[025/272] USB: EHCI: fix DMA deallocation bug

Greg KH
2011-02-16T00:18:38Z

From: Alan Stern <stern@rowland.harvard.edu>

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

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

--- 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 */