Commit Graph

948914 Commits

Author SHA1 Message Date
Murali Karicheri
fa4dc89531 net: hsr: define and use proto_ops ptrs to handle hsr specific frames
As a preparatory patch to introduce PRP, refactor the code specific to
handling HSR frames into separate functions and call them through
proto_ops function pointers.

Signed-off-by: Murali Karicheri <m-karicheri2@ti.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-07-27 12:20:40 -07:00
Murali Karicheri
c643ff0383 net: prp: add supervision frame generation utility function
Add support for generation of PRP supervision frames. For PRP,
supervision frame format is similar to HSR version 0, but have
a PRP Redundancy Control Trailer (RCT) added and uses a different
message type, PRP_TLV_LIFE_CHECK_DD. Also update
is_supervision_frame() to include the new message type used for
PRP supervision frame.

Signed-off-by: Murali Karicheri <m-karicheri2@ti.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-07-27 12:20:40 -07:00
Murali Karicheri
28e458e097 net: hsr: introduce protocol specific function pointers
As a preparatory patch to introduce support for PRP protocol, add a
protocol ops ptr in the private hsr structure to hold function
pointers as some of the functions at protocol level packet
handling is different for HSR vs PRP. It is expected that PRP will
add its of set of functions for protocol handling. Modify existing
hsr_announce() function to call proto_ops->send_sv_frame() to send
supervision frame for HSR. This is expected to be different for PRP.
So introduce a ops function ptr, send_sv_frame() for the same and
initialize it to send_hsr_supervsion_frame(). Modify hsr_announce()
to call proto_ops->send_sv_frame().

Signed-off-by: Murali Karicheri <m-karicheri2@ti.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-07-27 12:20:40 -07:00
Murali Karicheri
121c33b07b net: hsr: introduce common code for skb initialization
As a preparatory patch to introduce PRP protocol support in the
driver, refactor the skb init code to a separate function.

Signed-off-by: Murali Karicheri <m-karicheri2@ti.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-07-27 12:20:40 -07:00
Murali Karicheri
8f4c0e0178 hsr: enhance netlink socket interface to support PRP
Parallel Redundancy Protocol (PRP) is another redundancy protocol
introduced by IEC 63439 standard. It is similar to HSR in many
aspects:-

 - Use a pair of Ethernet interfaces to created the PRP device
 - Use a 6 byte redundancy protocol part (RCT, Redundancy Check
   Trailer) similar to HSR Tag.
 - Has Link Redundancy Entity (LRE) that works with RCT to implement
   redundancy.

Key difference is that the protocol unit is a trailer instead of a
prefix as in HSR. That makes it inter-operable with tradition network
components such as bridges/switches which treat it as pad bytes,
whereas HSR nodes requires some kind of translators (Called redbox) to
talk to regular network devices. This features allows regular linux box
to be converted to a DAN-P box. DAN-P stands for Dual Attached Node - PRP
similar to DAN-H (Dual Attached Node - HSR).

Add a comment at the header/source code to explicitly state that the
driver files also handles PRP protocol as well.

Signed-off-by: Murali Karicheri <m-karicheri2@ti.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-07-27 12:20:40 -07:00
Alexander Lobakin
1775da47c3 qed: fix the allocation of the chains with an external PBL
Dan reports static checker warning:

"The patch 9b6ee3cf95: "qed: sanitize PBL chains allocation" from Jul
23, 2020, leads to the following static checker warning:

	drivers/net/ethernet/qlogic/qed/qed_chain.c:299 qed_chain_alloc_pbl()
	error: uninitialized symbol 'pbl_virt'.

drivers/net/ethernet/qlogic/qed/qed_chain.c
   249  static int qed_chain_alloc_pbl(struct qed_dev *cdev, struct qed_chain *chain)
   250  {
   251          struct device *dev = &cdev->pdev->dev;
   252          struct addr_tbl_entry *addr_tbl;
   253          dma_addr_t phys, pbl_phys;
   254          __le64 *pbl_virt;
                ^^^^^^^^^^^^^^^^
[...]
   271          if (chain->b_external_pbl)
   272                  goto alloc_pages;
                        ^^^^^^^^^^^^^^^^ uninitialized
[...]
   298                  /* Fill the PBL table with the physical address of the page */
   299                  pbl_virt[i] = cpu_to_le64(phys);
                        ^^^^^^^^^^^
[...]
"

This issue was introduced with commit c3a321b06a ("qed: simplify
initialization of the chains with an external PBL"), when
chain->pbl_sp.table_virt initialization was moved up to
qed_chain_init_params().
Fix it by initializing pbl_virt with an already filled chain struct field.

Fixes: c3a321b06a ("qed: simplify initialization of the chains with an external PBL")
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Alexander Lobakin <alobakin@marvell.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-07-27 12:17:14 -07:00
laurent brando
5fd82200d8 net: mscc: ocelot: fix hardware timestamp dequeue logic
The next hw timestamp should be snapshoot to the read registers
only once the current timestamp has been read.
If none of the pending skbs matches the current HW timestamp
just gracefully flush the available timestamp by reading it.

Signed-off-by: laurent brando <laurent.brando@nxp.com>
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: Yangbo Lu <yangbo.lu@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-07-27 12:04:40 -07:00
Christian Hewitt
f1bb924e8f arm64: dts: meson: fix mmc0 tuning error on Khadas VIM3
Similar to other G12B devices using the W400 dtsi, I see reports of mmc0
tuning errors on VIM3 after a few hours uptime:

[12483.917391] mmc0: tuning execution failed: -5
[30535.551221] mmc0: tuning execution failed: -5
[35359.953671] mmc0: tuning execution failed: -5
[35561.875332] mmc0: tuning execution failed: -5
[61733.348709] mmc0: tuning execution failed: -5

I do not see the same on VIM3L, so remove sd-uhs-sdr50 from the common dtsi
to silence the error, then (re)add it to the VIM3L dts.

Fixes: 4f26cc1c96 ("arm64: dts: khadas-vim3: move common nodes into meson-khadas-vim3.dtsi")
Fixes: 700ab8d839 ("arm64: dts: khadas-vim3: add support for the SM1 based VIM3L")
Signed-off-by: Christian Hewitt <christianshewitt@gmail.com>
Signed-off-by: Kevin Hilman <khilman@baylibre.com>
Link: https://lore.kernel.org/r/20200721015950.11816-1-christianshewitt@gmail.com
2020-07-27 11:53:47 -07:00
Christian Hewitt
2fa17dd095 arm64: dts: meson: misc fixups for w400 dtsi
Current devices using the W400 dtsi show mmc tuning errors:

[12483.917391] mmc0: tuning execution failed: -5
[30535.551221] mmc0: tuning execution failed: -5
[35359.953671] mmc0: tuning execution failed: -5
[35561.875332] mmc0: tuning execution failed: -5
[61733.348709] mmc0: tuning execution failed: -5

Removing "sd-uhs-sdr50" from the SDIO node prevents this. We also add
keep-power-in-suspend to the SDIO node and fix an indentation.

Fixes: 3cb74db9b2 ("arm64: dts: meson: convert ugoos-am6 to common w400 dtsi")
Signed-off-by: Christian Hewitt <christianshewitt@gmail.com>
Signed-off-by: Kevin Hilman <khilman@baylibre.com>
Link: https://lore.kernel.org/r/20200721013952.11635-1-christianshewitt@gmail.com
2020-07-27 11:52:14 -07:00
Matthieu Baerts
367fe04eb6 mptcp: fix joined subflows with unblocking sk
Unblocking sockets used for outgoing connections were not containing
inet info about the initial connection due to a typo there: the value of
"err" variable is negative in the kernelspace.

This fixes the creation of additional subflows where the remote port has
to be reused if the other host didn't announce another one. This also
fixes inet_diag showing blank info about MPTCP sockets from unblocking
sockets doing a connect().

Fixes: 41be81a8d3 ("mptcp: fix unblocking connect()")
Signed-off-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Acked-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-07-27 11:50:57 -07:00
David S. Miller
43e7a0e5ad Merge branch 'bnxt_en-update'
Michael Chan says:

====================
bnxt_en update.

This patchset removes the PCIe histogram and other debug register
data from ethtool -S. The removed data are not counters and they have
very large and constantly fluctuating values that are not suitable for
the ethtool -S decimal counter display.

The rest of the patches implement counter rollover for all hardware
counters that are not 64-bit counters.  Different generations of
hardware have different counter widths.  The driver will now query
the counter widths of all counters from firmware and implement
rollover support on all non-64-bit counters.

The last patch adds the PCIe histogram and other PCIe register data back
using the ethtool -d interface.

v2: Fix bnxt_re RDMA driver compile issue.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>
2020-07-27 11:47:33 -07:00
Vasundhara Volam
b5d600b027 bnxt_en: Add support for 'ethtool -d'
Add support to dump PXP registers and PCIe statistics.

Signed-off-by: Vasundhara Volam <vasundhara-v.volam@broadcom.com>
Signed-off-by: Michael Chan <michael.chan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-07-27 11:47:33 -07:00
Michael Chan
a0c30621c2 bnxt_en: Switch over to use the 64-bit software accumulated counters.
Now we can report all the full 64-bit CPU endian software accumulated
counters instead of the hw counters, some of which may be less than
64-bit wide.  Define the necessary macros to access the software
counters.

Reviewed-by: Vasundhara Volam <vasundhara-v.volam@broadcom.com>
Signed-off-by: Michael Chan <michael.chan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-07-27 11:47:33 -07:00
Michael Chan
fea6b33355 bnxt_en: Accumulate all counters.
Now that we have the infrastructure in place, add the new function
bnxt_accumulate_all_stats() to periodically accumulate and check for
counter rollover of all ring stats and port stats.

A chip bug was also discovered that could cause some ring counters to
become 0 during DMA.  Workaround by ignoring zeros on the affected
chips.

Some older frimware will reset port counters during ifdown.  We need
to check for that and free the accumulated port counters during ifdown
to prevent bogus counter overflow detection during ifup.

Reviewed-by: Vasundhara Volam <vasundhara-v.volam@broadcom.com>
Signed-off-by: Michael Chan <michael.chan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-07-27 11:47:33 -07:00
Michael Chan
531d1d269c bnxt_en: Retrieve hardware masks for port counters.
If supported by newer firmware, make the firmware call to query all
the port counter masks.  If not supported, assume 40-bit port
counter masks.

Reviewed-by: Vasundhara Volam <vasundhara-v.volam@broadcom.com>
Signed-off-by: Michael Chan <michael.chan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-07-27 11:47:33 -07:00
Michael Chan
d752d0536c bnxt_en: Retrieve hardware counter masks from firmware if available.
Newer firmware has a new call HWRM_FUNC_QSTATS_EXT to retrieve the
masks of all ring counters.  Make this call when supported to
initialize the hardware masks of all ring counters.  If the call
is not available, assume 48-bit ring counter masks on P5 chips.

Reviewed-by: Vasundhara Volam <vasundhara-v.volam@broadcom.com>
Signed-off-by: Michael Chan <michael.chan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-07-27 11:47:33 -07:00
Michael Chan
a37120b22e bnxt_en: Allocate additional memory for all statistics blocks.
Some of these DMAed hardware counters are not full 64-bit counters and
so we need to accumulate them as they overflow.  Allocate copies of these
DMA statistics memory blocks with the same size for accumulation.  The
hardware counter widths are also counter specific so we allocate
memory for masks that correspond to each counter.

Reviewed-by: Vasundhara Volam <vasundhara-v.volam@broadcom.com>
Signed-off-by: Michael Chan <michael.chan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-07-27 11:47:33 -07:00
Michael Chan
177a6cde47 bnxt_en: Refactor statistics code and structures.
The driver manages multiple statistics structures of different sizes.
They are all allocated, freed, and handled practically the same.  Define
a new bnxt_stats_mem structure and common allocation and free functions
for all staistics memory blocks.

Reviewed-by: Vasundhara Volam <vasundhara-v.volam@broadcom.com>
Signed-off-by: Michael Chan <michael.chan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-07-27 11:47:33 -07:00
Michael Chan
24c93443fe bnxt_en: Use macros to define port statistics size and offset.
The port statistics structures have hard coded padding and offset.
Define macros to make this look cleaner.

Reviewed-by: Pavan Chebbi <pavan.chebbi@broadcom.com>
Reviewed-by: Vasundhara Volam <vasundhara-v.volam@broadcom.com>
Signed-off-by: Michael Chan <michael.chan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-07-27 11:47:33 -07:00
Michael Chan
bfc6e5fbcb bnxt_en: Update firmware interface to 1.10.1.54.
Main changes are 200G support and fixing the definitions of discard and
error counters to match the hardware definitions.

Because the HWRM_PORT_PHY_QCFG message size has now exceeded the max.
encapsulated response message size of 96 bytes from the PF to the VF,
we now need to cap this message to 96 bytes for forwarding.  The forwarded
response only needs to contain the basic link status and speed information
and can be capped without adding the new information.

v2: Fix bnxt_re compile error.

Cc: Selvin Xavier <selvin.xavier@broadcom.com>
Reviewed-by: Vasundhara Volam <vasundhara-v.volam@broadcom.com>
Reviewed-by: Edwin Peer <edwin.peer@broadcom.com>
Signed-off-by: Michael Chan <michael.chan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-07-27 11:47:33 -07:00
Vasundhara Volam
dfe64de974 bnxt_en: Remove PCIe non-counters from ethtool statistics
Remove PCIe non-counters display from ethtool statistics, as
they are not simple counters but register dump.  The next few
patches will add logic to detect counter roll-over and it won't
work with these PCIe non-counters.

There will be a follow up patch to get PCIe information via
ethtool register dump.

Signed-off-by: Vasundhara Volam <vasundhara-v.volam@broadcom.com>
Signed-off-by: Michael Chan <michael.chan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-07-27 11:47:32 -07:00
Martin Varghese
350e7ab92d net: Removed the device type check to add mpls support for devices
MPLS has no dependency with the device type of underlying devices.
Hence the device type check to add mpls support for devices can be
avoided.

Signed-off-by: Martin Varghese <martin.varghese@nokia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-07-27 11:40:47 -07:00
Ido Schimmel
73cb11933c ipmr: Copy option to correct variable
Cited commit mistakenly copied provided option to 'val' instead of to
'mfc':

```
-               if (copy_from_user(&mfc, optval, sizeof(mfc))) {
+               if (copy_from_sockptr(&val, optval, sizeof(val))) {
```

Fix this by copying the option to 'mfc'.

selftest router_multicast.sh before:

$ ./router_multicast.sh
smcroutectl: Unknown or malformed IPC message 'a' from client.
smcroutectl: failed removing multicast route, does not exist.
TEST: mcast IPv4                                                    [FAIL]
        Multicast not received on first host
TEST: mcast IPv6                                                    [ OK ]
smcroutectl: Unknown or malformed IPC message 'a' from client.
smcroutectl: failed removing multicast route, does not exist.
TEST: RPF IPv4                                                      [FAIL]
        Multicast not received on first host
TEST: RPF IPv6                                                      [ OK ]

selftest router_multicast.sh after:

$ ./router_multicast.sh
TEST: mcast IPv4                                                    [ OK ]
TEST: mcast IPv6                                                    [ OK ]
TEST: RPF IPv4                                                      [ OK ]
TEST: RPF IPv6                                                      [ OK ]

Fixes: 01ccb5b48f ("net/ipv4: switch ip_mroute_setsockopt to sockptr_t")
Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-07-27 11:39:55 -07:00
Eric Biggers
6414e9b09f fs: define inode flags using bit numbers
Define the VFS inode flags using bit numbers instead of hardcoding
powers of 2, which has become unwieldy now that we're up to 65536.

No change in the actual values.

Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2020-07-27 14:39:53 -04:00
Al Viro
bb1a773d5b kill unused dump_fpu() instances
dump_fpu() is used only on the architectures that support elf
and have neither CORE_DUMP_USE_REGSET nor ELF_CORE_COPY_FPREGS
defined.

Currently that's csky, m68k, microblaze, nds32 and unicore32.  The rest
of the instances are dead code.

NB: THIS MUST GO AFTER ELF_FDPIC CONVERSION

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2020-07-27 14:33:10 -04:00
Al Viro
5d2c56ec0e Merge branch 'work.fdpic' into regset.followup 2020-07-27 14:32:44 -04:00
Al Viro
ce327e1c54 regset: kill user_regset_copyout{,_zero}()
no callers left

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2020-07-27 14:31:13 -04:00
Al Viro
c522401e06 regset(): kill ->get_size()
not used anymore

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2020-07-27 14:31:13 -04:00
Al Viro
1e6986c9db regset: kill ->get()
no instances left

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2020-07-27 14:31:12 -04:00
Al Viro
dcad7854fc csky: switch to ->regset_get()
NB: WTF is fpregs_get() playing at???

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2020-07-27 14:31:12 -04:00
Al Viro
a6ea5b4588 xtensa: switch to ->regset_get()
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2020-07-27 14:31:12 -04:00
Al Viro
bd0409a856 parisc: switch to ->regset_get()
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2020-07-27 14:31:12 -04:00
Al Viro
1b5b456e39 nds32: switch to ->regset_get()
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2020-07-27 14:31:11 -04:00
Al Viro
6bda768887 nios2: switch to ->regset_get()
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2020-07-27 14:31:11 -04:00
Al Viro
8320514c91 hexagon: switch to ->regset_get()
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2020-07-27 14:31:11 -04:00
Al Viro
4e5e7ea48e h8300: switch to ->regset_get()
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2020-07-27 14:31:10 -04:00
Al Viro
f04b2b7cde openrisc: switch to ->regset_get()
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2020-07-27 14:31:10 -04:00
Al Viro
2cb6cd495d riscv: switch to ->regset_get()
Note: riscv_fpr_get() used to forget to zero-pad at the end.
Not worth -stable...

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2020-07-27 14:31:10 -04:00
Al Viro
c7a0faa21e c6x: switch to ->regset_get()
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2020-07-27 14:31:10 -04:00
Al Viro
4ff8a356da ia64: switch to ->regset_get()
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2020-07-27 14:31:09 -04:00
Al Viro
5a806e0a1c arc: switch to ->regset_get()
NB: it used to do short store; fix is needed earlier in the series.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2020-07-27 14:31:09 -04:00
Al Viro
3598e9f096 arm: switch to ->regset_get()
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2020-07-27 14:31:09 -04:00
Al Viro
3399d90ce6 sh: convert to ->regset_get()
NB: there's a direct call of fpregs_get() left in dump_fpu().
To be taken out once we convert ELF_FDPIC to use of regset.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2020-07-27 14:31:09 -04:00
Al Viro
759de58f28 arm64: switch to ->regset_get()
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2020-07-27 14:31:08 -04:00
Al Viro
a0faf966a4 mips: switch to ->regset_get()
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2020-07-27 14:31:08 -04:00
Al Viro
4d617aaae4 sparc: switch to ->regset_get()
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2020-07-27 14:31:08 -04:00
Al Viro
b69c632052 s390: switch to ->regset_get()
NB: compat NT_S390_LAST_BREAK might be better as compat_long_t
rather than long.  User-visible ABI, again...

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2020-07-27 14:31:08 -04:00
Al Viro
47e12855a9 powerpc: switch to ->regset_get()
Note: compat variant of REGSET_TM_CGPR is almost certainly wrong;
it claims to be 48*64bit, but just as compat REGSET_GPR it stores
44*32bit of (truncated) registers + 4 32bit zeros... followed by
48 more 32bit zeroes.  Might be too late to change - it's a userland
ABI, after all ;-/

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2020-07-27 14:31:07 -04:00
Al Viro
0557d64d98 x86: switch to ->regset_get()
All instances of ->get() in arch/x86 switched; that might or might
not be worth splitting up.  Notes:

	* for xstateregs_get() the amount we want to store is determined at
the boot time; see init_xstate_size() and update_regset_xstate_info() for
details.  task->thread.fpu.state.xsave ends with a flexible array member and
the amount of data in it depends upon the FPU features supported/enabled.

	* fpregs_get() writes slightly less than full ->thread.fpu.state.fsave
(the last word is not copied); we pass the full size of state.fsave and let
membuf_write() trim to the amount declared by regset - __regset_get() will
make sure that the space in buffer is no more than that.

	* copy_xstate_to_user() and its helpers are gone now.

	* fpregs_soft_get() was getting user_regset_copyout() arguments
wrong.  Since "x86: x86 user_regset math_emu" back in 2008...  I really
doubt that it's worth splitting out for -stable, though - you need
a 486SX box for that to trigger...

[Kevin's braino fix for copy_xstate_to_kernel() essentially duplicated here]

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2020-07-27 14:31:07 -04:00
Al Viro
7717cb9bdd regset: new method and helpers for it
->regset_get() takes task+regset+buffer, returns the amount of free space
left in the buffer on success and -E... on error.

buffer is represented as struct membuf - a pair of (kernel) pointer
and amount of space left

Primitives for writing to such:
	* membuf_write(buf, data, size)
	* membuf_zero(buf, size)
	* membuf_store(buf, value)

These are implemented as inlines (in case of membuf_store - a macro).
All writes are sequential; they become no-ops when there's no space
left.  Return value of all primitives is the amount of space left
after the operation, so they can be used as return values of ->regset_get().

Example of use:

// stores pt_regs of task + 64 bytes worth of zeroes + 32bit PID of task
int foo_get(struct task_struct *task, const struct regset *regset,
	    struct membuf to)
{
	membuf_write(&to, task_pt_regs(task), sizeof(struct pt_regs));
	membuf_zero(&to, 64);
	return membuf_store(&to, (u32)task_tgid_vnr(task));
}

regset_get()/regset_get_alloc() taught to use that thing if present.
By the end of the series all users of ->get() will be converted;
then ->get() and ->get_size() can go.

Note that unlike ->get() this thing always starts at offset 0 and,
since it only writes to kernel buffer, can't fail on copyout.
It can, of course, fail for other reasons, but those tend to
be less numerous.

The caller guarantees that the buffer size won't be bigger than
regset->n * regset->size.  That simplifies life for quite a few
instances.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2020-07-27 14:31:07 -04:00