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mirror_zfs/module/spl/spl-generic.c
Brian Behlendorf 9fe45dc1ac Add Thread Specific Data (TSD) Implementation 
Thread specific data has implemented using a hash table, this avoids
the need to add a member to the task structure and allows maximum
portability between kernels.  This implementation has been optimized
to keep the tsd_set() and tsd_get() times as small as possible.

The majority of the entries in the hash table are for specific tsd
entries.  These entries are hashed by the product of their key and
pid because by design the key and pid are guaranteed to be unique.
Their product also has the desirable properly that it will be uniformly
distributed over the hash bins providing neither the pid nor key is zero.
Under linux the zero pid is always the init process and thus won't be
used, and this implementation is careful to never to assign a zero key.
By default the hash table is sized to 512 bins which is expected to
be sufficient for light to moderate usage of thread specific data.

The hash table contains two additional type of entries.  They first
type is entry is called a 'key' entry and it is added to the hash during
tsd_create().  It is used to store the address of the destructor function
and it is used as an anchor point.  All tsd entries which use the same
key will be linked to this entry.  This is used during tsd_destory() to
quickly call the destructor function for all tsd associated with the key.
The 'key' entry may be looked up with tsd_hash_search() by passing the
key you wish to lookup and DTOR_PID constant as the pid.

The second type of entry is called a 'pid' entry and it is added to the
hash the first time a process set a key.  The 'pid' entry is also used
as an anchor and all tsd for the process will be linked to it.  This
list is using during tsd_exit() to ensure all registered destructors
are run for the process.  The 'pid' entry may be looked up with
tsd_hash_search() by passing the PID_KEY constant as the key, and
the process pid.  Note that tsd_exit() is called by thread_exit()
so if your using the Solaris thread API you should not need to call
tsd_exit() directly.
2010-12-07 10:02:32 -08:00

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/*****************************************************************************\
* Copyright (C) 2007-2010 Lawrence Livermore National Security, LLC.
* Copyright (C) 2007 The Regents of the University of California.
* Produced at Lawrence Livermore National Laboratory (cf, DISCLAIMER).
* Written by Brian Behlendorf <behlendorf1@llnl.gov>.
* UCRL-CODE-235197
*
* This file is part of the SPL, Solaris Porting Layer.
* For details, see <http://github.com/behlendorf/spl/>.
*
* The SPL is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the
* Free Software Foundation; either version 2 of the License, or (at your
* option) any later version.
*
* The SPL is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* for more details.
*
* You should have received a copy of the GNU General Public License along
* with the SPL. If not, see <http://www.gnu.org/licenses/>.
*****************************************************************************
* Solaris Porting Layer (SPL) Generic Implementation.
\*****************************************************************************/
#include <sys/sysmacros.h>
#include <sys/systeminfo.h>
#include <sys/vmsystm.h>
#include <sys/vnode.h>
#include <sys/kmem.h>
#include <sys/mutex.h>
#include <sys/rwlock.h>
#include <sys/taskq.h>
#include <sys/tsd.h>
#include <sys/debug.h>
#include <sys/proc.h>
#include <sys/kstat.h>
#include <sys/utsname.h>
#include <sys/file.h>
#include <linux/kmod.h>
#include <linux/proc_compat.h>
#include <spl-debug.h>
#ifdef SS_DEBUG_SUBSYS
#undef SS_DEBUG_SUBSYS
#endif
#define SS_DEBUG_SUBSYS SS_GENERIC
char spl_version[16] = "SPL v" SPL_META_VERSION;
EXPORT_SYMBOL(spl_version);
long spl_hostid = 0;
EXPORT_SYMBOL(spl_hostid);
char hw_serial[HW_HOSTID_LEN] = "<none>";
EXPORT_SYMBOL(hw_serial);
proc_t p0 = { 0 };
EXPORT_SYMBOL(p0);
#ifndef HAVE_KALLSYMS_LOOKUP_NAME
kallsyms_lookup_name_t spl_kallsyms_lookup_name_fn = SYMBOL_POISON;
#endif
int
highbit(unsigned long i)
{
register int h = 1;
SENTRY;
if (i == 0)
SRETURN(0);
#if BITS_PER_LONG == 64
if (i & 0xffffffff00000000ul) {
h += 32; i >>= 32;
}
#endif
if (i & 0xffff0000) {
h += 16; i >>= 16;
}
if (i & 0xff00) {
h += 8; i >>= 8;
}
if (i & 0xf0) {
h += 4; i >>= 4;
}
if (i & 0xc) {
h += 2; i >>= 2;
}
if (i & 0x2) {
h += 1;
}
SRETURN(h);
}
EXPORT_SYMBOL(highbit);
#if BITS_PER_LONG == 32
/*
* Support 64/64 => 64 division on a 32-bit platform. While the kernel
* provides a div64_u64() function for this we do not use it because the
* implementation is flawed. There are cases which return incorrect
* results as late as linux-2.6.35. Until this is fixed upstream the
* spl must provide its own implementation.
*
* This implementation is a slightly modified version of the algorithm
* proposed by the book 'Hacker's Delight'. The original source can be
* found here and is available for use without restriction.
*
* http://www.hackersdelight.org/HDcode/newCode/divDouble.c
*/
/*
* Calculate number of leading of zeros for a 64-bit value.
*/
static int
nlz64(uint64_t x) {
register int n = 0;
if (x == 0)
return 64;
if (x <= 0x00000000FFFFFFFFULL) {n = n + 32; x = x << 32;}
if (x <= 0x0000FFFFFFFFFFFFULL) {n = n + 16; x = x << 16;}
if (x <= 0x00FFFFFFFFFFFFFFULL) {n = n + 8; x = x << 8;}
if (x <= 0x0FFFFFFFFFFFFFFFULL) {n = n + 4; x = x << 4;}
if (x <= 0x3FFFFFFFFFFFFFFFULL) {n = n + 2; x = x << 2;}
if (x <= 0x7FFFFFFFFFFFFFFFULL) {n = n + 1;}
return n;
}
/*
* Newer kernels have a div_u64() function but we define our own
* to simplify portibility between kernel versions.
*/
static inline uint64_t
__div_u64(uint64_t u, uint32_t v)
{
(void) do_div(u, v);
return u;
}
/*
* Implementation of 64-bit unsigned division for 32-bit machines.
*
* First the procedure takes care of the case in which the divisor is a
* 32-bit quantity. There are two subcases: (1) If the left half of the
* dividend is less than the divisor, one execution of do_div() is all that
* is required (overflow is not possible). (2) Otherwise it does two
* divisions, using the grade school method.
*/
uint64_t
__udivdi3(uint64_t u, uint64_t v)
{
uint64_t u0, u1, v1, q0, q1, k;
int n;
if (v >> 32 == 0) { // If v < 2**32:
if (u >> 32 < v) { // If u/v cannot overflow,
return __div_u64(u, v); // just do one division.
} else { // If u/v would overflow:
u1 = u >> 32; // Break u into two halves.
u0 = u & 0xFFFFFFFF;
q1 = __div_u64(u1, v); // First quotient digit.
k = u1 - q1 * v; // First remainder, < v.
u0 += (k << 32);
q0 = __div_u64(u0, v); // Seconds quotient digit.
return (q1 << 32) + q0;
}
} else { // If v >= 2**32:
n = nlz64(v); // 0 <= n <= 31.
v1 = (v << n) >> 32; // Normalize divisor, MSB is 1.
u1 = u >> 1; // To ensure no overflow.
q1 = __div_u64(u1, v1); // Get quotient from
q0 = (q1 << n) >> 31; // Undo normalization and
// division of u by 2.
if (q0 != 0) // Make q0 correct or
q0 = q0 - 1; // too small by 1.
if ((u - q0 * v) >= v)
q0 = q0 + 1; // Now q0 is correct.
return q0;
}
}
EXPORT_SYMBOL(__udivdi3);
/*
* Implementation of 64-bit signed division for 32-bit machines.
*/
int64_t
__divdi3(int64_t u, int64_t v)
{
int64_t q, t;
q = __udivdi3(abs64(u), abs64(v));
t = (u ^ v) >> 63; // If u, v have different
return (q ^ t) - t; // signs, negate q.
}
EXPORT_SYMBOL(__divdi3);
/*
* Implementation of 64-bit unsigned modulo for 32-bit machines.
*/
uint64_t
__umoddi3(uint64_t dividend, uint64_t divisor)
{
return (dividend - (divisor * __udivdi3(dividend, divisor)));
}
EXPORT_SYMBOL(__umoddi3);
#endif /* BITS_PER_LONG */
/* NOTE: The strtoxx behavior is solely based on my reading of the Solaris
* ddi_strtol(9F) man page. I have not verified the behavior of these
* functions against their Solaris counterparts. It is possible that I
* may have misinterpreted the man page or the man page is incorrect.
*/
int ddi_strtoul(const char *, char **, int, unsigned long *);
int ddi_strtol(const char *, char **, int, long *);
int ddi_strtoull(const char *, char **, int, unsigned long long *);
int ddi_strtoll(const char *, char **, int, long long *);
#define define_ddi_strtoux(type, valtype) \
int ddi_strtou##type(const char *str, char **endptr, \
int base, valtype *result) \
{ \
valtype last_value, value = 0; \
char *ptr = (char *)str; \
int flag = 1, digit; \
\
if (strlen(ptr) == 0) \
return EINVAL; \
\
/* Auto-detect base based on prefix */ \
if (!base) { \
if (str[0] == '0') { \
if (tolower(str[1])=='x' && isxdigit(str[2])) { \
base = 16; /* hex */ \
ptr += 2; \
} else if (str[1] >= '0' && str[1] < 8) { \
base = 8; /* octal */ \
ptr += 1; \
} else { \
return EINVAL; \
} \
} else { \
base = 10; /* decimal */ \
} \
} \
\
while (1) { \
if (isdigit(*ptr)) \
digit = *ptr - '0'; \
else if (isalpha(*ptr)) \
digit = tolower(*ptr) - 'a' + 10; \
else \
break; \
\
if (digit >= base) \
break; \
\
last_value = value; \
value = value * base + digit; \
if (last_value > value) /* Overflow */ \
return ERANGE; \
\
flag = 1; \
ptr++; \
} \
\
if (flag) \
*result = value; \
\
if (endptr) \
*endptr = (char *)(flag ? ptr : str); \
\
return 0; \
} \
#define define_ddi_strtox(type, valtype) \
int ddi_strto##type(const char *str, char **endptr, \
int base, valtype *result) \
{ \
int rc; \
\
if (*str == '-') { \
rc = ddi_strtou##type(str + 1, endptr, base, result); \
if (!rc) { \
if (*endptr == str + 1) \
*endptr = (char *)str; \
else \
*result = -*result; \
} \
} else { \
rc = ddi_strtou##type(str, endptr, base, result); \
} \
\
return rc; \
}
define_ddi_strtoux(l, unsigned long)
define_ddi_strtox(l, long)
define_ddi_strtoux(ll, unsigned long long)
define_ddi_strtox(ll, long long)
EXPORT_SYMBOL(ddi_strtoul);
EXPORT_SYMBOL(ddi_strtol);
EXPORT_SYMBOL(ddi_strtoll);
EXPORT_SYMBOL(ddi_strtoull);
int
ddi_copyin(const void *from, void *to, size_t len, int flags)
{
/* Fake ioctl() issued by kernel, 'from' is a kernel address */
if (flags & FKIOCTL) {
memcpy(to, from, len);
return 0;
}
return copyin(from, to, len);
}
EXPORT_SYMBOL(ddi_copyin);
int
ddi_copyout(const void *from, void *to, size_t len, int flags)
{
/* Fake ioctl() issued by kernel, 'from' is a kernel address */
if (flags & FKIOCTL) {
memcpy(to, from, len);
return 0;
}
return copyout(from, to, len);
}
EXPORT_SYMBOL(ddi_copyout);
#ifndef HAVE_PUT_TASK_STRUCT
/*
* This is only a stub function which should never be used. The SPL should
* never be putting away the last reference on a task structure so this will
* not be called. However, we still need to define it so the module does not
* have undefined symbol at load time. That all said if this impossible
* thing does somehow happen PANIC immediately so we know about it.
*/
void
__put_task_struct(struct task_struct *t)
{
PANIC("Unexpectly put last reference on task %d\n", (int)t->pid);
}
EXPORT_SYMBOL(__put_task_struct);
#endif /* HAVE_PUT_TASK_STRUCT */
struct new_utsname *__utsname(void)
{
#ifdef HAVE_INIT_UTSNAME
return init_utsname();
#else
return &system_utsname;
#endif
}
EXPORT_SYMBOL(__utsname);
static int
set_hostid(void)
{
char sh_path[] = "/bin/sh";
char *argv[] = { sh_path,
"-c",
"/usr/bin/hostid >/proc/sys/kernel/spl/hostid",
NULL };
char *envp[] = { "HOME=/",
"TERM=linux",
"PATH=/sbin:/usr/sbin:/bin:/usr/bin",
NULL };
int rc;
/* Doing address resolution in the kernel is tricky and just
* not a good idea in general. So to set the proper 'hw_serial'
* use the usermodehelper support to ask '/bin/sh' to run
* '/usr/bin/hostid' and redirect the result to /proc/sys/spl/hostid
* for us to use. It's a horrific solution but it will do for now.
*/
rc = call_usermodehelper(sh_path, argv, envp, 1);
if (rc)
printk("SPL: Failed user helper '%s %s %s', rc = %d\n",
argv[0], argv[1], argv[2], rc);
return rc;
}
uint32_t
zone_get_hostid(void *zone)
{
unsigned long hostid;
/* Only the global zone is supported */
ASSERT(zone == NULL);
if (ddi_strtoul(hw_serial, NULL, HW_HOSTID_LEN-1, &hostid) != 0)
return HW_INVALID_HOSTID;
return (uint32_t)hostid;
}
EXPORT_SYMBOL(zone_get_hostid);
#ifndef HAVE_KALLSYMS_LOOKUP_NAME
/*
* Because kallsyms_lookup_name() is no longer exported in the
* mainline kernel we are forced to resort to somewhat drastic
* measures. This function replaces the functionality by performing
* an upcall to user space where /proc/kallsyms is consulted for
* the requested address.
*/
#define GET_KALLSYMS_ADDR_CMD \
"gawk '{ if ( $3 == \"kallsyms_lookup_name\") { print $1 } }' " \
"/proc/kallsyms >/proc/sys/kernel/spl/kallsyms_lookup_name"
static int
set_kallsyms_lookup_name(void)
{
char sh_path[] = "/bin/sh";
char *argv[] = { sh_path,
"-c",
GET_KALLSYMS_ADDR_CMD,
NULL };
char *envp[] = { "HOME=/",
"TERM=linux",
"PATH=/sbin:/usr/sbin:/bin:/usr/bin",
NULL };
int rc;
rc = call_usermodehelper(sh_path, argv, envp, 1);
if (rc)
printk("SPL: Failed user helper '%s %s %s', rc = %d\n",
argv[0], argv[1], argv[2], rc);
return rc;
}
#endif
static int
__init spl_init(void)
{
int rc = 0;
if ((rc = debug_init()))
return rc;
if ((rc = spl_kmem_init()))
SGOTO(out1, rc);
if ((rc = spl_mutex_init()))
SGOTO(out2, rc);
if ((rc = spl_rw_init()))
SGOTO(out3, rc);
if ((rc = spl_taskq_init()))
SGOTO(out4, rc);
if ((rc = vn_init()))
SGOTO(out5, rc);
if ((rc = proc_init()))
SGOTO(out6, rc);
if ((rc = kstat_init()))
SGOTO(out7, rc);
if ((rc = tsd_init()))
SGOTO(out8, rc);
if ((rc = set_hostid()))
SGOTO(out9, rc = -EADDRNOTAVAIL);
#ifndef HAVE_KALLSYMS_LOOKUP_NAME
if ((rc = set_kallsyms_lookup_name()))
SGOTO(out9, rc = -EADDRNOTAVAIL);
#endif /* HAVE_KALLSYMS_LOOKUP_NAME */
if ((rc = spl_kmem_init_kallsyms_lookup()))
SGOTO(out9, rc);
printk(KERN_NOTICE "SPL: Loaded Solaris Porting Layer v%s%s\n",
SPL_META_VERSION, SPL_DEBUG_STR);
SRETURN(rc);
out9:
tsd_fini();
out8:
kstat_fini();
out7:
proc_fini();
out6:
vn_fini();
out5:
spl_taskq_fini();
out4:
spl_rw_fini();
out3:
spl_mutex_fini();
out2:
spl_kmem_fini();
out1:
debug_fini();
printk(KERN_NOTICE "SPL: Failed to Load Solaris Porting Layer v%s%s"
", rc = %d\n", SPL_META_VERSION, SPL_DEBUG_STR, rc);
return rc;
}
static void
spl_fini(void)
{
SENTRY;
printk(KERN_NOTICE "SPL: Unloaded Solaris Porting Layer v%s%s\n",
SPL_META_VERSION, SPL_DEBUG_STR);
tsd_fini();
kstat_fini();
proc_fini();
vn_fini();
spl_taskq_fini();
spl_rw_fini();
spl_mutex_fini();
spl_kmem_fini();
debug_fini();
}
/* Called when a dependent module is loaded */
void
spl_setup(void)
{
int rc;
/*
* At module load time the pwd is set to '/' on a Solaris system.
* On a Linux system will be set to whatever directory the caller
* was in when executing insmod/modprobe.
*/
rc = vn_set_pwd("/");
if (rc)
printk("SPL: Warning unable to set pwd to '/': %d\n", rc);
}
EXPORT_SYMBOL(spl_setup);
/* Called when a dependent module is unloaded */
void
spl_cleanup(void)
{
}
EXPORT_SYMBOL(spl_cleanup);
module_init(spl_init);
module_exit(spl_fini);
MODULE_AUTHOR("Lawrence Livermore National Labs");
MODULE_DESCRIPTION("Solaris Porting Layer");
MODULE_LICENSE("GPL");
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