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For device mapper targets to take advantage of IMA's measurement capabilities, the status functions for the individual targets need to be updated to handle the status_type_t case for value STATUSTYPE_IMA. Update status functions for the following target types, to log their respective attributes to be measured using IMA. 01. cache 02. crypt 03. integrity 04. linear 05. mirror 06. multipath 07. raid 08. snapshot 09. striped 10. verity For rest of the targets, handle the STATUSTYPE_IMA case by setting the measurement buffer to NULL. For IMA to measure the data on a given system, the IMA policy on the system needs to be updated to have the following line, and the system needs to be restarted for the measurements to take effect. /etc/ima/ima-policy measure func=CRITICAL_DATA label=device-mapper template=ima-buf The measurements will be reflected in the IMA logs, which are located at: /sys/kernel/security/integrity/ima/ascii_runtime_measurements /sys/kernel/security/integrity/ima/binary_runtime_measurements These IMA logs can later be consumed by various attestation clients running on the system, and send them to external services for attesting the system. The DM target data measured by IMA subsystem can alternatively be queried from userspace by setting DM_IMA_MEASUREMENT_FLAG with DM_TABLE_STATUS_CMD. Signed-off-by: Tushar Sugandhi <tusharsu@linux.microsoft.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
287 lines
6.0 KiB
C
287 lines
6.0 KiB
C
/*
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* Copyright (C) 2004-2005 IBM Corp. All Rights Reserved.
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* Copyright (C) 2006-2009 NEC Corporation.
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*
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* dm-queue-length.c
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*
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* Module Author: Stefan Bader, IBM
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* Modified by: Kiyoshi Ueda, NEC
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*
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* This file is released under the GPL.
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*
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* queue-length path selector - choose a path with the least number of
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* in-flight I/Os.
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*/
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#include "dm.h"
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#include "dm-path-selector.h"
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#include <linux/slab.h>
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#include <linux/ctype.h>
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#include <linux/errno.h>
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#include <linux/module.h>
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#include <linux/atomic.h>
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#define DM_MSG_PREFIX "multipath queue-length"
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#define QL_MIN_IO 1
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#define QL_VERSION "0.2.0"
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struct selector {
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struct list_head valid_paths;
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struct list_head failed_paths;
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spinlock_t lock;
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};
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struct path_info {
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struct list_head list;
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struct dm_path *path;
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unsigned repeat_count;
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atomic_t qlen; /* the number of in-flight I/Os */
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};
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static struct selector *alloc_selector(void)
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{
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struct selector *s = kmalloc(sizeof(*s), GFP_KERNEL);
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if (s) {
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INIT_LIST_HEAD(&s->valid_paths);
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INIT_LIST_HEAD(&s->failed_paths);
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spin_lock_init(&s->lock);
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}
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return s;
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}
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static int ql_create(struct path_selector *ps, unsigned argc, char **argv)
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{
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struct selector *s = alloc_selector();
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if (!s)
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return -ENOMEM;
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ps->context = s;
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return 0;
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}
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static void ql_free_paths(struct list_head *paths)
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{
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struct path_info *pi, *next;
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list_for_each_entry_safe(pi, next, paths, list) {
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list_del(&pi->list);
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kfree(pi);
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}
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}
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static void ql_destroy(struct path_selector *ps)
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{
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struct selector *s = ps->context;
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ql_free_paths(&s->valid_paths);
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ql_free_paths(&s->failed_paths);
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kfree(s);
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ps->context = NULL;
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}
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static int ql_status(struct path_selector *ps, struct dm_path *path,
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status_type_t type, char *result, unsigned maxlen)
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{
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unsigned sz = 0;
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struct path_info *pi;
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/* When called with NULL path, return selector status/args. */
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if (!path)
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DMEMIT("0 ");
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else {
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pi = path->pscontext;
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switch (type) {
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case STATUSTYPE_INFO:
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DMEMIT("%d ", atomic_read(&pi->qlen));
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break;
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case STATUSTYPE_TABLE:
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DMEMIT("%u ", pi->repeat_count);
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break;
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case STATUSTYPE_IMA:
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*result = '\0';
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break;
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}
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}
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return sz;
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}
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static int ql_add_path(struct path_selector *ps, struct dm_path *path,
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int argc, char **argv, char **error)
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{
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struct selector *s = ps->context;
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struct path_info *pi;
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unsigned repeat_count = QL_MIN_IO;
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char dummy;
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unsigned long flags;
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/*
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* Arguments: [<repeat_count>]
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* <repeat_count>: The number of I/Os before switching path.
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* If not given, default (QL_MIN_IO) is used.
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*/
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if (argc > 1) {
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*error = "queue-length ps: incorrect number of arguments";
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return -EINVAL;
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}
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if ((argc == 1) && (sscanf(argv[0], "%u%c", &repeat_count, &dummy) != 1)) {
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*error = "queue-length ps: invalid repeat count";
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return -EINVAL;
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}
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if (repeat_count > 1) {
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DMWARN_LIMIT("repeat_count > 1 is deprecated, using 1 instead");
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repeat_count = 1;
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}
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/* Allocate the path information structure */
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pi = kmalloc(sizeof(*pi), GFP_KERNEL);
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if (!pi) {
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*error = "queue-length ps: Error allocating path information";
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return -ENOMEM;
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}
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pi->path = path;
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pi->repeat_count = repeat_count;
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atomic_set(&pi->qlen, 0);
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path->pscontext = pi;
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spin_lock_irqsave(&s->lock, flags);
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list_add_tail(&pi->list, &s->valid_paths);
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spin_unlock_irqrestore(&s->lock, flags);
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return 0;
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}
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static void ql_fail_path(struct path_selector *ps, struct dm_path *path)
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{
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struct selector *s = ps->context;
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struct path_info *pi = path->pscontext;
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unsigned long flags;
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spin_lock_irqsave(&s->lock, flags);
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list_move(&pi->list, &s->failed_paths);
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spin_unlock_irqrestore(&s->lock, flags);
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}
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static int ql_reinstate_path(struct path_selector *ps, struct dm_path *path)
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{
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struct selector *s = ps->context;
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struct path_info *pi = path->pscontext;
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unsigned long flags;
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spin_lock_irqsave(&s->lock, flags);
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list_move_tail(&pi->list, &s->valid_paths);
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spin_unlock_irqrestore(&s->lock, flags);
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return 0;
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}
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/*
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* Select a path having the minimum number of in-flight I/Os
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*/
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static struct dm_path *ql_select_path(struct path_selector *ps, size_t nr_bytes)
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{
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struct selector *s = ps->context;
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struct path_info *pi = NULL, *best = NULL;
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struct dm_path *ret = NULL;
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unsigned long flags;
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spin_lock_irqsave(&s->lock, flags);
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if (list_empty(&s->valid_paths))
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goto out;
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list_for_each_entry(pi, &s->valid_paths, list) {
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if (!best ||
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(atomic_read(&pi->qlen) < atomic_read(&best->qlen)))
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best = pi;
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if (!atomic_read(&best->qlen))
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break;
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}
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if (!best)
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goto out;
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/* Move most recently used to least preferred to evenly balance. */
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list_move_tail(&best->list, &s->valid_paths);
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ret = best->path;
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out:
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spin_unlock_irqrestore(&s->lock, flags);
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return ret;
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}
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static int ql_start_io(struct path_selector *ps, struct dm_path *path,
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size_t nr_bytes)
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{
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struct path_info *pi = path->pscontext;
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atomic_inc(&pi->qlen);
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return 0;
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}
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static int ql_end_io(struct path_selector *ps, struct dm_path *path,
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size_t nr_bytes, u64 start_time)
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{
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struct path_info *pi = path->pscontext;
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atomic_dec(&pi->qlen);
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return 0;
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}
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static struct path_selector_type ql_ps = {
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.name = "queue-length",
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.module = THIS_MODULE,
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.table_args = 1,
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.info_args = 1,
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.create = ql_create,
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.destroy = ql_destroy,
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.status = ql_status,
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.add_path = ql_add_path,
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.fail_path = ql_fail_path,
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.reinstate_path = ql_reinstate_path,
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.select_path = ql_select_path,
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.start_io = ql_start_io,
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.end_io = ql_end_io,
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};
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static int __init dm_ql_init(void)
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{
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int r = dm_register_path_selector(&ql_ps);
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if (r < 0)
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DMERR("register failed %d", r);
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DMINFO("version " QL_VERSION " loaded");
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return r;
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}
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static void __exit dm_ql_exit(void)
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{
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int r = dm_unregister_path_selector(&ql_ps);
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if (r < 0)
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DMERR("unregister failed %d", r);
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}
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module_init(dm_ql_init);
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module_exit(dm_ql_exit);
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MODULE_AUTHOR("Stefan Bader <Stefan.Bader at de.ibm.com>");
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MODULE_DESCRIPTION(
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"(C) Copyright IBM Corp. 2004,2005 All Rights Reserved.\n"
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DM_NAME " path selector to balance the number of in-flight I/Os"
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);
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MODULE_LICENSE("GPL");
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