Copy msg buffer back to userspace on ENOMEM.

dacut · Jun 14, 2016 · 2e25a3c · 2e25a3c
1 parent e94b0df
commit 2e25a3c
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diff --git a/client/ublkdev-c++/s3.cc b/client/ublkdev-c++/s3.cc
@@ -956,7 +956,11 @@ void UBDS3Handler::run() {
                 if (e.getError() == ENOMEM) {
                     // Resize the buffer
                     try {
+                        cerr << "ENOMEM -- allocated " << m_buffer_size
+                             << " bytes but need " << m_message.ubd_size
+                             << " bytes" << endl;
                         resizeBuffer(m_message.ubd_size);
+                        cerr << "Now have " << m_buffer_size << " bytes" << endl;
                     }
                     catch (bad_alloc &) {
                         cerr << "Thread " << std::this_thread::get_id()

diff --git a/src/ublkdev.c b/src/ublkdev.c
@@ -964,6 +964,7 @@ static long ubdctl_ioctl_getrequest(
             ubd_warning("Insufficient buffer space: need %u bytes; userspace "
                         "provided only %u bytes.", write_size, msg.ubd_size);
             msg.ubd_size = write_size;
+            copy_to_user((void *) data, &msg, sizeof(msg));
             spin_unlock_irqrestore(&dev->wait.lock, lock_flags);
             return -ENOMEM;
         }