cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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objects.c (4215B)

      1// SPDX-License-Identifier: GPL-2.0-only
      2/* Object lifetime handling and tracing.
      3 *
      4 * Copyright (C) 2022 Red Hat, Inc. All Rights Reserved.
      5 * Written by David Howells (dhowells@redhat.com)
      6 */
      7
      8#include <linux/slab.h>
      9#include "internal.h"
     10
     11/*
     12 * Allocate an I/O request and initialise it.
     13 */
     14struct netfs_io_request *netfs_alloc_request(struct address_space *mapping,
     15					     struct file *file,
     16					     loff_t start, size_t len,
     17					     enum netfs_io_origin origin)
     18{
     19	static atomic_t debug_ids;
     20	struct inode *inode = file ? file_inode(file) : mapping->host;
     21	struct netfs_inode *ctx = netfs_inode(inode);
     22	struct netfs_io_request *rreq;
     23	int ret;
     24
     25	rreq = kzalloc(sizeof(struct netfs_io_request), GFP_KERNEL);
     26	if (!rreq)
     27		return ERR_PTR(-ENOMEM);
     28
     29	rreq->start	= start;
     30	rreq->len	= len;
     31	rreq->origin	= origin;
     32	rreq->netfs_ops	= ctx->ops;
     33	rreq->mapping	= mapping;
     34	rreq->inode	= inode;
     35	rreq->i_size	= i_size_read(inode);
     36	rreq->debug_id	= atomic_inc_return(&debug_ids);
     37	INIT_LIST_HEAD(&rreq->subrequests);
     38	refcount_set(&rreq->ref, 1);
     39	__set_bit(NETFS_RREQ_IN_PROGRESS, &rreq->flags);
     40	if (rreq->netfs_ops->init_request) {
     41		ret = rreq->netfs_ops->init_request(rreq, file);
     42		if (ret < 0) {
     43			kfree(rreq);
     44			return ERR_PTR(ret);
     45		}
     46	}
     47
     48	netfs_stat(&netfs_n_rh_rreq);
     49	return rreq;
     50}
     51
     52void netfs_get_request(struct netfs_io_request *rreq, enum netfs_rreq_ref_trace what)
     53{
     54	int r;
     55
     56	__refcount_inc(&rreq->ref, &r);
     57	trace_netfs_rreq_ref(rreq->debug_id, r + 1, what);
     58}
     59
     60void netfs_clear_subrequests(struct netfs_io_request *rreq, bool was_async)
     61{
     62	struct netfs_io_subrequest *subreq;
     63
     64	while (!list_empty(&rreq->subrequests)) {
     65		subreq = list_first_entry(&rreq->subrequests,
     66					  struct netfs_io_subrequest, rreq_link);
     67		list_del(&subreq->rreq_link);
     68		netfs_put_subrequest(subreq, was_async,
     69				     netfs_sreq_trace_put_clear);
     70	}
     71}
     72
     73static void netfs_free_request(struct work_struct *work)
     74{
     75	struct netfs_io_request *rreq =
     76		container_of(work, struct netfs_io_request, work);
     77
     78	trace_netfs_rreq(rreq, netfs_rreq_trace_free);
     79	netfs_clear_subrequests(rreq, false);
     80	if (rreq->netfs_ops->free_request)
     81		rreq->netfs_ops->free_request(rreq);
     82	if (rreq->cache_resources.ops)
     83		rreq->cache_resources.ops->end_operation(&rreq->cache_resources);
     84	kfree(rreq);
     85	netfs_stat_d(&netfs_n_rh_rreq);
     86}
     87
     88void netfs_put_request(struct netfs_io_request *rreq, bool was_async,
     89		       enum netfs_rreq_ref_trace what)
     90{
     91	unsigned int debug_id = rreq->debug_id;
     92	bool dead;
     93	int r;
     94
     95	dead = __refcount_dec_and_test(&rreq->ref, &r);
     96	trace_netfs_rreq_ref(debug_id, r - 1, what);
     97	if (dead) {
     98		if (was_async) {
     99			rreq->work.func = netfs_free_request;
    100			if (!queue_work(system_unbound_wq, &rreq->work))
    101				BUG();
    102		} else {
    103			netfs_free_request(&rreq->work);
    104		}
    105	}
    106}
    107
    108/*
    109 * Allocate and partially initialise an I/O request structure.
    110 */
    111struct netfs_io_subrequest *netfs_alloc_subrequest(struct netfs_io_request *rreq)
    112{
    113	struct netfs_io_subrequest *subreq;
    114
    115	subreq = kzalloc(sizeof(struct netfs_io_subrequest), GFP_KERNEL);
    116	if (subreq) {
    117		INIT_LIST_HEAD(&subreq->rreq_link);
    118		refcount_set(&subreq->ref, 2);
    119		subreq->rreq = rreq;
    120		netfs_get_request(rreq, netfs_rreq_trace_get_subreq);
    121		netfs_stat(&netfs_n_rh_sreq);
    122	}
    123
    124	return subreq;
    125}
    126
    127void netfs_get_subrequest(struct netfs_io_subrequest *subreq,
    128			  enum netfs_sreq_ref_trace what)
    129{
    130	int r;
    131
    132	__refcount_inc(&subreq->ref, &r);
    133	trace_netfs_sreq_ref(subreq->rreq->debug_id, subreq->debug_index, r + 1,
    134			     what);
    135}
    136
    137static void netfs_free_subrequest(struct netfs_io_subrequest *subreq,
    138				  bool was_async)
    139{
    140	struct netfs_io_request *rreq = subreq->rreq;
    141
    142	trace_netfs_sreq(subreq, netfs_sreq_trace_free);
    143	kfree(subreq);
    144	netfs_stat_d(&netfs_n_rh_sreq);
    145	netfs_put_request(rreq, was_async, netfs_rreq_trace_put_subreq);
    146}
    147
    148void netfs_put_subrequest(struct netfs_io_subrequest *subreq, bool was_async,
    149			  enum netfs_sreq_ref_trace what)
    150{
    151	unsigned int debug_index = subreq->debug_index;
    152	unsigned int debug_id = subreq->rreq->debug_id;
    153	bool dead;
    154	int r;
    155
    156	dead = __refcount_dec_and_test(&subreq->ref, &r);
    157	trace_netfs_sreq_ref(debug_id, debug_index, r - 1, what);
    158	if (dead)
    159		netfs_free_subrequest(subreq, was_async);
    160}