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net: cdc_ncm: fix typo in test for supported formats

PATCH Applied Dan Carpenter 3 participants 3 messages May 22, 2014

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Networking Network drivers Kernel janitors USB networking drivers +1 more subsystems
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Dan Carpenter

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#0 lore raw

PATCH 1/1 net: cdc_ncm: fix typo in test for supported formats

There is a typo here where we test for USB_CDC_NCM_NTH32_SIGN instead of USB_CDC_NCM_NTB32_SUPPORTED. The test probably still works as written because 0x686D636E has (1 << 1) set and doesn't have (1 << 0) set.

Fixes f8afb73da375 ('net: cdc_ncm: factor out one-time device initialization')
Signed-off-by Dan Carpenter <[email protected]>

---
Static analysis. Untested. Applies on -next

drivers/net/usb/cdc_ncm.c +2 -1
index ad2a386..93c9ca9 100644
@@ -357,7 +357,8 @@ static int cdc_ncm_init(struct usbnet *dev)
 	 * "The host shall only send this command while the NCM Data
 	 *  Interface is in alternate setting 0."
 	 */
-	if (le16_to_cpu(ctx->ncm_parm.bmNtbFormatsSupported) & USB_CDC_NCM_NTH32_SIGN) {
+	if (le16_to_cpu(ctx->ncm_parm.bmNtbFormatsSupported) &
+						USB_CDC_NCM_NTB32_SUPPORTED) {
 		dev_dbg(&dev->intf->dev, "Setting NTB format to 16-bit\n");
 		err = usbnet_write_cmd(dev, USB_CDC_SET_NTB_FORMAT,
 				       USB_TYPE_CLASS | USB_DIR_OUT
#1 lore raw
Quoted 15 lines · Dan Carpenter

There is a typo here where we test for USB_CDC_NCM_NTH32_SIGN instead of USB_CDC_NCM_NTB32_SUPPORTED. The test probably still works as written because 0x686D636E has (1 << 1) set and doesn't have (1 << 0) set.

Fixes f8afb73da375 ('net: cdc_ncm: factor out one-time device initialization')
Signed-off-by Dan Carpenter <[email protected]>

---
Static analysis. Untested. Applies on -next

drivers/net/usb/cdc_ncm.c +0 -0
index ad2a386..93c9ca9 100644

drivers/net/usb/cdc_ncm.c static int cdc_ncm_init(struct usbnet *dev) · line 364

Quoted 9 lines
drivers/net/usb/cdc_ncm.c +2 -1
@@ -357,7 +357,8 @@ static int cdc_ncm_init(struct usbnet *dev)
 	 * "The host shall only send this command while the NCM Data
 	 *  Interface is in alternate setting 0."
 	 */
-	if (le16_to_cpu(ctx->ncm_parm.bmNtbFormatsSupported) & USB_CDC_NCM_NTH32_SIGN) {
+	if (le16_to_cpu(ctx->ncm_parm.bmNtbFormatsSupported) &
+						USB_CDC_NCM_NTB32_SUPPORTED) {
 		dev_dbg(&dev->intf->dev, "Setting NTB format to 16-bit\n");
 		err = usbnet_write_cmd(dev, USB_CDC_SET_NTB_FORMAT,
 				       USB_TYPE_CLASS | USB_DIR_OUT

Thanks! Yes, that is correct.

I actually thought I had fixed that bug a while ago, but instead I managed to just copy it while refactoring. Impressive...

It doesn't matter whether (1 << 0) is set. In fact it always will be. What makes this work despite the bug is that no other bits will ever be set - they are all reserved and must be zero. But the spec also requires us to ignore them, so your fix is definitely needed.

Bjørn
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maintainer Applied
#2 lore raw
In reply to Dan Carpenter

From: Dan Carpenter <[email protected]>
Date: Thu, 22 May 2014 10:52:29 +0300

Quoted 7 lines

There is a typo here where we test for USB_CDC_NCM_NTH32_SIGN instead of USB_CDC_NCM_NTB32_SUPPORTED. The test probably still works as written because 0x686D636E has (1 << 1) set and doesn't have (1 << 0) set.

Fixes f8afb73da375 ('net: cdc_ncm: factor out one-time device initialization')
Signed-off-by Dan Carpenter <[email protected]>

Applied to net-next, thanks.