| /* net/core/xdp.c |
| * |
| * Copyright (c) 2017 Jesper Dangaard Brouer, Red Hat Inc. |
| * Released under terms in GPL version 2. See COPYING. |
| */ |
| #include <linux/types.h> |
| #include <linux/mm.h> |
| #include <linux/slab.h> |
| #include <linux/idr.h> |
| #include <linux/rhashtable.h> |
| #include <net/page_pool.h> |
| |
| #include <net/xdp.h> |
| |
| #define REG_STATE_NEW 0x0 |
| #define REG_STATE_REGISTERED 0x1 |
| #define REG_STATE_UNREGISTERED 0x2 |
| #define REG_STATE_UNUSED 0x3 |
| |
| static DEFINE_IDA(mem_id_pool); |
| static DEFINE_MUTEX(mem_id_lock); |
| #define MEM_ID_MAX 0xFFFE |
| #define MEM_ID_MIN 1 |
| static int mem_id_next = MEM_ID_MIN; |
| |
| static bool mem_id_init; /* false */ |
| static struct rhashtable *mem_id_ht; |
| |
| struct xdp_mem_allocator { |
| struct xdp_mem_info mem; |
| union { |
| void *allocator; |
| struct page_pool *page_pool; |
| struct zero_copy_allocator *zc_alloc; |
| }; |
| struct rhash_head node; |
| struct rcu_head rcu; |
| }; |
| |
| static u32 xdp_mem_id_hashfn(const void *data, u32 len, u32 seed) |
| { |
| const u32 *k = data; |
| const u32 key = *k; |
| |
| BUILD_BUG_ON(FIELD_SIZEOF(struct xdp_mem_allocator, mem.id) |
| != sizeof(u32)); |
| |
| /* Use cyclic increasing ID as direct hash key, see rht_bucket_index */ |
| return key << RHT_HASH_RESERVED_SPACE; |
| } |
| |
| static int xdp_mem_id_cmp(struct rhashtable_compare_arg *arg, |
| const void *ptr) |
| { |
| const struct xdp_mem_allocator *xa = ptr; |
| u32 mem_id = *(u32 *)arg->key; |
| |
| return xa->mem.id != mem_id; |
| } |
| |
| static const struct rhashtable_params mem_id_rht_params = { |
| .nelem_hint = 64, |
| .head_offset = offsetof(struct xdp_mem_allocator, node), |
| .key_offset = offsetof(struct xdp_mem_allocator, mem.id), |
| .key_len = FIELD_SIZEOF(struct xdp_mem_allocator, mem.id), |
| .max_size = MEM_ID_MAX, |
| .min_size = 8, |
| .automatic_shrinking = true, |
| .hashfn = xdp_mem_id_hashfn, |
| .obj_cmpfn = xdp_mem_id_cmp, |
| }; |
| |
| static void __xdp_mem_allocator_rcu_free(struct rcu_head *rcu) |
| { |
| struct xdp_mem_allocator *xa; |
| |
| xa = container_of(rcu, struct xdp_mem_allocator, rcu); |
| |
| /* Allow this ID to be reused */ |
| ida_simple_remove(&mem_id_pool, xa->mem.id); |
| |
| /* Notice, driver is expected to free the *allocator, |
| * e.g. page_pool, and MUST also use RCU free. |
| */ |
| |
| /* Poison memory */ |
| xa->mem.id = 0xFFFF; |
| xa->mem.type = 0xF0F0; |
| xa->allocator = (void *)0xDEAD9001; |
| |
| kfree(xa); |
| } |
| |
| static void __xdp_rxq_info_unreg_mem_model(struct xdp_rxq_info *xdp_rxq) |
| { |
| struct xdp_mem_allocator *xa; |
| int id = xdp_rxq->mem.id; |
| int err; |
| |
| if (id == 0) |
| return; |
| |
| mutex_lock(&mem_id_lock); |
| |
| xa = rhashtable_lookup(mem_id_ht, &id, mem_id_rht_params); |
| if (!xa) { |
| mutex_unlock(&mem_id_lock); |
| return; |
| } |
| |
| err = rhashtable_remove_fast(mem_id_ht, &xa->node, mem_id_rht_params); |
| WARN_ON(err); |
| |
| call_rcu(&xa->rcu, __xdp_mem_allocator_rcu_free); |
| |
| mutex_unlock(&mem_id_lock); |
| } |
| |
| void xdp_rxq_info_unreg(struct xdp_rxq_info *xdp_rxq) |
| { |
| /* Simplify driver cleanup code paths, allow unreg "unused" */ |
| if (xdp_rxq->reg_state == REG_STATE_UNUSED) |
| return; |
| |
| WARN(!(xdp_rxq->reg_state == REG_STATE_REGISTERED), "Driver BUG"); |
| |
| __xdp_rxq_info_unreg_mem_model(xdp_rxq); |
| |
| xdp_rxq->reg_state = REG_STATE_UNREGISTERED; |
| xdp_rxq->dev = NULL; |
| |
| /* Reset mem info to defaults */ |
| xdp_rxq->mem.id = 0; |
| xdp_rxq->mem.type = 0; |
| } |
| EXPORT_SYMBOL_GPL(xdp_rxq_info_unreg); |
| |
| static void xdp_rxq_info_init(struct xdp_rxq_info *xdp_rxq) |
| { |
| memset(xdp_rxq, 0, sizeof(*xdp_rxq)); |
| } |
| |
| /* Returns 0 on success, negative on failure */ |
| int xdp_rxq_info_reg(struct xdp_rxq_info *xdp_rxq, |
| struct net_device *dev, u32 queue_index) |
| { |
| if (xdp_rxq->reg_state == REG_STATE_UNUSED) { |
| WARN(1, "Driver promised not to register this"); |
| return -EINVAL; |
| } |
| |
| if (xdp_rxq->reg_state == REG_STATE_REGISTERED) { |
| WARN(1, "Missing unregister, handled but fix driver"); |
| xdp_rxq_info_unreg(xdp_rxq); |
| } |
| |
| if (!dev) { |
| WARN(1, "Missing net_device from driver"); |
| return -ENODEV; |
| } |
| |
| /* State either UNREGISTERED or NEW */ |
| xdp_rxq_info_init(xdp_rxq); |
| xdp_rxq->dev = dev; |
| xdp_rxq->queue_index = queue_index; |
| |
| xdp_rxq->reg_state = REG_STATE_REGISTERED; |
| return 0; |
| } |
| EXPORT_SYMBOL_GPL(xdp_rxq_info_reg); |
| |
| void xdp_rxq_info_unused(struct xdp_rxq_info *xdp_rxq) |
| { |
| xdp_rxq->reg_state = REG_STATE_UNUSED; |
| } |
| EXPORT_SYMBOL_GPL(xdp_rxq_info_unused); |
| |
| bool xdp_rxq_info_is_reg(struct xdp_rxq_info *xdp_rxq) |
| { |
| return (xdp_rxq->reg_state == REG_STATE_REGISTERED); |
| } |
| EXPORT_SYMBOL_GPL(xdp_rxq_info_is_reg); |
| |
| static int __mem_id_init_hash_table(void) |
| { |
| struct rhashtable *rht; |
| int ret; |
| |
| if (unlikely(mem_id_init)) |
| return 0; |
| |
| rht = kzalloc(sizeof(*rht), GFP_KERNEL); |
| if (!rht) |
| return -ENOMEM; |
| |
| ret = rhashtable_init(rht, &mem_id_rht_params); |
| if (ret < 0) { |
| kfree(rht); |
| return ret; |
| } |
| mem_id_ht = rht; |
| smp_mb(); /* mutex lock should provide enough pairing */ |
| mem_id_init = true; |
| |
| return 0; |
| } |
| |
| /* Allocate a cyclic ID that maps to allocator pointer. |
| * See: https://www.kernel.org/doc/html/latest/core-api/idr.html |
| * |
| * Caller must lock mem_id_lock. |
| */ |
| static int __mem_id_cyclic_get(gfp_t gfp) |
| { |
| int retries = 1; |
| int id; |
| |
| again: |
| id = ida_simple_get(&mem_id_pool, mem_id_next, MEM_ID_MAX, gfp); |
| if (id < 0) { |
| if (id == -ENOSPC) { |
| /* Cyclic allocator, reset next id */ |
| if (retries--) { |
| mem_id_next = MEM_ID_MIN; |
| goto again; |
| } |
| } |
| return id; /* errno */ |
| } |
| mem_id_next = id + 1; |
| |
| return id; |
| } |
| |
| static bool __is_supported_mem_type(enum xdp_mem_type type) |
| { |
| if (type == MEM_TYPE_PAGE_POOL) |
| return is_page_pool_compiled_in(); |
| |
| if (type >= MEM_TYPE_MAX) |
| return false; |
| |
| return true; |
| } |
| |
| int xdp_rxq_info_reg_mem_model(struct xdp_rxq_info *xdp_rxq, |
| enum xdp_mem_type type, void *allocator) |
| { |
| struct xdp_mem_allocator *xdp_alloc; |
| gfp_t gfp = GFP_KERNEL; |
| int id, errno, ret; |
| void *ptr; |
| |
| if (xdp_rxq->reg_state != REG_STATE_REGISTERED) { |
| WARN(1, "Missing register, driver bug"); |
| return -EFAULT; |
| } |
| |
| if (!__is_supported_mem_type(type)) |
| return -EOPNOTSUPP; |
| |
| xdp_rxq->mem.type = type; |
| |
| if (!allocator) { |
| if (type == MEM_TYPE_PAGE_POOL || type == MEM_TYPE_ZERO_COPY) |
| return -EINVAL; /* Setup time check page_pool req */ |
| return 0; |
| } |
| |
| /* Delay init of rhashtable to save memory if feature isn't used */ |
| if (!mem_id_init) { |
| mutex_lock(&mem_id_lock); |
| ret = __mem_id_init_hash_table(); |
| mutex_unlock(&mem_id_lock); |
| if (ret < 0) { |
| WARN_ON(1); |
| return ret; |
| } |
| } |
| |
| xdp_alloc = kzalloc(sizeof(*xdp_alloc), gfp); |
| if (!xdp_alloc) |
| return -ENOMEM; |
| |
| mutex_lock(&mem_id_lock); |
| id = __mem_id_cyclic_get(gfp); |
| if (id < 0) { |
| errno = id; |
| goto err; |
| } |
| xdp_rxq->mem.id = id; |
| xdp_alloc->mem = xdp_rxq->mem; |
| xdp_alloc->allocator = allocator; |
| |
| /* Insert allocator into ID lookup table */ |
| ptr = rhashtable_insert_slow(mem_id_ht, &id, &xdp_alloc->node); |
| if (IS_ERR(ptr)) { |
| errno = PTR_ERR(ptr); |
| goto err; |
| } |
| |
| mutex_unlock(&mem_id_lock); |
| |
| return 0; |
| err: |
| mutex_unlock(&mem_id_lock); |
| kfree(xdp_alloc); |
| return errno; |
| } |
| EXPORT_SYMBOL_GPL(xdp_rxq_info_reg_mem_model); |
| |
| /* XDP RX runs under NAPI protection, and in different delivery error |
| * scenarios (e.g. queue full), it is possible to return the xdp_frame |
| * while still leveraging this protection. The @napi_direct boolian |
| * is used for those calls sites. Thus, allowing for faster recycling |
| * of xdp_frames/pages in those cases. |
| */ |
| static void __xdp_return(void *data, struct xdp_mem_info *mem, bool napi_direct, |
| unsigned long handle) |
| { |
| struct xdp_mem_allocator *xa; |
| struct page *page; |
| |
| switch (mem->type) { |
| case MEM_TYPE_PAGE_POOL: |
| rcu_read_lock(); |
| /* mem->id is valid, checked in xdp_rxq_info_reg_mem_model() */ |
| xa = rhashtable_lookup(mem_id_ht, &mem->id, mem_id_rht_params); |
| page = virt_to_head_page(data); |
| if (xa) |
| page_pool_put_page(xa->page_pool, page, napi_direct); |
| else |
| put_page(page); |
| rcu_read_unlock(); |
| break; |
| case MEM_TYPE_PAGE_SHARED: |
| page_frag_free(data); |
| break; |
| case MEM_TYPE_PAGE_ORDER0: |
| page = virt_to_page(data); /* Assumes order0 page*/ |
| put_page(page); |
| break; |
| case MEM_TYPE_ZERO_COPY: |
| /* NB! Only valid from an xdp_buff! */ |
| rcu_read_lock(); |
| /* mem->id is valid, checked in xdp_rxq_info_reg_mem_model() */ |
| xa = rhashtable_lookup(mem_id_ht, &mem->id, mem_id_rht_params); |
| xa->zc_alloc->free(xa->zc_alloc, handle); |
| rcu_read_unlock(); |
| default: |
| /* Not possible, checked in xdp_rxq_info_reg_mem_model() */ |
| break; |
| } |
| } |
| |
| void xdp_return_frame(struct xdp_frame *xdpf) |
| { |
| __xdp_return(xdpf->data, &xdpf->mem, false, 0); |
| } |
| EXPORT_SYMBOL_GPL(xdp_return_frame); |
| |
| void xdp_return_frame_rx_napi(struct xdp_frame *xdpf) |
| { |
| __xdp_return(xdpf->data, &xdpf->mem, true, 0); |
| } |
| EXPORT_SYMBOL_GPL(xdp_return_frame_rx_napi); |
| |
| void xdp_return_buff(struct xdp_buff *xdp) |
| { |
| __xdp_return(xdp->data, &xdp->rxq->mem, true, xdp->handle); |
| } |
| EXPORT_SYMBOL_GPL(xdp_return_buff); |