diff options
| author | Dr. David Alan Gilbert <dgilbert@redhat.com> | 2019-10-07 15:36:37 +0100 |
|---|---|---|
| committer | Dr. David Alan Gilbert <dgilbert@redhat.com> | 2019-10-11 14:19:49 +0100 |
| commit | 5626f8c6d46832b02ce4fdc0bd109516bc812043 (patch) | |
| tree | 1f5ebde7290eb695f62e050a047168cc5c745feb /docs | |
| parent | 8f8d528e73144c063deafc534df0a04c67f6f98e (diff) | |
rcu: Add automatically released rcu_read_lock variants
RCU_READ_LOCK_GUARD() takes the rcu_read_lock and then uses glib's
g_auto infrastructure (and thus whatever the compiler's hooks are) to
release it on all exits of the block.
WITH_RCU_READ_LOCK_GUARD() is similar but is used as a wrapper for the
lock, i.e.:
WITH_RCU_READ_LOCK_GUARD() {
stuff under lock
}
Note the 'unused' attribute is needed to work around clang bug:
https://bugs.llvm.org/show_bug.cgi?id=43482
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Message-Id: <20191007143642.301445-2-dgilbert@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Diffstat (limited to 'docs')
| -rw-r--r-- | docs/devel/rcu.txt | 16 |
1 files changed, 16 insertions, 0 deletions
diff --git a/docs/devel/rcu.txt b/docs/devel/rcu.txt index c84e7f42b2..d83fed2f79 100644 --- a/docs/devel/rcu.txt +++ b/docs/devel/rcu.txt @@ -187,6 +187,22 @@ The following APIs must be used before RCU is used in a thread: Note that these APIs are relatively heavyweight, and should _not_ be nested. +Convenience macros +================== + +Two macros are provided that automatically release the read lock at the +end of the scope. + + RCU_READ_LOCK_GUARD() + + Takes the lock and will release it at the end of the block it's + used in. + + WITH_RCU_READ_LOCK_GUARD() { code } + + Is used at the head of a block to protect the code within the block. + +Note that 'goto'ing out of the guarded block will also drop the lock. DIFFERENCES WITH LINUX ====================== |