FreeBSD/Linux Kernel Cross Reference
sys/contrib/openzfs/module/os/linux/spl/spl-generic.c

     /*
      *  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.
      *
     *  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/isa_defs.h>
    #include <sys/sysmacros.h>
    #include <sys/systeminfo.h>
    #include <sys/vmsystm.h>
    #include <sys/kmem.h>
    #include <sys/kmem_cache.h>
    #include <sys/vmem.h>
    #include <sys/mutex.h>
    #include <sys/rwlock.h>
    #include <sys/taskq.h>
    #include <sys/tsd.h>
    #include <sys/zmod.h>
    #include <sys/debug.h>
    #include <sys/proc.h>
    #include <sys/kstat.h>
    #include <sys/file.h>
    #include <sys/sunddi.h>
    #include <linux/ctype.h>
    #include <sys/disp.h>
    #include <sys/random.h>
    #include <sys/string.h>
    #include <linux/kmod.h>
    #include <linux/mod_compat.h>
    #include <sys/cred.h>
    #include <sys/vnode.h>
    #include <sys/misc.h>
    #include <linux/mod_compat.h>
    
    unsigned long spl_hostid = 0;
    EXPORT_SYMBOL(spl_hostid);
    
    /* CSTYLED */
    module_param(spl_hostid, ulong, 0644);
    MODULE_PARM_DESC(spl_hostid, "The system hostid.");
    
    proc_t p0;
    EXPORT_SYMBOL(p0);
    
    /*
     * xoshiro256++ 1.0 PRNG by David Blackman and Sebastiano Vigna
     *
     * "Scrambled Linear Pseudorandom Number Generators∗"
     * https://vigna.di.unimi.it/ftp/papers/ScrambledLinear.pdf
     *
     * random_get_pseudo_bytes() is an API function on Illumos whose sole purpose
     * is to provide bytes containing random numbers. It is mapped to /dev/urandom
     * on Illumos, which uses a "FIPS 186-2 algorithm". No user of the SPL's
     * random_get_pseudo_bytes() needs bytes that are of cryptographic quality, so
     * we can implement it using a fast PRNG that we seed using Linux' actual
     * equivalent to random_get_pseudo_bytes(). We do this by providing each CPU
     * with an independent seed so that all calls to random_get_pseudo_bytes() are
     * free of atomic instructions.
     *
     * A consequence of using a fast PRNG is that using random_get_pseudo_bytes()
     * to generate words larger than 256 bits will paradoxically be limited to
     * `2^256 - 1` possibilities. This is because we have a sequence of `2^256 - 1`
     * 256-bit words and selecting the first will implicitly select the second. If
     * a caller finds this behavior undesirable, random_get_bytes() should be used
     * instead.
     *
     * XXX: Linux interrupt handlers that trigger within the critical section
     * formed by `s[3] = xp[3];` and `xp[0] = s[0];` and call this function will
     * see the same numbers. Nothing in the code currently calls this in an
     * interrupt handler, so this is considered to be okay. If that becomes a
     * problem, we could create a set of per-cpu variables for interrupt handlers
     * and use them when in_interrupt() from linux/preempt_mask.h evaluates to
     * true.
     */
    static void __percpu *spl_pseudo_entropy;
    
    /*
     * rotl()/spl_rand_next()/spl_rand_jump() are copied from the following CC-0
     * licensed file:
     *
    * https://prng.di.unimi.it/xoshiro256plusplus.c
    */
   
   static inline uint64_t rotl(const uint64_t x, int k)
   {
           return ((x << k) | (x >> (64 - k)));
   }
   
   static inline uint64_t
   spl_rand_next(uint64_t *s)
   {
           const uint64_t result = rotl(s[0] + s[3], 23) + s[0];
   
           const uint64_t t = s[1] << 17;
   
           s[2] ^= s[0];
           s[3] ^= s[1];
           s[1] ^= s[2];
           s[0] ^= s[3];
   
           s[2] ^= t;
   
           s[3] = rotl(s[3], 45);
   
           return (result);
   }
   
   static inline void
   spl_rand_jump(uint64_t *s)
   {
           static const uint64_t JUMP[] = { 0x180ec6d33cfd0aba,
               0xd5a61266f0c9392c, 0xa9582618e03fc9aa, 0x39abdc4529b1661c };
   
           uint64_t s0 = 0;
           uint64_t s1 = 0;
           uint64_t s2 = 0;
           uint64_t s3 = 0;
           int i, b;
           for (i = 0; i < sizeof (JUMP) / sizeof (*JUMP); i++)
                   for (b = 0; b < 64; b++) {
                           if (JUMP[i] & 1ULL << b) {
                                   s0 ^= s[0];
                                   s1 ^= s[1];
                                   s2 ^= s[2];
                                   s3 ^= s[3];
                           }
                           (void) spl_rand_next(s);
                   }
   
           s[0] = s0;
           s[1] = s1;
           s[2] = s2;
           s[3] = s3;
   }
   
   int
   random_get_pseudo_bytes(uint8_t *ptr, size_t len)
   {
           uint64_t *xp, s[4];
   
           ASSERT(ptr);
   
           xp = get_cpu_ptr(spl_pseudo_entropy);
   
           s[0] = xp[0];
           s[1] = xp[1];
           s[2] = xp[2];
           s[3] = xp[3];
   
           while (len) {
                   union {
                           uint64_t ui64;
                           uint8_t byte[sizeof (uint64_t)];
                   }entropy;
                   int i = MIN(len, sizeof (uint64_t));
   
                   len -= i;
                   entropy.ui64 = spl_rand_next(s);
   
                   /*
                    * xoshiro256++ has low entropy lower bytes, so we copy the
                    * higher order bytes first.
                    */
                   while (i--)
   #ifdef _ZFS_BIG_ENDIAN
                           *ptr++ = entropy.byte[i];
   #else
                           *ptr++ = entropy.byte[7 - i];
   #endif
           }
   
           xp[0] = s[0];
           xp[1] = s[1];
           xp[2] = s[2];
           xp[3] = s[3];
   
           put_cpu_ptr(spl_pseudo_entropy);
   
           return (0);
   }
   
   
   EXPORT_SYMBOL(random_get_pseudo_bytes);
   
   #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 portability between kernel versions.
    */
   static inline uint64_t
   __div_u64(uint64_t u, uint32_t v)
   {
           (void) do_div(u, v);
           return (u);
   }
   
   /*
    * Turn off missing prototypes warning for these functions. They are
    * replacements for libgcc-provided functions and will never be called
    * directly.
    */
   #if defined(__GNUC__) && !defined(__clang__)
   #pragma GCC diagnostic push
   #pragma GCC diagnostic ignored "-Wmissing-prototypes"
   #endif
   
   /*
    * 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);
   
   #ifndef abs64
   /* CSTYLED */
   #define abs64(x)        ({ uint64_t t = (x) >> 63; ((x) ^ t) - t; })
   #endif
   
   /*
    * 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);
   
   /* 64-bit signed modulo for 32-bit machines. */
   int64_t
   __moddi3(int64_t n, int64_t d)
   {
           int64_t q;
           boolean_t nn = B_FALSE;
   
           if (n < 0) {
                   nn = B_TRUE;
                   n = -n;
           }
           if (d < 0)
                   d = -d;
   
           q = __umoddi3(n, d);
   
           return (nn ? -q : q);
   }
   EXPORT_SYMBOL(__moddi3);
   
   /*
    * Implementation of 64-bit unsigned division/modulo for 32-bit machines.
    */
   uint64_t
   __udivmoddi4(uint64_t n, uint64_t d, uint64_t *r)
   {
           uint64_t q = __udivdi3(n, d);
           if (r)
                   *r = n - d * q;
           return (q);
   }
   EXPORT_SYMBOL(__udivmoddi4);
   
   /*
    * Implementation of 64-bit signed division/modulo for 32-bit machines.
    */
   int64_t
   __divmoddi4(int64_t n, int64_t d, int64_t *r)
   {
           int64_t q, rr;
           boolean_t nn = B_FALSE;
           boolean_t nd = B_FALSE;
           if (n < 0) {
                   nn = B_TRUE;
                   n = -n;
           }
           if (d < 0) {
                   nd = B_TRUE;
                   d = -d;
           }
   
           q = __udivmoddi4(n, d, (uint64_t *)&rr);
   
           if (nn != nd)
                   q = -q;
           if (nn)
                   rr = -rr;
           if (r)
                   *r = rr;
           return (q);
   }
   EXPORT_SYMBOL(__divmoddi4);
   
   #if defined(__arm) || defined(__arm__)
   /*
    * Implementation of 64-bit (un)signed division for 32-bit arm machines.
    *
    * Run-time ABI for the ARM Architecture (page 20).  A pair of (unsigned)
    * long longs is returned in {{r0, r1}, {r2,r3}}, the quotient in {r0, r1},
    * and the remainder in {r2, r3}.  The return type is specifically left
    * set to 'void' to ensure the compiler does not overwrite these registers
    * during the return.  All results are in registers as per ABI
    */
   void
   __aeabi_uldivmod(uint64_t u, uint64_t v)
   {
           uint64_t res;
           uint64_t mod;
   
           res = __udivdi3(u, v);
           mod = __umoddi3(u, v);
           {
                   register uint32_t r0 asm("r0") = (res & 0xFFFFFFFF);
                   register uint32_t r1 asm("r1") = (res >> 32);
                   register uint32_t r2 asm("r2") = (mod & 0xFFFFFFFF);
                   register uint32_t r3 asm("r3") = (mod >> 32);
   
                   asm volatile(""
                       : "+r"(r0), "+r"(r1), "+r"(r2), "+r"(r3)  /* output */
                       : "r"(r0), "r"(r1), "r"(r2), "r"(r3));    /* input */
   
                   return; /* r0; */
           }
   }
   EXPORT_SYMBOL(__aeabi_uldivmod);
   
   void
   __aeabi_ldivmod(int64_t u, int64_t v)
   {
           int64_t res;
           uint64_t mod;
   
           res =  __divdi3(u, v);
           mod = __umoddi3(u, v);
           {
                   register uint32_t r0 asm("r0") = (res & 0xFFFFFFFF);
                   register uint32_t r1 asm("r1") = (res >> 32);
                   register uint32_t r2 asm("r2") = (mod & 0xFFFFFFFF);
                   register uint32_t r3 asm("r3") = (mod >> 32);
   
                   asm volatile(""
                       : "+r"(r0), "+r"(r1), "+r"(r2), "+r"(r3)  /* output */
                       : "r"(r0), "r"(r1), "r"(r2), "r"(r3));    /* input */
   
                   return; /* r0; */
           }
   }
   EXPORT_SYMBOL(__aeabi_ldivmod);
   #endif /* __arm || __arm__ */
   
   #if defined(__GNUC__) && !defined(__clang__)
   #pragma GCC diagnostic pop
   #endif
   
   #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_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_strtox(type, valtype)                                \
   int ddi_strto##type(const char *str, char **endptr,                     \
       int base, valtype *result)                                          \
   {                                                                       \
           valtype last_value, value = 0;                                  \
           char *ptr = (char *)str;                                        \
           int digit, minus = 0;                                           \
                                                                           \
           while (strchr(" \t\n\r\f", *ptr))                               \
                   ++ptr;                                                  \
                                                                           \
           if (strlen(ptr) == 0)                                           \
                   return (EINVAL);                                        \
                                                                           \
           switch (*ptr) {                                                 \
           case '-':                                                       \
                   minus = 1;                                              \
                   zfs_fallthrough;                                        \
           case '+':                                                       \
                   ++ptr;                                                  \
                   break;                                                  \
           }                                                               \
                                                                           \
           /* Auto-detect base based on prefix */                          \
           if (!base) {                                                    \
                   if (str[0] == '') {                                    \
                           if (tolower(str[1]) == 'x' && isxdigit(str[2])) { \
                                   base = 16; /* hex */                    \
                                   ptr += 2;                               \
                           } else if (str[1] >= '' && str[1] < 8) {       \
                                   base = 8; /* octal */                   \
                                   ptr += 1;                               \
                           } else {                                        \
                                   return (EINVAL);                        \
                           }                                               \
                   } else {                                                \
                           base = 10; /* decimal */                        \
                   }                                                       \
           }                                                               \
                                                                           \
           while (1) {                                                     \
                   if (isdigit(*ptr))                                      \
                           digit = *ptr - '';                             \
                   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);                                \
                                                                           \
                   ptr++;                                                  \
           }                                                               \
                                                                           \
           *result = minus ? -value : value;                               \
                                                                           \
           if (endptr)                                                     \
                   *endptr = ptr;                                          \
                                                                           \
           return (0);                                                     \
   }                                                                       \
   
   define_ddi_strtox(l, long)
   define_ddi_strtox(ull, unsigned long long)
   define_ddi_strtox(ll, long long)
   
   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);
   
   #define define_spl_param(type, fmt)                                     \
   int                                                                     \
   spl_param_get_##type(char *buf, zfs_kernel_param_t *kp)                 \
   {                                                                       \
           return (scnprintf(buf, PAGE_SIZE, fmt "\n",                     \
               *(type *)kp->arg));                                         \
   }                                                                       \
   int                                                                     \
   spl_param_set_##type(const char *buf, zfs_kernel_param_t *kp)           \
   {                                                                       \
           return (kstrto##type(buf, 0, (type *)kp->arg));                 \
   }                                                                       \
   const struct kernel_param_ops spl_param_ops_##type = {                  \
           .set = spl_param_set_##type,                                    \
           .get = spl_param_get_##type,                                    \
   };                                                                      \
   EXPORT_SYMBOL(spl_param_get_##type);                                    \
   EXPORT_SYMBOL(spl_param_set_##type);                                    \
   EXPORT_SYMBOL(spl_param_ops_##type);
   
   define_spl_param(s64, "%lld")
   define_spl_param(u64, "%llu")
   
   /*
    * Post a uevent to userspace whenever a new vdev adds to the pool. It is
    * necessary to sync blkid information with udev, which zed daemon uses
    * during device hotplug to identify the vdev.
    */
   void
   spl_signal_kobj_evt(struct block_device *bdev)
   {
   #if defined(HAVE_BDEV_KOBJ) || defined(HAVE_PART_TO_DEV)
   #ifdef HAVE_BDEV_KOBJ
           struct kobject *disk_kobj = bdev_kobj(bdev);
   #else
           struct kobject *disk_kobj = &part_to_dev(bdev->bd_part)->kobj;
   #endif
           if (disk_kobj) {
                   int ret = kobject_uevent(disk_kobj, KOBJ_CHANGE);
                   if (ret) {
                           pr_warn("ZFS: Sending event '%d' to kobject: '%s'"
                               " (%p): failed(ret:%d)\n", KOBJ_CHANGE,
                               kobject_name(disk_kobj), disk_kobj, ret);
                   }
           }
   #else
   /*
    * This is encountered if neither bdev_kobj() nor part_to_dev() is available
    * in the kernel - likely due to an API change that needs to be chased down.
    */
   #error "Unsupported kernel: unable to get struct kobj from bdev"
   #endif
   }
   EXPORT_SYMBOL(spl_signal_kobj_evt);
   
   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);
   
   static ssize_t
   spl_kernel_read(struct file *file, void *buf, size_t count, loff_t *pos)
   {
   #if defined(HAVE_KERNEL_READ_PPOS)
           return (kernel_read(file, buf, count, pos));
   #else
           mm_segment_t saved_fs;
           ssize_t ret;
   
           saved_fs = get_fs();
           set_fs(KERNEL_DS);
   
           ret = vfs_read(file, (void __user *)buf, count, pos);
   
           set_fs(saved_fs);
   
           return (ret);
   #endif
   }
   
   static int
   spl_getattr(struct file *filp, struct kstat *stat)
   {
           int rc;
   
           ASSERT(filp);
           ASSERT(stat);
   
   #if defined(HAVE_4ARGS_VFS_GETATTR)
           rc = vfs_getattr(&filp->f_path, stat, STATX_BASIC_STATS,
               AT_STATX_SYNC_AS_STAT);
   #elif defined(HAVE_2ARGS_VFS_GETATTR)
           rc = vfs_getattr(&filp->f_path, stat);
   #elif defined(HAVE_3ARGS_VFS_GETATTR)
           rc = vfs_getattr(filp->f_path.mnt, filp->f_dentry, stat);
   #else
   #error "No available vfs_getattr()"
   #endif
           if (rc)
                   return (-rc);
   
           return (0);
   }
   
   /*
    * Read the unique system identifier from the /etc/hostid file.
    *
    * The behavior of /usr/bin/hostid on Linux systems with the
    * regular eglibc and coreutils is:
    *
    *   1. Generate the value if the /etc/hostid file does not exist
    *      or if the /etc/hostid file is less than four bytes in size.
    *
    *   2. If the /etc/hostid file is at least 4 bytes, then return
    *      the first four bytes [0..3] in native endian order.
    *
    *   3. Always ignore bytes [4..] if they exist in the file.
    *
    * Only the first four bytes are significant, even on systems that
    * have a 64-bit word size.
    *
    * See:
    *
    *   eglibc: sysdeps/unix/sysv/linux/gethostid.c
    *   coreutils: src/hostid.c
    *
    * Notes:
    *
    * The /etc/hostid file on Solaris is a text file that often reads:
    *
    *   # DO NOT EDIT
    *   "0123456789"
    *
    * Directly copying this file to Linux results in a constant
    * hostid of 4f442023 because the default comment constitutes
    * the first four bytes of the file.
    *
    */
   
   static char *spl_hostid_path = HW_HOSTID_PATH;
   module_param(spl_hostid_path, charp, 0444);
   MODULE_PARM_DESC(spl_hostid_path, "The system hostid file (/etc/hostid)");
   
   static int
   hostid_read(uint32_t *hostid)
   {
           uint64_t size;
           uint32_t value = 0;
           int error;
           loff_t off;
           struct file *filp;
           struct kstat stat;
   
           filp = filp_open(spl_hostid_path, 0, 0);
   
           if (IS_ERR(filp))
                   return (ENOENT);
   
           error = spl_getattr(filp, &stat);
           if (error) {
                   filp_close(filp, 0);
                   return (error);
           }
           size = stat.size;
           // cppcheck-suppress sizeofwithnumericparameter
           if (size < sizeof (HW_HOSTID_MASK)) {
                   filp_close(filp, 0);
                   return (EINVAL);
           }
   
           off = 0;
           /*
            * Read directly into the variable like eglibc does.
            * Short reads are okay; native behavior is preserved.
            */
           error = spl_kernel_read(filp, &value, sizeof (value), &off);
           if (error < 0) {
                   filp_close(filp, 0);
                   return (EIO);
           }
   
           /* Mask down to 32 bits like coreutils does. */
           *hostid = (value & HW_HOSTID_MASK);
           filp_close(filp, 0);
   
           return (0);
   }
   
   /*
    * Return the system hostid.  Preferentially use the spl_hostid module option
    * when set, otherwise use the value in the /etc/hostid file.
    */
   uint32_t
   zone_get_hostid(void *zone)
   {
           uint32_t hostid;
   
           ASSERT3P(zone, ==, NULL);
   
           if (spl_hostid != 0)
                   return ((uint32_t)(spl_hostid & HW_HOSTID_MASK));
   
           if (hostid_read(&hostid) == 0)
                   return (hostid);
   
           return (0);
   }
   EXPORT_SYMBOL(zone_get_hostid);
   
   static int
   spl_kvmem_init(void)
   {
           int rc = 0;
   
           rc = spl_kmem_init();
           if (rc)
                   return (rc);
   
           rc = spl_vmem_init();
           if (rc) {
                   spl_kmem_fini();
                   return (rc);
           }
   
           return (rc);
   }
   
   /*
    * We initialize the random number generator with 128 bits of entropy from the
    * system random number generator. In the improbable case that we have a zero
    * seed, we fallback to the system jiffies, unless it is also zero, in which
    * situation we use a preprogrammed seed. We step forward by 2^64 iterations to
    * initialize each of the per-cpu seeds so that the sequences generated on each
    * CPU are guaranteed to never overlap in practice.
    */
   static int __init
   spl_random_init(void)
   {
           uint64_t s[4];
           int i = 0;
   
           spl_pseudo_entropy = __alloc_percpu(4 * sizeof (uint64_t),
               sizeof (uint64_t));
   
           if (!spl_pseudo_entropy)
                   return (-ENOMEM);
   
           get_random_bytes(s, sizeof (s));
   
           if (s[0] == 0 && s[1] == 0 && s[2] == 0 && s[3] == 0) {
                   if (jiffies != 0) {
                           s[0] = jiffies;
                           s[1] = ~0 - jiffies;
                           s[2] = ~jiffies;
                           s[3] = jiffies - ~0;
                   } else {
                           (void) memcpy(s, "improbable seed", 16);
                   }
                   printk("SPL: get_random_bytes() returned 0 "
                       "when generating random seed. Setting initial seed to "
                       "0x%016llx%016llx%016llx%016llx.\n", cpu_to_be64(s[0]),
                       cpu_to_be64(s[1]), cpu_to_be64(s[2]), cpu_to_be64(s[3]));
           }
   
           for_each_possible_cpu(i) {
                   uint64_t *wordp = per_cpu_ptr(spl_pseudo_entropy, i);
   
                   spl_rand_jump(s);
   
                   wordp[0] = s[0];
                   wordp[1] = s[1];
                   wordp[2] = s[2];
                   wordp[3] = s[3];
           }
   
           return (0);
   }
   
   static void
   spl_random_fini(void)
   {
           free_percpu(spl_pseudo_entropy);
   }
   
   static void
   spl_kvmem_fini(void)
   {
           spl_vmem_fini();
           spl_kmem_fini();
   }
   
   static int __init
   spl_init(void)
   {
           int rc = 0;
   
           if ((rc = spl_random_init()))
                   goto out0;
   
           if ((rc = spl_kvmem_init()))
                   goto out1;
   
           if ((rc = spl_tsd_init()))
                   goto out2;
   
           if ((rc = spl_taskq_init()))
                   goto out3;
   
           if ((rc = spl_kmem_cache_init()))
                   goto out4;
   
           if ((rc = spl_proc_init()))
                   goto out5;
   
           if ((rc = spl_kstat_init()))
                   goto out6;
   
           if ((rc = spl_zlib_init()))
                   goto out7;
   
           if ((rc = spl_zone_init()))
                   goto out8;
   
           return (rc);
   
   out8:
           spl_zlib_fini();
   out7:
           spl_kstat_fini();
   out6:
           spl_proc_fini();
   out5:
           spl_kmem_cache_fini();
   out4:
           spl_taskq_fini();
   out3:
           spl_tsd_fini();
   out2:
           spl_kvmem_fini();
   out1:
           spl_random_fini();
   out0:
           return (rc);
   }
   
   static void __exit
   spl_fini(void)
   {
           spl_zone_fini();
           spl_zlib_fini();
           spl_kstat_fini();
           spl_proc_fini();
           spl_kmem_cache_fini();
           spl_taskq_fini();
           spl_tsd_fini();
           spl_kvmem_fini();
           spl_random_fini();
   }
   
   module_init(spl_init);
   module_exit(spl_fini);
   
   MODULE_DESCRIPTION("Solaris Porting Layer");
   MODULE_AUTHOR(ZFS_META_AUTHOR);
   MODULE_LICENSE("GPL");
   MODULE_VERSION(ZFS_META_VERSION "-" ZFS_META_RELEASE);

Cache object: 9708ca51771cf407f7022c7d5964467b