// 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 "internal.h" static void netfs_free_request(struct work_struct *work); /* * 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;	gfp_t gfp = GFP_KERNEL;	int ret; 	/* Writeback is part of memory reclaim and must not fail due to ENOMEM. */	if (origin == NETFS_WRITEBACK || origin == NETFS_WRITEBACK_SINGLE) {		gfp = GFP_NOFS; /* Allows use of mempools. */ 		rreq = mempool_alloc(mempool, gfp);	} else {		rreq = mempool->alloc(gfp, mempool->pool_data);		if (!rreq)			return ERR_PTR(-ENOMEM);	} 	memset(rreq, 0, kmem_cache_size(cache));	INIT_WORK(&rreq->cleanup_work, netfs_free_request);	rreq->gfp	= gfp;	rreq->start	= start;	rreq->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;	rreq->io_streams[0].sreq_max_len = ULONG_MAX;	rreq->io_streams[0].sreq_max_segs = 0;	spin_lock_init(&rreq->lock);	INIT_LIST_HEAD(&rreq->io_streams[0].subrequests);	INIT_LIST_HEAD(&rreq->io_streams[1].subrequests);	init_waitqueue_head(&rreq->waitq);	refcount_set(&rreq->ref, 2); 	if (origin == NETFS_READAHEAD ||	    origin == NETFS_READPAGE ||	    origin == NETFS_READ_GAPS ||	    origin == NETFS_READ_SINGLE ||	    origin == NETFS_READ_FOR_WRITE ||	    origin == NETFS_UNBUFFERED_READ ||	    origin == NETFS_DIO_READ) {		INIT_WORK(&rreq->work, netfs_read_collection_worker);		rreq->io_streams[0].avail = true;	} else {		INIT_WORK(&rreq->work, netfs_write_collection_worker);	} 	__set_bit(NETFS_RREQ_IN_PROGRESS, &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, refcount_read(&rreq->ref), 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){	struct netfs_io_subrequest *subreq;	struct netfs_io_stream *stream;	int s; 	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, 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_deinit_request(struct netfs_io_request *rreq){	struct netfs_inode *ictx = netfs_inode(rreq->inode);	unsigned int i; 	trace_netfs_rreq(rreq, netfs_rreq_trace_free); 	/* Cancel/flush the result collection worker.  That does not carry a	 * ref of its own, so we must wait for it somewhere.	 */	cancel_work_sync(&rreq->work); 	netfs_proc_del_rreq(rreq);	netfs_clear_subrequests(rreq);	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);	}	rolling_buffer_clear(&rreq->buffer); 	if (atomic_dec_and_test(&ictx->io_count))		wake_up_var(&ictx->io_count);} static void netfs_free_request(struct work_struct *work){	struct netfs_io_request *rreq =		container_of(work, struct netfs_io_request, cleanup_work); 	netfs_deinit_request(rreq);	call_rcu(&rreq->rcu, netfs_free_request_rcu);} void netfs_put_request(struct netfs_io_request *rreq, 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)			WARN_ON(!queue_work(system_dfl_wq, &rreq->cleanup_work));	}} /* * Free a request (synchronously) that was just allocated but has * failed before it could be submitted. */void netfs_put_failed_request(struct netfs_io_request *rreq){	int r = refcount_read(&rreq->ref); 	/* new requests have two references (see	 * netfs_alloc_request(), and this function is only allowed on	 * new request objects	 */	WARN_ON_ONCE(r != 2); 	trace_netfs_rreq_ref(rreq->debug_id, r, netfs_rreq_trace_put_failed);	netfs_free_request(&rreq->cleanup_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; 	if (rreq->gfp == GFP_KERNEL)		subreq = mempool->alloc(rreq->gfp, mempool->pool_data);	else		subreq = mempool_alloc(mempool, rreq->gfp);	if (!subreq)		return NULL; 	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){	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, netfs_rreq_trace_put_subreq);} void netfs_put_subrequest(struct netfs_io_subrequest *subreq,			  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);}