dmaengine: provide a common 'issue_pending_all' implementation

async_tx and net_dma each have open-coded versions of issue_pending_all,
so provide a common routine in dmaengine.

The implementation needs to walk the global device list, so implement
rcu to allow dma_issue_pending_all to run lockless.  Clients protect
themselves from channel removal events by holding a dmaengine reference.

Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

1 files changed, 1 insertions, 8 deletions

diff --git a/net/core/dev.c b/net/core/dev.c
index 09c66a449da6..e40b0d57f8ff 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -2635,14 +2635,7 @@ out:
          * There may not be any more sk_buffs coming right now, so push
          * any pending DMA copies to hardware
          */
-        if (!cpus_empty(net_dma.channel_mask)) {
-                int chan_idx;
-                for_each_cpu_mask_nr(chan_idx, net_dma.channel_mask) {
-                        struct dma_chan *chan = net_dma.channels[chan_idx];
-                        if (chan)
-                                dma_async_memcpy_issue_pending(chan);
-                }
-        }
+        dma_issue_pending_all();
 #endif
 
         return;