net_dma: poll for a descriptor after allocation failure
Handle descriptor allocation failures by polling for a descriptor. The
driver will force forward progress when polled. In the best case this
polling interval will be the time it takes for one dma memcpy
transaction to complete. In the worst case, channel hang, we will need
to wait 100ms for the cleanup watchdog to fire (ioatdma driver).
Signed-off-by: Maciej Sosnowski <maciej.sosnowski@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
diff --git a/drivers/dma/iovlock.c b/drivers/dma/iovlock.c
index 9f6fe46..c0a272c7 100644
--- a/drivers/dma/iovlock.c
+++ b/drivers/dma/iovlock.c
@@ -183,6 +183,11 @@
iov_byte_offset,
kdata,
copy);
+ /* poll for a descriptor slot */
+ if (unlikely(dma_cookie < 0)) {
+ dma_async_issue_pending(chan);
+ continue;
+ }
len -= copy;
iov[iovec_idx].iov_len -= copy;
@@ -248,6 +253,11 @@
page,
offset,
copy);
+ /* poll for a descriptor slot */
+ if (unlikely(dma_cookie < 0)) {
+ dma_async_issue_pending(chan);
+ continue;
+ }
len -= copy;
iov[iovec_idx].iov_len -= copy;