diff options
Diffstat (limited to 'net/xdp/xdp_umem.c')
| -rw-r--r-- | net/xdp/xdp_umem.c | 260 |
1 files changed, 260 insertions, 0 deletions
diff --git a/net/xdp/xdp_umem.c b/net/xdp/xdp_umem.c new file mode 100644 index 000000000000..881dfdefe235 --- /dev/null +++ b/net/xdp/xdp_umem.c @@ -0,0 +1,260 @@ +// SPDX-License-Identifier: GPL-2.0 +/* XDP user-space packet buffer + * Copyright(c) 2018 Intel Corporation. + * + * This program is free software; you can redistribute it and/or modify it + * under the terms and conditions of the GNU General Public License, + * version 2, as published by the Free Software Foundation. + * + * This program is distributed in the hope it will be useful, but WITHOUT + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for + * more details. + */ + +#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 "xdp_umem.h" + +#define XDP_UMEM_MIN_FRAME_SIZE 2048 + +int xdp_umem_create(struct xdp_umem **umem) +{ + *umem = kzalloc(sizeof(**umem), GFP_KERNEL); + + if (!(*umem)) + return -ENOMEM; + + return 0; +} + +static void xdp_umem_unpin_pages(struct xdp_umem *umem) +{ + unsigned int i; + + if (umem->pgs) { + for (i = 0; i < umem->npgs; i++) { + struct page *page = umem->pgs[i]; + + set_page_dirty_lock(page); + put_page(page); + } + + kfree(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_release(struct xdp_umem *umem) +{ + struct task_struct *task; + struct mm_struct *mm; + + if (umem->fq) { + xskq_destroy(umem->fq); + umem->fq = NULL; + } + + if (umem->cq) { + xskq_destroy(umem->cq); + umem->cq = NULL; + } + + if (umem->pgs) { + xdp_umem_unpin_pages(umem); + + task = get_pid_task(umem->pid, PIDTYPE_PID); + put_pid(umem->pid); + if (!task) + goto out; + mm = get_task_mm(task); + put_task_struct(task); + if (!mm) + goto out; + + mmput(mm); + umem->pgs = NULL; + } + + xdp_umem_unaccount_pages(umem); +out: + 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) +{ + atomic_inc(&umem->users); +} + +void xdp_put_umem(struct xdp_umem *umem) +{ + if (!umem) + return; + + if (atomic_dec_and_test(&umem->users)) { + INIT_WORK(&umem->work, xdp_umem_release_deferred); + schedule_work(&umem->work); + } +} + +static int xdp_umem_pin_pages(struct xdp_umem *umem) +{ + unsigned int gup_flags = FOLL_WRITE; + long npgs; + int err; + + umem->pgs = kcalloc(umem->npgs, sizeof(*umem->pgs), GFP_KERNEL); + if (!umem->pgs) + return -ENOMEM; + + down_write(¤t->mm->mmap_sem); + npgs = get_user_pages(umem->address, umem->npgs, + gup_flags, &umem->pgs[0], NULL); + up_write(¤t->mm->mmap_sem); + + 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: + kfree(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; +} + +int xdp_umem_reg(struct xdp_umem *umem, struct xdp_umem_reg *mr) +{ + u32 frame_size = mr->frame_size, frame_headroom = mr->frame_headroom; + u64 addr = mr->addr, size = mr->len; + unsigned int nframes, nfpp; + int size_chk, err; + + if (!umem) + return -EINVAL; + + if (frame_size < XDP_UMEM_MIN_FRAME_SIZE || frame_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 (!is_power_of_2(frame_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; + + nframes = size / frame_size; + if (nframes == 0 || nframes > UINT_MAX) + return -EINVAL; + + nfpp = PAGE_SIZE / frame_size; + if (nframes < nfpp || nframes % nfpp) + return -EINVAL; + + frame_headroom = ALIGN(frame_headroom, 64); + + size_chk = frame_size - frame_headroom - XDP_PACKET_HEADROOM; + if (size_chk < 0) + return -EINVAL; + + umem->pid = get_task_pid(current, PIDTYPE_PID); + umem->size = (size_t)size; + umem->address = (unsigned long)addr; + umem->props.frame_size = frame_size; + umem->props.nframes = nframes; + umem->frame_headroom = frame_headroom; + umem->npgs = size / PAGE_SIZE; + umem->pgs = NULL; + umem->user = NULL; + + umem->frame_size_log2 = ilog2(frame_size); + umem->nfpp_mask = nfpp - 1; + umem->nfpplog2 = ilog2(nfpp); + atomic_set(&umem->users, 1); + + err = xdp_umem_account_pages(umem); + if (err) + goto out; + + err = xdp_umem_pin_pages(umem); + if (err) + goto out_account; + return 0; + +out_account: + xdp_umem_unaccount_pages(umem); +out: + put_pid(umem->pid); + return err; +} + +bool xdp_umem_validate_queues(struct xdp_umem *umem) +{ + return (umem->fq && umem->cq); +} |