d/freebsd-dev
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

subr_hints: simplify a little bit

Browse Source 
Some complexity exists in these bits that isn't needed. The sysctl handler,
upon change to '2', runs through the current set of hints and sets them in
the kenv.

However, this isn't at all necessary if we're pulling hints from the kenv,
static or dynamic, as the former will get added to the latter in
init_dynamic_kenv (see: kern_environment.c). We can reduce this
configuration to just adding static_hints to the kenv if we were previously
using them.

The changes in res_find are minimal and based on the observation that once
use_kenv gets set to '1' it will never be reset to '0', and it gets set to
'1' as soon as we hit fallback mode. Later work will refactor res_find a
little bit and eliminate this now-local, because it's become clear that
there's some funkiness revolving around use_kenv=1 and it being used to
imply that we're certainly looking at the dynamic_kenv.

Reviewed by:	ray
MFC after:	2 weeks
Differential Revision:	https://reviews.freebsd.org/D15940
This commit is contained in:
Kyle Evans 2018-06-21 14:04:02 +00:00
parent c43e3c8659
commit 770488d202
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=335479
1 changed files with 24 additions and 38 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

62
sys/kern/subr_hints.c
View File

@ -37,12 +37,15 @@ __FBSDID("$FreeBSD$");
#include <sys/systm.h>
#include <sys/bus.h>
#define HINTMODE_KENV 0
#define HINTMODE_STATIC 1
#define HINTMODE_FALLBACK 2
/*
* Access functions for device resources.
*/
static int checkmethod = 1;
static int use_kenv;
static char *hintp;
/*
@ -56,10 +59,8 @@ sysctl_hintmode(SYSCTL_HANDLER_ARGS)
{
const char *cp;
char *line, *eq;
int eqidx, error, from_kenv, i, value;
int eqidx, error, i, value;
from_kenv = 0;
cp = kern_envp;
value = hintmode;
/* Fetch candidate for new hintmode value */
@ -67,47 +68,33 @@ sysctl_hintmode(SYSCTL_HANDLER_ARGS)
if (error || req->newptr == NULL)
return (error);
if (value != 2)
if (value != HINTMODE_FALLBACK)
/* Only accept swithing to hintmode 2 */
return (EINVAL);
/* Migrate from static to dynamic hints */
switch (hintmode) {
case 0:
if (dynamic_kenv) {
/*
* Already here. But assign hintmode to 2, to not
* check it in the future.
*/
hintmode = 2;
return (0);
}
from_kenv = 1;
cp = kern_envp;
break;
case 1:
cp = static_hints;
break;
case 2:
/* Nothing to do, hintmode already 2 */
/*
* The rest of the sysctl handler is just making sure that our
* environment is consistent with the world we've already seen.
* If we came from kenv at all, then we have nothing to do: static
* kenv will get merged into dynamic kenv as soon as kmem becomes
* available, dynamic kenv is the environment we'd be setting these
* things in anyways. Therefore, we have nothing left to do unless
* we came from a static hints configuration.
*/
if (hintmode != HINTMODE_STATIC) {
hintmode = value;
return (0);
}
while (cp) {
i = strlen(cp);
if (i == 0)
break;
if (from_kenv) {
if (strncmp(cp, "hint.", 5) != 0)
/* kenv can have not only hints */
continue;
}
cp = static_hints;
while (cp && *cp != '\0') {
eq = strchr(cp, '=');
if (eq == NULL)
/* Bad hint value */
continue;
eqidx = eq - cp;
i = strlen(cp);
line = malloc(i+1, M_TEMP, M_WAITOK);
strcpy(line, cp);
line[eqidx] = '\0';
@ -117,7 +104,6 @@ sysctl_hintmode(SYSCTL_HANDLER_ARGS)
}
hintmode = value;
use_kenv = 1;
return (0);
}
@ -137,7 +123,7 @@ res_find(int *line, int *startln,
{
int n = 0, hit, i = 0;
char r_name[32];
int r_unit;
int r_unit, use_kenv = (hintmode == HINTMODE_FALLBACK);
char r_resname[32];
char r_value[128];
const char *s, *cp;
@ -147,13 +133,13 @@ res_find(int *line, int *startln,
hintp = NULL;
switch (hintmode) {
case 0: /* loader hints in environment only */
case HINTMODE_KENV: /* loader hints in environment only */
break;
case 1: /* static hints only */
case HINTMODE_STATIC: /* static hints only */
hintp = static_hints;
checkmethod = 0;
break;
case 2: /* fallback mode */
case HINTMODE_FALLBACK: /* fallback mode */
if (dynamic_kenv) {
mtx_lock(&kenv_lock);
cp = kenvp[0];