USB: set device dma_mask without reference to global data
Many USB host drivers contain code such as:
if (!pdev->dev.dma_mask)
pdev->dev.dma_mask = &tegra_ehci_dma_mask;
... where tegra_ehci_dma_mask is a global. I suspect this code originated
in commit 4a53f4e "USB: ehci-tegra: add probing through device tree" and
was simply copied everywhere else.
This works fine when the code is built-in, but can cause a crash when the
code is in a module. The first module load sets up the dma_mask pointer,
but if the module is removed and re-inserted, the value is now non-NULL,
and hence is not updated to point at the new location, and hence points
at a stale location within the previous module load address, which in
turn causes a crash if the pointer is de-referenced.
The simplest way of solving this seems to be to copy the code from
ehci-platform.c, which uses the coherent_dma_mask as the target for the
dma_mask pointer.
Suggested-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Stephen Warren <swarren@nvidia.com>
Acked-by: Tony Prisk <linux@prisktech.co.nz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/usb/host/ehci-omap.c b/drivers/usb/host/ehci-omap.c
index 3d1491b..16d7150 100644
--- a/drivers/usb/host/ehci-omap.c
+++ b/drivers/usb/host/ehci-omap.c
@@ -90,8 +90,6 @@
.extra_priv_size = sizeof(struct omap_hcd),
};
-static u64 omap_ehci_dma_mask = DMA_BIT_MASK(32);
-
/**
* ehci_hcd_omap_probe - initialize TI-based HCDs
*
@@ -146,8 +144,10 @@
* Since shared usb code relies on it, set it here for now.
* Once we have dma capability bindings this can go away.
*/
- if (!pdev->dev.dma_mask)
- pdev->dev.dma_mask = &omap_ehci_dma_mask;
+ if (!dev->dma_mask)
+ dev->dma_mask = &dev->coherent_dma_mask;
+ if (!dev->coherent_dma_mask)
+ dev->coherent_dma_mask = DMA_BIT_MASK(32);
hcd = usb_create_hcd(&ehci_omap_hc_driver, dev,
dev_name(dev));