path: root/fs/cifs/transport.c

// SPDX-License-Identifier: LGPL-2.1
/*
 *
 *   Copyright (C) International Business Machines  Corp., 2002,2008
 *   Author(s): Steve French (sfrench@us.ibm.com)
 *   Jeremy Allison (jra@samba.org) 2006.
 *
 */

#include <linux/fs.h>
#include <linux/list.h>
#include <linux/gfp.h>
#include <linux/wait.h>
#include <linux/net.h>
#include <linux/delay.h>
#include <linux/freezer.h>
#include <linux/tcp.h>
#include <linux/bvec.h>
#include <linux/highmem.h>
#include <linux/uaccess.h>
#include <asm/processor.h>
#include <linux/mempool.h>
#include <linux/sched/signal.h>
#include "cifspdu.h"
#include "cifsglob.h"
#include "cifsproto.h"
#include "cifs_debug.h"
#include "smb2proto.h"
#include "smbdirect.h"

/* Max number of iovectors we can use off the stack when sending requests. */
#define CIFS_MAX_IOV_SIZE 8

void
cifs_wake_up_task(struct mid_q_entry *mid)
{
	wake_up_process(mid->callback_data);
}

struct mid_q_entry *
AllocMidQEntry(const struct smb_hdr *smb_buffer, struct TCP_Server_Info *server)
{
	struct mid_q_entry *temp;

	if (server == NULL) {
		cifs_dbg(VFS, "Null TCP session in AllocMidQEntry\n");
		return NULL;
	}

	temp = mempool_alloc(cifs_mid_poolp, GFP_NOFS);
	memset(temp, 0, sizeof(struct mid_q_entry));
	kref_init(&temp->refcount);
	temp->mid = get_mid(smb_buffer);
	temp->pid = current->pid;
	temp->command = cpu_to_le16(smb_buffer->Command);
	cifs_dbg(FYI, "For smb_command %d\n", smb_buffer->Command);
	/*	do_gettimeofday(&temp->when_sent);*/ /* easier to use jiffies */
	/* when mid allocated can be before when sent */
	temp->when_alloc = jiffies;
	temp->server = server;

	/*
	 * The default is for the mid to be synchronous, so the
	 * default callback just wakes up the current task.
	 */
	get_task_struct(current);
	temp->creator = current;
	temp->callback = cifs_wake_up_task;
	temp->callback_data = current;

	atomic_inc(&midCount);
	temp->mid_state = MID_REQUEST_ALLOCATED;
	return temp;
}

static void _cifs_mid_q_entry_release(struct kref *refcount)
{
	struct mid_q_entry *midEntry =
			container_of(refcount, struct mid_q_entry, refcount);
#ifdef CONFIG_CIFS_STATS2
	__le16 command = midEntry->server->vals->lock_cmd;
	__u16 smb_cmd = le16_to_cpu(midEntry->command);
	unsigned long now;
	unsigned long roundtrip_time;
#endif
	struct TCP_Server_Info *server = midEntry->server;

	if (midEntry->resp_buf && (midEntry->mid_flags & MID_WAIT_CANCELLED) &&
	    midEntry->mid_state == MID_RESPONSE_RECEIVED &&
	    server->ops->handle_cancelled_mid)
		server->ops->handle_cancelled_mid(midEntry, server);

	midEntry->mid_state = MID_FREE;
	atomic_dec(&midCount);
	if (midEntry->large_buf)
		cifs_buf_release(midEntry->resp_buf);
	else
		cifs_small_buf_release(midEntry->resp_buf);
#ifdef CONFIG_CIFS_STATS2
	now = jiffies;
	if (now < midEntry->when_alloc)
		cifs_server_dbg(VFS, "Invalid mid allocation time\n");
	roundtrip_time = now - midEntry->when_alloc;

	if (smb_cmd < NUMBER_OF_SMB2_COMMANDS) {
		if (atomic_read(&server->num_cmds[smb_cmd]) == 0) {
			server->slowest_cmd[smb_cmd] = roundtrip_time;
			server->fastest_cmd[smb_cmd] = roundtrip_time;
		} else {
			if (server->slowest_cmd[smb_cmd] < roundtrip_time)
				server->slowest_cmd[smb_cmd] = roundtrip_time;
			else if (server->fastest_cmd[smb_cmd] > roundtrip_time)
				server->fastest_cmd[smb_cmd] = roundtrip_time;
		}
		cifs_stats_inc(&server->num_cmds[smb_cmd]);
		server->time_per_cmd[smb_cmd] += roundtrip_time;
	}
	/*
	 * commands taking longer than one second (default) can be indications
	 * that something is wrong, unless it is quite a slow link or a very
	 * busy server. Note that this calc is unlikely or impossible to wrap
	 * as long as slow_rsp_threshold is not set way above recommended max
	 * value (32767 ie 9 hours) and is generally harmless even if wrong
	 * since only affects debug counters - so leaving the calc as simple
	 * comparison rather than doing multiple conversions and overflow
	 * checks
	 */
	if ((slow_rsp_threshold != 0) &&
	    time_after(now, midEntry->when_alloc + (slow_rsp_threshold * HZ)) &&
	    (midEntry->command != command)) {
		/*
		 * smb2s