Module: xenomai-2.5
Branch: master
Commit: d0b4bb3f4ec669ac0b82b64cde811f90b02d2288
URL:
http://git.xenomai.org/?p=xenomai-2.5.git;a=commit;h=d0b4bb3f4ec669ac0b82b64cde811f90b02d2288
Author: Philippe Gerum <r...@xenomai.org>
Date: Mon Mar 29 10:42:36 2010 +0200
rtipc/bufp: reset buffer descriptor upon r/w preemption
In order to perform data copy while reading/writing data from/to a
buffer descriptor in a lockless manner, we rely on a control token for
detecting any preemption that shall lead to invalidating the current
buffer, before redoing the data acquisition.
Make sure to reset the buffer descriptor appropriately, before redoing
the acquisition, so that the old contents are discarded.
---
ksrc/drivers/ipc/bufp.c | 8 ++++++--
1 files changed, 6 insertions(+), 2 deletions(-)
diff --git a/ksrc/drivers/ipc/bufp.c b/ksrc/drivers/ipc/bufp.c
index 04b3209..7517b79 100644
--- a/ksrc/drivers/ipc/bufp.c
+++ b/ksrc/drivers/ipc/bufp.c
@@ -220,8 +220,10 @@ redo:
* the message, we have to re-read the whole
* thing.
*/
- if (sk->rdtoken != rdtoken)
+ if (sk->rdtoken != rdtoken) {
+ xnbufd_reset(bufd);
goto redo;
+ }
rdoff = (rdoff + n) % sk->bufsz;
rbytes -= n;
@@ -465,8 +467,10 @@ redo:
* message, we have to write the whole thing
* again.
*/
- if (rsk->wrtoken != wrtoken)
+ if (rsk->wrtoken != wrtoken) {
+ xnbufd_reset(bufd);
goto redo;
+ }
wroff = (wroff + n) % rsk->bufsz;
wbytes -= n;
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