[PATCH] [22/275] USB: EHCI: fix DMA deallocation bug

[Andi Kleen]

2.6.35-longterm review patch.  If anyone has any objections, please let me know.

------------------
From: Alan Stern <stern@xxxxxxxxxxxxxxxxxxx>

commit f75593ceaa08e6d27aec1a5de31cded19e850dd1 upstream.

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@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Andi Kleen <ak@xxxxxxxxxxxxxxx>
Tested-by: Larry Finger <Larry.Finger@xxxxxxxxxxxx>
CC: David Brownell <david-b@xxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>

---
 drivers/usb/host/ehci-hcd.c |   19 ++++++++++++-------
 1 file changed, 12 insertions(+), 7 deletions(-)

Index: linux-2.6.35.y/drivers/usb/host/ehci-hcd.c
===================================================================
--- linux-2.6.35.y.orig/drivers/usb/host/ehci-hcd.c	2011-03-29 23:02:58.277344248 -0700
+++ linux-2.6.35.y/drivers/usb/host/ehci-hcd.c	2011-03-29 23:02:58.672334141 -0700
@@ -544,6 +544,8 @@
 	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.
@@ -551,11 +553,20 @@
 	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
@@ -604,12 +615,6 @@
 		/* 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();
-		}
 	}
 	ehci->command = temp;
 
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/