python: Release GIL on blocking calls

Release Python's GIL (global interpreter lock) when invoking blocking
functions from multithreaded Python applications. This is to prevent
long running threads to block all other threads.

Signed-off-by: Martin Belanger <martin.belanger@dell.com>

diff --git a/libnvme/nvme.i b/libnvme/nvme.i
index 6f20e2cccf8912404d19f213c76cdbadbc8b8c8b..0c6b73ca46a962f73821dc2071a18fee8623d23a 100644 (file)
--- a/libnvme/nvme.i
+++ b/libnvme/nvme.i
@@ -585,7 +585,11 @@ struct nvme_ns {
       connect_err = 1;
       return;
     }
+
+    Py_BEGIN_ALLOW_THREADS  /* Release Python GIL */
     ret = nvmf_add_ctrl(h, $self, cfg);
+    Py_END_ALLOW_THREADS    /* Reacquire Python GIL */
+
     if (ret < 0) {
       connect_err = 2;
       return;
@@ -601,7 +605,9 @@ struct nvme_ns {
     nvme_rescan_ctrl($self);
   }
   void disconnect() {
+    Py_BEGIN_ALLOW_THREADS  /* Release Python GIL */
     nvme_disconnect_ctrl($self);
+    Py_END_ALLOW_THREADS    /* Reacquire Python GIL */
   }
 
   %feature("autodoc", "@return: True if controller supports explicit registration. False otherwise.") is_registration_supported;
@@ -614,7 +620,10 @@ struct nvme_ns {
     __u32 result;
     int   status;
 
+    Py_BEGIN_ALLOW_THREADS  /* Release Python GIL */
     status = nvmf_register_ctrl($self, NVMF_DIM_TAS_REGISTER, &result);
+    Py_END_ALLOW_THREADS    /* Reacquire Python GIL */
+
     if (status != NVME_SC_SUCCESS) {
       /* On error, return an error message */
       if (status < 0)
@@ -629,6 +638,7 @@ struct nvme_ns {
 
   %newobject discover;
   struct nvmf_discovery_log *discover(int lsp = 0, int max_retries = 6) {
+    struct nvmf_discovery_log *logp;
     struct nvme_get_discovery_args args = {
       .c = $self,
       .args_size = sizeof(args),
@@ -637,7 +647,11 @@ struct nvme_ns {
       .timeout = NVME_DEFAULT_IOCTL_TIMEOUT,
       .lsp = lsp,
     };
-    struct nvmf_discovery_log *logp = nvmf_get_discovery_wargs(&args);
+
+    Py_BEGIN_ALLOW_THREADS  /* Release Python GIL */
+    logp = nvmf_get_discovery_wargs(&args);
+    Py_END_ALLOW_THREADS    /* Reacquire Python GIL */
+
     if (logp == NULL)
       discover_err = 1;
     return logp;
@@ -649,7 +663,10 @@ struct nvme_ns {
     PyObject *obj = NULL;
     int ret = 0;
 
+    Py_BEGIN_ALLOW_THREADS  /* Release Python GIL */
     ret = nvme_get_log_supported_log_pages(nvme_ctrl_get_fd($self), rae, &log);
+    Py_END_ALLOW_THREADS    /* Reacquire Python GIL */
+
     if (ret < 0) {
       Py_RETURN_NONE;
     }