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// SPDX-License-Identifier: GPL-2.0-only
/* Object lifetime handling and tracing.
*
* Copyright (C) 2022 Red Hat, Inc. All Rights Reserved.
* Written by David Howells (dhowells@redhat.com)
*/
#include <linux/slab.h>
#include <linux/mempool.h>
#include <linux/delay.h>
#include "internal.h"
/*
* Allocate an I/O request and initialise it.
*/
struct netfs_io_request *netfs_alloc_request(struct address_space *mapping,
struct file *file,
loff_t start, size_t len,
enum netfs_io_origin origin)
{
static atomic_t debug_ids;
struct inode *inode = file ? file_inode(file) : mapping->host;
struct netfs_inode *ctx = netfs_inode(inode);
struct netfs_io_request *rreq;
mempool_t *mempool = ctx->ops->request_pool ?: &netfs_request_pool;
struct kmem_cache *cache = mempool->pool_data;
bool is_unbuffered = (origin == NETFS_UNBUFFERED_WRITE ||
origin == NETFS_DIO_READ ||
origin == NETFS_DIO_WRITE);
bool cached = !is_unbuffered && netfs_is_cache_enabled(ctx);
int ret;
for (;;) {
rreq = mempool_alloc(mempool, GFP_KERNEL);
if (rreq)
break;
msleep(10);
}
memset(rreq, 0, kmem_cache_size(cache));
rreq->start = start;
rreq->len = len;
rreq->upper_len = len;
rreq->origin = origin;
rreq->netfs_ops = ctx->ops;
rreq->mapping = mapping;
rreq->inode = inode;
rreq->i_size = i_size_read(inode);
rreq->debug_id = atomic_inc_return(&debug_ids);
rreq->wsize = INT_MAX;
spin_lock_init(&rreq->lock);
INIT_LIST_HEAD(&rreq->io_streams[0].subrequests);
INIT_LIST_HEAD(&rreq->io_streams[1].subrequests);
INIT_LIST_HEAD(&rreq->subrequests);
INIT_WORK(&rreq->work, NULL);
refcount_set(&rreq->ref, 1);
__set_bit(NETFS_RREQ_IN_PROGRESS, &rreq->flags);
if (cached) {
__set_bit(NETFS_RREQ_WRITE_TO_CACHE, &rreq->flags);
if (test_bit(NETFS_ICTX_USE_PGPRIV2, &ctx->flags))
/* Filesystem uses deprecated PG_private_2 marking. */
__set_bit(NETFS_RREQ_USE_PGPRIV2, &rreq->flags);
}
if (file && file->f_flags & O_NONBLOCK)
__set_bit(NETFS_RREQ_NONBLOCK, &rreq->flags);
if (rreq->netfs_ops->init_request) {
ret = rreq->netfs_ops->init_request(rreq, file);
if (ret < 0) {
mempool_free(rreq, rreq->netfs_ops->request_pool ?: &netfs_request_pool);
return ERR_PTR(ret);
}
}
atomic_inc(&ctx->io_count);
trace_netfs_rreq_ref(rreq->debug_id, 1, netfs_rreq_trace_new);
netfs_proc_add_rreq(rreq);
netfs_stat(&netfs_n_rh_rreq);
return rreq;
}
void netfs_get_request(struct netfs_io_request *rreq, enum netfs_rreq_ref_trace what)
{
int r;
__refcount_inc(&rreq->ref, &r);
trace_netfs_rreq_ref(rreq->debug_id, r + 1, what);
}
void netfs_clear_subrequests(struct netfs_io_request *rreq, bool was_async)
{
struct netfs_io_subrequest *subreq;
struct netfs_io_stream *stream;
int s;
while (!list_empty(&rreq->subrequests)) {
subreq = list_first_entry(&rreq->subrequests,
struct netfs_io_subrequest, rreq_link);
list_del(&subreq->rreq_link);
netfs_put_subrequest(subreq, was_async,
netfs_sreq_trace_put_clear);
}
for (s = 0; s < ARRAY_SIZE(rreq->io_streams); s++) {
stream = &rreq->io_streams[s];
while (!list_empty(&stream->subrequests)) {
subreq = list_first_entry(&stream->subrequests,
struct netfs_io_subrequest, rreq_link);
list_del(&subreq->rreq_link);
netfs_put_subrequest(subreq, was_async,
netfs_sreq_trace_put_clear);
}
}
}
static void netfs_free_request_rcu(struct rcu_head *rcu)
{
struct netfs_io_request *rreq = container_of(rcu, struct netfs_io_request, rcu);
mempool_free(rreq, rreq->netfs_ops->request_pool ?: &netfs_request_pool);
netfs_stat_d(&netfs_n_rh_rreq);
}
static void netfs_free_request(struct work_struct *work)
{
struct netfs_io_request *rreq =
container_of(work, struct netfs_io_request, work);
struct netfs_inode *ictx = netfs_inode(rreq->inode);
unsigned int i;
trace_netfs_rreq(rreq, netfs_rreq_trace_free);
netfs_proc_del_rreq(rreq);
netfs_clear_subrequests(rreq, false);
if (rreq->netfs_ops->free_request)
rreq->netfs_ops->free_request(rreq);
if (rreq->cache_resources.ops)
rreq->cache_resources.ops->end_operation(&rreq->cache_resources);
if (rreq->direct_bv) {
for (i = 0; i < rreq->direct_bv_count; i++) {
if (rreq->direct_bv[i].bv_page) {
if (rreq->direct_bv_unpin)
unpin_user_page(rreq->direct_bv[i].bv_page);
}
}
kvfree(rreq->direct_bv);
}
if (atomic_dec_and_test(&ictx->io_count))
wake_up_var(&ictx->io_count);
call_rcu(&rreq->rcu, netfs_free_request_rcu);
}
void netfs_put_request(struct netfs_io_request *rreq, bool was_async,
enum netfs_rreq_ref_trace what)
{
unsigned int debug_id;
bool dead;
int r;
if (rreq) {
debug_id = rreq->debug_id;
dead = __refcount_dec_and_test(&rreq->ref, &r);
trace_netfs_rreq_ref(debug_id, r - 1, what);
if (dead) {
if (was_async) {
rreq->work.func = netfs_free_request;
if (!queue_work(system_unbound_wq, &rreq->work))
BUG();
} else {
netfs_free_request(&rreq->work);
}
}
}
}
/*
* Allocate and partially initialise an I/O request structure.
*/
struct netfs_io_subrequest *netfs_alloc_subrequest(struct netfs_io_request *rreq)
{
struct netfs_io_subrequest *subreq;
mempool_t *mempool = rreq->netfs_ops->subrequest_pool ?: &netfs_subrequest_pool;
struct kmem_cache *cache = mempool->pool_data;
for (;;) {
subreq = mempool_alloc(rreq->netfs_ops->subrequest_pool ?: &netfs_subrequest_pool,
GFP_KERNEL);
if (subreq)
break;
msleep(10);
}
memset(subreq, 0, kmem_cache_size(cache));
INIT_WORK(&subreq->work, NULL);
INIT_LIST_HEAD(&subreq->rreq_link);
refcount_set(&subreq->ref, 2);
subreq->rreq = rreq;
subreq->debug_index = atomic_inc_return(&rreq->subreq_counter);
netfs_get_request(rreq, netfs_rreq_trace_get_subreq);
netfs_stat(&netfs_n_rh_sreq);
return subreq;
}
void netfs_get_subrequest(struct netfs_io_subrequest *subreq,
enum netfs_sreq_ref_trace what)
{
int r;
__refcount_inc(&subreq->ref, &r);
trace_netfs_sreq_ref(subreq->rreq->debug_id, subreq->debug_index, r + 1,
what);
}
static void netfs_free_subrequest(struct netfs_io_subrequest *subreq,
bool was_async)
{
struct netfs_io_request *rreq = subreq->rreq;
trace_netfs_sreq(subreq, netfs_sreq_trace_free);
if (rreq->netfs_ops->free_subrequest)
rreq->netfs_ops->free_subrequest(subreq);
mempool_free(subreq, rreq->netfs_ops->subrequest_pool ?: &netfs_subrequest_pool);
netfs_stat_d(&netfs_n_rh_sreq);
netfs_put_request(rreq, was_async, netfs_rreq_trace_put_subreq);
}
void netfs_put_subrequest(struct netfs_io_subrequest *subreq, bool was_async,
enum netfs_sreq_ref_trace what)
{
unsigned int debug_index = subreq->debug_index;
unsigned int debug_id = subreq->rreq->debug_id;
bool dead;
int r;
dead = __refcount_dec_and_test(&subreq->ref, &r);
trace_netfs_sreq_ref(debug_id, debug_index, r - 1, what);
if (dead)
netfs_free_subrequest(subreq, was_async);
}
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