From: Alan Stern <stern@rowland.harvard.edu>
Date: Thu, 6 Jan 2011 15:17:09 +0000 (-0500)
Subject: USB: EHCI: fix DMA deallocation bug
X-Git-Tag: v2.6.38-rc3~7^2~17
X-Git-Url: https://asedeno.scripts.mit.edu/gitweb/?a=commitdiff_plain;h=f75593ceaa08e6d27aec1a5de31cded19e850dd1;p=linux.git

USB: EHCI: fix DMA deallocation bug

This patch (as1440) fixes a bug in ehci-hcd.  ehci->periodic_size is
used to compute the size in a dma_alloc_coherent() call, but then it
gets changed later on.  As a result, the corresponding call to
dma_free_coherent() passes a different size from the original
allocation.  Fix the problem by adjusting ehci->periodic_size before
carrying out any of the memory allocations.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Tested-by: Larry Finger <Larry.Finger@lwfinger.net>
CC: David Brownell <david-b@pacbell.net>
CC: <stable@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
---

diff --git a/drivers/usb/host/ehci-hcd.c b/drivers/usb/host/ehci-hcd.c
index 6fee3cd58efe..74dcf49bd015 100644
--- a/drivers/usb/host/ehci-hcd.c
+++ b/drivers/usb/host/ehci-hcd.c
@@ -572,6 +572,8 @@ static int ehci_init(struct usb_hcd *hcd)
 	ehci->iaa_watchdog.function = ehci_iaa_watchdog;
 	ehci->iaa_watchdog.data = (unsigned long) ehci;
 
+	hcc_params = ehci_readl(ehci, &ehci->caps->hcc_params);
+
 	/*
 	 * hw default: 1K periodic list heads, one per frame.
 	 * periodic_size can shrink by USBCMD update if hcc_params allows.
@@ -579,11 +581,20 @@ static int ehci_init(struct usb_hcd *hcd)
 	ehci->periodic_size = DEFAULT_I_TDPS;
 	INIT_LIST_HEAD(&ehci->cached_itd_list);
 	INIT_LIST_HEAD(&ehci->cached_sitd_list);
+
+	if (HCC_PGM_FRAMELISTLEN(hcc_params)) {
+		/* periodic schedule size can be smaller than default */
+		switch (EHCI_TUNE_FLS) {
+		case 0: ehci->periodic_size = 1024; break;
+		case 1: ehci->periodic_size = 512; break;
+		case 2: ehci->periodic_size = 256; break;
+		default:	BUG();
+		}
+	}
 	if ((retval = ehci_mem_init(ehci, GFP_KERNEL)) < 0)
 		return retval;
 
 	/* controllers may cache some of the periodic schedule ... */
-	hcc_params = ehci_readl(ehci, &ehci->caps->hcc_params);
 	if (HCC_ISOC_CACHE(hcc_params))		// full frame cache
 		ehci->i_thresh = 2 + 8;
 	else					// N microframes cached
@@ -637,12 +648,6 @@ static int ehci_init(struct usb_hcd *hcd)
 		/* periodic schedule size can be smaller than default */
 		temp &= ~(3 << 2);
 		temp |= (EHCI_TUNE_FLS << 2);
-		switch (EHCI_TUNE_FLS) {
-		case 0: ehci->periodic_size = 1024; break;
-		case 1: ehci->periodic_size = 512; break;
-		case 2: ehci->periodic_size = 256; break;
-		default:	BUG();
-		}
 	}
 	if (HCC_LPM(hcc_params)) {
 		/* support link power management EHCI 1.1 addendum */