More comments
diff --git a/src/core/lib/iomgr/ev_epoll_linux.c b/src/core/lib/iomgr/ev_epoll_linux.c
index 04d0781..cc7beec 100644
--- a/src/core/lib/iomgr/ev_epoll_linux.c
+++ b/src/core/lib/iomgr/ev_epoll_linux.c
@@ -144,14 +144,42 @@
other than GRPC_ERROR_NONE, it indicates that the fd is shutdown and this
contains the reason for shutdown. Once an fd is shutdown, any pending or
future read/write closures on the fd should fail */
- gpr_atm shutdown_error1;
+ gpr_atm shutdown_error;
- /* The fd is either closed or we relinquished control of it. In either cases,
- this indicates that the 'fd' on this structure is no longer valid */
+ /* The fd is either closed or we relinquished control of it. In either
+ cases, this indicates that the 'fd' on this structure is no longer
+ valid */
bool orphaned;
- /* Closures to call when the fd is readable or writable. The actual type
- stored in these is (grpc_closure *) */
+ /* Closures to call when the fd is readable or writable respectively. These
+ fields contain one of the following values:
+ CLOSURE_READY : The fd has an I/O event of interest but there is no
+ closure yet to execute
+
+ CLOSURE_NOT_READY : The fd has no I/O event of interest
+
+ closure ptr : The closure to be executed when the fd has an I/O event
+ of interest.
+ shutdown_error |
+ CLOSURE_SHUTDOWN : 'shutdown_error' field OR'ed with CLOSURE_SHUTDOWN.
+ This indicates that the fd is shutdown. Since all
+ memory allocations are word-aligned, the lower to
+ bits of the shutdown_error pointer are always 0. So
+ it is safe to OR these with CLOSURE_SHUTDOWN.
+
+ Valid state transitions:
+
+ <closure ptr> <-----3------ CLOSURE_NOT_READY ----1----> CLOSURE_READY
+ | | ^ | ^ | |
+ | | | | | | |
+ | +--------------4----------+ 6 +---------2---------------+ |
+ | | |
+ | v |
+ +-----5-------> [shutdown_error | CLOSURE_SHUTDOWN] <--------7----+
+
+ For 1, 4 : See set_ready() function
+ For 2, 3 : See notify_on() function
+ For 5,6,7: See set_shutdown() function */
gpr_atm read_closure;
gpr_atm write_closure;
@@ -185,7 +213,6 @@
#define CLOSURE_NOT_READY ((gpr_atm)0)
#define CLOSURE_READY ((gpr_atm)1)
-
#define CLOSURE_SHUTDOWN ((gpr_atm)2)
/*******************************************************************************
@@ -1212,7 +1239,7 @@
}
static bool fd_is_shutdown(grpc_fd *fd) {
- grpc_error *err = (grpc_error *)gpr_atm_acq_load(&fd->shutdown_error1);
+ grpc_error *err = (grpc_error *)gpr_atm_acq_load(&fd->shutdown_error);
return (err != GRPC_ERROR_NONE);
}
@@ -1224,7 +1251,7 @@
why = GRPC_ERROR_INTERNAL;
}
- if (gpr_atm_acq_cas(&fd->shutdown_error1, (gpr_atm)GRPC_ERROR_NONE,
+ if (gpr_atm_acq_cas(&fd->shutdown_error, (gpr_atm)GRPC_ERROR_NONE,
(gpr_atm)why)) {
shutdown(fd->fd, SHUT_RDWR);
@@ -1234,22 +1261,6 @@
// Shutdown already called
GRPC_ERROR_UNREF(why);
}
-
- // gpr_mu_lock(&fd->po.mu);
- /* Do the actual shutdown only once */
- // if (!fd->shutdown) {
- // fd->shutdown = true;
- // fd->shutdown_error = why;
-
- // shutdown(fd->fd, SHUT_RDWR);
- /* Flush any pending read and write closures. Since fd->shutdown is 'true'
- at this point, the closures would be called with 'success = false' */
- // set_ready(exec_ctx, fd, &fd->read_closure);
- // set_ready(exec_ctx, fd, &fd->write_closure);
- // } else {
- // GRPC_ERROR_UNREF(why);
- // }
- // gpr_mu_unlock(&fd->po.mu);
}
static void fd_notify_on_read(grpc_exec_ctx *exec_ctx, grpc_fd *fd,