* Re: [PATCH net-next] net: fec: implement TSO descriptor cleanup
2025-01-16 13:09 [PATCH net-next] net: fec: implement TSO descriptor cleanup Dheeraj Reddy Jonnalagadda
@ 2025-01-16 18:24 ` Simon Horman
2025-01-17 2:47 ` Wei Fang
2025-01-17 15:30 ` kernel test robot
2 siblings, 0 replies; 5+ messages in thread
From: Simon Horman @ 2025-01-16 18:24 UTC (permalink / raw)
To: Dheeraj Reddy Jonnalagadda
Cc: wei.fang, shenwei.wang, xiaoning.wang, andrew+netdev, davem,
edumazet, kuba, pabeni, imx, netdev, linux-kernel
On Thu, Jan 16, 2025 at 06:39:20PM +0530, Dheeraj Reddy Jonnalagadda wrote:
> Implement the TODO in fec_enet_txq_submit_tso() error path to properly
> release buffer descriptors that were allocated during a failed TSO
> operation. This prevents descriptor leaks when TSO operations fail
> partway through.
>
> The cleanup iterates from the starting descriptor to where the error
> occurred, resetting the status and buffer address fields of each
> descriptor.
>
> Signed-off-by: Dheeraj Reddy Jonnalagadda <dheeraj.linuxdev@gmail.com>
> ---
> drivers/net/ethernet/freescale/fec_main.c | 13 ++++++++++++-
> 1 file changed, 12 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/net/ethernet/freescale/fec_main.c b/drivers/net/ethernet/freescale/fec_main.c
> index b2daed55bf6c..eff065010c9e 100644
> --- a/drivers/net/ethernet/freescale/fec_main.c
> +++ b/drivers/net/ethernet/freescale/fec_main.c
> @@ -913,7 +913,18 @@ static int fec_enet_txq_submit_tso(struct fec_enet_priv_tx_q *txq,
> return 0;
>
> err_release:
> - /* TODO: Release all used data descriptors for TSO */
> + /* Release all used data descriptors for TSO */
> + struct bufdesc *tmp_bdp = txq->bd.cur;
Hi Dheeraj,
This is not a full review. But variable declarations
should appear at the top of the block they are in,
in this case that would be at the top of the function.
> +
> + while (tmp_bdp != bdp) {
> + tmp_bdp->cbd_sc = 0;
> + tmp_bdp->cbd_bufaddr = 0;
> + tmp_bdp->cbd_datlen = 0;
> + tmp_bdp = fec_enet_get_nextdesc(tmp_bdp, &txq->bd);
> + }
> +
> + dev_kfree_skb_any(skb);
> +
> return ret;
> }
--
pw-bot: changes-requested
^ permalink raw reply [flat|nested] 5+ messages in thread* RE: [PATCH net-next] net: fec: implement TSO descriptor cleanup
2025-01-16 13:09 [PATCH net-next] net: fec: implement TSO descriptor cleanup Dheeraj Reddy Jonnalagadda
2025-01-16 18:24 ` Simon Horman
@ 2025-01-17 2:47 ` Wei Fang
2025-01-18 4:23 ` Dheeraj Reddy Jonnalagadda
2025-01-17 15:30 ` kernel test robot
2 siblings, 1 reply; 5+ messages in thread
From: Wei Fang @ 2025-01-17 2:47 UTC (permalink / raw)
To: Dheeraj Reddy Jonnalagadda, Shenwei Wang, Clark Wang
Cc: andrew+netdev@lunn.ch, davem@davemloft.net, edumazet@google.com,
kuba@kernel.org, pabeni@redhat.com, imx@lists.linux.dev,
netdev@vger.kernel.org, linux-kernel@vger.kernel.org
> Implement the TODO in fec_enet_txq_submit_tso() error path to properly
> release buffer descriptors that were allocated during a failed TSO
> operation. This prevents descriptor leaks when TSO operations fail
> partway through.
>
> The cleanup iterates from the starting descriptor to where the error
> occurred, resetting the status and buffer address fields of each
> descriptor.
>
> Signed-off-by: Dheeraj Reddy Jonnalagadda <dheeraj.linuxdev@gmail.com>
> ---
> drivers/net/ethernet/freescale/fec_main.c | 13 ++++++++++++-
> 1 file changed, 12 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/net/ethernet/freescale/fec_main.c
> b/drivers/net/ethernet/freescale/fec_main.c
> index b2daed55bf6c..eff065010c9e 100644
> --- a/drivers/net/ethernet/freescale/fec_main.c
> +++ b/drivers/net/ethernet/freescale/fec_main.c
> @@ -913,7 +913,18 @@ static int fec_enet_txq_submit_tso(struct
> fec_enet_priv_tx_q *txq,
> return 0;
>
> err_release:
> - /* TODO: Release all used data descriptors for TSO */
> + /* Release all used data descriptors for TSO */
> + struct bufdesc *tmp_bdp = txq->bd.cur;
> +
> + while (tmp_bdp != bdp) {
> + tmp_bdp->cbd_sc = 0;
> + tmp_bdp->cbd_bufaddr = 0;
> + tmp_bdp->cbd_datlen = 0;
> + tmp_bdp = fec_enet_get_nextdesc(tmp_bdp, &txq->bd);
> + }
There is still some cleanup to do.
1. If bufdesc_ex is used, we also need to clear it, such as ebdp->cbd_esc.
2. The data buffers have been mapped in fec_enet_txq_put_data_tso(),
I think we need to unmap them in the error path. But do not unmap
the TSO header buff, which is a DMA memory. Actually it is not necessary
for fec_enet_txq_put_hdr_tso() to call dma_map_single(). If you are
interested, you can add a separate patch to remove dma_map_single()
in fec_enet_txq_put_hdr_tso().
> +
> + dev_kfree_skb_any(skb);
> +
> return ret;
> }
>
> --
> 2.34.1
^ permalink raw reply [flat|nested] 5+ messages in thread* Re: [PATCH net-next] net: fec: implement TSO descriptor cleanup
2025-01-17 2:47 ` Wei Fang
@ 2025-01-18 4:23 ` Dheeraj Reddy Jonnalagadda
0 siblings, 0 replies; 5+ messages in thread
From: Dheeraj Reddy Jonnalagadda @ 2025-01-18 4:23 UTC (permalink / raw)
To: Wei Fang
Cc: Shenwei Wang, Clark Wang, andrew+netdev@lunn.ch,
davem@davemloft.net, edumazet@google.com, kuba@kernel.org,
pabeni@redhat.com, imx@lists.linux.dev, netdev@vger.kernel.org,
linux-kernel@vger.kernel.org
On Fri, Jan 17, 2025 at 02:47:33AM +0000, Wei Fang wrote:
> > Implement the TODO in fec_enet_txq_submit_tso() error path to properly
> > release buffer descriptors that were allocated during a failed TSO
> > operation. This prevents descriptor leaks when TSO operations fail
> > partway through.
> >
> > The cleanup iterates from the starting descriptor to where the error
> > occurred, resetting the status and buffer address fields of each
> > descriptor.
> >
> > Signed-off-by: Dheeraj Reddy Jonnalagadda <dheeraj.linuxdev@gmail.com>
> > ---
> > drivers/net/ethernet/freescale/fec_main.c | 13 ++++++++++++-
> > 1 file changed, 12 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/net/ethernet/freescale/fec_main.c
> > b/drivers/net/ethernet/freescale/fec_main.c
> > index b2daed55bf6c..eff065010c9e 100644
> > --- a/drivers/net/ethernet/freescale/fec_main.c
> > +++ b/drivers/net/ethernet/freescale/fec_main.c
> > @@ -913,7 +913,18 @@ static int fec_enet_txq_submit_tso(struct
> > fec_enet_priv_tx_q *txq,
> > return 0;
> >
> > err_release:
> > - /* TODO: Release all used data descriptors for TSO */
> > + /* Release all used data descriptors for TSO */
> > + struct bufdesc *tmp_bdp = txq->bd.cur;
> > +
> > + while (tmp_bdp != bdp) {
> > + tmp_bdp->cbd_sc = 0;
> > + tmp_bdp->cbd_bufaddr = 0;
> > + tmp_bdp->cbd_datlen = 0;
> > + tmp_bdp = fec_enet_get_nextdesc(tmp_bdp, &txq->bd);
> > + }
>
> There is still some cleanup to do.
> 1. If bufdesc_ex is used, we also need to clear it, such as ebdp->cbd_esc.
> 2. The data buffers have been mapped in fec_enet_txq_put_data_tso(),
> I think we need to unmap them in the error path. But do not unmap
> the TSO header buff, which is a DMA memory. Actually it is not necessary
> for fec_enet_txq_put_hdr_tso() to call dma_map_single(). If you are
> interested, you can add a separate patch to remove dma_map_single()
> in fec_enet_txq_put_hdr_tso().
>
> > +
> > + dev_kfree_skb_any(skb);
> > +
> > return ret;
> > }
> >
> > --
> > 2.34.1
>
Hello Simon and Fang,
Thank you you valuable feedback. I will incorporate the suggestions and
send the updated patch.
-Dheeraj
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH net-next] net: fec: implement TSO descriptor cleanup
2025-01-16 13:09 [PATCH net-next] net: fec: implement TSO descriptor cleanup Dheeraj Reddy Jonnalagadda
2025-01-16 18:24 ` Simon Horman
2025-01-17 2:47 ` Wei Fang
@ 2025-01-17 15:30 ` kernel test robot
2 siblings, 0 replies; 5+ messages in thread
From: kernel test robot @ 2025-01-17 15:30 UTC (permalink / raw)
To: Dheeraj Reddy Jonnalagadda, wei.fang, shenwei.wang, xiaoning.wang
Cc: llvm, oe-kbuild-all, andrew+netdev, davem, edumazet, kuba, pabeni,
imx, netdev, linux-kernel, Dheeraj Reddy Jonnalagadda
Hi Dheeraj,
kernel test robot noticed the following build warnings:
[auto build test WARNING on net-next/main]
url: https://github.com/intel-lab-lkp/linux/commits/Dheeraj-Reddy-Jonnalagadda/net-fec-implement-TSO-descriptor-cleanup/20250116-211046
base: net-next/main
patch link: https://lore.kernel.org/r/20250116130920.30984-1-dheeraj.linuxdev%40gmail.com
patch subject: [PATCH net-next] net: fec: implement TSO descriptor cleanup
config: s390-allmodconfig (https://download.01.org/0day-ci/archive/20250117/202501172328.IoOTB8n0-lkp@intel.com/config)
compiler: clang version 19.1.3 (https://github.com/llvm/llvm-project ab51eccf88f5321e7c60591c5546b254b6afab99)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250117/202501172328.IoOTB8n0-lkp@intel.com/reproduce)
If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202501172328.IoOTB8n0-lkp@intel.com/
All warnings (new ones prefixed by >>):
In file included from drivers/net/ethernet/freescale/fec_main.c:25:
In file included from include/linux/module.h:19:
In file included from include/linux/elf.h:6:
In file included from arch/s390/include/asm/elf.h:181:
In file included from arch/s390/include/asm/mmu_context.h:11:
In file included from arch/s390/include/asm/pgalloc.h:18:
In file included from include/linux/mm.h:2224:
include/linux/vmstat.h:504:43: warning: arithmetic between different enumeration types ('enum zone_stat_item' and 'enum numa_stat_item') [-Wenum-enum-conversion]
504 | return vmstat_text[NR_VM_ZONE_STAT_ITEMS +
| ~~~~~~~~~~~~~~~~~~~~~ ^
505 | item];
| ~~~~
include/linux/vmstat.h:511:43: warning: arithmetic between different enumeration types ('enum zone_stat_item' and 'enum numa_stat_item') [-Wenum-enum-conversion]
511 | return vmstat_text[NR_VM_ZONE_STAT_ITEMS +
| ~~~~~~~~~~~~~~~~~~~~~ ^
512 | NR_VM_NUMA_EVENT_ITEMS +
| ~~~~~~~~~~~~~~~~~~~~~~
include/linux/vmstat.h:524:43: warning: arithmetic between different enumeration types ('enum zone_stat_item' and 'enum numa_stat_item') [-Wenum-enum-conversion]
524 | return vmstat_text[NR_VM_ZONE_STAT_ITEMS +
| ~~~~~~~~~~~~~~~~~~~~~ ^
525 | NR_VM_NUMA_EVENT_ITEMS +
| ~~~~~~~~~~~~~~~~~~~~~~
>> drivers/net/ethernet/freescale/fec_main.c:917:2: warning: label followed by a declaration is a C23 extension [-Wc23-extensions]
917 | struct bufdesc *tmp_bdp = txq->bd.cur;
| ^
4 warnings generated.
vim +917 drivers/net/ethernet/freescale/fec_main.c
835
836 static int fec_enet_txq_submit_tso(struct fec_enet_priv_tx_q *txq,
837 struct sk_buff *skb,
838 struct net_device *ndev)
839 {
840 struct fec_enet_private *fep = netdev_priv(ndev);
841 int hdr_len, total_len, data_left;
842 struct bufdesc *bdp = txq->bd.cur;
843 struct tso_t tso;
844 unsigned int index = 0;
845 int ret;
846
847 if (tso_count_descs(skb) >= fec_enet_get_free_txdesc_num(txq)) {
848 dev_kfree_skb_any(skb);
849 if (net_ratelimit())
850 netdev_err(ndev, "NOT enough BD for TSO!\n");
851 return NETDEV_TX_OK;
852 }
853
854 /* Protocol checksum off-load for TCP and UDP. */
855 if (fec_enet_clear_csum(skb, ndev)) {
856 dev_kfree_skb_any(skb);
857 return NETDEV_TX_OK;
858 }
859
860 /* Initialize the TSO handler, and prepare the first payload */
861 hdr_len = tso_start(skb, &tso);
862
863 total_len = skb->len - hdr_len;
864 while (total_len > 0) {
865 char *hdr;
866
867 index = fec_enet_get_bd_index(bdp, &txq->bd);
868 data_left = min_t(int, skb_shinfo(skb)->gso_size, total_len);
869 total_len -= data_left;
870
871 /* prepare packet headers: MAC + IP + TCP */
872 hdr = txq->tso_hdrs + index * TSO_HEADER_SIZE;
873 tso_build_hdr(skb, hdr, &tso, data_left, total_len == 0);
874 ret = fec_enet_txq_put_hdr_tso(txq, skb, ndev, bdp, index);
875 if (ret)
876 goto err_release;
877
878 while (data_left > 0) {
879 int size;
880
881 size = min_t(int, tso.size, data_left);
882 bdp = fec_enet_get_nextdesc(bdp, &txq->bd);
883 index = fec_enet_get_bd_index(bdp, &txq->bd);
884 ret = fec_enet_txq_put_data_tso(txq, skb, ndev,
885 bdp, index,
886 tso.data, size,
887 size == data_left,
888 total_len == 0);
889 if (ret)
890 goto err_release;
891
892 data_left -= size;
893 tso_build_data(skb, &tso, size);
894 }
895
896 bdp = fec_enet_get_nextdesc(bdp, &txq->bd);
897 }
898
899 /* Save skb pointer */
900 txq->tx_buf[index].buf_p = skb;
901
902 skb_tx_timestamp(skb);
903 txq->bd.cur = bdp;
904
905 /* Trigger transmission start */
906 if (!(fep->quirks & FEC_QUIRK_ERR007885) ||
907 !readl(txq->bd.reg_desc_active) ||
908 !readl(txq->bd.reg_desc_active) ||
909 !readl(txq->bd.reg_desc_active) ||
910 !readl(txq->bd.reg_desc_active))
911 writel(0, txq->bd.reg_desc_active);
912
913 return 0;
914
915 err_release:
916 /* Release all used data descriptors for TSO */
> 917 struct bufdesc *tmp_bdp = txq->bd.cur;
918
919 while (tmp_bdp != bdp) {
920 tmp_bdp->cbd_sc = 0;
921 tmp_bdp->cbd_bufaddr = 0;
922 tmp_bdp->cbd_datlen = 0;
923 tmp_bdp = fec_enet_get_nextdesc(tmp_bdp, &txq->bd);
924 }
925
926 dev_kfree_skb_any(skb);
927
928 return ret;
929 }
930
--
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki
^ permalink raw reply [flat|nested] 5+ messages in thread