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Diffstat (limited to 'net/xdp/xdp_umem.c')
-rw-r--r--net/xdp/xdp_umem.c361
1 files changed, 361 insertions, 0 deletions
diff --git a/net/xdp/xdp_umem.c b/net/xdp/xdp_umem.c
new file mode 100644
index 0000000000000..7eb4948a38d23
--- /dev/null
+++ b/net/xdp/xdp_umem.c
@@ -0,0 +1,361 @@
+// 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 "xdp_umem.h"
+#include "xsk_queue.h"
+
+#define XDP_UMEM_MIN_CHUNK_SIZE 2048
+
+void xdp_add_sk_umem(struct xdp_umem *umem, struct xdp_sock *xs)
+{
+ unsigned long flags;
+
+ spin_lock_irqsave(&umem->xsk_list_lock, flags);
+ list_add_rcu(&xs->list, &umem->xsk_list);
+ spin_unlock_irqrestore(&umem->xsk_list_lock, flags);
+}
+
+void xdp_del_sk_umem(struct xdp_umem *umem, struct xdp_sock *xs)
+{
+ unsigned long flags;
+
+ if (xs->dev) {
+ spin_lock_irqsave(&umem->xsk_list_lock, flags);
+ list_del_rcu(&xs->list);
+ spin_unlock_irqrestore(&umem->xsk_list_lock, flags);
+
+ if (umem->zc)
+ synchronize_net();
+ }
+}
+
+int xdp_umem_assign_dev(struct xdp_umem *umem, struct net_device *dev,
+ u32 queue_id, u16 flags)
+{
+ bool force_zc, force_copy;
+ struct netdev_bpf bpf;
+ int err;
+
+ force_zc = flags & XDP_ZEROCOPY;
+ force_copy = flags & XDP_COPY;
+
+ if (force_zc && force_copy)
+ return -EINVAL;
+
+ if (force_copy)
+ return 0;
+
+ dev_hold(dev);
+
+ if (dev->netdev_ops->ndo_bpf && dev->netdev_ops->ndo_xsk_async_xmit) {
+ bpf.command = XDP_QUERY_XSK_UMEM;
+
+ rtnl_lock();
+ err = dev->netdev_ops->ndo_bpf(dev, &bpf);
+ rtnl_unlock();
+
+ if (err) {
+ dev_put(dev);
+ return force_zc ? -ENOTSUPP : 0;
+ }
+
+ bpf.command = XDP_SETUP_XSK_UMEM;
+ bpf.xsk.umem = umem;
+ bpf.xsk.queue_id = queue_id;
+
+ rtnl_lock();
+ err = dev->netdev_ops->ndo_bpf(dev, &bpf);
+ rtnl_unlock();
+
+ if (err) {
+ dev_put(dev);
+ return force_zc ? err : 0; /* fail or fallback */
+ }
+
+ umem->dev = dev;
+ umem->queue_id = queue_id;
+ umem->zc = true;
+ return 0;
+ }
+
+ dev_put(dev);
+ return force_zc ? -ENOTSUPP : 0; /* fail or fallback */
+}
+
+static void xdp_umem_clear_dev(struct xdp_umem *umem)
+{
+ struct netdev_bpf bpf;
+ int err;
+
+ if (umem->dev) {
+ bpf.command = XDP_SETUP_XSK_UMEM;
+ bpf.xsk.umem = NULL;
+ bpf.xsk.queue_id = umem->queue_id;
+
+ rtnl_lock();
+ err = umem->dev->netdev_ops->ndo_bpf(umem->dev, &bpf);
+ rtnl_unlock();
+
+ if (err)
+ WARN(1, "failed to disable umem!\n");
+
+ dev_put(umem->dev);
+ umem->dev = NULL;
+ }
+}
+
+static void xdp_umem_unpin_pages(struct xdp_umem *umem)
+{
+ unsigned int i;
+
+ 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)
+{
+ 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;
+
+ xdp_umem_clear_dev(umem);
+
+ if (umem->fq) {
+ xskq_destroy(umem->fq);
+ umem->fq = NULL;
+ }
+
+ if (umem->cq) {
+ xskq_destroy(umem->cq);
+ umem->cq = NULL;
+ }
+
+ 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);
+ kfree(umem->pages);
+ umem->pages = 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)
+{
+ refcount_inc(&umem->users);
+}
+
+void xdp_put_umem(struct xdp_umem *umem)
+{
+ if (!umem)
+ return;
+
+ if (refcount_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(&current->mm->mmap_sem);
+ npgs = get_user_pages(umem->address, umem->npgs,
+ gup_flags, &umem->pgs[0], NULL);
+ up_write(&current->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;
+}
+
+static int xdp_umem_reg(struct xdp_umem *umem, struct xdp_umem_reg *mr)
+{
+ u32 chunk_size = mr->chunk_size, headroom = mr->headroom;
+ unsigned int chunks, chunks_per_page;
+ u64 addr = mr->addr, size = mr->len;
+ int size_chk, err, i;
+
+ 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 (!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;
+
+ chunks = (unsigned int)div_u64(size, chunk_size);
+ if (chunks == 0)
+ return -EINVAL;
+
+ chunks_per_page = PAGE_SIZE / chunk_size;
+ if (chunks < chunks_per_page || chunks % chunks_per_page)
+ return -EINVAL;
+
+ headroom = ALIGN(headroom, 64);
+
+ size_chk = chunk_size - headroom - XDP_PACKET_HEADROOM;
+ if (size_chk < 0)
+ return -EINVAL;
+
+ umem->pid = get_task_pid(current, PIDTYPE_PID);
+ umem->address = (unsigned long)addr;
+ umem->props.chunk_mask = ~((u64)chunk_size - 1);
+ umem->props.size = size;
+ umem->headroom = headroom;
+ umem->chunk_size_nohr = chunk_size - headroom;
+ umem->npgs = size / PAGE_SIZE;
+ umem->pgs = NULL;
+ umem->user = NULL;
+ INIT_LIST_HEAD(&umem->xsk_list);
+ spin_lock_init(&umem->xsk_list_lock);
+
+ refcount_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;
+
+ umem->pages = kcalloc(umem->npgs, sizeof(*umem->pages), GFP_KERNEL);
+ if (!umem->pages) {
+ err = -ENOMEM;
+ goto out_account;
+ }
+
+ for (i = 0; i < umem->npgs; i++)
+ umem->pages[i].addr = page_address(umem->pgs[i]);
+
+ return 0;
+
+out_account:
+ xdp_umem_unaccount_pages(umem);
+out:
+ put_pid(umem->pid);
+ 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 = xdp_umem_reg(umem, mr);
+ if (err) {
+ kfree(umem);
+ return ERR_PTR(err);
+ }
+
+ return umem;
+}
+
+bool xdp_umem_validate_queues(struct xdp_umem *umem)
+{
+ return umem->fq && umem->cq;
+}