The mtk_iommu_add_device() function keeps the fwspec in an
on-stack pointer and calls mtk_iommu_create_mapping(), which
might change its source, dev->iommu_fwspec. This causes the
on-stack pointer to be obsoleted and the device
initialization to fail. Update the on-stack fwspec pointer
after mtk_iommu_create_mapping() has been called.
Reported-by: Frank Wunderlich <frank-w@public-files.de>
Fixes: a9bf2eec5a ('iommu/mediatek: Use helper functions to access dev->iommu_fwspec')
Tested-by: Frank Wunderlich <frank-w@public-files.de>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Spansion S25FL512S ID is erroneously using 5-byte JEDEC ID, while the chip
family ID is stored in the 6th byte. Due to using only 5-byte ID, it's also
covering S25FS512S and now that we have added 6-byte ID for that chip, we
can convert S25FL512S to using a proper 6-byte ID as well...
Signed-off-by: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>
Reviewed-by: Tudor Ambarus <tudor.ambarus@microchip.com>
Signed-off-by: Boris Brezillon <bbrezillon@kernel.org>
Spansion S25FS512S flash is currently misdetected as S25FL512S since the
latter uses 5-byte JEDEC ID, while the 6th ID byte (family ID) is different
on those chips. Add the 6-byte S25FS512S ID before S25FL512S ID in order
not to break the existing S25FS512S users.
Signed-off-by: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>
Reviewed-by: Tudor Ambarus <tudor.ambarus@microchip.com>
Signed-off-by: Boris Brezillon <bbrezillon@kernel.org>
We just got aware that there was more IDs available
at spec, so let's add them already.
Cc: James Ausmus <james.ausmus@intel.com>
Cc: José Roberto de Souza <jose.souza@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Reviewed-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Reviewed-by: José Roberto de Souza <jose.souza@intel.com>
Signed-off-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190118055943.10252-1-rodrigo.vivi@intel.com
When reading GEN11_GT_INTR_DWx closely after enabling the interrupts
in gen11_irq_postinstall, the returned value is garbage. This can
cause other parts of the setup code (e.g. gen11_reset_one_iir) to
think that there are interrupts to be cleared when there are none.
The garbage value is only seen on the first read done after the enable,
so this looks like a posting issue. Adding a posting read after enabling
the interrupts does indeed fix the problem.
Note that the posting read has been purposely added outside of
gen11_master_intr_enable since the issue has only been observed when the
full interrupt setup is performed.
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Signed-off-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Acked-by: Chris Wilson <chris@chris-wilson.co.uk>
Acked-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Signed-off-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190123023227.8117-1-daniele.ceraolospurio@intel.com
system() is calling shell which should find the appropriate full path
via $PATH. On some systems, full path to iptables and/or nc might be
different that we one we have hardcoded.
Signed-off-by: Stanislav Fomichev <sdf@google.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
When converting to autogenerated compat syscall wrappers all system
call entry points got a different symbol name: they all got a __s390x_
prefix.
This caused breakage with system call tracing, since an appropriate
arch_syscall_match_sym_name() was not provided. Add this function, and
while at it also add code to avoid compat system call tracing. s390
has different system call tables for native 64 bit system calls and
compat system calls. This isn't really supported in the common
code. However there are hardly any compat binaries left, therefore
just ignore compat system calls, like x86 and arm64 also do for the
same reason.
Fixes: aa0d6e70d3 ("s390: autogenerate compat syscall wrappers")
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
The function l2cap_get_conf_opt will return L2CAP_CONF_OPT_SIZE + opt->len
as length value. The opt->len however is in control over the remote user
and can be used by an attacker to gain access beyond the bounds of the
actual packet.
To prevent any potential leak of heap memory, it is enough to check that
the resulting len calculation after calling l2cap_get_conf_opt is not
below zero. A well formed packet will always return >= 0 here and will
end with the length value being zero after the last option has been
parsed. In case of malformed packets messing with the opt->len field the
length value will become negative. If that is the case, then just abort
and ignore the option.
In case an attacker uses a too short opt->len value, then garbage will
be parsed, but that is protected by the unknown option handling and also
the option parameter size checks.
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
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.
There is no need to save the dentries for the debugfs files, so drop
those variables to save a bit of space and make the code simpler.
Cc: Bob Peterson <rpeterso@redhat.com>
Cc: Andreas Gruenbacher <agruenba@redhat.com>
Cc: cluster-devel@redhat.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
We need to let users check their wrong ELF section name with proper
ELF section names when they fail to get a prog/attach type from it.
Because users can't realize libbpf guess prog/attach types from given
ELF section names. For example, when a 'cgroup' section name of a
BPF program is used, show available ELF section names(types).
Before:
$ bpftool prog load bpf-prog.o /sys/fs/bpf/prog1
Error: failed to guess program type based on ELF section name cgroup
After:
libbpf: failed to guess program type based on ELF section name 'cgroup'
libbpf: supported section(type) names are: socket kprobe/ kretprobe/ classifier action tracepoint/ raw_tracepoint/ xdp perf_event lwt_in lwt_out lwt_xmit lwt_seg6local cgroup_skb/ingress cgroup_skb/egress cgroup/skb cgroup/sock cgroup/post_bind4 cgroup/post_bind6 cgroup/dev sockops sk_skb/stream_parser sk_skb/stream_verdict sk_skb sk_msg lirc_mode2 flow_dissector cgroup/bind4 cgroup/bind6 cgroup/connect4 cgroup/connect6 cgroup/sendmsg4 cgroup/sendmsg6
Signed-off-by: Taeung Song <treeze.taeung@gmail.com>
Cc: Quentin Monnet <quentin.monnet@netronome.com>
Cc: Jakub Kicinski <jakub.kicinski@netronome.com>
Cc: Andrey Ignatov <rdna@fb.com>
Reviewed-by: Quentin Monnet <quentin.monnet@netronome.com>
Acked-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
When sock recvbuff is set by bpf_setsockopt(), the value must by
limited by rmem_max. It is the same with sendbuff.
Fixes: 8c4b4c7e9f ("bpf: Add setsockopt helper function to bpf")
Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Acked-by: Lawrence Brakmo <brakmo@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
It's also a slave controller driver now, calling it "master" is slightly
misleading.
Signed-off-by: Lubomir Rintel <lkundrak@v3.sk>
Acked-by: Robert Jarzmik <robert.jarzmik@free.fr>
Signed-off-by: Mark Brown <broonie@kernel.org>
On a NOP double buffer update where current buffer address is the same
as the next buffer address, the SDW_UPDATE bit clears too late. As we
are now using this bit to determine when it is safe to signal flip
completion to userspace this will delay completion of atomic commits
where one plane doesn't change the buffer by a whole frame period.
Fix this by remembering the last buffer address and just skip the
double buffer update if it would not change the buffer address.
Signed-off-by: Lucas Stach <l.stach@pengutronix.de>
[p.zabel@pengutronix.de: initialize last_bufaddr in ipu_pre_configure]
Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
When doing option parsing for standard type values of 1, 2 or 4 octets,
the value is converted directly into a variable instead of a pointer. To
avoid being tricked into being a pointer, check that for these option
types that sizes actually match. In L2CAP every option is fixed size and
thus it is prudent anyway to ensure that the remote side sends us the
right option size along with option paramters.
If the option size is not matching the option type, then that option is
silently ignored. It is a protocol violation and instead of trying to
give the remote attacker any further hints just pretend that option is
not present and proceed with the default values. Implementation
following the specification and its qualification procedures will always
use the correct size and thus not being impacted here.
To keep the code readable and consistent accross all options, a few
cosmetic changes were also required.
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
This patch enable HDMI output on sun8i-h3-nanopi-m1-plus.
Signed-off-by: Corentin Labbe <clabbe@baylibre.com>
Signed-off-by: Maxime Ripard <maxime.ripard@bootlin.com>
Fix a static code checker warning:
drivers/spi/spi-bcm2835aux.c:460
bcm2835aux_spi_probe() warn: passing zero to 'PTR_ERR'
In case of error, the function devm_clk_get() returns ERR_PTR()
and not returns NULL.
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
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.
[ bp: Make edac_debugfs_init() return void too, while at it. ]
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: James Morse <james.morse@arm.com>
Cc: Mauro Carvalho Chehab <mchehab@kernel.org>
Cc: linux-edac <linux-edac@vger.kernel.org>
Link: https://lkml.kernel.org/r/20190122152151.16139-17-gregkh@linuxfoundation.org
Add support for Renesas RZ/A2M evaluation board.
Signed-off-by: Chris Brandt <chris.brandt@renesas.com>
Reviewed-by: Ulrich Hecht <uli+renesas@fpond.eu>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>
Basic support for the RZ/A2 (R7S9210) SoC.
Signed-off-by: Chris Brandt <chris.brandt@renesas.com>
Reviewed-by: Ulrich Hecht <uli+renesas@fpond.eu>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>
The internal LVDS encoder now has DT bindings separate from the DU. Port
the device tree over to the new model.
Fixes: c6a27fa41f ("drm: rcar-du: Convert LVDS encoder code to bridge driver")
Signed-off-by: Biju Das <biju.das@bp.renesas.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>
When updating a percpu map, bpftool currently copies the provided
value only into the first per CPU copy of the specified value,
all others instances are left zeroed.
This change explicitly copies the user-provided bytes to all the
per CPU instances, keeping the sub-command syntax unchanged.
v2 -> v3:
- drop unused argument, as per Quentin's suggestion
v1 -> v2:
- rename the helper as per Quentin's suggestion
Fixes: 71bb428fe2 ("tools: bpf: add bpftool")
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Quentin Monnet <quentin.monnet@netronome.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Lance reported an issue with bpftool not being able to
dump program if there are more programs loaded and you
want to dump any but the first program, like:
# bpftool prog
28: kprobe name trace_req_start tag 1dfc28ba8b3dd597 gpl
loaded_at 2019-01-18T17:02:40+1100 uid 0
xlated 112B jited 109B memlock 4096B map_ids 13
29: kprobe name trace_req_compl tag 5b6a5ecc6030a683 gpl
loaded_at 2019-01-18T17:02:40+1100 uid 0
xlated 928B jited 575B memlock 4096B map_ids 13,14
# bpftool prog dum jited tag 1dfc28ba8b3dd597
0: push %rbp
1: mov %rsp,%rbp
...
# bpftool prog dum jited tag 5b6a5ecc6030a683
Error: can't get prog info (29): Bad address
The problem is in the prog_fd_by_tag function not cleaning
the struct bpf_prog_info before another request, so the
previous program length is still in there and kernel assumes
it needs to dump the program, which fails because there's no
user pointer set.
Moving the struct bpf_prog_info declaration into the loop,
so it gets cleaned before each query.
Fixes: 71bb428fe2 ("tools: bpf: add bpftool")
Reported-by: Lance Digby <ldigby@redhat.com>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Reviewed-by: Quentin Monnet <quentin.monnet@netronome.com>
Acked-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
This patch adds ethernet support to the sub board.
Signed-off-by: Biju Das <biju.das@bp.renesas.com>
Signed-off-by: Fabrizio Castro <fabrizio.castro@bp.renesas.com>
Reviewed-by: Chris Paterson <Chris.Paterson2@renesas.com>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>
This patch adds pincontrol support to scif2.
Signed-off-by: Biju Das <biju.das@bp.renesas.com>
Reviewed-by: Fabrizio Castro <fabrizio.castro@bp.renesas.com>
Reviewed-by: Chris Paterson <Chris.Paterson2@renesas.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>
The EK874 development kit from Silicon Linux is made of CAT874 (the main
board) and CAT875 (the sub board that goes on top of CAT874).
Signed-off-by: Biju Das <biju.das@bp.renesas.com>
Signed-off-by: Fabrizio Castro <fabrizio.castro@bp.renesas.com>
Reviewed-by: Chris Paterson <Chris.Paterson2@renesas.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>
Basic support for the Si-Linux board based on RZ/G2E:
- Memory,
- Main crystal,
- Serial console
Signed-off-by: Biju Das <biju.das@bp.renesas.com>
Signed-off-by: Fabrizio Castro <fabrizio.castro@bp.renesas.com>
Reviewed-by: Chris Paterson <Chris.Paterson2@renesas.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>
Enable HS400 of SDHI3 using the corresponding DT property.
No further changes are required.
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>
Tested-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
SCIF2 on R-Car E3 can be used with both DMAC1 and DMAC2.
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>
SCIF2 on RZ/G2E can be used with both DMAC1 and DMAC2.
Fixes: 1b24f9e8ea3ff95f ("arm64: dts: renesas: r8a774c0: Add SCIF and HSCIF nodes")
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>
There are two regulator1 nodes in the Ebisu DTS right now, one 3.3V for
the eMMC and one 12V for the backlight. This causes one to be overwritten
by the other, ultimatelly resulting in inoperable eMMC, which depends on
the former. Fix this by renumbering the backlight regulator to regulator2.
Signed-off-by: Marek Vasut <marek.vasut+renesas@gmail.com>
Reported-by: Simon Horman <horms+renesas@verge.net.au>
Fixes: 9d16c4a10e ("arm64: dts: renesas: r8a77990: ebisu: Add backlight")
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Tested-by: Simon Horman <horms+renesas@verge.net.au>
Reviewed-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>
Specify EtherAVB PHY IRQ in the V3M Starter Kit board's device tree, now
that we have the GPIO support (previously phylib had to resort to polling).
Signed-off-by: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>
Current Ebisu board is using simple-scu-audio-card
which is used for Sampling Rate Convert, or MIXer, etc.
But, Ebisu is not using such feature.
Then, simple-audio-card is very enough.
This patch fixup it.
Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>
Before, BUSIF which is needed for DMA transfer was automatically handled
via SSI, but it cared BUSIF0 only.
Now, rsnd driver can handle BUSIF0-7 (= for Gen3) BUSIF0-3 (= for Gen2)
via SSIU, and it is keeping compatibility.
Thus, BUSIF0 settings via SSI had been kept to avoid git merge timing
issue / git bisect issue, but it is no longer needed.
This patch removes it.
Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>
Before, BUSIF which is needed for DMA transfer was automatically handled
via SSI, but it cared BUSIF0 only.
Now, rsnd driver can handle BUSIF0-7 (= for Gen3) BUSIF0-3 (= for Gen2)
via SSIU, and it is keeping compatibility.
Thus, BUSIF0 settings via SSI had been kept to avoid git merge timing
issue / git bisect issue, but it is no longer needed.
This patch removes it.
Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>
KingFisher has pcm3168 sound codec. This patch enables it.
Because pcm3168 can't handle symmetric channel on playback/
capture, we need to handle it as different DAI.
Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>
This patch adds missing ULCB HDMI sound support.
To use sound card, HDMI video is mandatory.
Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>
ULCB can use daughter board which is called as KingFisher.
It has extra sound interface, thus we want to use it.
But, basically, ALSA SoC can't use Multiple sound card with single
CPU sound interface (= SSI). Thus we need to use Single Sound Card
with multiple DAI interface.
To be easy to expand ULCB sound card on KingFisher, it is better to
use multi-dai-link style sound card on ULCB sound DT.
Now, "simple-audio-card" / "audio-graph-card" both can support
multi-dai-link style, but HDMI sound support (which is not yet supported
on ULCB) needs "audio-graph-card".
Using audio-graph-card is better selection.
This patch exchange current sound card to use it.
Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>
As of commit 6d2ca85279 ("dt-bindings: display: renesas: Deprecate
LVDS support in the DU bindings"), the internal LVDS encoder has DT
bindings separate from the DU. The device trees for all R-Car H3 and
M3-W development boards were ported over to the new model, but
Salvator-XS boards equipped with an R-Car M3-W SoC were forgotten.
Fixes: 58e8ed2ee9 ("arm64: dts: renesas: Convert to new LVDS DT bindings")
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>
Move the i2c nodes so that sub-nodes of the soc node are sorted by bus
address.
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>
Move the pciec0 node so that sub-nodes of the soc node are
sorted by bus address.
This change has no run-time affect.
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Mixed C99 and kernel types use is getting ugly. Prefer kernel types.
sed -i 's/\buint\(8\|16\|32\|64\)_t\b/u\1/g'
v2: rebase
Acked-by: Chris Wilson <chris@chris-wilson.co.uk>
Acked-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: José Roberto de Souza <jose.souza@intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190118120125.15484-1-jani.nikula@intel.com
This patch added documentation for BTF (BPF Debug Format).
The document is placed under linux:Documentation/bpf directory.
Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
In preparation to enabling -Wimplicit-fallthrough, mark switch cases
where we are expecting to fall through.
This patch fixes the following warning:
net/9p/trans_xen.c:514:6: warning: this statement may fall through [-Wimplicit-fallthrough=]
Warning level 3 was used: -Wimplicit-fallthrough=3
This patch is part of the ongoing efforts to enabling
-Wimplicit-fallthrough
Link: http://lkml.kernel.org/r/20190123071632.GA8039@embeddedor
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: Dominique Martinet <dominique.martinet@cea.fr>
After the previous code refactoring, the PCM stream locking code
became nothing but the PCM group lock with self_group object. Use the
existing helper function for simplifying the code.
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Remove the hackish down_write_nonfifo() that was introduced as a
workaround of rwsem deadlock.
It used to be a problem for non-atomic PCM streams that take the rwsem
for the locking and hit the high lock contention. Since the current
PCM locking refactoring, we'll no longer hit it as the hot code-paths
don't take global locks.
Signed-off-by: Takashi Iwai <tiwai@suse.de>
We have currently two global locks, a rwlock and a rwsem, that are
used for managing linking the PCM streams. Due to these global locks,
once when a linked stream is used, the lock granularity suffers a
lot.
This patch attempts to eliminate the former global lock for atomic
ops. The latter rwsem needs remaining because of the loosy way of the
loop calls in snd_pcm_action_nonatomic(), as well as for avoiding the
deadlock at linking. However, these are used far rarely, actually
only by two actions (prepare and reset), where both are no timing
critical ones. So this can be still seen as a good improvement.
The basic strategy to eliminate the rwlock is to assure group->lock at
adding or removing a stream to / from the group. Since we already
takes the group lock whenever taking the all substream locks under the
group, this shouldn't be a big problem. The reference to group
pointer in snd_pcm_substream object is protected by the stream lock
itself.
However, there are still pitfalls: a race window at re-locking and the
lifecycle of group object. The former is a small race window for
dereferencing the substream group object opened while snd_pcm_action()
performs re-locking to avoid ABBA deadlocks. This includes the unlink
of group during that window, too. And the latter is the kfree
performed after all streams are removed from the group while it's
still dereferenced.
For addressing these corner cases, two new tricks are introduced:
- After re-locking, the group assigned to the stream is checked again;
if the group is changed, we retry the whole procedure.
- Introduce a refcount to snd_pcm_group object, so that it's freed
only when it's empty and really no one refers to it.
(Some readers might wonder why not RCU for the latter. RCU in this
case would cost more than refcounting, unfortunately. We take the
group lock sooner or later, hence the performance improvement by RCU
would be negligible. Meanwhile, because we need to deal with
schedulable context depending on the pcm->nonatomic flag, it'll become
dynamic RCU/SRCU switch, and the grace period may become too long.)
Along with these changes, there are a significant amount of code
refactoring. The complex group re-lock & ref code is factored out to
snd_pcm_stream_group_ref() function, for example.
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Quentin Monnet says:
====================
Hi,
This set adds a new command to bpftool in order to dump a list of
eBPF-related parameters for the system (or for a specific network
device) to the console. Once again, this is based on a suggestion from
Daniel.
At this time, output includes:
- Availability of bpf() system call
- Availability of bpf() system call for unprivileged users
- JIT status (enabled or not, with or without debugging traces)
- JIT hardening status
- JIT kallsyms exports status
- Global memory limit for JIT compiler for unprivileged users
- Status of kernel compilation options related to BPF features
- Availability of known eBPF program types
- Availability of known eBPF map types
- Availability of known eBPF helper functions
There are three different ways to dump this information at this time:
- Plain output dumps probe results in plain text. It is the most
flexible options for providing descriptive output to the user, but
should not be relied upon for parsing the output.
- JSON output is supported.
- A third mode, available through the "macros" keyword appended to the
command line, dumps some of those parameters (not all) as a series of
"#define" directives, that can be included into a C header file for
example.
Probes for supported program and map types, and supported helpers, are
directly added to libbpf, so that other applications (or selftests) can
reuse them as necessary.
If the user does not have root privileges (or more precisely, the
CAP_SYS_ADMIN capability) detection will be erroneous for most
parameters. Therefore, forbid non-root users to run the command.
v5:
- Move exported symbols to a new LIBBPF_0.0.2 section in libbpf.map
(patches 4 to 6).
- Minor fixes on patches 3 and 4.
v4:
- Probe bpf_jit_limit parameter (patch 2).
- Probe some additional kernel config options (patch 3).
- Minor fixes on patch 6.
v3:
- Do not probe kernel version in bpftool (just retrieve it to probe support
for kprobes in libbpf).
- Change the way results for helper support is displayed: now one list of
compatible helpers for each program type (and C-style output gets a
HAVE_PROG_TYPE_HELPER(prog_type, helper) macro to help with tests. See
patches 6, 7.
- Address other comments from feedback from v2 (please refer to individual
patches' history).
v2 (please also refer to individual patches' history):
- Move probes for prog/map types, helpers, from bpftool to libbpf.
- Move C-style output as a separate patch, and restrict it to a subset of
collected information (bpf() availability, prog/map types, helpers).
- Now probe helpers with all supported program types, and display a list of
compatible program types (as supported on the system) for each helper.
- NOT addressed: grouping compilation options for kernel into subsections
(patch 3) (I don't see an easy way of grouping them at the moment, please
see also the discussion on v1 thread).
====================
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
