return -1;
}
/* Write to the ring buffer */
nextWriteLocation = GetNextWriteLocation(OutRingInfo);
for_each_sg(sglist, sg, sgcount, i)
{
nextWriteLocation = CopyToRingBuffer(OutRingInfo,
nextWriteLocation,
sg_virt(sg),
sg->length);
}
/* Set previous packet start */
prevIndices = GetRingBufferIndices(OutRingInfo);
nextWriteLocation = CopyToRingBuffer(OutRingInfo,
nextWriteLocation,
&prevIndices,
sizeof(u64));
/* Make sure we flush all writes before updating the writeIndex */
mb();
/* Now, update the write location */
SetNextWriteLocation(OutRingInfo, nextWriteLocation);
/* DumpRingInfo(OutRingInfo, "AFTER "); */
spin_unlock_irqrestore(&OutRingInfo->ring_lock, flags);
/*++
Name:
RingBufferWrite()
Description:
Write to the ring buffer
--*/
int
RingBufferWrite(
RING_BUFFER_INFO* OutRingInfo,
SG_BUFFER_LIST SgBuffers[],
UINT32 SgBufferCount
)
{
int i=0;
UINT32 byteAvailToWrite;
UINT32 byteAvailToRead;
UINT32 totalBytesToWrite=0;
volatile UINT32 nextWriteLocation;
UINT64 prevIndices=0;
DPRINT_ENTER(VMBUS);
for (i=0; i < SgBufferCount; i++)
{
totalBytesToWrite += SgBuffers[i].Length;
}
totalBytesToWrite += sizeof(UINT64);
SpinlockAcquire(OutRingInfo->RingLock);
GetRingBufferAvailBytes(OutRingInfo, &byteAvailToRead, &byteAvailToWrite);
DPRINT_DBG(VMBUS, "Writing %u bytes...", totalBytesToWrite);
//DumpRingInfo(OutRingInfo, "BEFORE ");
// If there is only room for the packet, assume it is full. Otherwise, the next time around, we think the ring buffer
// is empty since the read index == write index
if (byteAvailToWrite <= totalBytesToWrite)
{
DPRINT_DBG(VMBUS, "No more space left on outbound ring buffer (needed %u, avail %u)", totalBytesToWrite, byteAvailToWrite);
SpinlockRelease(OutRingInfo->RingLock);
DPRINT_EXIT(VMBUS);
return -1;
}
// Write to the ring buffer
nextWriteLocation = GetNextWriteLocation(OutRingInfo);
for (i=0; i < SgBufferCount; i++)
{
nextWriteLocation = CopyToRingBuffer(OutRingInfo,
nextWriteLocation,
SgBuffers[i].Data,
SgBuffers[i].Length);
}
// Set previous packet start
prevIndices = GetRingBufferIndices(OutRingInfo);
nextWriteLocation = CopyToRingBuffer(OutRingInfo,
nextWriteLocation,
&prevIndices,
sizeof(UINT64));
// Make sure we flush all writes before updating the writeIndex
MemoryFence();
// Now, update the write location
SetNextWriteLocation(OutRingInfo, nextWriteLocation);
//DumpRingInfo(OutRingInfo, "AFTER ");
SpinlockRelease(OutRingInfo->RingLock);
DPRINT_EXIT(VMBUS);
return 0;
}
