Otherwise, we can have a stale state after a disconnect and reconnect
causing errors on the first SETUP packet to the device.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>
This bit should be only set when the port enable goes down, for
example, on errors. Not when it gets set after a port reset. Some
USB stacks seem to be sensitive to this and fails enumeration.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>
clang warns:
arch/mips/mm/tlbex.c:634:19: error: use of logical '&&' with constant
operand [-Werror,-Wconstant-logical-operand]
if (cpu_has_rixi && _PAGE_NO_EXEC) {
^ ~~~~~~~~~~~~~
arch/mips/mm/tlbex.c:634:19: note: use '&' for a bitwise operation
if (cpu_has_rixi && _PAGE_NO_EXEC) {
^~
&
arch/mips/mm/tlbex.c:634:19: note: remove constant to silence this
warning
if (cpu_has_rixi && _PAGE_NO_EXEC) {
~^~~~~~~~~~~~~~~~
1 error generated.
Explicitly cast this value to a boolean so that clang understands we
intend for this to be a non-zero value.
Fixes: 00bf1c691d ("MIPS: tlbex: Avoid placing software PTE bits in Entry* PFN fields")
Link: https://github.com/ClangBuiltLinux/linux/issues/609
Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
Signed-off-by: Paul Burton <paul.burton@mips.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: James Hogan <jhogan@kernel.org>
Cc: Nick Desaulniers <ndesaulniers@google.com>
Cc: linux-mips@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: clang-built-linux@googlegroups.com
clang warns:
arch/mips/include/asm/syscall.h:136:3: error: variable 'ret' is
uninitialized when used here [-Werror,-Wuninitialized]
ret |= mips_get_syscall_arg(args++, task, regs, i++);
^~~
arch/mips/include/asm/syscall.h:129:9: note: initialize the variable
'ret' to silence this warning
int ret;
^
= 0
1 error generated.
It's not wrong; however, it's not an issue in practice because ret is
only assigned to, not read from. ret could just be initialized to zero
but looking into it further, ret has been unused since it was first
added in 2012 so just get rid of it and update mips_get_syscall_arg's
return type since none of the return values are ever checked. If it is
ever needed again, this commit can be reverted and ret can be properly
initialized.
Fixes: c0ff3c53d4 ("MIPS: Enable HAVE_ARCH_TRACEHOOK.")
Link: https://github.com/ClangBuiltLinux/linux/issues/604
Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
Signed-off-by: Paul Burton <paul.burton@mips.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: James Hogan <jhogan@kernel.org>
Cc: Nick Desaulniers <ndesaulniers@google.com>
Cc: linux-mips@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: clang-built-linux@googlegroups.com
clang warns:
drivers/net/ethernet/toshiba/tc35815.c:1507:30: warning: use of logical
'&&' with constant operand [-Wconstant-logical-operand]
if (!HAVE_DMA_RXALIGN(lp) && NET_IP_ALIGN)
^ ~~~~~~~~~~~~
drivers/net/ethernet/toshiba/tc35815.c:1507:30: note: use '&' for a
bitwise operation
if (!HAVE_DMA_RXALIGN(lp) && NET_IP_ALIGN)
^~
&
drivers/net/ethernet/toshiba/tc35815.c:1507:30: note: remove constant to
silence this warning
if (!HAVE_DMA_RXALIGN(lp) && NET_IP_ALIGN)
~^~~~~~~~~~~~~~~
1 warning generated.
Explicitly check that NET_IP_ALIGN is not zero, which matches how this
is checked in other parts of the tree. Because NET_IP_ALIGN is a build
time constant, this check will be constant folded away during
optimization.
Fixes: 82a9928db5 ("tc35815: Enable StripCRC feature")
Link: https://github.com/ClangBuiltLinux/linux/issues/608
Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
We set the field 'addr_trial_end' to 'jiffies', instead of the current
value 0, at the moment the node address is initialized. This guarantees
we don't inadvertently enter an address trial period when the node
address is explicitly set by the user.
Signed-off-by: Chris Packham <chris.packham@alliedtelesis.co.nz>
Acked-by: Jon Maloy <jon.maloy@ericsson.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
To identify timestamps for matching with their packets, Spectrum-1 uses a
five-tuple of (port, direction, domain number, message type, sequence ID).
If there are several clients from the same domain behind a single port
sending Delay_Req's, the only thing differentiating these packets, as far
as Spectrum-1 is concerned, is the sequence ID. Should sequence IDs between
individual clients be similar, conflicts may arise. That is not a problem
to hardware, which will simply deliver timestamps on a first comes, first
served basis.
However the driver uses a simple hash table to store the unmatched pieces.
When a new conflicting piece arrives, it pushes out the previously stored
one, which if it is a packet, is delivered without timestamp. Later on as
the corresponding timestamps arrive, the first one is mismatched to the
second packet, and the second one is never matched and eventually is GCd.
To correct this issue, instead of using a simple rhashtable, use rhltable
to keep the unmatched entries.
Previously, a found unmatched entry would always be removed from the hash
table. That is not the case anymore--an incompatible entry is left in the
hash table. Therefore removal from the hash table cannot be used to confirm
the validity of the looked-up pointer, instead the lookup would simply need
to be redone. Therefore move it inside the critical section. This
simplifies a lot of the code.
Fixes: 8748642751 ("mlxsw: spectrum: PTP: Support SIOCGHWTSTAMP, SIOCSHWTSTAMP ioctls")
Reported-by: Alex Veber <alexve@mellanox.com>
Signed-off-by: Petr Machata <petrm@mellanox.com>
Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Adjust the function names in two doc comments to match the corresponding
functions.
Signed-off-by: Jonathan Neuschäfer <j.neuschaefer@gmx.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
When calling debugfs functions, there is no need to ever check the
return value. The function can work or not, but the code logic should
never do something different based on this.
Cc: Richard Fontana <rfontana@redhat.com>
Cc: Steve Winslow <swinslow@gmail.com>
Cc: netdev@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
When calling debugfs functions, there is no need to ever check the
return value. The function can work or not, but the code logic should
never do something different based on this.
Cc: Wei Liu <wei.liu@kernel.org>
Cc: Paul Durrant <paul.durrant@citrix.com>
Cc: xen-devel@lists.xenproject.org
Cc: netdev@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Wei Liu <wei.liu@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Fix rxrpc_unuse_local() to handle a NULL local pointer as it can be called
on an unbound socket on which rx->local is not yet set.
The following reproduced (includes omitted):
int main(void)
{
socket(AF_RXRPC, SOCK_DGRAM, AF_INET);
return 0;
}
causes the following oops to occur:
BUG: kernel NULL pointer dereference, address: 0000000000000010
...
RIP: 0010:rxrpc_unuse_local+0x8/0x1b
...
Call Trace:
rxrpc_release+0x2b5/0x338
__sock_release+0x37/0xa1
sock_close+0x14/0x17
__fput+0x115/0x1e9
task_work_run+0x72/0x98
do_exit+0x51b/0xa7a
? __context_tracking_exit+0x4e/0x10e
do_group_exit+0xab/0xab
__x64_sys_exit_group+0x14/0x17
do_syscall_64+0x89/0x1d4
entry_SYSCALL_64_after_hwframe+0x49/0xbe
Reported-by: syzbot+20dee719a2e090427b5f@syzkaller.appspotmail.com
Fixes: 730c5fd42c ("rxrpc: Fix local endpoint refcounting")
Signed-off-by: David Howells <dhowells@redhat.com>
cc: Jeffrey Altman <jaltman@auristor.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Vivien Didelot says:
====================
net: dsa: mv88e6xxx: prepare Wait Bit operation
The Remote Management Interface has its own implementation of a Wait
Bit operation, which requires a bit number and a value to wait for.
In order to prepare the introduction of this implementation, rework the
code waiting for bits and masks in mv88e6xxx to match this signature.
This has the benefit to unify the implementation of wait routines while
removing obsolete wait and update functions and also reducing the code.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
The mv88e6xxx_smi_direct_wait routine is used to wait on indirect
registers access. It is of no exception and must delay between read
attempts, like other wait routines.
Signed-off-by: Vivien Didelot <vivien.didelot@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The current mv88e6xxx_smi_direct_wait function is only used to check
the 16th bit of the (16-bit) SMI Command register. But the bit shift
operation is not enough if we eventually use this function to check
other bits, thus replace it with a mask.
Fixes: e7ba0fad9c ("net: dsa: mv88e6xxx: refine SMI support")
Signed-off-by: Vivien Didelot <vivien.didelot@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Now that we have proper Wait Bit and Wait Mask routines, remove the
unused mv88e6xxx_wait routine and its Global 1 and Global 2 variants.
The indirect tables such as the Device Mapping Table or Priority
Override Table make use of an Update bit to distinguish reading (0)
from writing (1) operations. After a write operation occurs, the bit
self clears right away so there's no need to wait on it. Thus keep
things simple and remove the mv88e6xxx_update helper as well.
Signed-off-by: Vivien Didelot <vivien.didelot@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The AVB is not an indirect table using an Update bit, but a unit using
a Busy bit. This means that we must ensure that this bit is cleared
before setting it and wait until it gets cleared again after writing
an operation. Reflect that.
Signed-off-by: Vivien Didelot <vivien.didelot@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Many portions of the driver need to wait until a given bit is set
or cleared. Some busses even have a specific implementation for this
operation. In preparation for such variant, implement a generic Wait
Bit routine that can be used by the driver core functions.
This allows us to get rid of the custom implementations we may find
in the driver. Note that for the EEPROM bits, BUSY and RUNNING bits
are independent, thus it is more efficient to wait independently for
each bit instead of waiting for their mask.
Signed-off-by: Vivien Didelot <vivien.didelot@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The current mv88e6xxx_wait routine is used to wait for a given mask
to be cleared to zero. However in some cases, the driver may have
to wait for a given mask to be of a certain non-zero value.
Thus provide a generic wait mask routine that will be used to implement
the current mv88e6xxx_wait function, and use it to wait for 88E6185
PPU states.
Signed-off-by: Vivien Didelot <vivien.didelot@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The PPU state of 88E6185 can be either "Disabled at Reset" or
"Disabled after Initialization". Because we intentionally clear the
PPU Enabled bit before checking its state, it is safe to wait for the
MV88E6185_G1_STS_PPU_STATE_DISABLED state explicitly instead of waiting
for any state different than MV88E6185_G1_STS_PPU_STATE_POLLING.
Signed-off-by: Vivien Didelot <vivien.didelot@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
rtl8169_free_rx_databuff is used in only one place, so let's inline it.
We can improve the loop because rtl8169_init_ring zero's RX_databuff
before calling rtl8169_rx_fill, and rtl8169_rx_fill fills
Rx_databuff starting from index 0.
Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Heiner Kallweit says:
====================
net: phy: realtek: add support for integrated 2.5Gbps PHY in RTL8125
This series adds support for the integrated 2.5Gbps PHY in RTL8125.
First three patches add necessary functionality to phylib.
Changes in v2:
- added patch 1
- changed patch 4 to use a fake PHY ID that is injected by the
network driver. This allows to use a dedicated PHY driver.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
This adds support for the integrated 2.5Gbps PHY in Realtek RTL8125.
Advertisement of 2.5Gbps mode is done via a vendor-specific register.
Same applies to reading NBase-T link partner advertisement.
Unfortunately this 2.5Gbps PHY shares the PHY ID with the integrated
1Gbps PHY's in other Realtek network chips and so far no method is
known to differentiate them. As a workaround use a dedicated fake PHY ID
that is set by the network driver by intercepting the MDIO PHY ID read.
v2:
- Create dedicated PHY driver and use a fake PHY ID that is injected by
the network driver. Suggested by Andrew Lunn.
Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>
Add helper function phy_modify_paged_changed, behavios is the same
as for phy_modify_changed.
Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>
The integrated PHY in 2.5Gbps chip RTL8125 is the first (known to me)
PHY that uses standard Clause 22 for all modes up to 1Gbps and adds
2.5Gbps control using vendor-specific registers. To use phylib for
the standard part little extensions are needed:
- Move most of genphy_config_aneg to a new function
__genphy_config_aneg that takes a parameter whether restarting
auto-negotiation is needed (depending on whether content of
vendor-specific advertisement register changed).
- Don't clear phydev->lp_advertising in genphy_read_status so that
we can set non-C22 mode flags before.
Basically both changes mimic the behavior of the equivalent Clause 45
functions.
Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Using linkmode_adv_to_mii_adv_t and linkmode_adv_to_mii_ctrl1000_t
allows to simplify the code. In addition avoiding the conversion to
the legacy u32 advertisement format allows to remove the warning.
Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Suggested-by: Andrew Lunn <andrew@lunn.ch>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>
Register couple of devlink params, one generic, one driver-specific.
Make the values available over debugfs.
Example:
$ echo "111" > /sys/bus/netdevsim/new_device
$ devlink dev param
netdevsim/netdevsim111:
name max_macs type generic
values:
cmode driverinit value 32
name test1 type driver-specific
values:
cmode driverinit value true
$ cat /sys/kernel/debug/netdevsim/netdevsim111/max_macs
32
$ cat /sys/kernel/debug/netdevsim/netdevsim111/test1
Y
$ devlink dev param set netdevsim/netdevsim111 name max_macs cmode driverinit value 16
$ devlink dev param set netdevsim/netdevsim111 name test1 cmode driverinit value false
$ devlink dev reload netdevsim/netdevsim111
$ cat /sys/kernel/debug/netdevsim/netdevsim111/max_macs
16
$ cat /sys/kernel/debug/netdevsim/netdevsim111/test1
Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
drm-next-5.4-2019-08-09:
Same as drm-next-5.4-2019-08-06, but with the
readq/writeq stuff fixed and 5.3-rc3 backmerged.
amdgpu:
- Add navi14 support
- Add navi12 support
- Add Arcturus support
- Enable mclk DPM for Navi
- Misc DC display fixes
- Add perfmon support for DF
- Add scatter/gather display support for Raven
- Improve SMU handling for GPU reset
- RAS support for GFX
- Drop last of drmP.h
- Add support for wiping memory on buffer release
- Allow cursor async updates for fb swaps
- Misc fixes and cleanups
amdkfd:
- Add navi14 support
- Add navi12 support
- Add Arcturus support
- CWSR trap handlers updates for gfx9, 10
- Drop last of drmP.h
- Update MAINTAINERS
radeon:
- Misc fixes and cleanups
- Make kexec more reliable by tearing down the GPU
ttm:
- Add release_notify callback
uapi:
- Add wipe memory on release flag for buffer creation
Signed-off-by: Dave Airlie <airlied@redhat.com>
[airlied: resolved conflicts with ttm resv moving]
From: Alex Deucher <alexdeucher@gmail.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190809184807.3381-1-alexander.deucher@amd.com
Prior to the commit in the fixes tag, the resource controller in netdevsim
tracked fib entries and rules per network namespace. Restore that behavior.
Fixes: 5fc494225c ("netdevsim: create devlink instance per netdevsim instance")
Signed-off-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Daniel Borkmann says:
====================
pull-request: bpf 2019-08-11
The following pull-request contains BPF updates for your *net* tree.
The main changes are:
1) x64 JIT code generation fix for backward-jumps to 1st insn, from Alexei.
2) Fix buggy multi-closing of BTF file descriptor in libbpf, from Andrii.
3) Fix libbpf_num_possible_cpus() to make it thread safe, from Takshak.
4) Fix bpftool to dump an error if pinning fails, from Jakub.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
Add missing break statement in order to prevent the code from falling
through to case SH_BREAKPOINT_WRITE.
Fixes: 09a0729477 ("sh: hw-breakpoints: Add preliminary support for SH-4A UBC.")
Cc: stable@vger.kernel.org
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Tested-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Remove logically dead code and mark switch cases where we are expecting
to fall through.
Fix the following warnings (Building: defconfig sh):
arch/sh/kernel/disassemble.c:478:8: warning: this statement may fall
through [-Wimplicit-fallthrough=]
arch/sh/kernel/disassemble.c:487:8: warning: this statement may fall
through [-Wimplicit-fallthrough=]
arch/sh/kernel/disassemble.c:496:8: warning: this statement may fall
through [-Wimplicit-fallthrough=]
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Tested-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
For debugging reasons, it's useful to know the contents of the extent
cache. Since the extent cache contains much of what is in the fiemap
ioctl, use an fiemap-style interface to return this information.
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
The new ioctl EXT4_IOC_GETSTATE returns some of the dynamic state of
an ext4 inode for debugging purposes.
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
The new ioctl EXT4_IOC_CLEAR_ES_CACHE will force an inode's extent
status cache to be cleared out. This is intended for use for
debugging.
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
When executing generic/388 on a ppc64le machine, we notice the following
call trace,
VFS: brelse: Trying to free free buffer
WARNING: CPU: 0 PID: 6637 at /root/repos/linux/fs/buffer.c:1195 __brelse+0x84/0xc0
Call Trace:
__brelse+0x80/0xc0 (unreliable)
invalidate_bh_lru+0x78/0xc0
on_each_cpu_mask+0xa8/0x130
on_each_cpu_cond_mask+0x130/0x170
invalidate_bh_lrus+0x44/0x60
invalidate_bdev+0x38/0x70
ext4_put_super+0x294/0x560
generic_shutdown_super+0xb0/0x170
kill_block_super+0x38/0xb0
deactivate_locked_super+0xa4/0xf0
cleanup_mnt+0x164/0x1d0
task_work_run+0x110/0x160
do_notify_resume+0x414/0x460
ret_from_except_lite+0x70/0x74
The warning happens because flush_descriptor() drops bh reference it
does not own. The bh reference acquired by
jbd2_journal_get_descriptor_buffer() is owned by the log_bufs list and
gets released when this list is processed. The reference for doing IO is
only acquired in write_dirty_buffer() later in flush_descriptor().
Reported-by: Harish Sriram <harish@linux.ibm.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Chandan Rajendra <chandan@linux.ibm.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Remove unnecessary error check in ext4_file_write_iter(),
because this check will be done in upcoming later function --
ext4_write_checks() -> generic_write_checks()
Change-Id: I7b0ab27f693a50765c15b5eaa3f4e7c38f42e01e
Signed-off-by: shisiyuan <shisiyuan@xiaomi.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
mkfs.ext4 -O inline_data /dev/vdb
mount -o dioread_nolock /dev/vdb /mnt
echo "some inline data..." >> /mnt/test-file
echo "some inline data..." >> /mnt/test-file
sync
The above script will trigger "WARN_ON(!io_end->handle && sbi->s_journal)"
because ext4_should_dioread_nolock() returns false for a file with inline
data. Move the check to a place after we have already removed the inline
data and prepared inode to write normal pages.
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: yangerkun <yangerkun@huawei.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
- Fix dax_layout_busy_page() to not discard private cow pages of fs/dax
private mappings.
- Update the memremap_pages core to properly cleanup on behalf of
internal reference-count users like device-dax.
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Merge tag 'dax-fixes-5.3-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm
Pull dax fixes from Dan Williams:
"A filesystem-dax and device-dax fix for v5.3.
The filesystem-dax fix is tagged for stable as the implementation has
been mistakenly throwing away all cow pages on any truncate or hole
punch operation as part of the solution to coordinate device-dma vs
truncate to dax pages.
The device-dax change fixes up a regression this cycle from the
introduction of a common 'internal per-cpu-ref' implementation.
Summary:
- Fix dax_layout_busy_page() to not discard private cow pages of
fs/dax private mappings.
- Update the memremap_pages core to properly cleanup on behalf of
internal reference-count users like device-dax"
* tag 'dax-fixes-5.3-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm:
mm/memremap: Fix reuse of pgmap instances with internal references
dax: dax_layout_busy_page() should not unmap cow pages
Ido Schimmel says:
====================
drop_monitor: Capture dropped packets and metadata
So far drop monitor supported only one mode of operation in which a
summary of recent packet drops is periodically sent to user space as a
netlink event. The event only includes the drop location (program
counter) and number of drops in the last interval.
While this mode of operation allows one to understand if the system is
dropping packets, it is not sufficient if a more detailed analysis is
required. Both the packet itself and related metadata are missing.
This patchset extends drop monitor with another mode of operation where
the packet - potentially truncated - and metadata (e.g., drop location,
timestamp, netdev) are sent to user space as a netlink event. Thanks to
the extensible nature of netlink, more metadata can be added in the
future.
To avoid performing expensive operations in the context in which
kfree_skb() is called, the dropped skbs are cloned and queued on per-CPU
skb drop list. The list is then processed in process context (using a
workqueue), where the netlink messages are allocated, prepared and
finally sent to user space.
A follow-up patchset will integrate drop monitor with devlink and allow
the latter to call into drop monitor to report hardware drops. In the
future, XDP drops can be added as well, thereby making drop monitor the
go-to netlink channel for diagnosing all packet drops.
Example usage with patched dropwatch [1] can be found here [2]. Example
dissection of drop monitor netlink events with patched wireshark [3] can
be found here [4]. I will submit both changes upstream after the kernel
changes are accepted. Another change worth making is adding a dropmon
pseudo interface to libpcap, similar to the nflog interface [5]. This
will allow users to specifically listen on dropmon traffic instead of
capturing all netlink packets via the nlmon netdev.
Patches #1-#5 prepare the code towards the actual changes in later
patches.
Patch #6 adds another mode of operation to drop monitor in which the
dropped packet itself is notified to user space along with metadata.
Patch #7 allows users to truncate reported packets to a specific length,
in case only the headers are of interest. The original length of the
packet is added as metadata to the netlink notification.
Patch #8 allows user to query the current configuration of drop monitor
(e.g., alert mode, truncation length).
Patches #9-#10 allow users to tune the length of the per-CPU skb drop
list according to their needs.
Changes since v1 [6]:
* Add skb protocol as metadata. This allows user space to correctly
dissect the packet instead of blindly assuming it is an Ethernet
packet
Changes since RFC [7]:
* Limit the length of the per-CPU skb drop list and make it configurable
* Do not use the hysteresis timer in packet alert mode
* Introduce alert mode operations in a separate patch and only then
introduce the new alert mode
* Use 'skb->skb_iif' instead of 'skb->dev' because the latter is inside
a union with 'dev_scratch' and therefore not guaranteed to point to a
valid netdev
* Return '-EBUSY' instead of '-EOPNOTSUPP' when trying to configure drop
monitor while it is monitoring
* Did not change schedule_work() in favor of schedule_work_on() as I did
not observe a change in number of tail drops
[1] https://github.com/idosch/dropwatch/tree/packet-mode
[2] https://gist.github.com/idosch/3d524b887e16bc11b4b19e25c23dcc23#file-gistfile1-txt
[3] https://github.com/idosch/wireshark/tree/drop-monitor-v2
[4] https://gist.github.com/idosch/3d524b887e16bc11b4b19e25c23dcc23#file-gistfile2-txt
[5] https://github.com/the-tcpdump-group/libpcap/blob/master/pcap-netfilter-linux.c
[6] https://patchwork.ozlabs.org/cover/1143443/
[7] https://patchwork.ozlabs.org/cover/1135226/
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
Previous patch made the length of the per-CPU skb drop list
configurable. Expose a counter that shows how many packets could not be
enqueued to this list.
This allows users determine the desired queue length.
Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
In packet alert mode, each CPU holds a list of dropped skbs that need to
be processed in process context and sent to user space. To avoid
exhausting the system's memory the maximum length of this queue is
currently set to 1000.
Allow users to tune the length of this queue according to their needs.
The configured length is reported to user space when drop monitor
configuration is queried.
Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Users should be able to query the current configuration of drop monitor
before they start using it. Add a command to query the existing
configuration which currently consists of alert mode and packet
truncation length.
Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
When sending dropped packets to user space it is not always necessary to
copy the entire packet as usually only the headers are of interest.
Allow user to specify the truncation length and add the original length
of the packet as additional metadata to the netlink message.
By default no truncation is performed.
Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
