dasd_devmap.c

linux-2.6.15.6

/*
 * File...........: linux/drivers/s390/block/dasd_devmap.c
 * Author(s)......: Holger Smolinski <[e-mail]>
 *		    Horst Hummel <[e-mail]>
 *		    Carsten Otte <[e-mail]>
 *		    Martin Schwidefsky <[e-mail]>
 * Bugreports.to..: <[e-mail]>
 * (C) IBM Corporation, IBM Deutschland Entwicklung GmbH, 1999-2001
 *
 * Device mapping and dasd= parameter parsing functions. All devmap
 * functions may not be called from interrupt context. In particular
 * dasd_get_device is a no-no from interrupt context.
 *
 * $Revision: 1.43 $
 */

#include <linux/config.h>
#include <linux/ctype.h>
#include <linux/init.h>

#include <asm/debug.h>
#include <asm/uaccess.h>

/* This is ugly... */
#define PRINTK_HEADER "dasd_devmap:"

#include "dasd_int.h"

kmem_cache_t *dasd_page_cache;
EXPORT_SYMBOL(dasd_page_cache);

/*
 * dasd_devmap_t is used to store the features and the relation
 * between device number and device index. To find a dasd_devmap_t
 * that corresponds to a device number of a device index each
 * dasd_devmap_t is added to two linked lists, one to search by
 * the device number and one to search by the device index. As
 * soon as big minor numbers are available the device index list
 * can be removed since the device number will then be identical
 * to the device index.
 */
struct dasd_devmap {
	struct list_head list;
	char bus_id[BUS_ID_SIZE];
        unsigned int devindex;
        unsigned short features;
	struct dasd_device *device;
};

/*
 * Parameter parsing functions for dasd= parameter. The syntax is:
 *   <devno>		: (0x)?[0-9a-fA-F]+
 *   <busid>		: [0-0a-f]\.[0-9a-f]\.(0x)?[0-9a-fA-F]+
 *   <feature>		: ro
 *   <feature_list>	: \(<feature>(:<feature>)*\)
 *   <devno-range>	: <devno>(-<devno>)?<feature_list>?
 *   <busid-range>	: <busid>(-<busid>)?<feature_list>?
 *   <devices>		: <devno-range>|<busid-range>
 *   <dasd_module>	: dasd_diag_mod|dasd_eckd_mod|dasd_fba_mod
 *
 *   <dasd>		: autodetect|probeonly|<devices>(,<devices>)*
 */

int dasd_probeonly =  0;	/* is true, when probeonly mode is active */
int dasd_autodetect = 0;	/* is true, when autodetection is active */

/*
 * char *dasd[] is intended to hold the ranges supplied by the dasd= statement
 * it is named 'dasd' to directly be filled by insmod with the comma separated
 * strings when running as a module.
 */
static char *dasd[256];
/*
 * Single spinlock to protect devmap structures and lists.
 */
static DEFINE_SPINLOCK(dasd_devmap_lock);

/*
 * Hash lists for devmap structures.
 */
static struct list_head dasd_hashlists[256];
int dasd_max_devindex;

static struct dasd_devmap *dasd_add_busid(char *, int);

static inline int
dasd_hash_busid(char *bus_id)
{
	int hash, i;

	hash = 0;
	for (i = 0; (i < BUS_ID_SIZE) && *bus_id; i++, bus_id++)
		hash += *bus_id;
	return hash & 0xff;
}

#ifndef MODULE
/*
 * The parameter parsing functions for builtin-drivers are called
 * before kmalloc works. Store the pointers to the parameters strings
 * into dasd[] for later processing.
 */
static int __init
dasd_call_setup(char *str)
{
	static int count = 0;

	if (count < 256)
		dasd[count++] = str;
	return 1;
}

__setup ("dasd=", dasd_call_setup);
#endif	/* #ifndef MODULE */

/*
 * Read a device busid/devno from a string.
 */
static inline int
dasd_busid(char **str, int *id0, int *id1, int *devno)
{
	int val, old_style;
 
	/* check for leading '0x' */
	old_style = 0;
	if ((*str)[0] == '0' && (*str)[1] == 'x') {
		*str += 2;
		old_style = 1;
	}
	if (!isxdigit((*str)[0]))	/* We require at least one hex digit */
		return -EINVAL;
	val = simple_strtoul(*str, str, 16);
	if (old_style || (*str)[0] != '.') {
		*id0 = *id1 = 0;
		if (val < 0 || val > 0xffff)
			return -EINVAL;
		*devno = val;
		return 0;
	}
	/* New style x.y.z busid */
	if (val < 0 || val > 0xff)
		return -EINVAL;
	*id0 = val;
	(*str)++;
	if (!isxdigit((*str)[0]))	/* We require at least one hex digit */
		return -EINVAL;
	val = simple_strtoul(*str, str, 16);
	if (val < 0 || val > 0xff || (*str)++[0] != '.')
		return -EINVAL;
	*id1 = val;
	if (!isxdigit((*str)[0]))	/* We require at least one hex digit */
		return -EINVAL;
	val = simple_strtoul(*str, str, 16);
	if (val < 0 || val > 0xffff)
		return -EINVAL;
	*devno = val;
	return 0;
}

/*
 * Read colon separated list of dasd features. Currently there is
 * only one: "ro" for read-only devices. The default feature set
 * is empty (value 0).
 */
static inline int
dasd_feature_list(char *str, char **endp)
{
	int features, len, rc;

	rc = 0;
	if (*str != '(') {
		*endp = str;
		return DASD_FEATURE_DEFAULT;
	}
	str++;
	features = 0;

	while (1) {
		for (len = 0; 
		     str[len] && str[len] != ':' && str[len] != ')'; len++);
		if (len == 2 && !strncmp(str, "ro", 2))
			features |= DASD_FEATURE_READONLY;
		else if (len == 4 && !strncmp(str, "diag", 4))
			features |= DASD_FEATURE_USEDIAG;
		else {
			MESSAGE(KERN_WARNING,
				"unsupported feature: %*s, "
				"ignoring setting", len, str);
			rc = -EINVAL;
		}
		str += len;
		if (*str != ':')
			break;
		str++;
	}
	if (*str != ')') {
		MESSAGE(KERN_WARNING, "%s",
			"missing ')' in dasd parameter string\n");
		rc = -EINVAL;
	} else
		str++;
	*endp = str;
	if (rc != 0)
		return rc;
	return features;
}

/*
 * Try to match the first element on the comma separated parse string
 * with one of the known keywords. If a keyword is found, take the approprate
 * action and return a pointer to the residual string. If the first element
 * could not be matched to any keyword then return an error code.
 */
static char *
dasd_parse_keyword( char *parsestring ) {

	char *nextcomma, *residual_str;
	int length;

	nextcomma = strchr(parsestring,',');
	if (nextcomma) {
		length = nextcomma - parsestring;
		residual_str = nextcomma + 1;
	} else {
		length = strlen(parsestring);
		residual_str = parsestring + length;
        }
	if (strncmp ("autodetect", parsestring, length) == 0) {
		dasd_autodetect = 1;
		MESSAGE (KERN_INFO, "%s",
			 "turning to autodetection mode");
                return residual_str;
        }
        if (strncmp ("probeonly", parsestring, length) == 0) {
		dasd_probeonly = 1;
		MESSAGE(KERN_INFO, "%s",
			"turning to probeonly mode");
                return residual_str;
        }
        if (strncmp ("fixedbuffers", parsestring, length) == 0) {
		if (dasd_page_cache)
			return residual_str;
		dasd_page_cache =
			kmem_cache_create("dasd_page_cache", PAGE_SIZE, 0,
					  SLAB_CACHE_DMA, NULL, NULL );
		if (!dasd_page_cache)
			MESSAGE(KERN_WARNING, "%s", "Failed to create slab, "
				"fixed buffer mode disabled.");
		else
			MESSAGE (KERN_INFO, "%s",
				 "turning on fixed buffer mode");
                return residual_str;
        }
	return ERR_PTR(-EINVAL);
}

/*
 * Try to interprete the first element on the comma separated parse string
 * as a device number or a range of devices. If the interpretation is
 * successfull, create the matching dasd_devmap entries and return a pointer
 * to the residual string.
 * If interpretation fails or in case of an error, return an error code.
 */
static char *
dasd_parse_range( char *parsestring ) {

	struct dasd_devmap *devmap;
	int from, from_id0, from_id1;
	int to, to_id0, to_id1;
	int features, rc;
	char bus_id[BUS_ID_SIZE+1], *str;

	str = parsestring;
	rc = dasd_busid(&str, &from_id0, &from_id1, &from);
	if (rc == 0) {
		to = from;
		to_id0 = from_id0;
		to_id1 = from_id1;
		if (*str == '-') {
			str++;
			rc = dasd_busid(&str, &to_id0, &to_id1, &to);
		}
	}
	if (rc == 0 &&
	    (from_id0 != to_id0 || from_id1 != to_id1 || from > to))
		rc = -EINVAL;
	if (rc) {
		MESSAGE(KERN_ERR, "Invalid device range %s", parsestring);
		return ERR_PTR(rc);
	}
	features = dasd_feature_list(str, &str);
	if (features < 0)
		return ERR_PTR(-EINVAL);
	while (from <= to) {
		sprintf(bus_id, "%01x.%01x.%04x",
			from_id0, from_id1, from++);
		devmap = dasd_add_busid(bus_id, features);
		if (IS_ERR(devmap))
			return (char *)devmap;
	}
	if (*str == ',')
		return str + 1;
	if (*str == '\0')
		return str;
	MESSAGE(KERN_WARNING,
		"junk at end of dasd parameter string: %s\n", str);
	return ERR_PTR(-EINVAL);
}

static inline char *
dasd_parse_next_element( char *parsestring ) {
	char * residual_str;
	residual_str = dasd_parse_keyword(parsestring);
	if (!IS_ERR(residual_str))
		return residual_str;
	residual_str = dasd_parse_range(parsestring);
	return residual_str;
}

/*
 * Parse parameters stored in dasd[]
 * The 'dasd=...' parameter allows to specify a comma separated list of
 * keywords and device ranges. When the dasd driver is build into the kernel,
 * the complete list will be stored as one element of the dasd[] array.
 * When the dasd driver is build as a module, then the list is broken into
 * it's elements and each dasd[] entry contains one element.
 */
int
dasd_parse(void)
{
	int rc, i;
	char *parsestring;

	rc = 0;
	for (i = 0; i < 256; i++) {
		if (dasd[i] == NULL)
			break;
		parsestring = dasd[i];
		/* loop over the comma separated list in the parsestring */
		while (*parsestring) {
			parsestring = dasd_parse_next_element(parsestring);
			if(IS_ERR(parsestring)) {
				rc = PTR_ERR(parsestring);
				break;
			}
		}
		if (rc) {
			DBF_EVENT(DBF_ALERT, "%s", "invalid range found");
			break;
		}
	}
	return rc;
}

/*
 * Add a devmap for the device specified by busid. It is possible that
 * the devmap already exists (dasd= parameter). The order of the devices
 * added through this function will define the kdevs for the individual
 * devices. 
 */
static struct dasd_devmap *
dasd_add_busid(char *bus_id, int features)
{
	struct dasd_devmap *devmap, *new, *tmp;
	int hash;

	new = (struct dasd_devmap *)
		kmalloc(sizeof(struct dasd_devmap), GFP_KERNEL);
	if (!new)
		return ERR_PTR(-ENOMEM);
	spin_lock(&dasd_devmap_lock);
	devmap = 0;
	hash = dasd_hash_busid(bus_id);
	list_for_each_entry(tmp, &dasd_hashlists[hash], list)
		if (strncmp(tmp->bus_id, bus_id, BUS_ID_SIZE) == 0) {
			devmap = tmp;
			break;
		}
	if (!devmap) {
		/* This bus_id is new. */
		new->devindex = dasd_max_devindex++;
		strncpy(new->bus_id, bus_id, BUS_ID_SIZE);
		new->features = features;
		new->device = 0;
		list_add(&new->list, &dasd_hashlists[hash]);
		devmap = new;
		new = 0;
	}
	spin_unlock(&dasd_devmap_lock);
	kfree(new);
	return devmap;
}

/*
 * Find devmap for device with given bus_id.
 */
static struct dasd_devmap *
dasd_find_busid(char *bus_id)
{
	struct dasd_devmap *devmap, *tmp;
	int hash;