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Message-Id: <1181512917.3157.8.camel@localhost>
Date: Mon, 11 Jun 2007 01:01:57 +0300
From: Eduard-Gabriel Munteanu <maxdamage@...din.ro>
To: jdike@...aya.com
Cc: linux-kernel@...r.kernel.org
Subject: [PATCH 1/1] UML: fix missing non-blocking I/O, now DEBUG_SHIRQ
works
*This message was transferred with a trial version of CommuniGate(r) Pro*
DEBUG_SHIRQ generates spurious interrupts, triggering handlers such as
mconsole_interrupt() or line_interrupt(). They expect data to be
available to be read from their sockets/pipes, but in the case of
spurious interrupts, the host didn't actually send anything, so UML
hangs in read() and friends. Setting those fd's as O_NONBLOCK makes
DEBUG_SHIRQ-enabled UML kernels boot and run correctly.
The patch was written and tested on Linux 2.6.22-rc2-mm1.
I have also included a couple of short/minor fixes for potential
problems.
Signed-off-by: Eduard-Gabriel Munteanu <maxdamage@...din.ro>
---
arch/um/drivers/chan_user.c | 6 ++++++
arch/um/drivers/mconsole_kern.c | 11 +++++------
arch/um/drivers/mconsole_user.c | 5 +++--
arch/um/drivers/ubd_user.c | 6 ++++++
arch/um/drivers/xterm.c | 7 +++++++
5 files changed, 27 insertions(+), 8 deletions(-)
diff --git a/arch/um/drivers/chan_user.c b/arch/um/drivers/chan_user.c
index 13f0bf8..0a8b785 100644
--- a/arch/um/drivers/chan_user.c
+++ b/arch/um/drivers/chan_user.c
@@ -170,6 +170,12 @@ static int winch_tramp(int fd, struct tty_struct *tty, int *fd_out)
err = -EINVAL;
goto out_close;
}
+
+ if (os_set_fd_block(*fd_out, 0)) {
+ printk("winch_tramp: failed to set thread_fd non-blocking.\n");
+ goto out_close;
+ }
+
return err ;
out_close:
diff --git a/arch/um/drivers/mconsole_kern.c b/arch/um/drivers/mconsole_kern.c
index 542c9ef..02d132e 100644
--- a/arch/um/drivers/mconsole_kern.c
+++ b/arch/um/drivers/mconsole_kern.c
@@ -74,12 +74,11 @@ static DECLARE_WORK(mconsole_work, mc_work_proc);
static irqreturn_t mconsole_interrupt(int irq, void *dev_id)
{
- /* long to avoid size mismatch warnings from gcc */
- long fd;
+ int fd;
struct mconsole_entry *new;
static struct mc_request req; /* that's OK */
- fd = (long) dev_id;
+ fd = *((int *) dev_id);
while (mconsole_get_request(fd, &req)){
if(req.cmd->context == MCONSOLE_INTR)
(*req.cmd->handler)(&req);
@@ -798,10 +797,10 @@ void mconsole_stack(struct mc_request *req)
*/
static char *notify_socket = NULL;
+static int sock;
+
static int mconsole_init(void)
{
- /* long to avoid size mismatch warnings from gcc */
- long sock;
int err;
char file[256];
@@ -818,7 +817,7 @@ static int mconsole_init(void)
err = um_request_irq(MCONSOLE_IRQ, sock, IRQ_READ, mconsole_interrupt,
IRQF_DISABLED | IRQF_SHARED | IRQF_SAMPLE_RANDOM,
- "mconsole", (void *)sock);
+ "mconsole", &sock);
if (err){
printk("Failed to get IRQ for management console\n");
return(1);
diff --git a/arch/um/drivers/mconsole_user.c b/arch/um/drivers/mconsole_user.c
index 62e5ad6..f31e715 100644
--- a/arch/um/drivers/mconsole_user.c
+++ b/arch/um/drivers/mconsole_user.c
@@ -86,8 +86,9 @@ int mconsole_get_request(int fd, struct mc_request *req)
int len;
req->originlen = sizeof(req->origin);
- req->len = recvfrom(fd, &req->request, sizeof(req->request), 0,
- (struct sockaddr *) req->origin, &req->originlen);
+ req->len = recvfrom(fd, &req->request, sizeof(req->request),
+ MSG_DONTWAIT, (struct sockaddr *) req->origin,
+ &req->originlen);
if (req->len < 0)
return 0;
diff --git a/arch/um/drivers/ubd_user.c b/arch/um/drivers/ubd_user.c
index 4707b3f..56f2c23 100644
--- a/arch/um/drivers/ubd_user.c
+++ b/arch/um/drivers/ubd_user.c
@@ -43,6 +43,12 @@ int start_io_thread(unsigned long sp, int *fd_out)
kernel_fd = fds[0];
*fd_out = fds[1];
+ err = os_set_fd_block(*fd_out, 0);
+ if (err) {
+ printk("start_io_thread - failed to set nonblocking I/O.\n");
+ goto out_close;
+ }
+
pid = clone(io_thread, (void *) sp, CLONE_FILES | CLONE_VM | SIGCHLD,
NULL);
if(pid < 0){
diff --git a/arch/um/drivers/xterm.c b/arch/um/drivers/xterm.c
index 571c2b3..2b65b57 100644
--- a/arch/um/drivers/xterm.c
+++ b/arch/um/drivers/xterm.c
@@ -151,6 +151,13 @@ int xterm_open(int input, int output, int primary, void *d,
goto out;
}
+ err = os_set_fd_block(new, 0);
+ if (err) {
+ printk("xterm_open : failed to set xterm descriptor "
+ "non-blocking, err = %d\n", -err);
+ return(err);
+ }
+
CATCH_EINTR(err = tcgetattr(new, &data->tt));
if(err){
new = err;
-
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