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![Eric Sesterhenn](/assets/img/avatar_default.png)
this changes if() BUG(); constructs to BUG_ON() which is cleaner and can better optimized away Signed-off-by: Eric Sesterhenn <snakebyte@gmx.de> Signed-off-by: Adrian Bunk <bunk@stusta.de>
215 lines
4.3 KiB
C
215 lines
4.3 KiB
C
/*
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* Copyright (C) 2004 Red Hat, Inc. All rights reserved.
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*
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* This file is released under the GPL.
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*
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* Multipath hardware handler registration.
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*/
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#include "dm.h"
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#include "dm-hw-handler.h"
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#include <linux/slab.h>
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struct hwh_internal {
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struct hw_handler_type hwht;
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struct list_head list;
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long use;
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};
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#define hwht_to_hwhi(__hwht) container_of((__hwht), struct hwh_internal, hwht)
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static LIST_HEAD(_hw_handlers);
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static DECLARE_RWSEM(_hwh_lock);
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static struct hwh_internal *__find_hw_handler_type(const char *name)
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{
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struct hwh_internal *hwhi;
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list_for_each_entry(hwhi, &_hw_handlers, list) {
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if (!strcmp(name, hwhi->hwht.name))
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return hwhi;
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}
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return NULL;
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}
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static struct hwh_internal *get_hw_handler(const char *name)
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{
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struct hwh_internal *hwhi;
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down_read(&_hwh_lock);
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hwhi = __find_hw_handler_type(name);
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if (hwhi) {
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if ((hwhi->use == 0) && !try_module_get(hwhi->hwht.module))
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hwhi = NULL;
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else
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hwhi->use++;
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}
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up_read(&_hwh_lock);
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return hwhi;
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}
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struct hw_handler_type *dm_get_hw_handler(const char *name)
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{
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struct hwh_internal *hwhi;
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if (!name)
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return NULL;
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hwhi = get_hw_handler(name);
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if (!hwhi) {
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request_module("dm-%s", name);
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hwhi = get_hw_handler(name);
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}
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return hwhi ? &hwhi->hwht : NULL;
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}
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void dm_put_hw_handler(struct hw_handler_type *hwht)
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{
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struct hwh_internal *hwhi;
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if (!hwht)
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return;
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down_read(&_hwh_lock);
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hwhi = __find_hw_handler_type(hwht->name);
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if (!hwhi)
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goto out;
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if (--hwhi->use == 0)
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module_put(hwhi->hwht.module);
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BUG_ON(hwhi->use < 0);
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out:
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up_read(&_hwh_lock);
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}
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static struct hwh_internal *_alloc_hw_handler(struct hw_handler_type *hwht)
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{
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struct hwh_internal *hwhi = kmalloc(sizeof(*hwhi), GFP_KERNEL);
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if (hwhi) {
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memset(hwhi, 0, sizeof(*hwhi));
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hwhi->hwht = *hwht;
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}
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return hwhi;
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}
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int dm_register_hw_handler(struct hw_handler_type *hwht)
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{
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int r = 0;
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struct hwh_internal *hwhi = _alloc_hw_handler(hwht);
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if (!hwhi)
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return -ENOMEM;
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down_write(&_hwh_lock);
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if (__find_hw_handler_type(hwht->name)) {
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kfree(hwhi);
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r = -EEXIST;
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} else
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list_add(&hwhi->list, &_hw_handlers);
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up_write(&_hwh_lock);
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return r;
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}
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int dm_unregister_hw_handler(struct hw_handler_type *hwht)
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{
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struct hwh_internal *hwhi;
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down_write(&_hwh_lock);
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hwhi = __find_hw_handler_type(hwht->name);
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if (!hwhi) {
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up_write(&_hwh_lock);
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return -EINVAL;
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}
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if (hwhi->use) {
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up_write(&_hwh_lock);
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return -ETXTBSY;
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}
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list_del(&hwhi->list);
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up_write(&_hwh_lock);
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kfree(hwhi);
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return 0;
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}
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unsigned dm_scsi_err_handler(struct hw_handler *hwh, struct bio *bio)
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{
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#if 0
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int sense_key, asc, ascq;
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if (bio->bi_error & BIO_SENSE) {
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/* FIXME: This is just an initial guess. */
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/* key / asc / ascq */
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sense_key = (bio->bi_error >> 16) & 0xff;
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asc = (bio->bi_error >> 8) & 0xff;
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ascq = bio->bi_error & 0xff;
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switch (sense_key) {
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/* This block as a whole comes from the device.
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* So no point retrying on another path. */
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case 0x03: /* Medium error */
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case 0x05: /* Illegal request */
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case 0x07: /* Data protect */
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case 0x08: /* Blank check */
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case 0x0a: /* copy aborted */
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case 0x0c: /* obsolete - no clue ;-) */
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case 0x0d: /* volume overflow */
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case 0x0e: /* data miscompare */
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case 0x0f: /* reserved - no idea either. */
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return MP_ERROR_IO;
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/* For these errors it's unclear whether they
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* come from the device or the controller.
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* So just lets try a different path, and if
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* it eventually succeeds, user-space will clear
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* the paths again... */
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case 0x02: /* Not ready */
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case 0x04: /* Hardware error */
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case 0x09: /* vendor specific */
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case 0x0b: /* Aborted command */
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return MP_FAIL_PATH;
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case 0x06: /* Unit attention - might want to decode */
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if (asc == 0x04 && ascq == 0x01)
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/* "Unit in the process of
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* becoming ready" */
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return 0;
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return MP_FAIL_PATH;
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/* FIXME: For Unit Not Ready we may want
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* to have a generic pg activation
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* feature (START_UNIT). */
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/* Should these two ever end up in the
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* error path? I don't think so. */
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case 0x00: /* No sense */
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case 0x01: /* Recovered error */
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return 0;
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}
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}
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#endif
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/* We got no idea how to decode the other kinds of errors ->
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* assume generic error condition. */
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return MP_FAIL_PATH;
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}
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EXPORT_SYMBOL_GPL(dm_register_hw_handler);
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EXPORT_SYMBOL_GPL(dm_unregister_hw_handler);
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EXPORT_SYMBOL_GPL(dm_scsi_err_handler);
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