patch "drivers: base: dma-mapping: page align the size when" added to driver-core-next

patch "drivers: base: dma-mapping: page align the size when" added to driver-core-next

[gregkh]

This is a note to let you know that I've just added the patch titled

    drivers: base: dma-mapping: page align the size when

to my driver-core git tree which can be found at
    git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core.git
in the driver-core-next branch.

The patch will show up in the next release of the linux-next tree
(usually sometime within the next 24 hours during the week.)

The patch will also be merged in the next major kernel release
during the merge window.

If you have any questions about this process, please let me know.


>From 85714108e673cdebf1b96abfd50fb02a29e37577 Mon Sep 17 00:00:00 2001
From: Peng Fan <van.freenix@gmail.com>
Date: Thu, 21 Jul 2016 16:04:21 +0800
Subject: drivers: base: dma-mapping: page align the size when
 unmap_kernel_range

When dma_common_free_remap, the input parameter 'size' may not
be page aligned. And, met kernel warning when doing iommu dma
for usb on i.MX8 platform:
"
WARNING: CPU: 0 PID: 869 at mm/vmalloc.c:70 vunmap_page_range+0x1cc/0x1d0()
Modules linked in:
CPU: 0 PID: 869 Comm: kworker/u8:2 Not tainted 4.1.12-00444-gc5f9d1d-dirty #147
Hardware name: Freescale i.MX8DV Sabreauto (DT)
Workqueue: ci_otg ci_otg_work
Call trace:
[<ffffffc000089920>] dump_backtrace+0x0/0x124
[<ffffffc000089a54>] show_stack+0x10/0x1c
[<ffffffc0006d1e6c>] dump_stack+0x84/0xc8
[<ffffffc0000b4568>] warn_slowpath_common+0x98/0xd0
[<ffffffc0000b4664>] warn_slowpath_null+0x14/0x20
[<ffffffc000170348>] vunmap_page_range+0x1c8/0x1d0
[<ffffffc000170388>] unmap_kernel_range+0x20/0x88
[<ffffffc000460ad0>] dma_common_free_remap+0x74/0x84
[<ffffffc0000940d8>] __iommu_free_attrs+0x9c/0x178
[<ffffffc0005032bc>] ehci_mem_cleanup+0x140/0x194
[<ffffffc000503548>] ehci_stop+0x8c/0xdc
[<ffffffc0004e8258>] usb_remove_hcd+0xf0/0x1cc
[<ffffffc000516bc0>] host_stop+0x1c/0x58
[<ffffffc000514240>] ci_otg_work+0xdc/0x120
[<ffffffc0000c9c34>] process_one_work+0x134/0x33c
[<ffffffc0000c9f78>] worker_thread+0x13c/0x47c
[<ffffffc0000cf43c>] kthread+0xd8/0xf0
"

For dma_common_pages_remap:
dma_common_pages_remap
   |->get_vm_area_caller
        |->__get_vm_area_node
            |->size = PAGE_ALIGN(size);   Round up to page aligned

So, in dma_common_free_remap, we also need a page aligned size,
pass 'PAGE_ALIGN(size)' to unmap_kernel_range.

Signed-off-by: Peng Fan <van.freenix@gmail.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/base/dma-mapping.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/base/dma-mapping.c b/drivers/base/dma-mapping.c
index d799662f19eb..261420ddfe66 100644
--- a/drivers/base/dma-mapping.c
+++ b/drivers/base/dma-mapping.c
@@ -334,7 +334,7 @@ void dma_common_free_remap(void *cpu_addr, size_t size, unsigned long vm_flags)
 		return;
 	}
 
-	unmap_kernel_range((unsigned long)cpu_addr, size);
+	unmap_kernel_range((unsigned long)cpu_addr, PAGE_ALIGN(size));
 	vunmap(cpu_addr);
 }
 #endif
-- 
2.9.3