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author | Marko Zec <zec@FreeBSD.org> | 2009-05-05 10:56:12 +0000 |
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committer | Marko Zec <zec@FreeBSD.org> | 2009-05-05 10:56:12 +0000 |
commit | 21ca7b57bd9be4aa0b7f4e8d2fb62075319086b6 (patch) | |
tree | 79a0bccccf2c92504cdf23ad15f7c1813bb3f926 /sys/kern/kern_fork.c | |
parent | 49939083a0543593d9c2729c7d5a835cfb0ac2dd (diff) | |
download | src-21ca7b57bd9be4aa0b7f4e8d2fb62075319086b6.tar.gz src-21ca7b57bd9be4aa0b7f4e8d2fb62075319086b6.zip |
Change the curvnet variable from a global const struct vnet *,
previously always pointing to the default vnet context, to a
dynamically changing thread-local one. The currvnet context
should be set on entry to networking code via CURVNET_SET() macros,
and reverted to previous state via CURVNET_RESTORE(). Recursions
on curvnet are permitted, though strongly discuouraged.
This change should have no functional impact on nooptions VIMAGE
kernel builds, where CURVNET_* macros expand to whitespace.
The curthread->td_vnet (aka curvnet) variable's purpose is to be an
indicator of the vnet context in which the current network-related
operation takes place, in case we cannot deduce the current vnet
context from any other source, such as by looking at mbuf's
m->m_pkthdr.rcvif->if_vnet, sockets's so->so_vnet etc. Moreover, so
far curvnet has turned out to be an invaluable consistency checking
aid: it helps to catch cases when sockets, ifnets or any other
vnet-aware structures may have leaked from one vnet to another.
The exact placement of the CURVNET_SET() / CURVNET_RESTORE() macros
was a result of an empirical iterative process, whith an aim to
reduce recursions on CURVNET_SET() to a minimum, while still reducing
the scope of CURVNET_SET() to networking only operations - the
alternative would be calling CURVNET_SET() on each system call entry.
In general, curvnet has to be set in three typicall cases: when
processing socket-related requests from userspace or from within the
kernel; when processing inbound traffic flowing from device drivers
to upper layers of the networking stack, and when executing
timer-driven networking functions.
This change also introduces a DDB subcommand to show the list of all
vnet instances.
Approved by: julian (mentor)
Notes
Notes:
svn path=/head/; revision=191816
Diffstat (limited to 'sys/kern/kern_fork.c')
-rw-r--r-- | sys/kern/kern_fork.c | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/sys/kern/kern_fork.c b/sys/kern/kern_fork.c index e7e98b17b15b..76695e711713 100644 --- a/sys/kern/kern_fork.c +++ b/sys/kern/kern_fork.c @@ -68,6 +68,7 @@ __FBSDID("$FreeBSD$"); #include <sys/sdt.h> #include <sys/sx.h> #include <sys/signalvar.h> +#include <sys/vimage.h> #include <security/audit/audit.h> #include <security/mac/mac_framework.h> @@ -523,6 +524,11 @@ again: td2->td_sigmask = td->td_sigmask; td2->td_flags = TDF_INMEM; +#ifdef VIMAGE + td2->td_vnet = NULL; + td2->td_vnet_lpush = NULL; +#endif + /* * Duplicate sub-structures as needed. * Increase reference counts on shared objects. |