Keith Packard <keithp@xxxxxxxxxx> writes: > Yup, with a few minor fixes to pass the right arguments: Argh. Just after hitting 'send', I noticed that I'd not moved the URB deallocation out of the way when merging the first patch in this series. That means the driver won't build with only the first patch applied, which is always annoying for other people bisecting through this. Here's the patches again, this time build tested in the middle.
From d9ae8ca45c86e81a455bf19a4b4c580ec872c7df Mon Sep 17 00:00:00 2001
From: Oliver Neukum <oneukum@xxxxxxxx>
Date: Wed, 17 Feb 2016 09:58:11 -0800
Subject: [PATCH 1/2] usb/misc/chaoskey: Cleanup probe failure paths
Shares the cleanup code between all probe failure paths, instead of
having per-failure cleanup at each point in the function.
Signed-off-by: Oliver Neukum <oneukum@xxxxxxxx>
Signed-off-by: Keith Packard <keithp@xxxxxxxxxx>
---
drivers/usb/misc/chaoskey.c | 36 ++++++++++++++++++------------------
1 file changed, 18 insertions(+), 18 deletions(-)
diff --git a/drivers/usb/misc/chaoskey.c b/drivers/usb/misc/chaoskey.c
index 23c7948..cb1c239 100644
--- a/drivers/usb/misc/chaoskey.c
+++ b/drivers/usb/misc/chaoskey.c
@@ -93,10 +93,12 @@ struct chaoskey {
static void chaoskey_free(struct chaoskey *dev)
{
- usb_dbg(dev->interface, "free");
- kfree(dev->name);
- kfree(dev->buf);
- kfree(dev);
+ if (dev) {
+ usb_dbg(dev->interface, "free");
+ kfree(dev->name);
+ kfree(dev->buf);
+ kfree(dev);
+ }
}
static int chaoskey_probe(struct usb_interface *interface,
@@ -107,7 +109,7 @@ static int chaoskey_probe(struct usb_interface *interface,
int i;
int in_ep = -1;
struct chaoskey *dev;
- int result;
+ int result = -ENOMEM;
int size;
usb_dbg(interface, "probe %s-%s", udev->product, udev->serial);
@@ -142,14 +144,12 @@ static int chaoskey_probe(struct usb_interface *interface,
dev = kzalloc(sizeof(struct chaoskey), GFP_KERNEL);
if (dev == NULL)
- return -ENOMEM;
+ goto out;
dev->buf = kmalloc(size, GFP_KERNEL);
- if (dev->buf == NULL) {
- kfree(dev);
- return -ENOMEM;
- }
+ if (dev->buf == NULL)
+ goto out;
/* Construct a name using the product and serial values. Each
* device needs a unique name for the hwrng code
@@ -158,11 +158,8 @@ static int chaoskey_probe(struct usb_interface *interface,
if (udev->product && udev->serial) {
dev->name = kmalloc(strlen(udev->product) + 1 +
strlen(udev->serial) + 1, GFP_KERNEL);
- if (dev->name == NULL) {
- kfree(dev->buf);
- kfree(dev);
- return -ENOMEM;
- }
+ if (dev->name == NULL)
+ goto out;
strcpy(dev->name, udev->product);
strcat(dev->name, "-");
@@ -186,9 +183,7 @@ static int chaoskey_probe(struct usb_interface *interface,
result = usb_register_dev(interface, &chaoskey_class);
if (result) {
usb_err(interface, "Unable to allocate minor number.");
- usb_set_intfdata(interface, NULL);
- chaoskey_free(dev);
- return result;
+ goto out;
}
dev->hwrng.name = dev->name ? dev->name : chaoskey_driver.name;
@@ -215,6 +210,11 @@ static int chaoskey_probe(struct usb_interface *interface,
usb_dbg(interface, "chaoskey probe success, size %d", dev->size);
return 0;
+
+out:
+ usb_set_intfdata(interface, NULL);
+ chaoskey_free(dev);
+ return result;
}
static void chaoskey_disconnect(struct usb_interface *interface)
--
2.7.0
From 7271de7c68a2cd288d2735d617f4e15b17f23c2a Mon Sep 17 00:00:00 2001
From: Oliver Neukum <oneukum@xxxxxxxx>
Date: Wed, 17 Feb 2016 10:01:33 -0800
Subject: [PATCH 2/2] usb/misc/chaoskey: introduce an URB for asynchronous
reads
To allow for and clean handling of signals an URB is introduced.
Signed-off-by: Oliver Neukum <oneukum@xxxxxxxx>
Signed-off-by: Keith Packard <keithp@xxxxxxxxxx>
---
drivers/usb/misc/chaoskey.c | 86 ++++++++++++++++++++++++++++++++++-----------
1 file changed, 65 insertions(+), 21 deletions(-)
diff --git a/drivers/usb/misc/chaoskey.c b/drivers/usb/misc/chaoskey.c
index cb1c239..76350e4 100644
--- a/drivers/usb/misc/chaoskey.c
+++ b/drivers/usb/misc/chaoskey.c
@@ -73,6 +73,8 @@ static const struct usb_device_id chaoskey_table[] = {
};
MODULE_DEVICE_TABLE(usb, chaoskey_table);
+static void chaos_read_callback(struct urb *urb);
+
/* Driver-local specific stuff */
struct chaoskey {
struct usb_interface *interface;
@@ -80,7 +82,8 @@ struct chaoskey {
struct mutex lock;
struct mutex rng_lock;
int open; /* open count */
- int present; /* device not disconnected */
+ bool present; /* device not disconnected */
+ bool reading; /* ongoing IO */
int size; /* size of buf */
int valid; /* bytes of buf read */
int used; /* bytes of buf consumed */
@@ -88,6 +91,7 @@ struct chaoskey {
struct hwrng hwrng; /* Embedded struct for hwrng */
int hwrng_registered; /* registered with hwrng API */
wait_queue_head_t wait_q; /* for timeouts */
+ struct urb *urb; /* for performing IO */
char *buf;
};
@@ -95,6 +99,7 @@ static void chaoskey_free(struct chaoskey *dev)
{
if (dev) {
usb_dbg(dev->interface, "free");
+ usb_free_urb(dev->urb);
kfree(dev->name);
kfree(dev->buf);
kfree(dev);
@@ -151,6 +156,19 @@ static int chaoskey_probe(struct usb_interface *interface,
if (dev->buf == NULL)
goto out;
+ dev->urb = usb_alloc_urb(0, GFP_KERNEL);
+
+ if (!dev->urb)
+ goto out;
+
+ usb_fill_bulk_urb(dev->urb,
+ udev,
+ usb_rcvbulkpipe(udev, in_ep),
+ dev->buf,
+ size,
+ chaos_read_callback,
+ dev);
+
/* Construct a name using the product and serial values. Each
* device needs a unique name for the hwrng code
*/
@@ -237,6 +255,7 @@ static void chaoskey_disconnect(struct usb_interface *interface)
mutex_lock(&dev->lock);
dev->present = 0;
+ usb_poison_urb(dev->urb);
if (!dev->open) {
mutex_unlock(&dev->lock);
@@ -311,14 +330,33 @@ static int chaoskey_release(struct inode *inode, struct file *file)
return 0;
}
+static void chaos_read_callback(struct urb *urb)
+{
+ struct chaoskey *dev = urb->context;
+ int status = urb->status;
+
+ usb_dbg(dev->interface, "callback status (%d)", status);
+
+ if (status == 0)
+ dev->valid = urb->actual_length;
+ else
+ dev->valid = 0;
+
+ dev->used = 0;
+
+ /* must be seen first before validity is announced */
+ smp_wmb();
+
+ dev->reading = false;
+ wake_up(&dev->wait_q);
+}
+
/* Fill the buffer. Called with dev->lock held
*/
static int _chaoskey_fill(struct chaoskey *dev)
{
DEFINE_WAIT(wait);
int result;
- int this_read;
- struct usb_device *udev = interface_to_usbdev(dev->interface);
usb_dbg(dev->interface, "fill");
@@ -343,21 +381,31 @@ static int _chaoskey_fill(struct chaoskey *dev)
return result;
}
- result = usb_bulk_msg(udev,
- usb_rcvbulkpipe(udev, dev->in_ep),
- dev->buf, dev->size, &this_read,
- NAK_TIMEOUT);
+ dev->reading = true;
+ result = usb_submit_urb(dev->urb, GFP_KERNEL);
+ if (result < 0) {
+ result = usb_translate_errors(result);
+ dev->reading = false;
+ goto out;
+ }
+
+ result = wait_event_interruptible_timeout(
+ dev->wait_q,
+ !dev->reading,
+ NAK_TIMEOUT);
+ if (result < 0)
+ goto out;
+
+ if (result == 0)
+ result = -ETIMEDOUT;
+ else
+ result = dev->valid;
+out:
/* Let the device go back to sleep eventually */
usb_autopm_put_interface(dev->interface);
- if (result == 0) {
- dev->valid = this_read;
- dev->used = 0;
- }
-
- usb_dbg(dev->interface, "bulk_msg result %d this_read %d",
- result, this_read);
+ usb_dbg(dev->interface, "read %d bytes", dev->valid);
return result;
}
@@ -395,13 +443,7 @@ static ssize_t chaoskey_read(struct file *file,
goto bail;
if (dev->valid == dev->used) {
result = _chaoskey_fill(dev);
- if (result) {
- mutex_unlock(&dev->lock);
- goto bail;
- }
-
- /* Read returned zero bytes */
- if (dev->used == dev->valid) {
+ if (result < 0) {
mutex_unlock(&dev->lock);
goto bail;
}
@@ -435,6 +477,8 @@ bail:
return read_count;
}
usb_dbg(dev->interface, "empty read, result %d", result);
+ if (result == -ETIMEDOUT)
+ result = -EAGAIN;
return result;
}
--
2.7.0
-- -keith
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