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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-05-06 01:02:30 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-05-06 01:02:30 +0000 |
commit | 76cb841cb886eef6b3bee341a2266c76578724ad (patch) | |
tree | f5892e5ba6cc11949952a6ce4ecbe6d516d6ce58 /net/core/xdp.c | |
parent | Initial commit. (diff) | |
download | linux-76cb841cb886eef6b3bee341a2266c76578724ad.tar.xz linux-76cb841cb886eef6b3bee341a2266c76578724ad.zip |
Adding upstream version 4.19.249.upstream/4.19.249
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'net/core/xdp.c')
-rw-r--r-- | net/core/xdp.c | 400 |
1 files changed, 400 insertions, 0 deletions
diff --git a/net/core/xdp.c b/net/core/xdp.c new file mode 100644 index 000000000..89b6785ce --- /dev/null +++ b/net/core/xdp.c @@ -0,0 +1,400 @@ +/* net/core/xdp.c + * + * Copyright (c) 2017 Jesper Dangaard Brouer, Red Hat Inc. + * Released under terms in GPL version 2. See COPYING. + */ +#include <linux/bpf.h> +#include <linux/filter.h> +#include <linux/types.h> +#include <linux/mm.h> +#include <linux/netdevice.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 */ + return key; +} + +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; + + if (id == 0) + return; + + mutex_lock(&mem_id_lock); + + xa = rhashtable_lookup_fast(mem_id_ht, &id, mem_id_rht_params); + if (xa && !rhashtable_remove_fast(mem_id_ht, &xa->node, mem_id_rht_params)) + 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) { + napi_direct &= !xdp_return_frame_no_direct(); + 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); + +int xdp_attachment_query(struct xdp_attachment_info *info, + struct netdev_bpf *bpf) +{ + bpf->prog_id = info->prog ? info->prog->aux->id : 0; + bpf->prog_flags = info->prog ? info->flags : 0; + return 0; +} +EXPORT_SYMBOL_GPL(xdp_attachment_query); + +bool xdp_attachment_flags_ok(struct xdp_attachment_info *info, + struct netdev_bpf *bpf) +{ + if (info->prog && (bpf->flags ^ info->flags) & XDP_FLAGS_MODES) { + NL_SET_ERR_MSG(bpf->extack, + "program loaded with different flags"); + return false; + } + return true; +} +EXPORT_SYMBOL_GPL(xdp_attachment_flags_ok); + +void xdp_attachment_setup(struct xdp_attachment_info *info, + struct netdev_bpf *bpf) +{ + if (info->prog) + bpf_prog_put(info->prog); + info->prog = bpf->prog; + info->flags = bpf->flags; +} +EXPORT_SYMBOL_GPL(xdp_attachment_setup); |