Add locking to Driver

Author: PascalBoeschoten

src/Driver.cxx

@@ -9,6 +9,7 @@
 #include <Common/System.h>
 #include <InfoLogger/InfoLogger.hxx>
 #include "ReadoutCard/ParameterTypes/PciAddress.h"
+#include "Pda/PdaLock.h"
 
 namespace AliceO2 {
 namespace roc {
@@ -35,6 +36,7 @@ void freeUnusedChannelBuffers()
 {
   namespace bfs = boost::filesystem;
   InfoLogger::InfoLogger logger;
+  Pda::PdaLock lock(); // We're messing around with PDA buffers so we need this
 
   try {
     std::string pciPath = "/sys/bus/pci/drivers/uio_pci_dma/";

src/Pda/PdaDmaBuffer.cxx

@@ -8,22 +8,17 @@
 #include <InfoLogger/InfoLogger.hxx>
 #include "ExceptionInternal.h"
 #include "InterprocessLock.h"
+#include "Pda/PdaLock.h"
 
 namespace AliceO2 {
 namespace roc {
 namespace Pda {
-namespace {
-auto MUTEX_NAME = "AliceO2_roc_Pda_PdaDmaBuffer_Mutex";
-auto LOCK_FILE_PATH = "/dev/shm/alice_o2/rorc/AliceO2_roc_Pda_PdaDmaBuffer.lock";
-
-
-} // Anonymous namespace
 
 PdaDmaBuffer::PdaDmaBuffer(PdaDevice::PdaPciDevice pciDevice, void* userBufferAddress, size_t userBufferSize,
     int dmaBufferId, bool requireHugepage) : mPciDevice(pciDevice)
 {
   // Safeguard against PDA kernel module deadlocks, since it does not like parallel buffer registration
-  Interprocess::Lock lock {LOCK_FILE_PATH, MUTEX_NAME, true};
+  PdaLock lock();
 
   try {
     // Tell PDA we're using our already allocated userspace buffer.
@@ -105,7 +100,7 @@ PdaDmaBuffer::~PdaDmaBuffer()
   // Safeguard against PDA kernel module deadlocks, since it does not like parallel buffer registration
   // NOTE: not sure if necessary for deregistration as well
   try {
-    Interprocess::Lock lock {LOCK_FILE_PATH, MUTEX_NAME, true};
+    PdaLock lock();
     PciDevice_deleteDMABuffer(mPciDevice.get(), mDmaBuffer);
   } catch (std::exception& e) {
     // Nothing to be done?

src/Pda/PdaLock.h

@@ -0,0 +1,33 @@
+/// \file PdaDmaBuffer.h
+/// \brief Definition of the PdaDmaBuffer class.
+///
+/// \author Pascal Boeschoten ([email protected])
+
+#ifndef ALICEO2_SRC_READOUTCARD_PDA_PDALOCK_H_
+#define ALICEO2_SRC_READOUTCARD_PDA_PDALOCK_H_
+
+#include "InterprocessLock.h"
+
+namespace AliceO2 {
+namespace roc {
+namespace Pda {
+
+/// Represents a global, system-wide lock on ReadoutCard's PDA usage. This is needed because the PDA kernel module
+/// will lock up if buffers are created/freed in parallel.
+/// Just hope nobody else uses PDA in parallel.
+class PdaLock
+{
+    PdaLock() : mLock("/dev/shm/alice_o2/rorc/AliceO2_roc_Pda_PdaDmaBuffer.lock", "AliceO2_roc_Pda_PdaDmaBuffer_Mutex",
+      true)
+    {
+    }
+
+  private:
+    Interprocess::Lock mLock;
+};
+
+} // namespace Pda
+} // namespace roc
+} // namespace AliceO2
+
+#endif // ALICEO2_SRC_READOUTCARD_PDA_PDALOCK_H_