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-rw-r--r--net/xdp/xdp_umem.c259
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;
+}