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 6fee3cd..74dcf49 100644 (file)
--- 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 */