On Sat, Feb 23, 2008 at 11:14:51AM -0800, Anthony Brock wrote:
> My instance has the follow on the file system:
>
> # ls -lA /dev/*rand*
> crw-rw-rw- 1 root root 1, 8 2008-02-11 11:43 /dev/random
> crw-rw-rw- 1 root root 1, 9 2008-02-23 10:06 /dev/urandom
> #
>
> Is it possible that recent kernel versions are having issues with
> /dev/random? Any ideas on what would cause this behavior, or an I dealing
> with a known issue/misconfiguration?
See if the patch below helps...
Jeff
--
Work email - jdike at linux dot intel dot com
Index: linux-2.6.22/arch/um/drivers/random.c
===================================================================
--- linux-2.6.22.orig/arch/um/drivers/random.c 2008-01-17 12:51:06.000000000
-0500
+++ linux-2.6.22/arch/um/drivers/random.c 2008-01-29 10:49:16.000000000
-0500
@@ -8,16 +8,18 @@
#include <linux/sched.h>
#include <linux/module.h>
#include <linux/fs.h>
+#include <linux/interrupt.h>
#include <linux/miscdevice.h>
#include <linux/delay.h>
#include <asm/uaccess.h>
+#include "irq_kern.h"
#include "os.h"
/*
* core module and version information
*/
#define RNG_VERSION "1.0.0"
-#define RNG_MODULE_NAME "random"
+#define RNG_MODULE_NAME "hw_random"
#define RNG_MISCDEV_MINOR 183 /* official */
@@ -26,6 +28,7 @@
* protects against a module being loaded twice at the same time.
*/
static int random_fd = -1;
+static DECLARE_WAIT_QUEUE_HEAD(host_read_wait);
static int rng_dev_open (struct inode *inode, struct file *filp)
{
@@ -38,6 +41,8 @@ static int rng_dev_open (struct inode *i
return 0;
}
+static atomic_t host_sleep_count = ATOMIC_INIT(0);
+
static ssize_t rng_dev_read (struct file *filp, char __user *buf, size_t size,
loff_t * offp)
{
@@ -60,11 +65,26 @@ static ssize_t rng_dev_read (struct file
}
}
else if(n == -EAGAIN){
+ DECLARE_WAITQUEUE(wait, current);
+
if (filp->f_flags & O_NONBLOCK)
return ret ? : -EAGAIN;
- if(need_resched())
- schedule_timeout_interruptible(1);
+ atomic_inc(&host_sleep_count);
+ reactivate_fd(random_fd, RANDOM_IRQ);
+ add_sigio_fd(random_fd);
+
+ add_wait_queue(&host_read_wait, &wait);
+ set_task_state(current, TASK_INTERRUPTIBLE);
+
+ schedule();
+ set_task_state(current, TASK_RUNNING);
+ remove_wait_queue(&host_read_wait, &wait);
+
+ if(atomic_dec_and_test(&host_sleep_count)){
+ ignore_sigio_fd(random_fd);
+ deactivate_fd(random_fd, RANDOM_IRQ);
+ }
}
else return n;
if (signal_pending (current))
@@ -86,6 +106,14 @@ static struct miscdevice rng_miscdev = {
&rng_chrdev_ops,
};
+static irqreturn_t random_interrupt(int irq, void *data)
+{
+ wake_up(&host_read_wait);
+
+ return IRQ_HANDLED;
+}
+
+extern void sigio_broken(int fd, int read);
/*
* rng_init - initialize RNG module
*/
@@ -99,10 +127,14 @@ static int __init rng_init (void)
random_fd = err;
- err = os_set_fd_block(random_fd, 0);
+ err = um_request_irq(RANDOM_IRQ, random_fd, IRQ_READ, random_interrupt,
+ IRQF_DISABLED | IRQF_SAMPLE_RANDOM, "random",
+ NULL);
if(err)
goto err_out_cleanup_hw;
+ sigio_broken(random_fd, 1);
+
err = misc_register (&rng_miscdev);
if (err) {
printk (KERN_ERR RNG_MODULE_NAME ": misc device register
failed\n");
@@ -113,6 +145,7 @@ static int __init rng_init (void)
return err;
err_out_cleanup_hw:
+ os_close_file(random_fd);
random_fd = -1;
goto out;
}
@@ -122,6 +155,7 @@ static int __init rng_init (void)
*/
static void __exit rng_cleanup (void)
{
+ os_close_file(random_fd);
misc_deregister (&rng_miscdev);
}
Index: linux-2.6.22/arch/um/os-Linux/sigio.c
===================================================================
--- linux-2.6.22.orig/arch/um/os-Linux/sigio.c 2008-01-17 12:51:06.000000000
-0500
+++ linux-2.6.22/arch/um/os-Linux/sigio.c 2008-01-21 16:32:44.000000000
-0500
@@ -338,20 +338,10 @@ out_close1:
close(l_write_sigio_fds[1]);
}
-/* Changed during early boot */
-static int pty_output_sigio = 0;
-static int pty_close_sigio = 0;
-
-void maybe_sigio_broken(int fd, int read)
+void sigio_broken(int fd, int read)
{
int err;
- if (!isatty(fd))
- return;
-
- if ((read || pty_output_sigio) && (!read || pty_close_sigio))
- return;
-
write_sigio_workaround();
sigio_lock();
@@ -370,6 +360,21 @@ out:
sigio_unlock();
}
+/* Changed during early boot */
+static int pty_output_sigio = 0;
+static int pty_close_sigio = 0;
+
+void maybe_sigio_broken(int fd, int read)
+{
+ if (!isatty(fd))
+ return;
+
+ if ((read || pty_output_sigio) && (!read || pty_close_sigio))
+ return;
+
+ sigio_broken(fd, read);
+}
+
static void sigio_cleanup(void)
{
if (write_sigio_pid == -1)
Index: linux-2.6.22/include/asm-um/irq.h
===================================================================
--- linux-2.6.22.orig/include/asm-um/irq.h 2008-01-18 12:53:08.000000000
-0500
+++ linux-2.6.22/include/asm-um/irq.h 2008-01-21 16:33:50.000000000 -0500
@@ -15,8 +15,9 @@
#define SIGIO_WRITE_IRQ 11
#define TELNETD_IRQ 12
#define XTERM_IRQ 13
+#define RANDOM_IRQ 14
-#define LAST_IRQ XTERM_IRQ
+#define LAST_IRQ RANDOM_IRQ
#define NR_IRQS (LAST_IRQ + 1)
#endif
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