Re: [PATCH net-next v6] page_pool: disable dma mapping support for 32-bit arch with 64-bit DMA
From: Guillaume Tucker
Date: Fri Nov 12 2021 - 04:21:29 EST
On 09/11/2021 12:02, Yunsheng Lin wrote:
> On 2021/11/9 17:58, Guillaume Tucker wrote:
>> Hi Yunsheng,
>>
>> Please see the bisection report below about a boot failure on
>> rk3288-rock2-square which is pointing to this patch. The issue
>> appears to only happen with CONFIG_ARM_LPAE=y.
>>
>> Reports aren't automatically sent to the public while we're
>> trialing new bisection features on kernelci.org but this one
>> looks valid.
>>
>> Some more details can be found here:
>>
>> https://linux.kernelci.org/test/case/id/6189968c3ec0a3c06e3358fe/
>>
>> Here's the same revision on the same platform booting fine with a
>> plain multi_v7_defconfig build:
>>
>> https://linux.kernelci.org/test/plan/id/61899d322c0e9fee7e3358ec/
>>
>> Please let us know if you need any help debugging this issue or
>> if you have a fix to try.
>
> The patch below is removing the dma mapping support in page pool
> for 32 bit systems with 64 bit dma address, so it seems there
> is indeed a a drvier using the the page pool with PP_FLAG_DMA_MAP
> flags set in a 32 bit systems with 64 bit dma address.
>
> It seems we might need to revert the below patch or implement the
> DMA-mapping tracking support in the driver as mentioned in the below
> commit log.
>
> which ethernet driver do you use in your system?
Thanks for taking a look and sorry for the slow reply. Here's a
booting test job with LPAE disabled:
https://linux.kernelci.org/test/plan/id/618dbb81c60c4d94503358f1/
https://storage.kernelci.org/mainline/master/v5.15-12452-g5833291ab6de/arm/multi_v7_defconfig/gcc-10/lab-collabora/baseline-nfs-rk3288-rock2-square.html#L812
[ 8.314523] rk_gmac-dwmac ff290000.ethernet eth0: Link is Up - 1Gbps/Full - flow control rx/tx
So the driver is drivers/net/ethernet/stmicro/stmmac/dwmac-rk.c
Best wishes,
Guillaume
>> GitHub: https://github.com/kernelci/kernelci-project/issues/71
>>
>> -------------------------------------------------------------------------------
>>
>> * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
>> * This automated bisection report was sent to you on the basis *
>> * that you may be involved with the breaking commit it has *
>> * found. No manual investigation has been done to verify it, *
>> * and the root cause of the problem may be somewhere else. *
>> * *
>> * If you do send a fix, please include this trailer: *
>> * Reported-by: "kernelci.org bot" <bot@xxxxxxxxxxxx> *
>> * *
>> * Hope this helps! *
>> * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
>>
>> mainline/master bisection: baseline.login on rk3288-rock2-square
>>
>> Summary:
>> Start: e851dfae4371d Merge tag 'kgdb-5.16-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/danielt/linux
>> Plain log: https://storage.kernelci.org/mainline/master/v5.15-11387-ge851dfae4371/arm/multi_v7_defconfig+CONFIG_EFI=y+CONFIG_ARM_LPAE=y/gcc-10/lab-collabora/baseline-rk3288-rock2-square.txt
>> HTML log: https://storage.kernelci.org/mainline/master/v5.15-11387-ge851dfae4371/arm/multi_v7_defconfig+CONFIG_EFI=y+CONFIG_ARM_LPAE=y/gcc-10/lab-collabora/baseline-rk3288-rock2-square.html
>> Result: d00e60ee54b12 page_pool: disable dma mapping support for 32-bit arch with 64-bit DMA
>>
>> Checks:
>> revert: PASS
>> verify: PASS
>>
>> Parameters:
>> Tree: mainline
>> URL: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
>> Branch: master
>> Target: rk3288-rock2-square
>> CPU arch: arm
>> Lab: lab-collabora
>> Compiler: gcc-10
>> Config: multi_v7_defconfig+CONFIG_EFI=y+CONFIG_ARM_LPAE=y
>> Test case: baseline.login
>>
>> Breaking commit found:
>>
>> -------------------------------------------------------------------------------
>> commit d00e60ee54b12de945b8493cf18c1ada9e422514
>> Author: Yunsheng Lin <linyunsheng@xxxxxxxxxx>
>> Date: Wed Oct 13 17:19:20 2021 +0800
>>
>> page_pool: disable dma mapping support for 32-bit arch with 64-bit DMA
>>
>>
>> On 13/10/2021 10:19, Yunsheng Lin wrote:
>>> As the 32-bit arch with 64-bit DMA seems to rare those days,
>>> and page pool might carry a lot of code and complexity for
>>> systems that possibly.
>>>
>>> So disable dma mapping support for such systems, if drivers
>>> really want to work on such systems, they have to implement
>>> their own DMA-mapping fallback tracking outside page_pool.
>>>
>>> Reviewed-by: Ilias Apalodimas <ilias.apalodimas@xxxxxxxxxx>
>>> Signed-off-by: Yunsheng Lin <linyunsheng@xxxxxxxxxx>
>>> ---
>>> V6: Drop pp page tracking support
>>> ---
>>> include/linux/mm_types.h | 13 +------------
>>> include/net/page_pool.h | 12 +-----------
>>> net/core/page_pool.c | 10 ++++++----
>>> 3 files changed, 8 insertions(+), 27 deletions(-)
>>>
>>> diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
>>> index 7f8ee09c711f..436e0946d691 100644
>>> --- a/include/linux/mm_types.h
>>> +++ b/include/linux/mm_types.h
>>> @@ -104,18 +104,7 @@ struct page {
>>> struct page_pool *pp;
>>> unsigned long _pp_mapping_pad;
>>> unsigned long dma_addr;
>>> - union {
>>> - /**
>>> - * dma_addr_upper: might require a 64-bit
>>> - * value on 32-bit architectures.
>>> - */
>>> - unsigned long dma_addr_upper;
>>> - /**
>>> - * For frag page support, not supported in
>>> - * 32-bit architectures with 64-bit DMA.
>>> - */
>>> - atomic_long_t pp_frag_count;
>>> - };
>>> + atomic_long_t pp_frag_count;
>>> };
>>> struct { /* slab, slob and slub */
>>> union {
>>> diff --git a/include/net/page_pool.h b/include/net/page_pool.h
>>> index a4082406a003..3855f069627f 100644
>>> --- a/include/net/page_pool.h
>>> +++ b/include/net/page_pool.h
>>> @@ -216,24 +216,14 @@ static inline void page_pool_recycle_direct(struct page_pool *pool,
>>> page_pool_put_full_page(pool, page, true);
>>> }
>>>
>>> -#define PAGE_POOL_DMA_USE_PP_FRAG_COUNT \
>>> - (sizeof(dma_addr_t) > sizeof(unsigned long))
>>> -
>>> static inline dma_addr_t page_pool_get_dma_addr(struct page *page)
>>> {
>>> - dma_addr_t ret = page->dma_addr;
>>> -
>>> - if (PAGE_POOL_DMA_USE_PP_FRAG_COUNT)
>>> - ret |= (dma_addr_t)page->dma_addr_upper << 16 << 16;
>>> -
>>> - return ret;
>>> + return page->dma_addr;
>>> }
>>>
>>> static inline void page_pool_set_dma_addr(struct page *page, dma_addr_t addr)
>>> {
>>> page->dma_addr = addr;
>>> - if (PAGE_POOL_DMA_USE_PP_FRAG_COUNT)
>>> - page->dma_addr_upper = upper_32_bits(addr);
>>> }
>>>
>>> static inline void page_pool_set_frag_count(struct page *page, long nr)
>>> diff --git a/net/core/page_pool.c b/net/core/page_pool.c
>>> index 1a6978427d6c..9b60e4301a44 100644
>>> --- a/net/core/page_pool.c
>>> +++ b/net/core/page_pool.c
>>> @@ -49,6 +49,12 @@ static int page_pool_init(struct page_pool *pool,
>>> * which is the XDP_TX use-case.
>>> */
>>> if (pool->p.flags & PP_FLAG_DMA_MAP) {
>>> + /* DMA-mapping is not supported on 32-bit systems with
>>> + * 64-bit DMA mapping.
>>> + */
>>> + if (sizeof(dma_addr_t) > sizeof(unsigned long))
>>> + return -EOPNOTSUPP;
>>> +
>>> if ((pool->p.dma_dir != DMA_FROM_DEVICE) &&
>>> (pool->p.dma_dir != DMA_BIDIRECTIONAL))
>>> return -EINVAL;
>>> @@ -69,10 +75,6 @@ static int page_pool_init(struct page_pool *pool,
>>> */
>>> }
>>>
>>> - if (PAGE_POOL_DMA_USE_PP_FRAG_COUNT &&
>>> - pool->p.flags & PP_FLAG_PAGE_FRAG)
>>> - return -EINVAL;
>>> -
>>> if (ptr_ring_init(&pool->ring, ring_qsize, GFP_KERNEL) < 0)
>>> return -ENOMEM;
>>>
>>>
>>
>>
>>
>> Git bisection log:
>>
>> -------------------------------------------------------------------------------
>> git bisect start
>> # good: [bfc484fe6abba4b89ec9330e0e68778e2a9856b2] Merge branch 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6
>> git bisect good bfc484fe6abba4b89ec9330e0e68778e2a9856b2
>> # bad: [e851dfae4371d3c751f1e18e8eb5eba993de1467] Merge tag 'kgdb-5.16-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/danielt/linux
>> git bisect bad e851dfae4371d3c751f1e18e8eb5eba993de1467
>> # bad: [dcd68326d29b62f3039e4f4d23d3e38f24d37360] Merge tag 'devicetree-for-5.16' of git://git.kernel.org/pub/scm/linux/kernel/git/robh/linux
>> git bisect bad dcd68326d29b62f3039e4f4d23d3e38f24d37360
>> # bad: [b7b98f868987cd3e86c9bd9a6db048614933d7a0] Merge https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next
>> git bisect bad b7b98f868987cd3e86c9bd9a6db048614933d7a0
>> # bad: [9fd3d5dced976640f588e0a866b9611db2d2cb37] net: ethernet: ave: Add compatible string and SoC-dependent data for NX1 SoC
>> git bisect bad 9fd3d5dced976640f588e0a866b9611db2d2cb37
>> # good: [a96d317fb1a30b9f323548eb2ff05d4e4600ead9] ethernet: use eth_hw_addr_set()
>> git bisect good a96d317fb1a30b9f323548eb2ff05d4e4600ead9
>> # good: [f5396b8a663f7a78ee5b75a47ee524b40795b265] ice: switchdev slow path
>> git bisect good f5396b8a663f7a78ee5b75a47ee524b40795b265
>> # good: [20c3d9e45ba630a7156d682a40988c0e96be1b92] hamradio: use dev_addr_set() for setting device address
>> git bisect good 20c3d9e45ba630a7156d682a40988c0e96be1b92
>> # bad: [a64b442137669c9e839c6a70965989b01b1253b7] net: dpaa2: add support for manual setup of IRQ coalesing
>> git bisect bad a64b442137669c9e839c6a70965989b01b1253b7
>> # good: [30fc7efa38f21afa48b0be6bf2053e4c10ae2c78] net, neigh: Reject creating NUD_PERMANENT with NTF_MANAGED entries
>> git bisect good 30fc7efa38f21afa48b0be6bf2053e4c10ae2c78
>> # bad: [13ad5ccc093ff448b99ac7e138e91e78796adb48] dt-bindings: net: dsa: qca8k: Document qca,sgmii-enable-pll
>> git bisect bad 13ad5ccc093ff448b99ac7e138e91e78796adb48
>> # good: [40088915f547b52635f022c1e1e18df65ae3153a] Merge branch 'octeontx2-af-miscellaneous-changes-for-cpt'
>> git bisect good 40088915f547b52635f022c1e1e18df65ae3153a
>> # bad: [fdbf35df9c091db9c46e57e9938e3f7a4f603a7c] dt-bindings: net: dsa: qca8k: Add SGMII clock phase properties
>> git bisect bad fdbf35df9c091db9c46e57e9938e3f7a4f603a7c
>> # bad: [bacc8daf97d4199316328a5d18eeafbe447143c5] xen-netback: Remove redundant initialization of variable err
>> git bisect bad bacc8daf97d4199316328a5d18eeafbe447143c5
>> # bad: [d00e60ee54b12de945b8493cf18c1ada9e422514] page_pool: disable dma mapping support for 32-bit arch with 64-bit DMA
>> git bisect bad d00e60ee54b12de945b8493cf18c1ada9e422514
>> # first bad commit: [d00e60ee54b12de945b8493cf18c1ada9e422514] page_pool: disable dma mapping support for 32-bit arch with 64-bit DMA
>> -------------------------------------------------------------------------------
>> .
>>