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Code Issues Releases Activity

Remove the global cdev hash and use the cdevsw list instead.

Browse Source 
Don't remove the now unused element from cdev yet, wait until
we have a better reason to bump the version.
This commit is contained in:
Poul-Henning Kamp 2005-03-29 09:56:21 +00:00
parent 52baed478a
commit ff7284eeb4
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=144281
2 changed files with 10 additions and 38 deletions
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46
sys/kern/kern_conf.c
View File

@ -49,18 +49,8 @@ static MALLOC_DEFINE(M_DEVT, "cdev", "cdev storage");
/* Built at compile time from sys/conf/majors */
extern unsigned char reserved_majors[256];
/*
* This is the number of hash-buckets. Experiments with 'real-life'
* dev_t's show that a prime halfway between two powers of two works
* best.
*/
#define DEVT_HASH 83
static LIST_HEAD(, cdev) dev_hash[DEVT_HASH];
static struct mtx devmtx;
static void freedev(struct cdev *dev);
static struct cdev *newdev(int x, int y, struct cdev *);
static void destroy_devl(struct cdev *dev);
void
@ -234,14 +224,6 @@ no_poll(struct cdev *dev __unused, int events, struct thread *td __unused)
* struct cdev * and u_dev_t primitives
*/
static int
major(struct cdev *x)
{
if (x == NULL)
return NODEV;
return((x->si_drv0 >> 8) & 0xff);
}
int
minor(struct cdev *x)
{
@ -288,25 +270,21 @@ allocdev(void)
}
static struct cdev *
newdev(int x, int y, struct cdev *si)
newdev(struct cdevsw *csw, int y, struct cdev *si)
{
struct cdev *si2;
dev_t udev;
int hash;
mtx_assert(&devmtx, MA_OWNED);
if (x == umajor(NODEV) && y == uminor(NODEV))
panic("newdev of NODEV");
udev = (x << 8) | y;
hash = udev % DEVT_HASH;
LIST_FOREACH(si2, &dev_hash[hash], si_hash) {
udev = (csw->d_maj << 8) | y;
LIST_FOREACH(si2, &csw->d_devs, si_list) {
if (si2->si_drv0 == udev) {
freedev(si);
return (si2);
}
}
si->si_drv0 = udev;
LIST_INSERT_HEAD(&dev_hash[hash], si, si_hash);
LIST_INSERT_HEAD(&csw->d_devs, si, si_list);
return (si);
}
@ -430,7 +408,7 @@ make_dev(struct cdevsw *devsw, int minornr, uid_t uid, gid_t gid, int perms, con
}
dev = allocdev();
dev_lock();
dev = newdev(devsw->d_maj, minornr, dev);
dev = newdev(devsw, minornr, dev);
if (dev->si_flags & SI_CHEAPCLONE &&
dev->si_flags & SI_NAMED &&
dev->si_devsw == devsw) {
@ -443,8 +421,8 @@ make_dev(struct cdevsw *devsw, int minornr, uid_t uid, gid_t gid, int perms, con
return (dev);
}
KASSERT(!(dev->si_flags & SI_NAMED),
("make_dev() by driver %s on pre-existing device (maj=%d, min=%x, name=%s)",
devsw->d_name, major(dev), minor(dev), devtoname(dev)));
("make_dev() by driver %s on pre-existing device (min=%x, name=%s)",
devsw->d_name, minor(dev), devtoname(dev)));
va_start(ap, fmt);
i = vsnrprintf(dev->__si_namebuf, sizeof dev->__si_namebuf, 32, fmt, ap);
@ -457,7 +435,6 @@ make_dev(struct cdevsw *devsw, int minornr, uid_t uid, gid_t gid, int perms, con
dev->si_devsw = devsw;
dev->si_flags |= SI_NAMED;
LIST_INSERT_HEAD(&devsw->d_devs, dev, si_list);
devfs_create(dev);
dev_unlock();
return (dev);
@ -519,8 +496,7 @@ destroy_devl(struct cdev *dev)
mtx_assert(&devmtx, MA_OWNED);
KASSERT(dev->si_flags & SI_NAMED,
("WARNING: Driver mistake: destroy_dev on %d/%d\n",
major(dev), minor(dev)));
("WARNING: Driver mistake: destroy_dev on %d\n", minor(dev)));
devfs_destroy(dev);
@ -565,8 +541,6 @@ destroy_devl(struct cdev *dev)
/* If cdevsw has no struct cdev *'s, clean it */
if (LIST_EMPTY(&csw->d_devs))
fini_cdevsw(csw);
LIST_REMOVE(dev, si_hash);
}
dev->si_flags &= ~SI_ALIAS;
@ -595,8 +569,6 @@ devtoname(struct cdev *dev)
if (dev->si_name[0] == '#' || dev->si_name[0] == '\0') {
p = dev->si_name;
sprintf(p, "#%d", major(dev));
p += strlen(p);
csw = dev_refthread(dev);
if (csw != NULL) {
sprintf(p, "(%s)", csw->d_name);
@ -721,7 +693,7 @@ clone_create(struct clonedevs **cdp, struct cdevsw *csw, int *up, struct cdev **
}
if (unit == -1)
unit = low & CLONE_UNITMASK;
dev = newdev(csw->d_maj, unit2minor(unit | extra), ndev);
dev = newdev(csw, unit2minor(unit | extra), ndev);
if (dev->si_flags & SI_CLONELIST) {
printf("dev %p (%s) is on clonelist\n", dev, dev->si_name);
printf("unit=%d\n", unit);

2
sys/sys/conf.h
View File

@ -69,7 +69,7 @@ struct cdev {
int si_refcount;
LIST_ENTRY(cdev) si_list;
LIST_ENTRY(cdev) si_clone;
LIST_ENTRY(cdev) si_hash;
LIST_ENTRY(cdev) si_hash; /* UNUSED */
LIST_HEAD(,devfs_dirent)si_alist;
LIST_HEAD(, cdev) si_children;
LIST_ENTRY(cdev) si_siblings;