, from_this_page, + ctx, + sdma_mmu_rb_node_get, + sdma_mmu_rb_node_put); + if (ret) { + /* + * When there's a failure, the entire request is freed by + * user_sdma_send_pkts(). + */ + SDMA_DBG(req, + "sdma_txadd_page failed %d page_index %lu page_offset %u from_this_page %u", + ret, page_index, page_offset, from_this_page); + return ret; + } + start += from_this_page; + from_this_cache_entry -= from_this_page; + } + return 0; +} + +static int add_system_iovec_to_sdma_packet(struct user_sdma_request *req, + struct user_sdma_txreq *tx, + struct user_sdma_iovec *iovec, + size_t from_this_iovec) +{ + while (from_this_iovec > 0) { + struct sdma_mmu_node *cache_entry; + size_t from_this_cache_entry; + size_t start; + int ret; + + start = (uintptr_t)iovec->iov.iov_base + iovec->offset; + ret = get_system_cache_entry(req, &cache_entry, start, + from_this_iovec); + if (ret) { + SDMA_DBG(req, "pin system segment failed %d", ret); + return ret; + } + + from_this_cache_entry = cache_entry->rb.len - (start - cache_entry->rb.addr); + if (from_this_cache_entry > from_this_iovec) + from_this_cache_entry = from_this_iovec; + + ret = add_mapping_to_sdma_packet(req, tx, cache_entry, start, + from_this_cache_entry); + + /* + * Done adding cache_entry to zero or more sdma_desc. Can + * kref_put() the "safety" kref taken under + * get_system_cache_entry(). + */ + kref_put(&cache_entry->rb.refcount, hfi1_mmu_rb_release); + + if (ret) { + SDMA_DBG(req, "add system segment failed %d", ret); + return ret; + } + + iovec->offset += from_this_cache_entry; + from_this_iovec -= from_this_cache_entry; + } + + return 0; +} + +/* + * Add up to pkt_data_remaining bytes to the txreq, starting at the current + * offset in the given iovec entry and continuing until all data has been added + * to the iovec or the iovec entry type changes. + * + * On success, prior to returning, adjust pkt_data_remaining, req->iov_idx, and + * the offset value in req->iov[req->iov_idx] to reflect the data that has been + * consumed. + */ +int hfi1_add_pages_to_sdma_packet(struct user_sdma_request *req, + struct user_sdma_txreq *tx, + struct user_sdma_iovec *iovec, + u32 *pkt_data_remaining) +{ + size_t remaining_to_add = *pkt_data_remaining; + /* + * Walk through iovec entries, ensure the associated pages + * are pinned and mapped, add data to the packet until no more + * data remains to be added or the iovec entry type changes. + */ + while (remaining_to_add > 0) { + struct user_sdma_iovec *cur_iovec; + size_t from_this_iovec; + int ret; + + cur_iovec = iovec; + from_this_iovec = iovec->iov.iov_len - iovec->offset; + + if (from_this_iovec > remaining_to_add) { + from_this_iovec = remaining_to_add; + } else { + /* The current iovec entry will be consumed by this pass. */ + req->iov_idx++; + iovec++; + } + + ret = add_system_iovec_to_sdma_packet(req, tx, cur_iovec, + from_this_iovec); + if (ret) + return ret; + + remaining_to_add -= from_this_iovec; + } + *pkt_data_remaining = remaining_to_add; + + return 0; +} + +static bool sdma_rb_filter(struct mmu_rb_node *node, unsigned long addr, + unsigned long len) +{ + return (bool)(node->addr == addr); +} + +/* + * Return 1 to remove the node from the rb tree and call the remove op. + * + * Called with the rb tree lock held. + */ +static int sdma_rb_evict(void *arg, struct mmu_rb_node *mnode, + void *evict_arg, bool *stop) +{ + struct sdma_mmu_node *node = + container_of(mnode, struct sdma_mmu_node, rb); + struct evict_data *evict_data = evict_arg; + + /* this node will be evicted, add its pages to our count */ + evict_data->cleared += node->npages; + + /* have enough pages been cleared? */ + if (evict_data->cleared >= evict_data->target) + *stop = true; + + return 1; /* remove this node */ +} + +static void sdma_rb_remove(void *arg, struct mmu_rb_node *mnode) +{ + struct sdma_mmu_node *node = + container_of(mnode, struct sdma_mmu_node, rb); + + free_system_node(node); +} |