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hyperv/vmbus: Add a simplified version of channel close.

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So that the caller can know the channel close error and react accordingly.

MFC after:	1 week
Sponsored by:	Microsoft
Differential Revision:	https://reviews.freebsd.org/D8600
This commit is contained in:
Sepherosa Ziehau 2016-11-25 09:13:10 +00:00
parent 892b35bc36
commit 2641e75742
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=309140
2 changed files with 55 additions and 0 deletions
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20
sys/dev/hyperv/include/vmbus.h
View File

@ -131,6 +131,7 @@ vmbus_get_channel(device_t dev)
/*
* vmbus_chan_open_br()
*
* Return values:
* 0 Succeeded.
* EISCONN Failed, and the memory passed through 'br' is still
@ -139,6 +140,24 @@ vmbus_get_channel(device_t dev)
* other values Failed. The memory passed through 'br' is no longer
* connected. Callers are free to do anything with the
* memory passed through 'br'.
*
*
*
* vmbus_chan_close_direct()
*
* NOTE:
* Callers of this function _must_ make sure to close all sub-channels before
* closing the primary channel.
*
* Return values:
* 0 Succeeded.
* EISCONN Failed, and the memory associated with the bufring
* is still connected. Callers must _not_ free the the
* memory associated with the bufring, if this error
* happens.
* other values Failed. The memory associated with the bufring is
* no longer connected. Callers are free to do anything
* with the memory associated with the bufring.
*/
int vmbus_chan_open(struct vmbus_channel *chan,
int txbr_size, int rxbr_size, const void *udata, int udlen,
@ -147,6 +166,7 @@ int vmbus_chan_open_br(struct vmbus_channel *chan,
const struct vmbus_chan_br *cbr, const void *udata,
int udlen, vmbus_chan_callback_t cb, void *cbarg);
void vmbus_chan_close(struct vmbus_channel *chan);
int vmbus_chan_close_direct(struct vmbus_channel *chan);
void vmbus_chan_intr_drain(struct vmbus_channel *chan);
void vmbus_chan_run_task(struct vmbus_channel *chan,
struct task *task);

35
sys/dev/hyperv/vmbus/vmbus_chan.c
View File

@ -851,6 +851,41 @@ vmbus_chan_close_internal(struct vmbus_channel *chan)
return (error);
}
int
vmbus_chan_close_direct(struct vmbus_channel *chan)
{
int error;
#ifdef INVARIANTS
if (VMBUS_CHAN_ISPRIMARY(chan)) {
struct vmbus_channel *subchan;
/*
* All sub-channels _must_ have been closed, or are _not_
* opened at all.
*/
mtx_lock(&chan->ch_subchan_lock);
TAILQ_FOREACH(subchan, &chan->ch_subchans, ch_sublink) {
KASSERT(
(subchan->ch_stflags & VMBUS_CHAN_ST_OPENED) == 0,
("chan%u: subchan%u is still opened",
chan->ch_id, subchan->ch_subidx));
}
mtx_unlock(&chan->ch_subchan_lock);
}
#endif
error = vmbus_chan_close_internal(chan);
if (!VMBUS_CHAN_ISPRIMARY(chan)) {
/*
* This sub-channel is referenced, when it is linked to
* the primary channel; drop that reference now.
*/
vmbus_chan_detach(chan);
}
return (error);
}
/*
* Caller should make sure that all sub-channels have
* been added to 'chan' and all to-be-closed channels