forked from Minki/linux
921b68692a
Enable the sharing of dma mappings by moving them out from the buffer pool. Instead we put each dma mapped umem region in a list in the umem structure. If dma has already been mapped for this umem and device, it is not mapped again and the existing dma mappings are reused. Signed-off-by: Magnus Karlsson <magnus.karlsson@intel.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Björn Töpel <bjorn.topel@intel.com> Link: https://lore.kernel.org/bpf/1598603189-32145-9-git-send-email-magnus.karlsson@intel.com
250 lines
5.1 KiB
C
250 lines
5.1 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/* XDP user-space packet buffer
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* Copyright(c) 2018 Intel Corporation.
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*/
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#include <linux/init.h>
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#include <linux/sched/mm.h>
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#include <linux/sched/signal.h>
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#include <linux/sched/task.h>
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#include <linux/uaccess.h>
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#include <linux/slab.h>
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#include <linux/bpf.h>
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#include <linux/mm.h>
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#include <linux/netdevice.h>
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#include <linux/rtnetlink.h>
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#include <linux/idr.h>
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#include <linux/vmalloc.h>
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#include "xdp_umem.h"
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#include "xsk_queue.h"
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#define XDP_UMEM_MIN_CHUNK_SIZE 2048
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static DEFINE_IDA(umem_ida);
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static void xdp_umem_unpin_pages(struct xdp_umem *umem)
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{
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unpin_user_pages_dirty_lock(umem->pgs, umem->npgs, true);
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kfree(umem->pgs);
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umem->pgs = NULL;
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}
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static void xdp_umem_unaccount_pages(struct xdp_umem *umem)
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{
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if (umem->user) {
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atomic_long_sub(umem->npgs, &umem->user->locked_vm);
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free_uid(umem->user);
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}
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}
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static void xdp_umem_addr_unmap(struct xdp_umem *umem)
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{
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vunmap(umem->addrs);
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umem->addrs = NULL;
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}
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static int xdp_umem_addr_map(struct xdp_umem *umem, struct page **pages,
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u32 nr_pages)
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{
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umem->addrs = vmap(pages, nr_pages, VM_MAP, PAGE_KERNEL);
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if (!umem->addrs)
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return -ENOMEM;
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return 0;
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}
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static void xdp_umem_release(struct xdp_umem *umem)
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{
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umem->zc = false;
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ida_simple_remove(&umem_ida, umem->id);
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xdp_umem_addr_unmap(umem);
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xdp_umem_unpin_pages(umem);
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xdp_umem_unaccount_pages(umem);
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kfree(umem);
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}
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void xdp_get_umem(struct xdp_umem *umem)
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{
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refcount_inc(&umem->users);
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}
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void xdp_put_umem(struct xdp_umem *umem)
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{
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if (!umem)
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return;
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if (refcount_dec_and_test(&umem->users))
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xdp_umem_release(umem);
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}
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static int xdp_umem_pin_pages(struct xdp_umem *umem, unsigned long address)
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{
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unsigned int gup_flags = FOLL_WRITE;
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long npgs;
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int err;
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umem->pgs = kcalloc(umem->npgs, sizeof(*umem->pgs),
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GFP_KERNEL | __GFP_NOWARN);
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if (!umem->pgs)
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return -ENOMEM;
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mmap_read_lock(current->mm);
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npgs = pin_user_pages(address, umem->npgs,
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gup_flags | FOLL_LONGTERM, &umem->pgs[0], NULL);
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mmap_read_unlock(current->mm);
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if (npgs != umem->npgs) {
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if (npgs >= 0) {
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umem->npgs = npgs;
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err = -ENOMEM;
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goto out_pin;
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}
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err = npgs;
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goto out_pgs;
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}
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return 0;
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out_pin:
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xdp_umem_unpin_pages(umem);
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out_pgs:
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kfree(umem->pgs);
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umem->pgs = NULL;
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return err;
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}
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static int xdp_umem_account_pages(struct xdp_umem *umem)
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{
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unsigned long lock_limit, new_npgs, old_npgs;
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if (capable(CAP_IPC_LOCK))
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return 0;
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lock_limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT;
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umem->user = get_uid(current_user());
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do {
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old_npgs = atomic_long_read(&umem->user->locked_vm);
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new_npgs = old_npgs + umem->npgs;
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if (new_npgs > lock_limit) {
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free_uid(umem->user);
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umem->user = NULL;
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return -ENOBUFS;
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}
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} while (atomic_long_cmpxchg(&umem->user->locked_vm, old_npgs,
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new_npgs) != old_npgs);
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return 0;
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}
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static int xdp_umem_reg(struct xdp_umem *umem, struct xdp_umem_reg *mr)
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{
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bool unaligned_chunks = mr->flags & XDP_UMEM_UNALIGNED_CHUNK_FLAG;
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u32 chunk_size = mr->chunk_size, headroom = mr->headroom;
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u64 npgs, addr = mr->addr, size = mr->len;
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unsigned int chunks, chunks_per_page;
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int err;
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if (chunk_size < XDP_UMEM_MIN_CHUNK_SIZE || chunk_size > PAGE_SIZE) {
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/* Strictly speaking we could support this, if:
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* - huge pages, or*
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* - using an IOMMU, or
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* - making sure the memory area is consecutive
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* but for now, we simply say "computer says no".
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*/
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return -EINVAL;
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}
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if (mr->flags & ~XDP_UMEM_UNALIGNED_CHUNK_FLAG)
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return -EINVAL;
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if (!unaligned_chunks && !is_power_of_2(chunk_size))
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return -EINVAL;
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if (!PAGE_ALIGNED(addr)) {
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/* Memory area has to be page size aligned. For
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* simplicity, this might change.
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*/
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return -EINVAL;
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}
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if ((addr + size) < addr)
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return -EINVAL;
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npgs = size >> PAGE_SHIFT;
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if (npgs > U32_MAX)
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return -EINVAL;
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chunks = (unsigned int)div_u64(size, chunk_size);
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if (chunks == 0)
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return -EINVAL;
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if (!unaligned_chunks) {
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chunks_per_page = PAGE_SIZE / chunk_size;
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if (chunks < chunks_per_page || chunks % chunks_per_page)
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return -EINVAL;
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}
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if (headroom >= chunk_size - XDP_PACKET_HEADROOM)
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return -EINVAL;
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umem->size = size;
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umem->headroom = headroom;
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umem->chunk_size = chunk_size;
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umem->chunks = chunks;
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umem->npgs = (u32)npgs;
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umem->pgs = NULL;
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umem->user = NULL;
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umem->flags = mr->flags;
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INIT_LIST_HEAD(&umem->xsk_dma_list);
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refcount_set(&umem->users, 1);
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err = xdp_umem_account_pages(umem);
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if (err)
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return err;
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err = xdp_umem_pin_pages(umem, (unsigned long)addr);
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if (err)
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goto out_account;
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err = xdp_umem_addr_map(umem, umem->pgs, umem->npgs);
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if (err)
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goto out_unpin;
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return 0;
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out_unpin:
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xdp_umem_unpin_pages(umem);
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out_account:
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xdp_umem_unaccount_pages(umem);
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return err;
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}
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struct xdp_umem *xdp_umem_create(struct xdp_umem_reg *mr)
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{
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struct xdp_umem *umem;
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int err;
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umem = kzalloc(sizeof(*umem), GFP_KERNEL);
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if (!umem)
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return ERR_PTR(-ENOMEM);
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err = ida_simple_get(&umem_ida, 0, 0, GFP_KERNEL);
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if (err < 0) {
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kfree(umem);
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return ERR_PTR(err);
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}
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umem->id = err;
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err = xdp_umem_reg(umem, mr);
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if (err) {
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ida_simple_remove(&umem_ida, umem->id);
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kfree(umem);
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return ERR_PTR(err);
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}
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return umem;
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}
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