netdev - RFC: [PATCH 1/3] usb: cdc

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Date:	Fri, 8 Mar 2013 22:03:19 +0100
From:	Loic Domaigne <loic.domaigne@...glemail.com>
To:	netdev@...r.kernel.org
Cc:	linux-usb@...r.kernel.org
Subject: RFC: [PATCH 1/3] usb: cdc_ncm: patch for VMware

This patch limits the Rx URB size to 16kB if the driver is compiled for a
VMware environment. As of workstation 9, there are some major performance
problems if the Rx URB size exceeds that limit.

This patch applies to longterm kernel version 3.4.35.

Signed-Off-By: Loic Domaigne <loic.domaigne@...bit.com> 

--- linux-3.4.35/drivers/net/usb/cdc_ncm.c.orig	2013-03-05 09:36:02.858740489 +0100
+++ linux-3.4.35/drivers/net/usb/cdc_ncm.c	2013-03-05 10:20:18.092588668 +0100
@@ -80,6 +80,23 @@
 #define	CDC_NCM_TIMER_PENDING_CNT		2
 #define CDC_NCM_TIMER_INTERVAL			(400UL * NSEC_PER_USEC)
 
+/* maximum Rx URB size */
+/*
+ * in the original Linux driver, the rx urb size can be up to
+ * CDC_NCM_NTB_MAX_SIZE_RX.
+ *
+ * Under VMware (as of wks9), URB size greater than 16kB is a problem,
+ * so simply adjust this define when the driver is compiled for a VMware
+ * environment.
+ *
+ */
+#ifdef VMWARE_BUG
+#warning "Compiling for VMware"
+#define CDC_NCM_MAX_RX_URB_SIZE     16384
+#else
+#define CDC_NCM_MAX_RX_URB_SIZE     CDC_NCM_NTB_MAX_SIZE_RX
+#endif
+
 /* The following macro defines the minimum header space */
 #define	CDC_NCM_MIN_HDR_SIZE \
 	(sizeof(struct usb_cdc_ncm_nth16) + sizeof(struct usb_cdc_ncm_ndp16) + \
@@ -589,6 +606,9 @@ advance:
 		ctx->out_ep->desc.bEndpointAddress & USB_ENDPOINT_NUMBER_MASK);
 	dev->status = ctx->status_ep;
 	dev->rx_urb_size = ctx->rx_max;
+	if (dev->rx_urb_size > CDC_NCM_MAX_RX_URB_SIZE)
+		dev->rx_urb_size = CDC_NCM_MAX_RX_URB_SIZE;
+	pr_debug("dev->rx_urb_size = %zu", dev->rx_urb_size);
 
 	/*
 	 * We should get an event when network connection is "connected" or
--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html