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Document MAKEDEV_ETERNAL.

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MFC after:	3 days
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Konstantin Belousov 2010-09-05 14:47:46 +00:00
parent 52129fcd78
commit 5e9cd1dbf8
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15
share/man/man9/make_dev.9
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@ -24,7 +24,7 @@
.\"
.\" $FreeBSD$
.\"
.Dd May 6, 2010
.Dd September 5, 2010
.Dt MAKE_DEV 9
.Os
.Sh NAME
@ -135,6 +135,7 @@ The following values are currently accepted:
MAKEDEV_REF reference the created device
MAKEDEV_NOWAIT do not sleep, may return NULL
MAKEDEV_WAITOK allow the function to sleep to satisfy malloc
MAKEDEV_ETERNAL created device will be never destroyed
.Ed
.Pp
The
@ -154,6 +155,18 @@ the device created is destroyed immediately after
drops his reference to cdev.
.Pp
The
.Dv MAKEDEV_ETERNAL
flag allows the kernel to not acquire some locks when translating system
calls into the cdevsw methods calls.
It is responsibility of the driver author to make sure that
.Fn destroy_dev
is never called on the returned cdev.
For the convenience, use the
.Dv MAKEDEV_ETERNAL_KLD
flag for the code that can be compiled into kernel or loaded
(and unloaded) as loadable module.
.Pp
The
.Fn make_dev_cred
function is equivalent to the call
.Bd -literal -offset indent