There is no user for this interface. If in future it is needed it can
be reimplemented to walk the rbtree of buffers instead of doing
block-by-block lookups.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
64bit division is kind of expensive, and shift should do the job here.
Signed-off-by: Pavel Machek (CIP) <pavel@denx.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
Fix compile errors,warnings when CONFIG_IPV6 is disabled and
inconsistent indenting.
v1->v2:
- Corrected errors/warnings reported when used newer gcc version,
unused array.
Fixes: 6abde0b241 ("crypto/chtls: IPv6 support for inline TLS")
Signed-off-by: Vinay Kumar Yadav <vinay.yadav@chelsio.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Clearing the 'inet_num' field is necessary and safe if and
only if the socket is not bound. The MPTCP protocol calls
the destroy helper on bound sockets, as tcp_v{4,6}_syn_recv_sock
completed successfully.
Move the clearing of such field out of the common code, otherwise
the MPTCP MP_JOIN error path will find the wrong 'inet_num' value
on socket disposal, __inet_put_port() will acquire the wrong lock
and bind_node removal could race with other modifiers possibly
corrupting the bind hash table.
Reported-and-tested-by: Christoph Paasch <cpaasch@apple.com>
Fixes: 729cd6436f ("mptcp: cope better with MP_JOIN failure")
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
If register_netdev(dev) fails, free_netdev(dev) needs
to be called, otherwise a memory leak will occur.
Fixes: 1da177e4c3 ("Linux-2.6.12-rc2")
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Wang Hai <wanghai38@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Corrected the MAC_CR configuration bits for 1 GBit operation. The data
sheet allows MAC_CR(2:1) to be 10 and also 11 for 1 GBit/s speed, but
only 10 works correctly.
Devices tested:
Microchip Lan7431, fixed-phy mode
Microchip Lan7430, normal phy mode
Fixes: 6f197fb638 ("lan743x: Added fixed link and RGMII support")
Signed-off-by: Roelof Berg <rberg@berg-solutions.de>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>
net/sch_generic.h does not need to be included, remove it.
Signed-off-by: Valentin Longchamp <valentin@longchamp.me>
Signed-off-by: David S. Miller <davem@davemloft.net>
Th referenced change added an extra hw reset to rtl8169_net_suspend()
what makes WoL fail on few chip versions. Therefore skip the extra
reset if we're going down and WoL is enabled.
In rtl_shutdown() rtl8169_hw_reset() is called by rtl8169_net_suspend()
already if needed, therefore avoid issues issue by removing the extra
call. The fix was tested on a system with RTL8168g.
Meanwhile rtl8169_hw_reset() does more than a hw reset and should be
renamed. But that's net-next material.
Fixes: 8ac8e8c64b ("r8169: make rtl8169_down central chip quiesce function")
Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The code is return PTR_ERR(NULL) which is zero or success. We should
return -ENOMEM instead.
Fixes: 94abdad697 ("net: ethernet: dwmac: add ethernet glue logic for NXP imx8 chip")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Acked-by: Fugang Duan <fugang.duan@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The u64_stats mechanism uses sequence counters to protect against 64-bit
values tearing on 32-bit architectures. Updating u64_stats is thus a
sequence counter write side critical section where preemption must be
disabled.
For mdiobus_stats_acct(), disable preemption upon the u64_stats update.
It is called from process context through mdiobus_read() and
mdiobus_write().
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Ahmed S. Darwish <a.darwish@linutronix.de>
Reviewed-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
The u64_stats mechanism uses sequence counters to protect against 64-bit
values tearing on 32-bit architectures. Updating such statistics is a
sequence counter write side critical section.
Preemption must be disabled before entering this seqcount write critical
section. Failing to do so, the seqcount read side can preempt the write
side section and spin for the entire scheduler tick. If that reader
belongs to a real-time scheduling class, it can spin forever and the
kernel will livelock.
Document this statistics update side non-preemptibility requirement.
Reword the introductory paragraph to highlight u64_stats raison d'être:
64-bit values tearing protection on 32-bit architectures. Divide
documentation on a basis of internal design vs. usage constraints.
Reword the u64_stats header file top comment to always mention "Reader"
or "Writer" at the start of each bullet point, making it easier to
follow which side each point is actually for.
Clarify the statement "whole thing is a NOOP on 64bit arches or UP
kernels". For 32-bit UP kernels, preemption is always disabled for the
statistics read side section.
Signed-off-by: Ahmed S. Darwish <a.darwish@linutronix.de>
Reviewed-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
Commit bf7afb29d5 ("phy: improve safety of fixed-phy MII register
reading") protected the fixed PHY status with a sequence counter.
Two years later, commit d2b977939b ("net: phy: fixed-phy: remove
fixed_phy_update_state()") removed the sequence counter's write side
critical section -- neutralizing its read side retry loop.
Remove the unused seqcount.
Signed-off-by: Ahmed S. Darwish <a.darwish@linutronix.de>
Reviewed-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>
Sequence counters write paths are critical sections that must never be
preempted, and blocking, even for CONFIG_PREEMPTION=n, is not allowed.
Commit 5dbe7c178d ("net: fix kernel deadlock with interface rename and
netdev name retrieval.") handled a deadlock, observed with
CONFIG_PREEMPTION=n, where the devnet_rename seqcount read side was
infinitely spinning: it got scheduled after the seqcount write side
blocked inside its own critical section.
To fix that deadlock, among other issues, the commit added a
cond_resched() inside the read side section. While this will get the
non-preemptible kernel eventually unstuck, the seqcount reader is fully
exhausting its slice just spinning -- until TIF_NEED_RESCHED is set.
The fix is also still broken: if the seqcount reader belongs to a
real-time scheduling policy, it can spin forever and the kernel will
livelock.
Disabling preemption over the seqcount write side critical section will
not work: inside it are a number of GFP_KERNEL allocations and mutex
locking through the drivers/base/ :: device_rename() call chain.
>From all the above, replace the seqcount with a rwsem.
Fixes: 5dbe7c178d (net: fix kernel deadlock with interface rename and netdev name retrieval.)
Fixes: 30e6c9fa93 (net: devnet_rename_seq should be a seqcount)
Fixes: c91f6df2db (sockopt: Change getsockopt() of SO_BINDTODEVICE to return an interface name)
Cc: <stable@vger.kernel.org>
Reported-by: kbuild test robot <lkp@intel.com> [ v1 missing up_read() on error exit ]
Reported-by: Dan Carpenter <dan.carpenter@oracle.com> [ v1 missing up_read() on error exit ]
Signed-off-by: Ahmed S. Darwish <a.darwish@linutronix.de>
Reviewed-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
If the geneve interface is in collect_md (external) mode, it can't send any
packets submitted directly to its net interface, as such packets won't have
metadata attached. This is expected.
However, the kernel itself sends some packets to the interface, most
notably, IPv6 DAD, IPv6 multicast listener reports, etc. This is not wrong,
as tunnel metadata can be specified in routing table (although technically,
that has never worked for IPv6, but hopefully will be fixed eventually) and
then the interface must correctly participate in IPv6 housekeeping.
The problem is that any such attempt increases the tx_error counter. Just
bringing up a geneve interface with IPv6 enabled is enough to see a number
of tx_errors. That causes confusion among users, prompting them to find
a network error where there is none.
Change the counter used to tx_dropped. That better conveys the meaning
(there's nothing wrong going on, just some packets are getting dropped) and
hopefully will make admins panic less.
Signed-off-by: Jiri Benc <jbenc@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Sameeh Jubran says:
====================
Fix xdp in ena driver
This patchset includes 2 XDP related bug fixes
Difference from v1:
* Fixed "Fixes" tag
====================
Acked-by: Jakub Kicinski <kuba@kernel.org>
Acked-by: Jesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This patch fixes two issues with XDP:
1. If the XDP verdict is XDP_ABORTED we break the loop, which results in
us handling one buffer per napi cycle instead of the total budget
(usually 64). To overcome this simply change the xdp_verdict check to
!= XDP_PASS. When the verdict is XDP_PASS, the skb is not expected to
be NULL.
2. Update the residual budget for XDP_DROP and XDP_ABORTED, since
packets are handled in these cases.
Fixes: 548c4940b9 ("net: ena: Implement XDP_TX action")
Signed-off-by: Sameeh Jubran <sameehj@amazon.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
When sending very high packet rate, the XDP tx queues can get full and
start dropping packets. In this case we don't free the pages which
results in ena driver draining the system memory.
Fix:
Simply free the pages when necessary.
Fixes: 548c4940b9 ("net: ena: Implement XDP_TX action")
Signed-off-by: Sameeh Jubran <sameehj@amazon.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The seg6_validate_srh() is used to validate SRH for three cases:
case1: SRH of data-plane SRv6 packets to be processed by the Linux kernel.
Case2: SRH of the netlink message received from user-space (iproute2)
Case3: SRH injected into packets through setsockopt
In case1, the SRH can be encoded in the Reduced way (i.e., first SID is
carried in DA only and not represented as SID in the SRH) and the
seg6_validate_srh() now handles this case correctly.
In case2 and case3, the SRH shouldn’t be encoded in the Reduced way
otherwise we lose the first segment (i.e., the first hop).
The current implementation of the seg6_validate_srh() allow SRH of case2
and case3 to be encoded in the Reduced way. This leads a slab-out-of-bounds
problem.
This patch verifies SRH of case1, case2 and case3. Allowing case1 to be
reduced while preventing SRH of case2 and case3 from being reduced .
Reported-by: syzbot+e8c028b62439eac42073@syzkaller.appspotmail.com
Reported-by: YueHaibing <yuehaibing@huawei.com>
Fixes: 0cb7498f23 ("seg6: fix SRH processing to comply with RFC8754")
Signed-off-by: Ahmed Abdelsalam <ahabdels@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
syzbot found the following crash:
general protection fault, probably for non-canonical address 0xdffffc0000000019: 0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x00000000000000c8-0x00000000000000cf]
CPU: 1 PID: 7060 Comm: syz-executor394 Not tainted 5.7.0-rc6-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:__tipc_sendstream+0xbde/0x11f0 net/tipc/socket.c:1591
Code: 00 00 00 00 48 39 5c 24 28 48 0f 44 d8 e8 fa 3e db f9 48 b8 00 00 00 00 00 fc ff df 48 8d bb c8 00 00 00 48 89 fa 48 c1 ea 03 <80> 3c 02 00 0f 85 e2 04 00 00 48 8b 9b c8 00 00 00 48 b8 00 00 00
RSP: 0018:ffffc90003ef7818 EFLAGS: 00010202
RAX: dffffc0000000000 RBX: 0000000000000000 RCX: ffffffff8797fd9d
RDX: 0000000000000019 RSI: ffffffff8797fde6 RDI: 00000000000000c8
RBP: ffff888099848040 R08: ffff88809a5f6440 R09: fffffbfff1860b4c
R10: ffffffff8c305a5f R11: fffffbfff1860b4b R12: ffff88809984857e
R13: 0000000000000000 R14: ffff888086aa4000 R15: 0000000000000000
FS: 00000000009b4880(0000) GS:ffff8880ae700000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000020000140 CR3: 00000000a7fdf000 CR4: 00000000001406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
tipc_sendstream+0x4c/0x70 net/tipc/socket.c:1533
sock_sendmsg_nosec net/socket.c:652 [inline]
sock_sendmsg+0xcf/0x120 net/socket.c:672
____sys_sendmsg+0x32f/0x810 net/socket.c:2352
___sys_sendmsg+0x100/0x170 net/socket.c:2406
__sys_sendmmsg+0x195/0x480 net/socket.c:2496
__do_sys_sendmmsg net/socket.c:2525 [inline]
__se_sys_sendmmsg net/socket.c:2522 [inline]
__x64_sys_sendmmsg+0x99/0x100 net/socket.c:2522
do_syscall_64+0xf6/0x7d0 arch/x86/entry/common.c:295
entry_SYSCALL_64_after_hwframe+0x49/0xb3
RIP: 0033:0x440199
...
This bug was bisected to commit 0a3e060f34 ("tipc: add test for Nagle
algorithm effectiveness"). However, it is not the case, the trouble was
from the base in the case of zero data length message sending, we would
unexpectedly make an empty 'txq' queue after the 'tipc_msg_append()' in
Nagle mode.
A similar crash can be generated even without the bisected patch but at
the link layer when it accesses the empty queue.
We solve the issues by building at least one buffer to go with socket's
header and an optional data section that may be empty like what we had
with the 'tipc_msg_build()'.
Note: the previous commit 4c21daae3d ("tipc: Fix NULL pointer
dereference in __tipc_sendstream()") is obsoleted by this one since the
'txq' will be never empty and the check of 'skb != NULL' is unnecessary
but it is safe anyway.
Reported-by: syzbot+8eac6d030e7807c21d32@syzkaller.appspotmail.com
Fixes: c0bceb97db ("tipc: add smart nagle feature")
Acked-by: Jon Maloy <jmaloy@redhat.com>
Signed-off-by: Tuong Lien <tuong.t.lien@dektech.com.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
There are two kinds of memory leaks in genl_family_rcv_msg_dumpit():
1. Before we call ops->start(), whenever an error happens, we forget
to free the memory allocated in genl_family_rcv_msg_dumpit().
2. When ops->start() fails, the 'info' has been already installed on
the per socket control block, so we should not free it here. More
importantly, nlk->cb_running is still false at this point, so
netlink_sock_destruct() cannot free it either.
The first kind of memory leaks is easier to resolve, but the second
one requires some deeper thoughts.
After reviewing how netfilter handles this, the most elegant solution
I find is just to use a similar way to allocate the memory, that is,
moving memory allocations from caller into ops->start(). With this,
we can solve both kinds of memory leaks: for 1), no memory allocation
happens before ops->start(); for 2), ops->start() handles its own
failures and 'info' is installed to the socket control block only
when success. The only ugliness here is we have to pass all local
variables on stack via a struct, but this is not hard to understand.
Alternatively, we can introduce a ops->free() to solve this too,
but it is overkill as only genetlink has this problem so far.
Fixes: 1927f41a22 ("net: genetlink: introduce dump info struct to be available during dumpit op")
Reported-by: syzbot+21f04f481f449c8db840@syzkaller.appspotmail.com
Cc: "Jason A. Donenfeld" <Jason@zx2c4.com>
Cc: Florian Westphal <fw@strlen.de>
Cc: Pablo Neira Ayuso <pablo@netfilter.org>
Cc: Jiri Pirko <jiri@mellanox.com>
Cc: YueHaibing <yuehaibing@huawei.com>
Cc: Shaochun Chen <cscnull@gmail.com>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
cxgb4_uld_in_use() is used only by cxgb4_ktls_det_feature() which
is under CONFIG_CHELSIO_TLS_DEVICE macro.
Fixes: a3ac249a1a ("cxgb4/chcr: Enable ktls settings at run time")
Signed-off-by: Rohit Maheshwari <rohitm@chelsio.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Pull execve updates from Eric Biederman:
"Last cycle for the Nth time I ran into bugs and quality of
implementation issues related to exec that could not be easily be
fixed because of the way exec is implemented. So I have been digging
into exec and cleanup up what I can.
I don't think I have exec sorted out enough to fix the issues I
started with but I have made some headway this cycle with 4 sets of
changes.
- promised cleanups after introducing exec_update_mutex
- trivial cleanups for exec
- control flow simplifications
- remove the recomputation of bprm->cred
The net result is code that is a bit easier to understand and work
with and a decrease in the number of lines of code (if you don't count
the added tests)"
* 'exec-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace: (24 commits)
exec: Compute file based creds only once
exec: Add a per bprm->file version of per_clear
binfmt_elf_fdpic: fix execfd build regression
selftests/exec: Add binfmt_script regression test
exec: Remove recursion from search_binary_handler
exec: Generic execfd support
exec/binfmt_script: Don't modify bprm->buf and then return -ENOEXEC
exec: Move the call of prepare_binprm into search_binary_handler
exec: Allow load_misc_binary to call prepare_binprm unconditionally
exec: Convert security_bprm_set_creds into security_bprm_repopulate_creds
exec: Factor security_bprm_creds_for_exec out of security_bprm_set_creds
exec: Teach prepare_exec_creds how exec treats uids & gids
exec: Set the point of no return sooner
exec: Move handling of the point of no return to the top level
exec: Run sync_mm_rss before taking exec_update_mutex
exec: Fix spelling of search_binary_handler in a comment
exec: Move the comment from above de_thread to above unshare_sighand
exec: Rename flush_old_exec begin_new_exec
exec: Move most of setup_new_exec into flush_old_exec
exec: In setup_new_exec cache current in the local variable me
...
Pull proc updates from Eric Biederman:
"This has four sets of changes:
- modernize proc to support multiple private instances
- ensure we see the exit of each process tid exactly
- remove has_group_leader_pid
- use pids not tasks in posix-cpu-timers lookup
Alexey updated proc so each mount of proc uses a new superblock. This
allows people to actually use mount options with proc with no fear of
messing up another mount of proc. Given the kernel's internal mounts
of proc for things like uml this was a real problem, and resulted in
Android's hidepid mount options being ignored and introducing security
issues.
The rest of the changes are small cleanups and fixes that came out of
my work to allow this change to proc. In essence it is swapping the
pids in de_thread during exec which removes a special case the code
had to handle. Then updating the code to stop handling that special
case"
* 'proc-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace:
proc: proc_pid_ns takes super_block as an argument
remove the no longer needed pid_alive() check in __task_pid_nr_ns()
posix-cpu-timers: Replace __get_task_for_clock with pid_for_clock
posix-cpu-timers: Replace cpu_timer_pid_type with clock_pid_type
posix-cpu-timers: Extend rcu_read_lock removing task_struct references
signal: Remove has_group_leader_pid
exec: Remove BUG_ON(has_group_leader_pid)
posix-cpu-timer: Unify the now redundant code in lookup_task
posix-cpu-timer: Tidy up group_leader logic in lookup_task
proc: Ensure we see the exit of each process tid exactly once
rculist: Add hlists_swap_heads_rcu
proc: Use PIDTYPE_TGID in next_tgid
Use proc_pid_ns() to get pid_namespace from the proc superblock
proc: use named enums for better readability
proc: use human-readable values for hidepid
docs: proc: add documentation for "hidepid=4" and "subset=pid" options and new mount behavior
proc: add option to mount only a pids subset
proc: instantiate only pids that we can ptrace on 'hidepid=4' mount option
proc: allow to mount many instances of proc in one pid namespace
proc: rename struct proc_fs_info to proc_fs_opts
Pull ext2 and reiserfs cleanups from Jan Kara:
"Two small cleanups for ext2 and one for reiserfs"
* tag 'for_v5.8-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs:
reiserfs: Replace kmalloc with kcalloc in the comment
ext2: code cleanup by removing ifdef macro surrounding
ext2: Fix i_op setting for special inode
A recent commit added new variables only used if CONFIG_NETDEVICES is
set. A simple fix would be to only declare these variables if the same
condition is valid but Alexei suggested an even simpler solution:
since CONFIG_NETDEVICES doesn't change anything in .h I think the
best is to remove #ifdef CONFIG_NETDEVICES from net/core/filter.c
and rely on sock_bindtoindex() returning ENOPROTOOPT in the extreme
case of oddly configured kernels.
Fixes: 70c58997c1 ("bpf: Allow SO_BINDTODEVICE opt in bpf_setsockopt")
Suggested-by: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Signed-off-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Song Liu <songliubraving@fb.com>
Link: https://lore.kernel.org/bpf/20200603190347.2310320-1-matthieu.baerts@tessares.net
Pull fsnotify updates from Jan Kara:
"Several smaller fixes and cleanups for fsnotify subsystem"
* tag 'fsnotify_for_v5.8-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs:
fanotify: fix ignore mask logic for events on child and on dir
fanotify: don't write with size under sizeof(response)
fsnotify: Remove proc_fs.h include
fanotify: remove reference to fill_event_metadata()
fsnotify: add mutex destroy
fanotify: prefix should_merge()
fanotify: Replace zero-length array with flexible-array
inotify: Fix error return code assignment flow.
fsnotify: Add missing annotation for fsnotify_finish_user_wait() and for fsnotify_prepare_user_wait()
Pull zonefs update from Damien Le Moal:
"Only one patch in this pull request to cleanup handling of uuid using
the import_uuid() helper, from Andy"
* tag 'zonefs-5.8-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/dlemoal/zonefs:
zonefs: Replace uuid_copy() with import_uuid()
Right now, we always try to unplug single subblocks when processing an
online memory block. Let's try to unplug the complete online memory block
first, in case it is fully plugged and the unplug request is large
enough. Fallback to single subblocks in case the memory block cannot get
unplugged as a whole.
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Pankaj Gupta <pankaj.gupta.linux@gmail.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
Link: https://lore.kernel.org/r/20200507140139.17083-16-david@redhat.com
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Let's add a parent resource, named after the virtio device (inspired by
drivers/dax/kmem.c). This allows user space to identify which memory
belongs to which virtio-mem device.
With this change and two virtio-mem devices:
:/# cat /proc/iomem
00000000-00000fff : Reserved
00001000-0009fbff : System RAM
[...]
140000000-333ffffff : virtio0
140000000-147ffffff : System RAM
148000000-14fffffff : System RAM
150000000-157ffffff : System RAM
[...]
334000000-3033ffffff : virtio1
338000000-33fffffff : System RAM
340000000-347ffffff : System RAM
348000000-34fffffff : System RAM
[...]
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Pankaj Gupta <pankaj.gupta.linux@gmail.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
Link: https://lore.kernel.org/r/20200507140139.17083-12-david@redhat.com
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Pankaj Gupta <pankaj.gupta.linux@gmail.com>
virtio-mem wants to offline and remove a memory block once it unplugged
all subblocks (e.g., using alloc_contig_range()). Let's provide
an interface to do that from a driver. virtio-mem already supports to
offline partially unplugged memory blocks. Offlining a fully unplugged
memory block will not require to migrate any pages. All unplugged
subblocks are PageOffline() and have a reference count of 0 - so
offlining code will simply skip them.
All we need is an interface to offline and remove the memory from kernel
module context, where we don't have access to the memory block devices
(esp. find_memory_block() and device_offline()) and the device hotplug
lock.
To keep things simple, allow to only work on a single memory block.
Acked-by: Michal Hocko <mhocko@suse.com>
Tested-by: Pankaj Gupta <pankaj.gupta.linux@gmail.com>
Acked-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: Oscar Salvador <osalvador@suse.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Pavel Tatashin <pasha.tatashin@soleen.com>
Cc: Wei Yang <richard.weiyang@gmail.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Qian Cai <cai@lca.pw>
Signed-off-by: David Hildenbrand <david@redhat.com>
Link: https://lore.kernel.org/r/20200507140139.17083-9-david@redhat.com
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
virtio-mem wants to allow to offline memory blocks of which some parts
were unplugged (allocated via alloc_contig_range()), especially, to later
offline and remove completely unplugged memory blocks. The important part
is that PageOffline() has to remain set until the section is offline, so
these pages will never get accessed (e.g., when dumping). The pages should
not be handed back to the buddy (which would require clearing PageOffline()
and result in issues if offlining fails and the pages are suddenly in the
buddy).
Let's allow to do that by allowing to isolate any PageOffline() page
when offlining. This way, we can reach the memory hotplug notifier
MEM_GOING_OFFLINE, where the driver can signal that he is fine with
offlining this page by dropping its reference count. PageOffline() pages
with a reference count of 0 can then be skipped when offlining the
pages (like if they were free, however they are not in the buddy).
Anybody who uses PageOffline() pages and does not agree to offline them
(e.g., Hyper-V balloon, XEN balloon, VMWare balloon for 2MB pages) will not
decrement the reference count and make offlining fail when trying to
migrate such an unmovable page. So there should be no observable change.
Same applies to balloon compaction users (movable PageOffline() pages), the
pages will simply be migrated.
Note 1: If offlining fails, a driver has to increment the reference
count again in MEM_CANCEL_OFFLINE.
Note 2: A driver that makes use of this has to be aware that re-onlining
the memory block has to be handled by hooking into onlining code
(online_page_callback_t), resetting the page PageOffline() and
not giving them to the buddy.
Reviewed-by: Alexander Duyck <alexander.h.duyck@linux.intel.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Tested-by: Pankaj Gupta <pankaj.gupta.linux@gmail.com>
Acked-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Juergen Gross <jgross@suse.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Pavel Tatashin <pavel.tatashin@microsoft.com>
Cc: Alexander Duyck <alexander.h.duyck@linux.intel.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Anthony Yznaga <anthony.yznaga@oracle.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Mike Rapoport <rppt@linux.ibm.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Qian Cai <cai@lca.pw>
Cc: Pingfan Liu <kernelfans@gmail.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
Link: https://lore.kernel.org/r/20200507140139.17083-7-david@redhat.com
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
We also want to unplug online memory (contained in online memory blocks
and, therefore, managed by the buddy), and eventually replug it later.
When requested to unplug memory, we use alloc_contig_range() to allocate
subblocks in online memory blocks (so we are the owner) and send them to
our hypervisor. When requested to plug memory, we can replug such memory
using free_contig_range() after asking our hypervisor.
We also want to mark all allocated pages PG_offline, so nobody will
touch them. To differentiate pages that were never onlined when
onlining the memory block from pages allocated via alloc_contig_range(), we
use PageDirty(). Based on this flag, virtio_mem_fake_online() can either
online the pages for the first time or use free_contig_range().
It is worth noting that there are no guarantees on how much memory can
actually get unplugged again. All device memory might completely be
fragmented with unmovable data, such that no subblock can get unplugged.
We are not touching the ZONE_MOVABLE. If memory is onlined to the
ZONE_MOVABLE, it can only get unplugged after that memory was offlined
manually by user space. In normal operation, virtio-mem memory is
suggested to be onlined to ZONE_NORMAL. In the future, we will try to
make unplug more likely to succeed.
Add a module parameter to control if online memory shall be touched.
As we want to access alloc_contig_range()/free_contig_range() from
kernel module context, export the symbols.
Note: Whenever virtio-mem uses alloc_contig_range(), all affected pages
are on the same node, in the same zone, and contain no holes.
Acked-by: Michal Hocko <mhocko@suse.com> # to export contig range allocator API
Tested-by: Pankaj Gupta <pankaj.gupta.linux@gmail.com>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Jason Wang <jasowang@redhat.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Igor Mammedov <imammedo@redhat.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Pavel Tatashin <pasha.tatashin@soleen.com>
Cc: Stefan Hajnoczi <stefanha@redhat.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Mike Rapoport <rppt@linux.ibm.com>
Cc: Alexander Duyck <alexander.h.duyck@linux.intel.com>
Cc: Alexander Potapenko <glider@google.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
Link: https://lore.kernel.org/r/20200507140139.17083-6-david@redhat.com
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
