Fix build errors on some configurations

src/core/lib/iomgr/ev_epoll_linux.c

@@ -34,6 +34,7 @@
 #include <grpc/grpc_posix.h>
 #include <grpc/support/port_platform.h>
 
+/* This polling engine is only relevant on linux kernels supporting epoll() */
 #ifdef GPR_LINUX_EPOLL
 
 #include "src/core/lib/iomgr/ev_epoll_linux.h"
@@ -322,7 +323,7 @@ static void polling_island_add_fds_locked(polling_island *pi, grpc_fd **fds,
 
 #ifdef GRPC_TSAN
   /* See the definition of g_epoll_sync for more context */
-  gpr_atm_rel_store(&g_epoll_sync, 0);
+  gpr_atm_rel_store(&g_epoll_sync, (gpr_atm) 0);
 #endif /* defined(GRPC_TSAN) */
 
   for (i = 0; i < fd_count; i++) {
@@ -442,8 +443,8 @@ static polling_island *polling_island_create(grpc_fd *initial_fd) {
     pi->fds = NULL;
   }
 
-  gpr_atm_rel_store(&pi->ref_count, 0);
-  gpr_atm_rel_store(&pi->merged_to, NULL);
+  gpr_atm_rel_store(&pi->ref_count, (gpr_atm) 0);
+  gpr_atm_rel_store(&pi->merged_to, (gpr_atm) NULL);
 
   pi->epoll_fd = epoll_create1(EPOLL_CLOEXEC);
 
@@ -472,7 +473,7 @@ static polling_island *polling_island_create(grpc_fd *initial_fd) {
 static void polling_island_delete(polling_island *pi) {
   GPR_ASSERT(pi->fd_cnt == 0);
 
-  gpr_atm_rel_store(&pi->merged_to, NULL);
+  gpr_atm_rel_store(&pi->merged_to, (gpr_atm) NULL);
 
   close(pi->epoll_fd);
   pi->epoll_fd = -1;
@@ -648,7 +649,7 @@ static polling_island *polling_island_merge(polling_island *p,
   polling_island_add_wakeup_fd_locked(p, &polling_island_wakeup_fd);
 
   /* Add the 'merged_to' link from p --> q */
-  gpr_atm_rel_store(&p->merged_to, q);
+  gpr_atm_rel_store(&p->merged_to, (gpr_atm) q);
   PI_ADD_REF(q, "pi_merge"); /* To account for the new incoming ref from p */
 
   gpr_mu_unlock(&p->mu);
@@ -810,7 +811,7 @@ static grpc_fd *fd_create(int fd, const char *name) {
      holding a lock to it anyway. */
   gpr_mu_lock(&new_fd->mu);
 
-  gpr_atm_rel_store(&new_fd->refst, 1);
+  gpr_atm_rel_store(&new_fd->refst, (gpr_atm) 1);
   new_fd->fd = fd;
   new_fd->shutdown = false;
   new_fd->orphaned = false;

test/core/iomgr/ev_epoll_linux_test.c

@@ -30,7 +30,10 @@
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  *
  */
+#include <grpc/support/port_platform.h>
 
+/* This test only relevant on linux systems where epoll() is available */
+#ifdef GPR_LINUX_EPOLL
 #include "src/core/lib/iomgr/ev_epoll_linux.h"
 #include "src/core/lib/iomgr/ev_posix.h"
 
@@ -128,8 +131,10 @@ static void test_add_fd_to_pollset() {
   int i;
   int r;
 
-  /* Create some dummy file descriptors (using pipe fds for this test. Could be
-     anything). Also NUM_FDS should be even for this test. */
+  /* Create some dummy file descriptors. Currently using pipe file descriptors
+   * for this test but we could use any other type of file descriptors. Also,
+   * since pipe() used in this test creates two fds in each call, NUM_FDS should
+   * be an even number */
   for (i = 0; i < NUM_FDS; i = i + 2) {
     r = pipe(fds + i);
     if (r != 0) {
@@ -234,3 +239,4 @@ int main(int argc, char **argv) {
   grpc_iomgr_shutdown();
   return 0;
 }
+#endif /* defined(GPR_LINUX_EPOLL) */