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![Michel Lespinasse](/assets/img/avatar_default.png)
This change converts the existing mmap_sem rwsem calls to use the new mmap locking API instead. The change is generated using coccinelle with the following rule: // spatch --sp-file mmap_lock_api.cocci --in-place --include-headers --dir . @@ expression mm; @@ ( -init_rwsem +mmap_init_lock | -down_write +mmap_write_lock | -down_write_killable +mmap_write_lock_killable | -down_write_trylock +mmap_write_trylock | -up_write +mmap_write_unlock | -downgrade_write +mmap_write_downgrade | -down_read +mmap_read_lock | -down_read_killable +mmap_read_lock_killable | -down_read_trylock +mmap_read_trylock | -up_read +mmap_read_unlock ) -(&mm->mmap_sem) +(mm) Signed-off-by: Michel Lespinasse <walken@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Daniel Jordan <daniel.m.jordan@oracle.com> Reviewed-by: Laurent Dufour <ldufour@linux.ibm.com> Reviewed-by: Vlastimil Babka <vbabka@suse.cz> Cc: Davidlohr Bueso <dbueso@suse.de> Cc: David Rientjes <rientjes@google.com> Cc: Hugh Dickins <hughd@google.com> Cc: Jason Gunthorpe <jgg@ziepe.ca> Cc: Jerome Glisse <jglisse@redhat.com> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Liam Howlett <Liam.Howlett@oracle.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ying Han <yinghan@google.com> Link: http://lkml.kernel.org/r/20200520052908.204642-5-walken@google.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
420 lines
8.7 KiB
C
420 lines
8.7 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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void xdp_add_sk_umem(struct xdp_umem *umem, struct xdp_sock *xs)
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{
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unsigned long flags;
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if (!xs->tx)
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return;
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spin_lock_irqsave(&umem->xsk_tx_list_lock, flags);
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list_add_rcu(&xs->list, &umem->xsk_tx_list);
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spin_unlock_irqrestore(&umem->xsk_tx_list_lock, flags);
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}
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void xdp_del_sk_umem(struct xdp_umem *umem, struct xdp_sock *xs)
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{
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unsigned long flags;
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if (!xs->tx)
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return;
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spin_lock_irqsave(&umem->xsk_tx_list_lock, flags);
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list_del_rcu(&xs->list);
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spin_unlock_irqrestore(&umem->xsk_tx_list_lock, flags);
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}
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/* The umem is stored both in the _rx struct and the _tx struct as we do
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* not know if the device has more tx queues than rx, or the opposite.
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* This might also change during run time.
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*/
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static int xdp_reg_umem_at_qid(struct net_device *dev, struct xdp_umem *umem,
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u16 queue_id)
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{
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if (queue_id >= max_t(unsigned int,
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dev->real_num_rx_queues,
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dev->real_num_tx_queues))
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return -EINVAL;
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if (queue_id < dev->real_num_rx_queues)
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dev->_rx[queue_id].umem = umem;
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if (queue_id < dev->real_num_tx_queues)
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dev->_tx[queue_id].umem = umem;
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return 0;
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}
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struct xdp_umem *xdp_get_umem_from_qid(struct net_device *dev,
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u16 queue_id)
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{
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if (queue_id < dev->real_num_rx_queues)
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return dev->_rx[queue_id].umem;
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if (queue_id < dev->real_num_tx_queues)
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return dev->_tx[queue_id].umem;
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return NULL;
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}
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EXPORT_SYMBOL(xdp_get_umem_from_qid);
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static void xdp_clear_umem_at_qid(struct net_device *dev, u16 queue_id)
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{
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if (queue_id < dev->real_num_rx_queues)
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dev->_rx[queue_id].umem = NULL;
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if (queue_id < dev->real_num_tx_queues)
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dev->_tx[queue_id].umem = NULL;
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}
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int xdp_umem_assign_dev(struct xdp_umem *umem, struct net_device *dev,
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u16 queue_id, u16 flags)
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{
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bool force_zc, force_copy;
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struct netdev_bpf bpf;
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int err = 0;
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ASSERT_RTNL();
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force_zc = flags & XDP_ZEROCOPY;
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force_copy = flags & XDP_COPY;
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if (force_zc && force_copy)
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return -EINVAL;
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if (xdp_get_umem_from_qid(dev, queue_id))
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return -EBUSY;
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err = xdp_reg_umem_at_qid(dev, umem, queue_id);
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if (err)
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return err;
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umem->dev = dev;
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umem->queue_id = queue_id;
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if (flags & XDP_USE_NEED_WAKEUP) {
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umem->flags |= XDP_UMEM_USES_NEED_WAKEUP;
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/* Tx needs to be explicitly woken up the first time.
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* Also for supporting drivers that do not implement this
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* feature. They will always have to call sendto().
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*/
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xsk_set_tx_need_wakeup(umem);
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}
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dev_hold(dev);
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if (force_copy)
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/* For copy-mode, we are done. */
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return 0;
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if (!dev->netdev_ops->ndo_bpf || !dev->netdev_ops->ndo_xsk_wakeup) {
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err = -EOPNOTSUPP;
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goto err_unreg_umem;
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}
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bpf.command = XDP_SETUP_XSK_UMEM;
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bpf.xsk.umem = umem;
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bpf.xsk.queue_id = queue_id;
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err = dev->netdev_ops->ndo_bpf(dev, &bpf);
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if (err)
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goto err_unreg_umem;
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umem->zc = true;
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return 0;
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err_unreg_umem:
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if (!force_zc)
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err = 0; /* fallback to copy mode */
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if (err)
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xdp_clear_umem_at_qid(dev, queue_id);
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return err;
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}
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void xdp_umem_clear_dev(struct xdp_umem *umem)
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{
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struct netdev_bpf bpf;
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int err;
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ASSERT_RTNL();
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if (!umem->dev)
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return;
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if (umem->zc) {
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bpf.command = XDP_SETUP_XSK_UMEM;
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bpf.xsk.umem = NULL;
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bpf.xsk.queue_id = umem->queue_id;
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err = umem->dev->netdev_ops->ndo_bpf(umem->dev, &bpf);
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if (err)
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WARN(1, "failed to disable umem!\n");
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}
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xdp_clear_umem_at_qid(umem->dev, umem->queue_id);
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dev_put(umem->dev);
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umem->dev = NULL;
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umem->zc = false;
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}
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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_release(struct xdp_umem *umem)
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{
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rtnl_lock();
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xdp_umem_clear_dev(umem);
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rtnl_unlock();
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ida_simple_remove(&umem_ida, umem->id);
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if (umem->fq) {
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xskq_destroy(umem->fq);
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umem->fq = NULL;
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}
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if (umem->cq) {
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xskq_destroy(umem->cq);
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umem->cq = NULL;
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}
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xp_destroy(umem->pool);
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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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static void xdp_umem_release_deferred(struct work_struct *work)
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{
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struct xdp_umem *umem = container_of(work, struct xdp_umem, work);
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xdp_umem_release(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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INIT_WORK(&umem->work, xdp_umem_release_deferred);
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schedule_work(&umem->work);
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}
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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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XDP_UMEM_USES_NEED_WAKEUP))
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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->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_tx_list);
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spin_lock_init(&umem->xsk_tx_list_lock);
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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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umem->pool = xp_create(umem->pgs, umem->npgs, chunks, chunk_size,
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headroom, size, unaligned_chunks);
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if (!umem->pool) {
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err = -ENOMEM;
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goto out_pin;
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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_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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bool xdp_umem_validate_queues(struct xdp_umem *umem)
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{
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return umem->fq && umem->cq;
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}
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