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Index: head/share/man/man9/hashinit.9
===================================================================
--- head/share/man/man9/hashinit.9
+++ head/share/man/man9/hashinit.9
@@ -25,11 +25,11 @@
.\"
.\" $FreeBSD$
.\"
-.Dd January 23, 2016
+.Dd April 29, 2016
.Dt HASHINIT 9
.Os
.Sh NAME
-.Nm hashinit , hashinit_flags , hashdestroy , phashinit
+.Nm hashinit , hashinit_flags , hashdestroy , phashinit , phashinit_flags
.Nd manage kernel hash tables
.Sh SYNOPSIS
.In sys/malloc.h
@@ -45,12 +45,14 @@
.Fn hashdestroy "void *hashtbl" "struct malloc_type *type" "u_long hashmask"
.Ft "void *"
.Fn phashinit "int nelements" "struct malloc_type *type" "u_long *nentries"
+.Fn phashinit_flags "int nelements" "struct malloc_type *type" "u_long *nentries" "int flags"
.Sh DESCRIPTION
The
.Fn hashinit ,
-.Fn hashinit_flags
-and
+.Fn hashinit_flags ,
.Fn phashinit
+and
+.Fn phashinit_flags
functions allocate space for hash tables of size given by the argument
.Fa nelements .
.Pp
@@ -71,6 +73,12 @@
but also accepts an additional argument
.Fa flags
which control various options during allocation.
+.Fn phashinit_flags
+function operates like
+.Fn phashinit
+but also accepts an additional argument
+.Fa flags
+which control various options during allocation.
Allocated hash tables are contiguous arrays of
.Xr LIST_HEAD 3
entries, allocated using
@@ -100,13 +108,19 @@
.It Dv HASH_NOWAIT
Any malloc performed by the
.Fn hashinit_flags
+and
+.Fn phashinit_flags
function will not be allowed to wait, and therefore may fail.
.It Dv HASH_WAITOK
Any malloc performed by
.Fn hashinit_flags
+and
+.Fn phashinit_flags
function is allowed to wait for memory.
This is also the behavior of
-.Fn hashinit .
+.Fn hashinit
+and
+.Fn phashinit .
.El
.Sh IMPLEMENTATION NOTES
The largest prime hash value chosen by
Index: head/sys/kern/subr_hash.c
===================================================================
--- head/sys/kern/subr_hash.c
+++ head/sys/kern/subr_hash.c
@@ -104,16 +104,21 @@
#define NPRIMES nitems(primes)
/*
- * General routine to allocate a prime number sized hash table.
+ * General routine to allocate a prime number sized hash table with control of
+ * memory flags.
*/
void *
-phashinit(int elements, struct malloc_type *type, u_long *nentries)
+phashinit_flags(int elements, struct malloc_type *type, u_long *nentries, int flags)
{
long hashsize;
LIST_HEAD(generic, generic) *hashtbl;
- int i;
+ int i, m_flags;
KASSERT(elements > 0, ("%s: bad elements", __func__));
+ /* Exactly one of HASH_WAITOK and HASH_NOWAIT must be set. */
+ KASSERT((flags & HASH_WAITOK) ^ (flags & HASH_NOWAIT),
+ ("Bad flags (0x%x) passed to phashinit_flags", flags));
+
for (i = 1, hashsize = primes[1]; hashsize <= elements;) {
i++;
if (i == NPRIMES)
@@ -121,9 +126,25 @@
hashsize = primes[i];
}
hashsize = primes[i - 1];
- hashtbl = malloc((u_long)hashsize * sizeof(*hashtbl), type, M_WAITOK);
+
+ m_flags = (flags & HASH_NOWAIT) ? M_NOWAIT : M_WAITOK;
+ hashtbl = malloc((u_long)hashsize * sizeof(*hashtbl), type, m_flags);
+ if (hashtbl == NULL)
+ return (NULL);
+
for (i = 0; i < hashsize; i++)
LIST_INIT(&hashtbl[i]);
*nentries = hashsize;
return (hashtbl);
}
+
+/*
+ * Allocate and initialize a prime number sized hash table with default flag:
+ * may sleep.
+ */
+void *
+phashinit(int elements, struct malloc_type *type, u_long *nentries)
+{
+
+ return (phashinit_flags(elements, type, nentries, HASH_WAITOK));
+}
Index: head/sys/sys/systm.h
===================================================================
--- head/sys/sys/systm.h
+++ head/sys/sys/systm.h
@@ -189,6 +189,8 @@
#define HASH_WAITOK 0x00000002
void *phashinit(int count, struct malloc_type *type, u_long *nentries);
+void *phashinit_flags(int count, struct malloc_type *type, u_long *nentries,
+ int flags);
void g_waitidle(void);
void panic(const char *, ...) __dead2 __printflike(1, 2);

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