From 5283630d2c9d40deb0183696d278e02644fe4326 Mon Sep 17 00:00:00 2001
From: Sebastian Huber <sebastian.huber@embedded-brains.de>
Date: Tue, 9 Jul 2019 11:14:53 +0200
Subject: Update to FreeBSD stable/12 2019-07-09

Git mirror commit 3427c3416aa3c0f25124070959cca78024b94d85.
---
 freebsd/sys/kern/sys_pipe.c | 30 +++++++++++++++++-------------
 1 file changed, 17 insertions(+), 13 deletions(-)

(limited to 'freebsd/sys/kern/sys_pipe.c')

diff --git a/freebsd/sys/kern/sys_pipe.c b/freebsd/sys/kern/sys_pipe.c
index 817190b7..d714af89 100755
--- a/freebsd/sys/kern/sys_pipe.c
+++ b/freebsd/sys/kern/sys_pipe.c
@@ -817,7 +817,7 @@ pipe_read(struct file *fp, struct uio *uio, struct ucred *active_cred,
 			rpipe->pipe_map.pos += size;
 			rpipe->pipe_map.cnt -= size;
 			if (rpipe->pipe_map.cnt == 0) {
-				rpipe->pipe_state &= ~(PIPE_DIRECTW|PIPE_WANTW);
+				rpipe->pipe_state &= ~PIPE_WANTW;
 				wakeup(rpipe);
 			}
 #endif
@@ -1020,13 +1020,17 @@ pipe_build_write_buffer(struct pipe *wpipe, struct uio *uio)
 }
 
 /*
- * unmap and unwire the process buffer
+ * Unwire the process buffer.
  */
 static void
 pipe_destroy_write_buffer(struct pipe *wpipe)
 {
 
 	PIPE_LOCK_ASSERT(wpipe, MA_OWNED);
+	KASSERT((wpipe->pipe_state & PIPE_DIRECTW) != 0,
+	    ("%s: PIPE_DIRECTW not set on %p", __func__, wpipe));
+
+	wpipe->pipe_state &= ~PIPE_DIRECTW;
 	vm_page_unhold_pages(wpipe->pipe_map.ms, wpipe->pipe_map.npages);
 	wpipe->pipe_map.npages = 0;
 }
@@ -1045,13 +1049,15 @@ pipe_clone_write_buffer(struct pipe *wpipe)
 	int pos;
 
 	PIPE_LOCK_ASSERT(wpipe, MA_OWNED);
+	KASSERT((wpipe->pipe_state & PIPE_DIRECTW) != 0,
+	    ("%s: PIPE_DIRECTW not set on %p", __func__, wpipe));
+
 	size = wpipe->pipe_map.cnt;
 	pos = wpipe->pipe_map.pos;
 
 	wpipe->pipe_buffer.in = size;
 	wpipe->pipe_buffer.out = 0;
 	wpipe->pipe_buffer.cnt = size;
-	wpipe->pipe_state &= ~PIPE_DIRECTW;
 
 	PIPE_UNLOCK(wpipe);
 	iov.iov_base = wpipe->pipe_buffer.buffer;
@@ -1090,7 +1096,7 @@ retry:
 		pipeunlock(wpipe);
 		goto error1;
 	}
-	while (wpipe->pipe_state & PIPE_DIRECTW) {
+	if (wpipe->pipe_state & PIPE_DIRECTW) {
 		if (wpipe->pipe_state & PIPE_WANTR) {
 			wpipe->pipe_state &= ~PIPE_WANTR;
 			wakeup(wpipe);
@@ -1133,8 +1139,7 @@ retry:
 		goto error1;
 	}
 
-	error = 0;
-	while (!error && (wpipe->pipe_state & PIPE_DIRECTW)) {
+	while (wpipe->pipe_map.cnt != 0) {
 		if (wpipe->pipe_state & PIPE_EOF) {
 			pipe_destroy_write_buffer(wpipe);
 			pipeselwakeup(wpipe);
@@ -1152,20 +1157,19 @@ retry:
 		error = msleep(wpipe, PIPE_MTX(wpipe), PRIBIO | PCATCH,
 		    "pipdwt", 0);
 		pipelock(wpipe, 0);
+		if (error != 0)
+			break;
 	}
 
 	if (wpipe->pipe_state & PIPE_EOF)
 		error = EPIPE;
-	if (wpipe->pipe_state & PIPE_DIRECTW) {
-		/*
-		 * this bit of trickery substitutes a kernel buffer for
-		 * the process that might be going away.
-		 */
+	if (error == EINTR || error == ERESTART)
 		pipe_clone_write_buffer(wpipe);
-	} else {
+	else
 		pipe_destroy_write_buffer(wpipe);
-	}
 	pipeunlock(wpipe);
+	KASSERT((wpipe->pipe_state & PIPE_DIRECTW) == 0,
+	    ("pipe %p leaked PIPE_DIRECTW", wpipe));
 	return (error);
 
 error1:
-- 
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