diff options
Diffstat (limited to '')
| -rw-r--r-- | net/xdp/xdp_umem.c | 259 |
1 files changed, 259 insertions, 0 deletions
diff --git a/net/xdp/xdp_umem.c b/net/xdp/xdp_umem.c new file mode 100644 index 000000000..02207e852 --- /dev/null +++ b/net/xdp/xdp_umem.c @@ -0,0 +1,259 @@ +// SPDX-License-Identifier: GPL-2.0 +/* XDP user-space packet buffer + * Copyright(c) 2018 Intel Corporation. + */ + +#include <linux/init.h> +#include <linux/sched/mm.h> +#include <linux/sched/signal.h> +#include <linux/sched/task.h> +#include <linux/uaccess.h> +#include <linux/slab.h> +#include <linux/bpf.h> +#include <linux/mm.h> +#include <linux/netdevice.h> +#include <linux/rtnetlink.h> +#include <linux/idr.h> +#include <linux/vmalloc.h> + +#include "xdp_umem.h" +#include "xsk_queue.h" + +static DEFINE_IDA(umem_ida); + +static void xdp_umem_unpin_pages(struct xdp_umem *umem) +{ + unpin_user_pages_dirty_lock(umem->pgs, umem->npgs, true); + + kvfree(umem->pgs); + umem->pgs = NULL; +} + +static void xdp_umem_unaccount_pages(struct xdp_umem *umem) +{ + if (umem->user) { + atomic_long_sub(umem->npgs, &umem->user->locked_vm); + free_uid(umem->user); + } +} + +static void xdp_umem_addr_unmap(struct xdp_umem *umem) +{ + vunmap(umem->addrs); + umem->addrs = NULL; +} + +static int xdp_umem_addr_map(struct xdp_umem *umem, struct page **pages, + u32 nr_pages) +{ + umem->addrs = vmap(pages, nr_pages, VM_MAP, PAGE_KERNEL); + if (!umem->addrs) + return -ENOMEM; + return 0; +} + +static void xdp_umem_release(struct xdp_umem *umem) +{ + umem->zc = false; + ida_free(&umem_ida, umem->id); + + xdp_umem_addr_unmap(umem); + xdp_umem_unpin_pages(umem); + + xdp_umem_unaccount_pages(umem); + kfree(umem); +} + +static void xdp_umem_release_deferred(struct work_struct *work) +{ + struct xdp_umem *umem = container_of(work, struct xdp_umem, work); + + xdp_umem_release(umem); +} + +void xdp_get_umem(struct xdp_umem *umem) +{ + refcount_inc(&umem->users); +} + +void xdp_put_umem(struct xdp_umem *umem, bool defer_cleanup) +{ + if (!umem) + return; + + if (refcount_dec_and_test(&umem->users)) { + if (defer_cleanup) { + INIT_WORK(&umem->work, xdp_umem_release_deferred); + schedule_work(&umem->work); + } else { + xdp_umem_release(umem); + } + } +} + +static int xdp_umem_pin_pages(struct xdp_umem *umem, unsigned long address) +{ + unsigned int gup_flags = FOLL_WRITE; + long npgs; + int err; + + umem->pgs = kvcalloc(umem->npgs, sizeof(*umem->pgs), GFP_KERNEL | __GFP_NOWARN); + if (!umem->pgs) + return -ENOMEM; + + mmap_read_lock(current->mm); + npgs = pin_user_pages(address, umem->npgs, + gup_flags | FOLL_LONGTERM, &umem->pgs[0], NULL); + mmap_read_unlock(current->mm); + + if (npgs != umem->npgs) { + if (npgs >= 0) { + umem->npgs = npgs; + err = -ENOMEM; + goto out_pin; + } + err = npgs; + goto out_pgs; + } + return 0; + +out_pin: + xdp_umem_unpin_pages(umem); +out_pgs: + kvfree(umem->pgs); + umem->pgs = NULL; + return err; +} + +static int xdp_umem_account_pages(struct xdp_umem *umem) +{ + unsigned long lock_limit, new_npgs, old_npgs; + + if (capable(CAP_IPC_LOCK)) + return 0; + + lock_limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT; + umem->user = get_uid(current_user()); + + do { + old_npgs = atomic_long_read(&umem->user->locked_vm); + new_npgs = old_npgs + umem->npgs; + if (new_npgs > lock_limit) { + free_uid(umem->user); + umem->user = NULL; + return -ENOBUFS; + } + } while (atomic_long_cmpxchg(&umem->user->locked_vm, old_npgs, + new_npgs) != old_npgs); + return 0; +} + +static int xdp_umem_reg(struct xdp_umem *umem, struct xdp_umem_reg *mr) +{ + bool unaligned_chunks = mr->flags & XDP_UMEM_UNALIGNED_CHUNK_FLAG; + u32 chunk_size = mr->chunk_size, headroom = mr->headroom; + u64 addr = mr->addr, size = mr->len; + u32 chunks_rem, npgs_rem; + u64 chunks, npgs; + int err; + + if (chunk_size < XDP_UMEM_MIN_CHUNK_SIZE || chunk_size > PAGE_SIZE) { + /* Strictly speaking we could support this, if: + * - huge pages, or* + * - using an IOMMU, or + * - making sure the memory area is consecutive + * but for now, we simply say "computer says no". + */ + return -EINVAL; + } + + if (mr->flags & ~XDP_UMEM_UNALIGNED_CHUNK_FLAG) + return -EINVAL; + + if (!unaligned_chunks && !is_power_of_2(chunk_size)) + return -EINVAL; + + if (!PAGE_ALIGNED(addr)) { + /* Memory area has to be page size aligned. For + * simplicity, this might change. + */ + return -EINVAL; + } + + if ((addr + size) < addr) + return -EINVAL; + + npgs = div_u64_rem(size, PAGE_SIZE, &npgs_rem); + if (npgs_rem) + npgs++; + if (npgs > U32_MAX) + return -EINVAL; + + chunks = div_u64_rem(size, chunk_size, &chunks_rem); + if (!chunks || chunks > U32_MAX) + return -EINVAL; + + if (!unaligned_chunks && chunks_rem) + return -EINVAL; + + if (headroom >= chunk_size - XDP_PACKET_HEADROOM) + return -EINVAL; + + umem->size = size; + umem->headroom = headroom; + umem->chunk_size = chunk_size; + umem->chunks = chunks; + umem->npgs = npgs; + umem->pgs = NULL; + umem->user = NULL; + umem->flags = mr->flags; + + INIT_LIST_HEAD(&umem->xsk_dma_list); + refcount_set(&umem->users, 1); + + err = xdp_umem_account_pages(umem); + if (err) + return err; + + err = xdp_umem_pin_pages(umem, (unsigned long)addr); + if (err) + goto out_account; + + err = xdp_umem_addr_map(umem, umem->pgs, umem->npgs); + if (err) + goto out_unpin; + + return 0; + +out_unpin: + xdp_umem_unpin_pages(umem); +out_account: + xdp_umem_unaccount_pages(umem); + return err; +} + +struct xdp_umem *xdp_umem_create(struct xdp_umem_reg *mr) +{ + struct xdp_umem *umem; + int err; + + umem = kzalloc(sizeof(*umem), GFP_KERNEL); + if (!umem) + return ERR_PTR(-ENOMEM); + + err = ida_alloc(&umem_ida, GFP_KERNEL); + if (err < 0) { + kfree(umem); + return ERR_PTR(err); + } + umem->id = err; + + err = xdp_umem_reg(umem, mr); + if (err) { + ida_free(&umem_ida, umem->id); + kfree(umem); + return ERR_PTR(err); + } + + return umem; +} |