* FAILED: patch "[PATCH] swiotlb: manipulate orig_addr when tlb_addr has offset" failed to apply to 5.10-stable tree
@ 2021-06-25 9:26 ` gregkh
2021-06-28 6:57 ` [PATCH] swiotlb: manipulate orig_addr when tlb_addr has offset Chanho Park
0 siblings, 1 reply; 2+ messages in thread
From: gregkh @ 2021-06-25 9:26 UTC (permalink / raw)
To: bumyong.lee, chanho61.park, dominique.martinet, hch, horia.geanta,
konrad.wilk
Cc: stable
The patch below does not apply to the 5.10-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@vger.kernel.org>.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 5f89468e2f060031cd89fd4287298e0eaf246bf6 Mon Sep 17 00:00:00 2001
From: Bumyong Lee <bumyong.lee@samsung.com>
Date: Mon, 10 May 2021 18:10:04 +0900
Subject: [PATCH] swiotlb: manipulate orig_addr when tlb_addr has offset
MIME-Version: 1.0
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in case of driver wants to sync part of ranges with offset,
swiotlb_tbl_sync_single() copies from orig_addr base to tlb_addr with
offset and ends up with data mismatch.
It was removed from
"swiotlb: don't modify orig_addr in swiotlb_tbl_sync_single",
but said logic has to be added back in.
From Linus's email:
"That commit which the removed the offset calculation entirely, because the old
(unsigned long)tlb_addr & (IO_TLB_SIZE - 1)
was wrong, but instead of removing it, I think it should have just
fixed it to be
(tlb_addr - mem->start) & (IO_TLB_SIZE - 1);
instead. That way the slot offset always matches the slot index calculation."
(Unfortunatly that broke NVMe).
The use-case that drivers are hitting is as follow:
1. Get dma_addr_t from dma_map_single()
dma_addr_t tlb_addr = dma_map_single(dev, vaddr, vsize, DMA_TO_DEVICE);
|<---------------vsize------------->|
+-----------------------------------+
| | original buffer
+-----------------------------------+
vaddr
swiotlb_align_offset
|<----->|<---------------vsize------------->|
+-------+-----------------------------------+
| | | swiotlb buffer
+-------+-----------------------------------+
tlb_addr
2. Do something
3. Sync dma_addr_t through dma_sync_single_for_device(..)
dma_sync_single_for_device(dev, tlb_addr + offset, size, DMA_TO_DEVICE);
Error case.
Copy data to original buffer but it is from base addr (instead of
base addr + offset) in original buffer:
swiotlb_align_offset
|<----->|<- offset ->|<- size ->|
+-------+-----------------------------------+
| | |##########| | swiotlb buffer
+-------+-----------------------------------+
tlb_addr
|<- size ->|
+-----------------------------------+
|##########| | original buffer
+-----------------------------------+
vaddr
The fix is to copy the data to the original buffer and take into
account the offset, like so:
swiotlb_align_offset
|<----->|<- offset ->|<- size ->|
+-------+-----------------------------------+
| | |##########| | swiotlb buffer
+-------+-----------------------------------+
tlb_addr
|<- offset ->|<- size ->|
+-----------------------------------+
| |##########| | original buffer
+-----------------------------------+
vaddr
[One fix which was Linus's that made more sense to as it created a
symmetry would break NVMe. The reason for that is the:
unsigned int offset = (tlb_addr - mem->start) & (IO_TLB_SIZE - 1);
would come up with the proper offset, but it would lose the
alignment (which this patch contains).]
Fixes: 16fc3cef33a0 ("swiotlb: don't modify orig_addr in swiotlb_tbl_sync_single")
Signed-off-by: Bumyong Lee <bumyong.lee@samsung.com>
Signed-off-by: Chanho Park <chanho61.park@samsung.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reported-by: Dominique MARTINET <dominique.martinet@atmark-techno.com>
Reported-by: Horia Geantă <horia.geanta@nxp.com>
Tested-by: Horia Geantă <horia.geanta@nxp.com>
CC: stable@vger.kernel.org
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c
index 8ca7d505d61c..e50df8d8f87e 100644
--- a/kernel/dma/swiotlb.c
+++ b/kernel/dma/swiotlb.c
@@ -334,6 +334,14 @@ void __init swiotlb_exit(void)
io_tlb_default_mem = NULL;
}
+/*
+ * Return the offset into a iotlb slot required to keep the device happy.
+ */
+static unsigned int swiotlb_align_offset(struct device *dev, u64 addr)
+{
+ return addr & dma_get_min_align_mask(dev) & (IO_TLB_SIZE - 1);
+}
+
/*
* Bounce: copy the swiotlb buffer from or back to the original dma location
*/
@@ -346,10 +354,17 @@ static void swiotlb_bounce(struct device *dev, phys_addr_t tlb_addr, size_t size
size_t alloc_size = mem->slots[index].alloc_size;
unsigned long pfn = PFN_DOWN(orig_addr);
unsigned char *vaddr = phys_to_virt(tlb_addr);
+ unsigned int tlb_offset;
if (orig_addr == INVALID_PHYS_ADDR)
return;
+ tlb_offset = (tlb_addr & (IO_TLB_SIZE - 1)) -
+ swiotlb_align_offset(dev, orig_addr);
+
+ orig_addr += tlb_offset;
+ alloc_size -= tlb_offset;
+
if (size > alloc_size) {
dev_WARN_ONCE(dev, 1,
"Buffer overflow detected. Allocation size: %zu. Mapping size: %zu.\n",
@@ -390,14 +405,6 @@ static void swiotlb_bounce(struct device *dev, phys_addr_t tlb_addr, size_t size
#define slot_addr(start, idx) ((start) + ((idx) << IO_TLB_SHIFT))
-/*
- * Return the offset into a iotlb slot required to keep the device happy.
- */
-static unsigned int swiotlb_align_offset(struct device *dev, u64 addr)
-{
- return addr & dma_get_min_align_mask(dev) & (IO_TLB_SIZE - 1);
-}
-
/*
* Carefully handle integer overflow which can occur when boundary_mask == ~0UL.
*/
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