From 73fa56840b4158b203479eabf9be1e60da5ca4d2 Mon Sep 17 00:00:00 2001 From: Oliver Neukum Date: Wed, 17 Feb 2016 10:51:56 +0100 Subject: [PATCH 1/2] chaoskey: introduce an URB for asynchronous reads To get more bandwidth and clean handling of signals an URB is introduced. Also a cleanup of allocation and freeing resources. Signed-off-by: Oliver Neukum --- drivers/usb/misc/chaoskey.c | 46 ++++++++++++++++++++++++++------------------- 1 file changed, 27 insertions(+), 19 deletions(-) diff --git a/drivers/usb/misc/chaoskey.c b/drivers/usb/misc/chaoskey.c index 23c7948..5a67a04 100644 --- a/drivers/usb/misc/chaoskey.c +++ b/drivers/usb/misc/chaoskey.c @@ -80,7 +80,8 @@ 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 */ @@ -88,15 +89,19 @@ 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; }; 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"); + usb_free_urb(dev->urb); + kfree(dev->name); + kfree(dev->buf); + kfree(dev); + } } static int chaoskey_probe(struct usb_interface *interface, @@ -107,7 +112,7 @@ 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 +147,17 @@ 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; + + dev->urb = usb_alloc_urb(GFP_KERNEL, 0); + + if (!dev->urb) + goto out; /* Construct a name using the product and serial values. Each * device needs a unique name for the hwrng code @@ -158,11 +166,8 @@ 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 +191,7 @@ 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 +218,11 @@ 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) -- 2.1.4