In the latest revision of the hardware, if a packet is spanning
across multiple BDs then only VLD bit and current data size info
is valid in each BD, and rest of the information is only valid
in the last BD of the packet. In such case we should make sure
we are fetching RX packet size from the first descriptor and
information like VLAN should be fetched from last BD.
Signed-off-by: NPeng Li <lipeng321@huawei.com>
Reviewed-by: NYisen Zhuang <yisen.zhuang@huawei.com>
Signed-off-by: NSalil Mehta <salil.mehta@huawei.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

When vf module is loading, the cmd queue initialization should
happen before misc interrupt initialization, otherwise the misc
interrupt handle will cause using uninitialized cmd queue problem.
There is also the same issue when vf module is unloading.

This patch fixes it by adjusting the location of some function.

Fixes: e2cb1dec ("net: hns3: Add HNS3 VF HCL(Hardware Compatibility Layer) Support")
Signed-off-by: NYunsheng Lin <linyunsheng@huawei.com>
Signed-off-by: NPeng Li <lipeng321@huawei.com>
Signed-off-by: NSalil Mehta <salil.mehta@huawei.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

If CONFIG_ARM_SMMU_V3 is enabled, arm64's dma_ops will replace
arm64_swiotlb_dma_ops with iommu_dma_ops. When releasing contiguous
dma memory, the new ops will call the vunmap function which cannot
be run in interrupt context.

Currently, spin_lock_bh is called before vunmap is executed. This
disables BH and causes the interrupt context to be detected to
generate a kernel panic like below:

[ 2831.573400] kernel BUG at mm/vmalloc.c:1621!
[ 2831.577659] Internal error: Oops - BUG: 0 [#1] PREEMPT SMP
...
[ 2831.699907] Process rmmod (pid: 1893, stack limit = 0x0000000055103ee2)
[ 2831.706507] Call trace:
[ 2831.708941]  vunmap+0x48/0x50
[ 2831.711897]  dma_common_free_remap+0x78/0x88
[ 2831.716155]  __iommu_free_attrs+0xa8/0x1c0
[ 2831.720255]  hclge_free_cmd_desc+0xc8/0x118 [hclge]
[ 2831.725128]  hclge_destroy_cmd_queue+0x34/0x68 [hclge]
[ 2831.730261]  hclge_uninit_ae_dev+0x90/0x100 [hclge]
[ 2831.735127]  hnae3_unregister_ae_dev+0xb0/0x868 [hnae3]
[ 2831.740345]  hns3_remove+0x3c/0x90 [hns3]
[ 2831.744344]  pci_device_remove+0x48/0x108
[ 2831.748342]  device_release_driver_internal+0x164/0x200
[ 2831.753553]  driver_detach+0x4c/0x88
[ 2831.757116]  bus_remove_driver+0x60/0xc0
[ 2831.761026]  driver_unregister+0x34/0x60
[ 2831.764935]  pci_unregister_driver+0x30/0xb0
[ 2831.769197]  hns3_exit_module+0x10/0x978 [hns3]
[ 2831.773715]  SyS_delete_module+0x1f8/0x248
[ 2831.777799]  el0_svc_naked+0x30/0x34

This patch fixes it by using spin_lock instead of spin_lock_bh.

Fixes: 68c0a5c7 ("net: hns3: Add HNS3 IMP(Integrated Mgmt Proc) Cmd Interface Support")
Signed-off-by: NXi Wang <wangxi11@huawei.com>
Signed-off-by: NPeng Li <lipeng321@huawei.com>
Signed-off-by: NSalil Mehta <salil.mehta@huawei.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The link status update function is called by timer every second. But
net_stop and net_open may be called with very short intervals. The link
status update function can not detect the link state has changed. It
causes the netdev not running problem.

This patch fixes it by updating the link state in ae_stop function.

Fixes: 46a3df9f ("net: hns3: Add HNS3 Acceleration Engine & Compatibility Layer Support")
Signed-off-by: NFuyun Liang <liangfuyun1@huawei.com>
Signed-off-by: NPeng Li <lipeng321@huawei.com>
Signed-off-by: NSalil Mehta <salil.mehta@huawei.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch does bit of a clean-up by using already defined enums for
certain values in function hclge_is_special_opcode(). Below enums from
have been used as replacements for magic values:

enum hclge_opcode_type{
	<snip>
	HCLGE_OPC_STATS_64_BIT		= 0x0030,
	HCLGE_OPC_STATS_32_BIT		= 0x0031,
	HCLGE_OPC_STATS_MAC		= 0x0032,
	<snip>
};
Signed-off-by: NHuazhong Tan <tanhuazhong@huawei.com>
Signed-off-by: NPeng Li <lipeng321@huawei.com>
Signed-off-by: NSalil Mehta <salil.mehta@huawei.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

If the hns3 driver has been built into kernel and then loaded with
the same driver which built as KLM, it may trigger an error like
below:

[   20.009555] hns3: Hisilicon Ethernet Network Driver for Hip08 Family - version
[   20.016789] hns3: Copyright (c) 2017 Huawei Corporation.
[   20.022100] Error: Driver 'hns3' is already registered, aborting...
[   23.517397] Unable to handle kernel NULL pointer dereference at virtual address 00000000
...
[   23.691583] Process insmod (pid: 1982, stack limit = 0x00000000cd5f21cb)
[   23.698270] Call trace:
[   23.700705]  __list_del_entry_valid+0x2c/0xd8
[   23.705049]  hnae3_unregister_client+0x68/0xa8
[   23.709487]  hns3_init_module+0x98/0x1000 [hns3]
[   23.714093]  do_one_initcall+0x5c/0x170
[   23.717918]  do_init_module+0x64/0x1f4
[   23.721654]  load_module+0x1d14/0x24b0
[   23.725390]  SyS_init_module+0x158/0x208
[   23.729300]  el0_svc_naked+0x30/0x34

This patch fixes it by adding module version info.

Fixes: 38caee9d ("net: hns3: Add support of the HNAE3 framework")
Signed-off-by: NXi Wang <wangxi11@huawei.com>
Signed-off-by: NSalil Mehta <salil.mehta@huawei.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch fixes the missing initialization of the client list node
in the hnae3_register_client() function.

Fixes: 76ad4f0e ("net: hns3: Add support of HNS3 Ethernet Driver for hip08 SoC")
Signed-off-by: NXi Wang <wangxi11@huawei.com>
Signed-off-by: NPeng Li <lipeng321@huawei.com>
Signed-off-by: NSalil Mehta <salil.mehta@huawei.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Removes the goto and directly returns in case of errors as part of the
cleanup.
Signed-off-by: NJian Shen <shenjian15@huawei.com>
Signed-off-by: NPeng Li <lipeng321@huawei.com>
Signed-off-by: NSalil Mehta <salil.mehta@huawei.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

During the RX leg driver needs to fetch the ethernet header
length from the RX'ed Buffer Descriptor. Currently, proprietary
version hns3_nic_get_headlen is being used to fetch the header
length which uses l234info present in the Buffer Descriptor
which might not be valid for the first Buffer Descriptor if the
packet is spanning across multiple descriptors.
Kernel default eth_get_headlen API does the job correctly.

Fixes: 76ad4f0e ("net: hns3: Add support of HNS3 Ethernet Driver for hip08 SoC")
Signed-off-by: NPeng Li <lipeng321@huawei.com>
Reviewed-by: NYisen Zhuang <yisen.zhuang@huawei.com>
Signed-off-by: NSalil Mehta <salil.mehta@huawei.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch fixes the error reported by Intel's kbuild and fixes a
return value in one of the legs, caught during review of the original
patch sent by kbuild.

Fixes: fdb793670a00 ("net: hns3: Add support of .sriov_configure in HNS3 driver")
Signed-off-by: NFengguang Wu <fengguang.wu@intel.com>
Signed-off-by: NSalil Mehta <salil.mehta@huawei.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

We call pcim_iomap in hclge_pci_init, pcim_iounmap should be called
in error handle of hclge_init_ae_dev.

We call pcim_iomap in hclge_pci_init, but do not call pcim_iounmap in
hclge_pci_uninit. When we remove the hclge.ko and insert it again, a
problem that pci can not map will happen. pcim_iounmap need to be called
in hclge_pci_uninit.

Fixes: 46a3df9f ("net: hns3: Add HNS3 Acceleration Engine & Compatibility Layer Support")
Signed-off-by: NFuyun Liang <liangfuyun1@huawei.com>
Signed-off-by: NPeng Li <lipeng321@huawei.com>
Signed-off-by: NSalil Mehta <salil.mehta@huawei.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

As HNS3 driver will enable SRIOV default and enable all VFs the
HW support, if PF and VF driver compiled to kernel, VF driver
will work on host default, it is not right.

This patch adds support for hns3_driver.sriov_configure to support
user configs the VF_num, and do not enable sriov default.
Signed-off-by: NPeng Li <lipeng321@huawei.com>
Suggested-by: NZhou Wang <wangzhou1@hisilicon.com>
Signed-off-by: NSalil Mehta <salil.mehta@huawei.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

When hclge_ae_start is called, hdev->hw.mac.link may be set
to one after up/down multi-times, which does not correspond to
the link state of netdev when the netdev is up.

This fixes it by setting hdev->hw.mac.link to zero when
hclge_ae_start is called.

Fixes: 46a3df9f ("net: hns3: Add HNS3 Acceleration Engine & Compatibility Layer Support")
Signed-off-by: NYunsheng Lin <linyunsheng@huawei.com>
Signed-off-by: NPeng Li <lipeng321@huawei.com>
Signed-off-by: NSalil Mehta <salil.mehta@huawei.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

When sriov is enabled, the Qset and tc mapping is not longer one
to one relation.

This patch fixes it by mapping all pf and vf's Qset to tc.

Fixes: 84844054 ("net: hns3: Add support of TX Scheduler & Shaper to HNS3 driver")
Signed-off-by: NYunsheng Lin <linyunsheng@huawei.com>
Signed-off-by: NPeng Li <lipeng321@huawei.com>
Signed-off-by: NSalil Mehta <salil.mehta@huawei.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

A client includes many client instance. Just like ae_algo, Initializing
client instance failed does not represent registering client failed.
The action of registering client just is adding client to the client
list and the result always is true. This patch changes the return
value of hnae3_register_client form a variable value to a fixed value,
makes the function always return ok.
Signed-off-by: NFuyun Liang <liangfuyun1@huawei.com>
Signed-off-by: NPeng Li <lipeng321@huawei.com>
Signed-off-by: NSalil Mehta <salil.mehta@huawei.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The ae_algo is used by many ae_devs. It is not only belong to just a
ae_dev. Initializing ae_dev failed does not represent registering ae_algo
failed. Because the action of registering ae_algo just is adding ae_algo
to the ae_algo list and it is always is true, it make no sense to define
return type as int.

This patch changes the return type of hnae3_register_ae_algo from int to
void.
Signed-off-by: NFuyun Liang <liangfuyun1@huawei.com>
Signed-off-by: NPeng Li <lipeng321@huawei.com>
Signed-off-by: NSalil Mehta <salil.mehta@huawei.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

If hclge.ko has not been inserted, the value of ret always is zero
in hnae3_register_ae_dev. If hclge.ko has been inserted, the value
of ret is zero or non zero. Different execution ways have different
results. It is confusing.

The ae_dev which is initialized failed can be reinitialized when we
remove hclge.ko and insert it again. For the case initializing client
instance, it is just like the case initializing ae_dev. The main function
of hnae3_register_ae_dev is adding the ae_dev to ad_dev list. Because
adding ae_dev is always ok, we does not need to return any in this
function.

This patch changes the return type of hnae3_register_ae_dev from int
to void.
Signed-off-by: NFuyun Liang <liangfuyun1@huawei.com>
Signed-off-by: NPeng Li <lipeng321@huawei.com>
Signed-off-by: NSalil Mehta <salil.mehta@huawei.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

If the client instance is initializd failed, we do not need to uninit it.
This patch adds a state check to check init state of client instance.

Fixes: 38caee9d ("net: hns3: Add support of the HNAE3 framework")
Signed-off-by: NFuyun Liang <liangfuyun1@huawei.com>
Signed-off-by: NPeng Li <lipeng321@huawei.com>
Signed-off-by: NSalil Mehta <salil.mehta@huawei.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

When initializing ae_dev failed during loading hclge.ko, the drvdata will
be set to null. When removing hns3.ko, we get a null ae_dev. It causes the
null pointer problem.

This patch removes pci_set_drvdata from error handle of hclge_init_ae_dev
to fix the bug, since pci_set_drvdata has been called in hns3_remove.
Also, we do not need to uninit the ae_dev which is not initialized. And
it may be the one which is initialized failed.

Fixes: 46a3df9f ("net: hns3: Add HNS3 Acceleration Engine & Compatibility Layer Support")
Signed-off-by: NFuyun Liang <liangfuyun1@huawei.com>
Signed-off-by: NPeng Li <lipeng321@huawei.com>
Signed-off-by: NSalil Mehta <salil.mehta@huawei.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

When hnae3_unregister_ae_algo is called by PF, pci_disable_sriov is
called. And then, hns3_remove is called by VF. We get deadlocked in
this case.

Since VF pci device is dependent on PF pci device, When PF pci device
is removed, VF pci device must be removed. Also, To solve the deadlock
problem, VF pci device should be removed before PF pci device is removed.

This patch moves pci_enable/disable_sriov from hclge to hns3 to solve
the deadlock problem.

Also, we do not need to return EPROBE_DEFER in hnae3_register_ae_dev,
because SRIOV is no longer enabled in the context calling
hnae3_register_ae_dev. Mutex_trylock can be replaced with mutex_lock.

Fixes: 424eb834 ("net: hns3: Unified HNS3 {VF|PF} Ethernet Driver for hip08 SoC")
Signed-off-by: NFuyun Liang <liangfuyun1@huawei.com>
Signed-off-by: NPeng Li <lipeng321@huawei.com>
Signed-off-by: NSalil Mehta <salil.mehta@huawei.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch refactors the loopback related function in order
to support the serdes loopback.
Signed-off-by: NYunsheng Lin <linyunsheng@huawei.com>
Signed-off-by: NPeng Li <lipeng321@huawei.com>
Signed-off-by: NSalil Mehta <salil.mehta@huawei.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The head or tail in hardware is not longer valid when resetting,
current hns3_clear_all_ring use them to clean the ring, which
will cause problem during resetting.

This patch fixes it by using next_to_use and next_to_clean in
the ring struct.

Fixes: 76ad4f0e ("net: hns3: Add support of HNS3 Ethernet Driver for hip08 SoC")
Signed-off-by: NYunsheng Lin <linyunsheng@huawei.com>
Signed-off-by: NPeng Li <lipeng321@huawei.com>
Signed-off-by: NSalil Mehta <salil.mehta@huawei.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The add/del_tunnel_udp is not implemented in hclge_main moulde,
the NETIF_F_RX_UDP_TUNNEL_PORT feature bit is added automatically
by stack when ndo_udp_tunnel_add is not null in dev->netdev_ops.

This patch removes the add/del_tunnel_udp related function, for
we do not support this feature now.
Signed-off-by: NYunsheng Lin <linyunsheng@huawei.com>
Signed-off-by: NPeng Li <lipeng321@huawei.com>
Signed-off-by: NSalil Mehta <salil.mehta@huawei.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

When hns3_init_mac_addr is called during reset process, it will
get the mac address from NCL_CONFIG and set it to hardware. If
user has changed the mac address, then the mac address set by
user is lost during resetting.

This patch fixes it by not getting the mac address from NCL_CONFIG
when resetting.

Fixes: 424eb834 ("net: hns3: Unified HNS3 {VF|PF} Ethernet Driver for hip08 SoC")
Signed-off-by: NYunsheng Lin <linyunsheng@huawei.com>
Signed-off-by: NPeng Li <lipeng321@huawei.com>
Signed-off-by: NSalil Mehta <salil.mehta@huawei.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch adds support of hardware rx-vlan-offload to VF driver.
VF uses mailbox to convey PF to configure the hardware.
Signed-off-by: NYunsheng Lin <linyunsheng@huawei.com>
Signed-off-by: NPeng Li <lipeng321@huawei.com>
Signed-off-by: NSalil Mehta <salil.mehta@huawei.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Because the current statistics for size 8192~12287 are only valid for GE,
the ranges of 8192~9216 and 9217~12287 are valid only for LGE/CGE, and are
always 0 for GE interfaces. it is easy to cause confusion when viewing the
packet statistics using the command ethtool -S.

This patch removes the 8192~12287 range of packet statistics and uses the
8192~9216 and 9217~12287 ranges for statistics. This change depends on the
firmware upgrade.
Signed-off-by: NXi Wang <wangxi11@huawei.com>
Signed-off-by: NPeng Li <lipeng321@huawei.com>
Signed-off-by: NSalil Mehta <salil.mehta@huawei.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

There are two level of vlan tables in hardware, one is port vlan
which is shared by all functions, the other one is function
vlan table, each function has it's own function vlan table.
Currently, PF sets the port vlan table, and vf sets the function
vlan table, which will cause packet lost problem.

This patch fixes this problem by setting both vlan table, and
use hdev->vlan_table to manage thet port vlan table.
Signed-off-by: NYunsheng Lin <linyunsheng@huawei.com>
Signed-off-by: NPeng Li <lipeng321@huawei.com>
Signed-off-by: NSalil Mehta <salil.mehta@huawei.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

If head has invlid value then a dead loop can be triggered in
hclge_cmd_csq_clean. This patch adds sanity check for this case.

Fixes: 68c0a5c7 ("net: hns3: Add HNS3 IMP(Integrated Mgmt Proc) Cmd
Interface Support")
Signed-off-by: NHuazhong Tan <tanhuazhong@huawei.com>
Signed-off-by: NPeng Li <lipeng321@huawei.com>
Signed-off-by: NSalil Mehta <salil.mehta@huawei.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch adds a check to support autoneg(ethtool -A) only when PHY
is attached with the port.

Fixes: e2cb1dec ("net: hns3: Add HNS3 VF HCL(Hardware Compatibility
Layer) Support")
Signed-off-by: NFuyun Liang <liangfuyun1@huawei.com>
Signed-off-by: NPeng Li <lipeng321@huawei.com>
Signed-off-by: NSalil Mehta <salil.mehta@huawei.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

When phy exists, phy_addr must less than PHY_MAX_ADDR.
If not, hclge_mac_mdio_config should return error.
And for fiber(phy_addr=0xff), it does not need hclge_mac_mdio_config.
Signed-off-by: NHuazhong Tan <tanhuazhong@huawei.com>
Signed-off-by: NPeng Li <lipeng321@huawei.com>
Signed-off-by: NSalil Mehta <salil.mehta@huawei.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch fixes some of the missed error legs in the initialization
function of the ae device. This might cause leaks in case of failure.

Fixes: 46a3df9f ("net: hns3: Add HNS3 Acceleration Engine & Compatibility Layer
Support")
Signed-off-by: NHuazhong Tan <tanhuazhong@huawei.com>
Signed-off-by: NPeng Li <lipeng321@huawei.com>
Signed-off-by: NSalil Mehta <salil.mehta@huawei.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch fixes the handling of the check when number of vports
are detected to be more than available TPQs. Current handling causes
an out of bounds access in hclge_map_tqp().

Fixes: 7df7dad6 ("net: hns3: Refactor the mapping of tqp to vport")
Signed-off-by: NHuazhong Tan <tanhuazhong@huawei.com>
Signed-off-by: NPeng Li <lipeng321@huawei.com>
Signed-off-by: NSalil Mehta <salil.mehta@huawei.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch fixes the function being used to fetch L4
protocol outer header. Mistakenly skb_inner_transport_header
API was being used earlier.

Fixes: 76ad4f0e ("net: hns3: Add support of HNS3 Ethernet Driver for hip08 SoC")
Signed-off-by: NHuazhong Tan <tanhuazhong@huawei.com>
Signed-off-by: NPeng Li <lipeng321@huawei.com>
Signed-off-by: NSalil Mehta <salil.mehta@huawei.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

When mac supports DCB, but is in GE mode, it does not support
querying pfc stats, firmware returns error when trying to
query the pfc stats. this creates a lot of noise in the kernel
log when it prints the error log.

This patch fixes it by removing the error log, because it already
return the error to the user space, so the user should be aware of
the error.
Signed-off-by: NYunsheng Lin <linyunsheng@huawei.com>
Signed-off-by: NPeng Li <lipeng321@huawei.com>
Signed-off-by: NSalil Mehta <salil.mehta@huawei.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

When enable the config item "CONFIG_ARM64_64K_PAGES", the size of PAGE_SIZE
is 65536(64K). But the type of length is u16, it will overflow. So change it
to u32.
Signed-off-by: NTan Xiaojun <tanxiaojun@huawei.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

There is no need for explicit calls of devm_kfree(), as the allocated
memory will be freed during driver's detach.

The driver core clears the driver data to NULL after device_release.
Thus, it is not needed to manually clear the device driver data to NULL.

So remove the unnecessary pci_set_drvdata() and devm_kfree().
Signed-off-by: NWei Yongjun <weiyongjun1@huawei.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

IMP will not handle and command queue message any more when it is
in core/global, driver should not send command queue message to
IMP until reinitialize the NIC HW.

This patch checks the status and avoid the message sent to IMP when
reset.
Signed-off-by: NPeng Li <lipeng321@huawei.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Default rss_hash_key value should be given to all vports. But just the
PF rss_hash_key has the default value here. This patch adds rss_hash_key
Initialization for all vports.
Signed-off-by: NFuyun Liang <liangfuyun1@huawei.com>
Signed-off-by: NPeng Li <lipeng321@huawei.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Third parameter of hnae_set_field is shift, But a mask is given. This
patch fixes it by replacing HNS3_TXD_BDTYPE_M with HNS3_TXD_BDTYPE_S.
Signed-off-by: NFuyun Liang <liangfuyun1@huawei.com>
Signed-off-by: NPeng Li <lipeng321@huawei.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The return type of hns3_get_rss_indir_size is u32. But a negative value is
returned. This patch fixes it by replacing the negative value with zero.
Signed-off-by: NFuyun Liang <liangfuyun1@huawei.com>
Signed-off-by: NPeng Li <lipeng321@huawei.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>