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2018-08-11bpf: Introduce BPF_MAP_TYPE_REUSEPORT_SOCKARRAYMartin KaFai Lau
This patch introduces a new map type BPF_MAP_TYPE_REUSEPORT_SOCKARRAY. To unleash the full potential of a bpf prog, it is essential for the userspace to be capable of directly setting up a bpf map which can then be consumed by the bpf prog to make decision. In this case, decide which SO_REUSEPORT sk to serve the incoming request. By adding BPF_MAP_TYPE_REUSEPORT_SOCKARRAY, the userspace has total control and visibility on where a SO_REUSEPORT sk should be located in a bpf map. The later patch will introduce BPF_PROG_TYPE_SK_REUSEPORT such that the bpf prog can directly select a sk from the bpf map. That will raise the programmability of the bpf prog attached to a reuseport group (a group of sk serving the same IP:PORT). For example, in UDP, the bpf prog can peek into the payload (e.g. through the "data" pointer introduced in the later patch) to learn the application level's connection information and then decide which sk to pick from a bpf map. The userspace can tightly couple the sk's location in a bpf map with the application logic in generating the UDP payload's connection information. This connection info contact/API stays within the userspace. Also, when used with map-in-map, the userspace can switch the old-server-process's inner map to a new-server-process's inner map in one call "bpf_map_update_elem(outer_map, &index, &new_reuseport_array)". The bpf prog will then direct incoming requests to the new process instead of the old process. The old process can finish draining the pending requests (e.g. by "accept()") before closing the old-fds. [Note that deleting a fd from a bpf map does not necessary mean the fd is closed] During map_update_elem(), Only SO_REUSEPORT sk (i.e. which has already been added to a reuse->socks[]) can be used. That means a SO_REUSEPORT sk that is "bind()" for UDP or "bind()+listen()" for TCP. These conditions are ensured in "reuseport_array_update_check()". A SO_REUSEPORT sk can only be added once to a map (i.e. the same sk cannot be added twice even to the same map). SO_REUSEPORT already allows another sk to be created for the same IP:PORT. There is no need to re-create a similar usage in the BPF side. When a SO_REUSEPORT is deleted from the "reuse->socks[]" (e.g. "close()"), it will notify the bpf map to remove it from the map also. It is done through "bpf_sk_reuseport_detach()" and it will only be called if >=1 of the "reuse->sock[]" has ever been added to a bpf map. The map_update()/map_delete() has to be in-sync with the "reuse->socks[]". Hence, the same "reuseport_lock" used by "reuse->socks[]" has to be used here also. Care has been taken to ensure the lock is only acquired when the adding sk passes some strict tests. and freeing the map does not require the reuseport_lock. The reuseport_array will also support lookup from the syscall side. It will return a sock_gen_cookie(). The sock_gen_cookie() is on-demand (i.e. a sk's cookie is not generated until the very first map_lookup_elem()). The lookup cookie is 64bits but it goes against the logical userspace expectation on 32bits sizeof(fd) (and as other fd based bpf maps do also). It may catch user in surprise if we enforce value_size=8 while userspace still pass a 32bits fd during update. Supporting different value_size between lookup and update seems unintuitive also. We also need to consider what if other existing fd based maps want to return 64bits value from syscall's lookup in the future. Hence, reuseport_array supports both value_size 4 and 8, and assuming user will usually use value_size=4. The syscall's lookup will return ENOSPC on value_size=4. It will will only return 64bits value from sock_gen_cookie() when user consciously choose value_size=8 (as a signal that lookup is desired) which then requires a 64bits value in both lookup and update. Signed-off-by: Martin KaFai Lau <kafai@fb.com> Acked-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2018-08-11net: Add ID (if needed) to sock_reuseport and expose reuseport_lockMartin KaFai Lau
A later patch will introduce a BPF_MAP_TYPE_REUSEPORT_ARRAY which allows a SO_REUSEPORT sk to be added to a bpf map. When a sk is removed from reuse->socks[], it also needs to be removed from the bpf map. Also, when adding a sk to a bpf map, the bpf map needs to ensure it is indeed in a reuse->socks[]. Hence, reuseport_lock is needed by the bpf map to ensure its map_update_elem() and map_delete_elem() operations are in-sync with the reuse->socks[]. The BPF_MAP_TYPE_REUSEPORT_ARRAY map will only acquire the reuseport_lock after ensuring the adding sk is already in a reuseport group (i.e. reuse->socks[]). The map_lookup_elem() will be lockless. This patch also adds an ID to sock_reuseport. A later patch will introduce BPF_PROG_TYPE_SK_REUSEPORT which allows a bpf prog to select a sk from a bpf map. It is inflexible to statically enforce a bpf map can only contain the sk belonging to a particular reuse->socks[] (i.e. same IP:PORT) during the bpf verification time. For example, think about the the map-in-map situation where the inner map can be dynamically changed in runtime and the outer map may have inner maps belonging to different reuseport groups. Hence, when the bpf prog (in the new BPF_PROG_TYPE_SK_REUSEPORT type) selects a sk, this selected sk has to be checked to ensure it belongs to the requesting reuseport group (i.e. the group serving that IP:PORT). The "sk->sk_reuseport_cb" pointer cannot be used for this checking purpose because the pointer value will change after reuseport_grow(). Instead of saving all checking conditions like the ones preced calling "reuseport_add_sock()" and compare them everytime a bpf_prog is run, a 32bits ID is introduced to survive the reuseport_grow(). The ID is only acquired if any of the reuse->socks[] is added to the newly introduced "BPF_MAP_TYPE_REUSEPORT_ARRAY" map. If "BPF_MAP_TYPE_REUSEPORT_ARRAY" is not used, the changes in this patch is a no-op. Signed-off-by: Martin KaFai Lau <kafai@fb.com> Acked-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2018-08-11tcp: Avoid TCP syncookie rejected by SO_REUSEPORT socketMartin KaFai Lau
Although the actual cookie check "__cookie_v[46]_check()" does not involve sk specific info, it checks whether the sk has recent synq overflow event in "tcp_synq_no_recent_overflow()". The tcp_sk(sk)->rx_opt.ts_recent_stamp is updated every second when it has sent out a syncookie (through "tcp_synq_overflow()"). The above per sk "recent synq overflow event timestamp" works well for non SO_REUSEPORT use case. However, it may cause random connection request reject/discard when SO_REUSEPORT is used with syncookie because it fails the "tcp_synq_no_recent_overflow()" test. When SO_REUSEPORT is used, it usually has multiple listening socks serving TCP connection requests destinated to the same local IP:PORT. There are cases that the TCP-ACK-COOKIE may not be received by the same sk that sent out the syncookie. For example, if reuse->socks[] began with {sk0, sk1}, 1) sk1 sent out syncookies and tcp_sk(sk1)->rx_opt.ts_recent_stamp was updated. 2) the reuse->socks[] became {sk1, sk2} later. e.g. sk0 was first closed and then sk2 was added. Here, sk2 does not have ts_recent_stamp set. There are other ordering that will trigger the similar situation below but the idea is the same. 3) When the TCP-ACK-COOKIE comes back, sk2 was selected. "tcp_synq_no_recent_overflow(sk2)" returns true. In this case, all syncookies sent by sk1 will be handled (and rejected) by sk2 while sk1 is still alive. The userspace may create and remove listening SO_REUSEPORT sockets as it sees fit. E.g. Adding new thread (and SO_REUSEPORT sock) to handle incoming requests, old process stopping and new process starting...etc. With or without SO_ATTACH_REUSEPORT_[CB]BPF, the sockets leaving and joining a reuseport group makes picking the same sk to check the syncookie very difficult (if not impossible). The later patches will allow bpf prog more flexibility in deciding where a sk should be located in a bpf map and selecting a particular SO_REUSEPORT sock as it sees fit. e.g. Without closing any sock, replace the whole bpf reuseport_array in one map_update() by using map-in-map. Getting the syncookie check working smoothly across socks in the same "reuse->socks[]" is important. A partial solution is to set the newly added sk's ts_recent_stamp to the max ts_recent_stamp of a reuseport group but that will require to iterate through reuse->socks[] OR pessimistically set it to "now - TCP_SYNCOOKIE_VALID" when a sk is joining a reuseport group. However, neither of them will solve the existing sk getting moved around the reuse->socks[] and that sk may not have ts_recent_stamp updated, unlikely under continuous synflood but not impossible. This patch opts to treat the reuseport group as a whole when considering the last synq overflow timestamp since they are serving the same IP:PORT from the userspace (and BPF program) perspective. "synq_overflow_ts" is added to "struct sock_reuseport". The tcp_synq_overflow() and tcp_synq_no_recent_overflow() will update/check reuse->synq_overflow_ts if the sk is in a reuseport group. Similar to the reuseport decision in __inet_lookup_listener(), both sk->sk_reuseport and sk->sk_reuseport_cb are tested for SO_REUSEPORT usage. Update on "synq_overflow_ts" happens at roughly once every second. A synflood test was done with a 16 rx-queues and 16 reuseport sockets. No meaningful performance change is observed. Before and after the change is ~9Mpps in IPv4. Cc: Eric Dumazet <edumazet@google.com> Signed-off-by: Martin KaFai Lau <kafai@fb.com> Acked-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2018-08-10net/smc: send response to test link signalUrsula Braun
With SMC-D z/OS sends a test link signal every 10 seconds. Linux is supposed to answer, otherwise the SMC-D connection breaks. Signed-off-by: Ursula Braun <ubraun@linux.ibm.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-08-10Merge branch 'for-upstream' of ↵David S. Miller
git://git.kernel.org/pub/scm/linux/kernel/git/bluetooth/bluetooth-next Johan Hedberg says: ==================== pull request: bluetooth-next 2018-08-10 Here's one more (most likely last) bluetooth-next pull request for the 4.19 kernel. - Added support for MediaTek serial Bluetooth devices - Initial skeleton for controller-side address resolution support - Fix BT_HCIUART_RTL related Kconfig dependencies - A few other minor fixes/cleanups Please let me know if there are any issues pulling. Thanks. ==================== Signed-off-by: David S. Miller <davem@davemloft.net>
2018-08-10Merge git://git.kernel.org/pub/scm/linux/kernel/git/pablo/nf-nextDavid S. Miller
Pablo Neira Ayuso says: ==================== Netfilter updates for net-next The following batch contains netfilter updates for your net-next tree: 1) Expose NFT_OSF_MAXGENRELEN maximum OS name length from the new OS passive fingerprint matching extension, from Fernando Fernandez. 2) Add extension to support for fine grain conntrack timeout policies from nf_tables. As preparation works, this patchset moves nf_ct_untimeout() to nf_conntrack_timeout and it also decouples the timeout policy from the ctnl_timeout object, most work done by Harsha Sharma. 3) Enable connection tracking when conntrack helper is in place. 4) Missing enumeration in uapi header when splitting original xt_osf to nfnetlink_osf, also from Fernando. 5) Fix a sparse warning due to incorrect typing in the nf_osf_find(), from Wei Yongjun. ==================== Signed-off-by: David S. Miller <davem@davemloft.net>
2018-08-10Bluetooth: Add definitions for LE set address resolutionAnkit Navik
Add the definitions for LE address resolution enable HCI commands. When the LE address resolution enable gets changed via HCI commands make sure that flag gets updated. Signed-off-by: Ankit Navik <ankit.p.navik@intel.com> Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
2018-08-10xdp: Helpers for disabling napi_direct of xdp_return_frameToshiaki Makita
We need some mechanism to disable napi_direct on calling xdp_return_frame_rx_napi() from some context. When veth gets support of XDP_REDIRECT, it will redirects packets which are redirected from other devices. On redirection veth will reuse xdp_mem_info of the redirection source device to make return_frame work. But in this case .ndo_xdp_xmit() called from veth redirection uses xdp_mem_info which is not guarded by NAPI, because the .ndo_xdp_xmit() is not called directly from the rxq which owns the xdp_mem_info. This approach introduces a flag in bpf_redirect_info to indicate that napi_direct should be disabled even when _rx_napi variant is used as well as helper functions to use it. A NAPI handler who wants to use this flag needs to call xdp_set_return_frame_no_direct() before processing packets, and call xdp_clear_return_frame_no_direct() after xdp_do_flush_map() before exiting NAPI. v4: - Use bpf_redirect_info for storing the flag instead of xdp_mem_info to avoid per-frame copy cost. Signed-off-by: Toshiaki Makita <makita.toshiaki@lab.ntt.co.jp> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2018-08-10bpf: Make redirect_info accessible from modulesToshiaki Makita
We are going to add kern_flags field in redirect_info for kernel internal use. In order to avoid function call to access the flags, make redirect_info accessible from modules. Also as it is now non-static, add prefix bpf_ to redirect_info. v6: - Fix sparse warning around EXPORT_SYMBOL. Signed-off-by: Toshiaki Makita <makita.toshiaki@lab.ntt.co.jp> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2018-08-10net: Export skb_headers_offset_updateToshiaki Makita
This is needed for veth XDP which does skb_copy_expand()-like operation. v2: - Drop skb_copy_header part because it has already been exported now. Signed-off-by: Toshiaki Makita <makita.toshiaki@lab.ntt.co.jp> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2018-08-10Revert "xdp: add NULL pointer check in __xdp_return()"Björn Töpel
This reverts commit 36e0f12bbfd3016f495904b35e41c5711707509f. The reverted commit adds a WARN to check against NULL entries in the mem_id_ht rhashtable. Any kernel path implementing the XDP (generic or driver) fast path is required to make a paired xdp_rxq_info_reg/xdp_rxq_info_unreg call for proper function. In addition, a driver using a different allocation scheme than the default MEM_TYPE_PAGE_SHARED is required to additionally call xdp_rxq_info_reg_mem_model. For MEM_TYPE_ZERO_COPY, an xdp_rxq_info_reg_mem_model call ensures that the mem_id_ht rhashtable has a properly inserted allocator id. If not, this would be a driver bug. A NULL pointer kernel OOPS is preferred to the WARN. Suggested-by: Jesper Dangaard Brouer <brouer@redhat.com> Signed-off-by: Björn Töpel <bjorn.topel@intel.com> Acked-by: Jesper Dangaard Brouer <brouer@redhat.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2018-08-09net: allow to call netif_reset_xps_queues() under cpus_read_lockAndrei Vagin
The definition of static_key_slow_inc() has cpus_read_lock in place. In the virtio_net driver, XPS queues are initialized after setting the queue:cpu affinity in virtnet_set_affinity() which is already protected within cpus_read_lock. Lockdep prints a warning when we are trying to acquire cpus_read_lock when it is already held. This patch adds an ability to call __netif_set_xps_queue under cpus_read_lock(). Acked-by: Jason Wang <jasowang@redhat.com> ============================================ WARNING: possible recursive locking detected 4.18.0-rc3-next-20180703+ #1 Not tainted -------------------------------------------- swapper/0/1 is trying to acquire lock: 00000000cf973d46 (cpu_hotplug_lock.rw_sem){++++}, at: static_key_slow_inc+0xe/0x20 but task is already holding lock: 00000000cf973d46 (cpu_hotplug_lock.rw_sem){++++}, at: init_vqs+0x513/0x5a0 other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock(cpu_hotplug_lock.rw_sem); lock(cpu_hotplug_lock.rw_sem); *** DEADLOCK *** May be due to missing lock nesting notation 3 locks held by swapper/0/1: #0: 00000000244bc7da (&dev->mutex){....}, at: __driver_attach+0x5a/0x110 #1: 00000000cf973d46 (cpu_hotplug_lock.rw_sem){++++}, at: init_vqs+0x513/0x5a0 #2: 000000005cd8463f (xps_map_mutex){+.+.}, at: __netif_set_xps_queue+0x8d/0xc60 v2: move cpus_read_lock() out of __netif_set_xps_queue() Cc: "Nambiar, Amritha" <amritha.nambiar@intel.com> Cc: "Michael S. Tsirkin" <mst@redhat.com> Cc: Jason Wang <jasowang@redhat.com> Fixes: 8af2c06ff4b1 ("net-sysfs: Add interface for Rx queue(s) map per Tx queue") Signed-off-by: Andrei Vagin <avagin@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-08-09net: sched: fix block->refcnt decrementJiri Pirko
Currently the refcnt is never decremented in case the value is not 1. Fix it by adding decrement in case the refcnt is not 1. Reported-by: Vlad Buslov <vladbu@mellanox.com> Fixes: f71e0ca4db18 ("net: sched: Avoid implicit chain 0 creation") Signed-off-by: Jiri Pirko <jiri@mellanox.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-08-09decnet: fix using plain integer as NULL warningYueHaibing
Fixes the following sparse warning: net/decnet/dn_route.c:407:30: warning: Using plain integer as NULL pointer net/decnet/dn_route.c:1923:22: warning: Using plain integer as NULL pointer Signed-off-by: YueHaibing <yuehaibing@huawei.com> Reviewed-by: Kees Cook <keescook@chromium.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-08-09net: ipv6_gre: Fix GRO to work on IPv6 over GRE tapMaria Pasechnik
IPv6 GRO over GRE tap is not working while GRO is not set over the native interface. gro_list_prepare function updates the same_flow variable of existing sessions to 1 if their mac headers match the one of the incoming packet. same_flow is used to filter out non-matching sessions and keep potential ones for aggregation. The number of bytes to compare should be the number of bytes in the mac headers. In gro_list_prepare this number is set to be skb->dev->hard_header_len. For GRE interfaces this hard_header_len should be as it is set in the initialization process (when GRE is created), it should not be overridden. But currently it is being overridden by the value that is actually supposed to represent the needed_headroom. Therefore, the number of bytes compared in order to decide whether the the mac headers are the same is greater than the length of the headers. As it's documented in netdevice.h, hard_header_len is the maximum hardware header length, and needed_headroom is the extra headroom the hardware may need. hard_header_len is basically all the bytes received by the physical till layer 3 header of the packet received by the interface. For example, if the interface is a GRE tap then the needed_headroom should be the total length of the following headers: IP header of the physical, GRE header, mac header of GRE. It is often used to calculate the MTU of the created interface. This patch removes the override of the hard_header_len, and assigns the calculated value to needed_headroom. This way, the comparison in gro_list_prepare is really of the mac headers, and if the packets have the same mac headers the same_flow will be set to 1. Performance testing: 45% higher bandwidth. Measuring bandwidth of single-stream IPv4 TCP traffic over IPv6 GRE tap while GRO is not set on the native. NIC: ConnectX-4LX Before (GRO not working) : 7.2 Gbits/sec After (GRO working): 10.5 Gbits/sec Signed-off-by: Maria Pasechnik <mariap@mellanox.com> Signed-off-by: Tariq Toukan <tariqt@mellanox.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-08-09rpc: remove unneeded variable 'ret' in rdma_listen_handlerzhong jiang
The ret is not modified after initalization, So just remove the variable and return 0. Signed-off-by: zhong jiang <zhongjiang@huawei.com> Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2018-08-09NFSD: Handle full-length symlinksChuck Lever
I've given up on the idea of zero-copy handling of SYMLINK on the server side. This is because the Linux VFS symlink API requires the symlink pathname to be in a NUL-terminated kmalloc'd buffer. The NUL-termination is going to be problematic (watching out for landing on a page boundary and dealing with a 4096-byte pathname). I don't believe that SYMLINK creation is on a performance path or is requested frequently enough that it will cause noticeable CPU cache pollution due to data copies. There will be two places where a transport callout will be necessary to fill in the rqstp: one will be in the svc_fill_symlink_pathname() helper that is used by NFSv2 and NFSv3, and the other will be in nfsd4_decode_create(). Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2018-08-09NFSD: Refactor the generic write vector fill helperChuck Lever
fill_in_write_vector() is nearly the same logic as svc_fill_write_vector(), but there are a few differences so that the former can handle multiple WRITE payloads in a single COMPOUND. svc_fill_write_vector() can be adjusted so that it can be used in the NFSv4 WRITE code path too. Instead of assuming the pages are coming from rq_args.pages, have the caller pass in the page list. The immediate benefit is a reduction of code duplication. It also prevents the NFSv4 WRITE decoder from passing an empty vector element when the transport has provided the payload in the xdr_buf's page array. Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2018-08-09svcrdma: Clean up Read chunk pathChuck Lever
Simplify the error handling at the tail of recv_read_chunk() by re-arranging rq_pages[] housekeeping and documenting it properly. NB: In this path, svc_rdma_recvfrom returns zero. Therefore no subsequent reply processing is done on the svc_rqstp, and thus the rq_respages field does not need to be updated. Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2018-08-09svcrdma: Avoid releasing a page in svc_xprt_release()Chuck Lever
svc_xprt_release() invokes svc_free_res_pages(), which releases pages between rq_respages and rq_next_page. Historically, the RPC/RDMA transport has set these two pointers to be different by one, which means: - one page gets released when svc_recv returns 0. This normally happens whenever one or more RDMA Reads need to be dispatched to complete construction of an RPC Call. - one page gets released after every call to svc_send. In both cases, this released page is immediately refilled by svc_alloc_arg. There does not seem to be a reason for releasing this page. To avoid this unnecessary memory allocator traffic, set rq_next_page more carefully. Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2018-08-09sunrpc: remove redundant variables 'checksumlen','blocksize' and 'data'YueHaibing
Variables 'checksumlen','blocksize' and 'data' are being assigned, but are never used, hence they are redundant and can be removed. Fix the following warning: net/sunrpc/auth_gss/gss_krb5_wrap.c:443:7: warning: variable ‘blocksize’ set but not used [-Wunused-but-set-variable] net/sunrpc/auth_gss/gss_krb5_crypto.c:376:15: warning: variable ‘checksumlen’ set but not used [-Wunused-but-set-variable] net/sunrpc/xprtrdma/svc_rdma.c:97:9: warning: variable ‘data’ set but not used [-Wunused-but-set-variable] Signed-off-by: YueHaibing <yuehaibing@huawei.com> Reviewed-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2018-08-09Merge ra.kernel.org:/pub/scm/linux/kernel/git/davem/netDavid S. Miller
Overlapping changes in RXRPC, changing to ktime_get_seconds() whilst adding some tracepoints. Signed-off-by: David S. Miller <davem@davemloft.net>
2018-08-08dsa: slave: eee: Allow ports to use phylinkAndrew Lunn
For a port to be able to use EEE, both the MAC and the PHY must support EEE. A phy can be provided by both a phydev or phylink. Verify at least one of these exist, not just phydev. Fixes: aab9c4067d23 ("net: dsa: Plug in PHYLINK support") Signed-off-by: Andrew Lunn <andrew@lunn.ch> Reviewed-by: Florian Fainelli <f.fainelli@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-08-08net/smc: move sock lock in smc_ioctl()Ursula Braun
When an SMC socket is connecting it is decided whether fallback to TCP is needed. To avoid races between connect and ioctl move the sock lock before the use_fallback check. Reported-by: syzbot+5b2cece1a8ecb2ca77d8@syzkaller.appspotmail.com Reported-by: syzbot+19557374321ca3710990@syzkaller.appspotmail.com Fixes: 1992d99882af ("net/smc: take sock lock in smc_ioctl()") Signed-off-by: Ursula Braun <ubraun@linux.ibm.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-08-08net/smc: allow sysctl rmem and wmem defaults for serversUrsula Braun
Without setsockopt SO_SNDBUF and SO_RCVBUF settings, the sysctl defaults net.ipv4.tcp_wmem and net.ipv4.tcp_rmem should be the base for the sizes of the SMC sndbuf and rcvbuf. Any TCP buffer size optimizations for servers should be ignored. Signed-off-by: Ursula Braun <ubraun@linux.ibm.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-08-08net/smc: no shutdown in state SMC_LISTENUrsula Braun
Invoking shutdown for a socket in state SMC_LISTEN does not make sense. Nevertheless programs like syzbot fuzzing the kernel may try to do this. For SMC this means a socket refcounting problem. This patch makes sure a shutdown call for an SMC socket in state SMC_LISTEN simply returns with -ENOTCONN. Signed-off-by: Ursula Braun <ubraun@linux.ibm.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-08-08rxrpc: Fix the keepalive generator [ver #2]David Howells
AF_RXRPC has a keepalive message generator that generates a message for a peer ~20s after the last transmission to that peer to keep firewall ports open. The implementation is incorrect in the following ways: (1) It mixes up ktime_t and time64_t types. (2) It uses ktime_get_real(), the output of which may jump forward or backward due to adjustments to the time of day. (3) If the current time jumps forward too much or jumps backwards, the generator function will crank the base of the time ring round one slot at a time (ie. a 1s period) until it catches up, spewing out VERSION packets as it goes. Fix the problem by: (1) Only using time64_t. There's no need for sub-second resolution. (2) Use ktime_get_seconds() rather than ktime_get_real() so that time isn't perceived to go backwards. (3) Simplifying rxrpc_peer_keepalive_worker() by splitting it into two parts: (a) The "worker" function that manages the buckets and the timer. (b) The "dispatch" function that takes the pending peers and potentially transmits a keepalive packet before putting them back in the ring into the slot appropriate to the revised last-Tx time. (4) Taking everything that's pending out of the ring and splicing it into a temporary collector list for processing. In the case that there's been a significant jump forward, the ring gets entirely emptied and then the time base can be warped forward before the peers are processed. The warping can't happen if the ring isn't empty because the slot a peer is in is keepalive-time dependent, relative to the base time. (5) Limit the number of iterations of the bucket array when scanning it. (6) Set the timer to skip any empty slots as there's no point waking up if there's nothing to do yet. This can be triggered by an incoming call from a server after a reboot with AF_RXRPC and AFS built into the kernel causing a peer record to be set up before userspace is started. The system clock is then adjusted by userspace, thereby potentially causing the keepalive generator to have a meltdown - which leads to a message like: watchdog: BUG: soft lockup - CPU#0 stuck for 23s! [kworker/0:1:23] ... Workqueue: krxrpcd rxrpc_peer_keepalive_worker EIP: lock_acquire+0x69/0x80 ... Call Trace: ? rxrpc_peer_keepalive_worker+0x5e/0x350 ? _raw_spin_lock_bh+0x29/0x60 ? rxrpc_peer_keepalive_worker+0x5e/0x350 ? rxrpc_peer_keepalive_worker+0x5e/0x350 ? __lock_acquire+0x3d3/0x870 ? process_one_work+0x110/0x340 ? process_one_work+0x166/0x340 ? process_one_work+0x110/0x340 ? worker_thread+0x39/0x3c0 ? kthread+0xdb/0x110 ? cancel_delayed_work+0x90/0x90 ? kthread_stop+0x70/0x70 ? ret_from_fork+0x19/0x24 Fixes: ace45bec6d77 ("rxrpc: Fix firewall route keepalive") Reported-by: kernel test robot <lkp@intel.com> Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-08-08xprtrdma: Fix disconnect regressionChuck Lever
I found that injecting disconnects with v4.18-rc resulted in random failures of the multi-threaded git regression test. The root cause appears to be that, after a reconnect, the RPC/RDMA transport is waking pending RPCs before the transport has posted enough Receive buffers to receive the Replies. If a Reply arrives before enough Receive buffers are posted, the connection is dropped. A few connection drops happen in quick succession as the client and server struggle to regain credit synchronization. This regression was introduced with commit 7c8d9e7c8863 ("xprtrdma: Move Receive posting to Receive handler"). The client is supposed to post a single Receive when a connection is established because it's not supposed to send more than one RPC Call before it gets a fresh credit grant in the first RPC Reply [RFC 8166, Section 3.3.3]. Unfortunately there appears to be a longstanding bug in the Linux client's credit accounting mechanism. On connect, it simply dumps all pending RPC Calls onto the new connection. It's possible it has done this ever since the RPC/RDMA transport was added to the kernel ten years ago. Servers have so far been tolerant of this bad behavior. Currently no server implementation ever changes its credit grant over reconnects, and servers always repost enough Receives before connections are fully established. The Linux client implementation used to post a Receive before each of these Calls. This has covered up the flooding send behavior. I could try to correct this old bug so that the client sends exactly one RPC Call and waits for a Reply. Since we are so close to the next merge window, I'm going to instead provide a simple patch to post enough Receives before a reconnect completes (based on the number of credits granted to the previous connection). The spurious disconnects will be gone, but the client will still send multiple RPC Calls immediately after a reconnect. Addressing the latter problem will wait for a merge window because a) I expect it to be a large change requiring lots of testing, and b) obviously the Linux client has interoperated successfully since day zero while still being broken. Fixes: 7c8d9e7c8863 ("xprtrdma: Move Receive posting to ... ") Cc: stable@vger.kernel.org # v4.18+ Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2018-08-08netfilter: nfnetlink_osf: fix using plain integer as NULL warningWei Yongjun
Fixes the following sparse warning: net/netfilter/nfnetlink_osf.c:274:24: warning: Using plain integer as NULL pointer Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
2018-08-08net:mod: remove unneeded variable 'ret' in init_p9zhong jiang
The ret is modified after initalization, so just remove it and return 0. Signed-off-by: zhong jiang <zhongjiang@huawei.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-08-08net:af_iucv: get rid of the unneeded variable 'err' in afiucv_pm_freezezhong jiang
We will not use the variable 'err' after initalization, So remove it and return 0. Signed-off-by: zhong jiang <zhongjiang@huawei.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-08-07llc: use refcount_inc_not_zero() for llc_sap_find()Cong Wang
llc_sap_put() decreases the refcnt before deleting sap from the global list. Therefore, there is a chance llc_sap_find() could find a sap with zero refcnt in this global list. Close this race condition by checking if refcnt is zero or not in llc_sap_find(), if it is zero then it is being removed so we can just treat it as gone. Reported-by: <syzbot+278893f3f7803871f7ce@syzkaller.appspotmail.com> Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-08-07dccp: fix undefined behavior with 'cwnd' shift in ccid2_cwnd_restart()Alexey Kodanev
The shift of 'cwnd' with '(now - hc->tx_lsndtime) / hc->tx_rto' value can lead to undefined behavior [1]. In order to fix this use a gradual shift of the window with a 'while' loop, similar to what tcp_cwnd_restart() is doing. When comparing delta and RTO there is a minor difference between TCP and DCCP, the last one also invokes dccp_cwnd_restart() and reduces 'cwnd' if delta equals RTO. That case is preserved in this change. [1]: [40850.963623] UBSAN: Undefined behaviour in net/dccp/ccids/ccid2.c:237:7 [40851.043858] shift exponent 67 is too large for 32-bit type 'unsigned int' [40851.127163] CPU: 3 PID: 15940 Comm: netstress Tainted: G W E 4.18.0-rc7.x86_64 #1 ... [40851.377176] Call Trace: [40851.408503] dump_stack+0xf1/0x17b [40851.451331] ? show_regs_print_info+0x5/0x5 [40851.503555] ubsan_epilogue+0x9/0x7c [40851.548363] __ubsan_handle_shift_out_of_bounds+0x25b/0x2b4 [40851.617109] ? __ubsan_handle_load_invalid_value+0x18f/0x18f [40851.686796] ? xfrm4_output_finish+0x80/0x80 [40851.739827] ? lock_downgrade+0x6d0/0x6d0 [40851.789744] ? xfrm4_prepare_output+0x160/0x160 [40851.845912] ? ip_queue_xmit+0x810/0x1db0 [40851.895845] ? ccid2_hc_tx_packet_sent+0xd36/0x10a0 [dccp] [40851.963530] ccid2_hc_tx_packet_sent+0xd36/0x10a0 [dccp] [40852.029063] dccp_xmit_packet+0x1d3/0x720 [dccp] [40852.086254] dccp_write_xmit+0x116/0x1d0 [dccp] [40852.142412] dccp_sendmsg+0x428/0xb20 [dccp] [40852.195454] ? inet_dccp_listen+0x200/0x200 [dccp] [40852.254833] ? sched_clock+0x5/0x10 [40852.298508] ? sched_clock+0x5/0x10 [40852.342194] ? inet_create+0xdf0/0xdf0 [40852.388988] sock_sendmsg+0xd9/0x160 ... Fixes: 113ced1f52e5 ("dccp ccid-2: Perform congestion-window validation") Signed-off-by: Alexey Kodanev <alexey.kodanev@oracle.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-08-07RDS: IB: fix 'passing zero to ERR_PTR()' warningYueHaibing
Fix a static code checker warning: net/rds/ib_frmr.c:82 rds_ib_alloc_frmr() warn: passing zero to 'ERR_PTR' The error path for ib_alloc_mr failure should set err to PTR_ERR. Fixes: 1659185fb4d0 ("RDS: IB: Support Fastreg MR (FRMR) memory registration mode") Signed-off-by: YueHaibing <yuehaibing@huawei.com> Acked-by: Santosh Shilimkar <santosh.shilimkar@oracle.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-08-07tipc: fix an interrupt unsafe locking scenarioYing Xue
Commit 9faa89d4ed9d ("tipc: make function tipc_net_finalize() thread safe") tries to make it thread safe to set node address, so it uses node_list_lock lock to serialize the whole process of setting node address in tipc_net_finalize(). But it causes the following interrupt unsafe locking scenario: CPU0 CPU1 ---- ---- rht_deferred_worker() rhashtable_rehash_table() lock(&(&ht->lock)->rlock) tipc_nl_compat_doit() tipc_net_finalize() local_irq_disable(); lock(&(&tn->node_list_lock)->rlock); tipc_sk_reinit() rhashtable_walk_enter() lock(&(&ht->lock)->rlock); <Interrupt> tipc_disc_rcv() tipc_node_check_dest() tipc_node_create() lock(&(&tn->node_list_lock)->rlock); *** DEADLOCK *** When rhashtable_rehash_table() holds ht->lock on CPU0, it doesn't disable BH. So if an interrupt happens after the lock, it can create an inverse lock ordering between ht->lock and tn->node_list_lock. As a consequence, deadlock might happen. The reason causing the inverse lock ordering scenario above is because the initial purpose of node_list_lock is not designed to do the serialization of node address setting. As cmpxchg() can guarantee CAS (compare-and-swap) process is atomic, we use it to replace node_list_lock to ensure setting node address can be atomically finished. It turns out the potential deadlock can be avoided as well. Fixes: 9faa89d4ed9d ("tipc: make function tipc_net_finalize() thread safe") Signed-off-by: Ying Xue <ying.xue@windriver.com> Acked-by: Jon Maloy <maloy@donjonn.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-08-07vsock: split dwork to avoid reinitializationsCong Wang
syzbot reported that we reinitialize an active delayed work in vsock_stream_connect(): ODEBUG: init active (active state 0) object type: timer_list hint: delayed_work_timer_fn+0x0/0x90 kernel/workqueue.c:1414 WARNING: CPU: 1 PID: 11518 at lib/debugobjects.c:329 debug_print_object+0x16a/0x210 lib/debugobjects.c:326 The pattern is apparently wrong, we should only initialize the dealyed work once and could repeatly schedule it. So we have to move out the initializations to allocation side. And to avoid confusion, we can split the shared dwork into two, instead of re-using the same one. Fixes: d021c344051a ("VSOCK: Introduce VM Sockets") Reported-by: <syzbot+8a9b1bd330476a4f3db6@syzkaller.appspotmail.com> Cc: Andy king <acking@vmware.com> Cc: Stefan Hajnoczi <stefanha@redhat.com> Cc: Jorgen Hansen <jhansen@vmware.com> Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-08-07ip6_tunnel: collect_md xmit: Use ip_tunnel_key's provided src addressShmulik Ladkani
When using an ip6tnl device in collect_md mode, the xmit methods ignore the ipv6.src field present in skb_tunnel_info's key, both for route calculation purposes (flowi6 construction) and for assigning the packet's final ipv6h->saddr. This makes it impossible specifying a desired ipv6 local address in the encapsulating header (for example, when using tc action tunnel_key). This is also not aligned with behavior of ipip (ipv4) in collect_md mode, where the key->u.ipv4.src gets used. Fix, by assigning fl6.saddr with given key->u.ipv6.src. In case ipv6.src is not specified, ip6_tnl_xmit uses existing saddr selection code. Fixes: 8d79266bc48c ("ip6_tunnel: add collect_md mode to IPv6 tunnels") Signed-off-by: Shmulik Ladkani <shmulik.ladkani@gmail.com> Reviewed-by: Eyal Birger <eyal.birger@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-08-07net: sched: cls_flower: set correct offload data in fl_reoffloadVlad Buslov
fl_reoffload implementation sets following members of struct tc_cls_flower_offload incorrectly: - masked key instead of mask - key instead of masked key Fix fl_reoffload to provide correct data to offload callback. Fixes: 31533cba4327 ("net: sched: cls_flower: implement offload tcf_proto_op") Signed-off-by: Vlad Buslov <vladbu@mellanox.com> Acked-by: Jiri Pirko <jiri@mellanox.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-08-07net/sched: allow flower to match tunnel optionsPieter Jansen van Vuuren
Allow matching on options in Geneve tunnel headers. This makes use of existing tunnel metadata support. The options can be described in the form CLASS:TYPE:DATA/CLASS_MASK:TYPE_MASK:DATA_MASK, where CLASS is represented as a 16bit hexadecimal value, TYPE as an 8bit hexadecimal value and DATA as a variable length hexadecimal value. e.g. # ip link add name geneve0 type geneve dstport 0 external # tc qdisc add dev geneve0 ingress # tc filter add dev geneve0 protocol ip parent ffff: \ flower \ enc_src_ip 10.0.99.192 \ enc_dst_ip 10.0.99.193 \ enc_key_id 11 \ geneve_opts 0102:80:1122334421314151/ffff:ff:ffffffffffffffff \ ip_proto udp \ action mirred egress redirect dev eth1 This patch adds support for matching Geneve options in the order supplied by the user. This leads to an efficient implementation in the software datapath (and in our opinion hardware datapaths that offload this feature). It is also compatible with Geneve options matching provided by the Open vSwitch kernel datapath which is relevant here as the Flower classifier may be used as a mechanism to program flows into hardware as a form of Open vSwitch datapath offload (sometimes referred to as OVS-TC). The netlink Kernel/Userspace API may be extended, for example by adding a flag, if other matching options are desired, for example matching given options in any order. This would require an implementation in the TC software datapath. And be done in a way that drivers that facilitate offload of the Flower classifier can reject or accept such flows based on hardware datapath capabilities. This approach was discussed and agreed on at Netconf 2017 in Seoul. Signed-off-by: Simon Horman <simon.horman@netronome.com> Signed-off-by: Pieter Jansen van Vuuren <pieter.jansenvanvuuren@netronome.com> Acked-by: Jakub Kicinski <jakub.kicinski@netronome.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-08-07flow_dissector: allow dissection of tunnel options from metadataSimon Horman
Allow the existing 'dissection' of tunnel metadata to 'dissect' options already present in tunnel metadata. This dissection is controlled by a new dissector key, FLOW_DISSECTOR_KEY_ENC_OPTS. This dissection only occurs when skb_flow_dissect_tunnel_info() is called, currently only the Flower classifier makes that call. So there should be no impact on other users of the flow dissector. This is in preparation for allowing the flower classifier to match on Geneve options. Signed-off-by: Simon Horman <simon.horman@netronome.com> Signed-off-by: Pieter Jansen van Vuuren <pieter.jansenvanvuuren@netronome.com> Reviewed-by: Jakub Kicinski <jakub.kicinski@netronome.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-08-07Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-nextDavid S. Miller
Daniel Borkmann says: ==================== pull-request: bpf-next 2018-08-07 The following pull-request contains BPF updates for your *net-next* tree. The main changes are: 1) Add cgroup local storage for BPF programs, which provides a fast accessible memory for storing various per-cgroup data like number of transmitted packets, etc, from Roman. 2) Support bpf_get_socket_cookie() BPF helper in several more program types that have a full socket available, from Andrey. 3) Significantly improve the performance of perf events which are reported from BPF offload. Also convert a couple of BPF AF_XDP samples overto use libbpf, both from Jakub. 4) seg6local LWT provides the End.DT6 action, which allows to decapsulate an outer IPv6 header containing a Segment Routing Header. Adds this action now to the seg6local BPF interface, from Mathieu. 5) Do not mark dst register as unbounded in MOV64 instruction when both src and dst register are the same, from Arthur. 6) Define u_smp_rmb() and u_smp_wmb() to their respective barrier instructions on arm64 for the AF_XDP sample code, from Brian. 7) Convert the tcp_client.py and tcp_server.py BPF selftest scripts over from Python 2 to Python 3, from Jeremy. 8) Enable BTF build flags to the BPF sample code Makefile, from Taeung. 9) Remove an unnecessary rcu_read_lock() in run_lwt_bpf(), from Taehee. 10) Several improvements to the README.rst from the BPF documentation to make it more consistent with RST format, from Tobin. 11) Replace all occurrences of strerror() by calls to strerror_r() in libbpf and fix a FORTIFY_SOURCE build error along with it, from Thomas. 12) Fix a bug in bpftool's get_btf() function to correctly propagate an error via PTR_ERR(), from Yue. ==================== Signed-off-by: David S. Miller <davem@davemloft.net>
2018-08-07netfilter: nft_ct: enable conntrack for helpersPablo Neira Ayuso
Enable conntrack if the user defines a helper to be used from the ruleset policy. Fixes: 1a64edf54f55 ("netfilter: nft_ct: add helper set support") Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
2018-08-07netfilter: nft_ct: add ct timeout supportHarsha Sharma
This patch allows to add, list and delete connection tracking timeout policies via nft objref infrastructure and assigning these timeout via nft rule. %./libnftnl/examples/nft-ct-timeout-add ip raw cttime tcp Ruleset: table ip raw { ct timeout cttime { protocol tcp; policy = {established: 111, close: 13 } } chain output { type filter hook output priority -300; policy accept; ct timeout set "cttime" } } %./libnftnl/examples/nft-rule-ct-timeout-add ip raw output cttime %conntrack -E [NEW] tcp 6 111 ESTABLISHED src=172.16.19.128 dst=172.16.19.1 sport=22 dport=41360 [UNREPLIED] src=172.16.19.1 dst=172.16.19.128 sport=41360 dport=22 %nft delete rule ip raw output handle <handle> %./libnftnl/examples/nft-ct-timeout-del ip raw cttime Joint work with Pablo Neira. Signed-off-by: Harsha Sharma <harshasharmaiitr@gmail.com> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
2018-08-07netfilter: cttimeout: decouple timeout policy from nfnetlink_cttimeout objectPablo Neira Ayuso
The timeout policy is currently embedded into the nfnetlink_cttimeout object, move the policy into an independent object. This allows us to reuse part of the existing conntrack timeout extension from nf_tables without adding dependencies with the nfnetlink_cttimeout object layout. Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
2018-08-07netfilter: cttimeout: move ctnl_untimeout to nf_conntrackHarsha Sharma
As, ctnl_untimeout is required by nft_ct, so move ctnl_timeout from nfnetlink_cttimeout to nf_conntrack_timeout and rename as nf_ct_timeout. Signed-off-by: Harsha Sharma <harshasharmaiitr@gmail.com> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
2018-08-07netfilter: nft_osf: use NFT_OSF_MAXGENRELEN instead of IFNAMSIZFernando Fernandez Mancera
As no "genre" on pf.os exceed 16 bytes of length, we reduce NFT_OSF_MAXGENRELEN parameter to 16 bytes and use it instead of IFNAMSIZ. Signed-off-by: Fernando Fernandez Mancera <ffmancera@riseup.net> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
2018-08-06packet: refine ring v3 block size test to hold one frameWillem de Bruijn
TPACKET_V3 stores variable length frames in fixed length blocks. Blocks must be able to store a block header, optional private space and at least one minimum sized frame. Frames, even for a zero snaplen packet, store metadata headers and optional reserved space. In the block size bounds check, ensure that the frame of the chosen configuration fits. This includes sockaddr_ll and optional tp_reserve. Syzbot was able to construct a ring with insuffient room for the sockaddr_ll in the header of a zero-length frame, triggering an out-of-bounds write in dev_parse_header. Convert the comparison to less than, as zero is a valid snap len. This matches the test for minimum tp_frame_size immediately below. Fixes: f6fb8f100b80 ("af-packet: TPACKET_V3 flexible buffer implementation.") Fixes: eb73190f4fbe ("net/packet: refine check for priv area size") Reported-by: syzbot <syzkaller@googlegroups.com> Signed-off-by: Willem de Bruijn <willemb@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-08-06Merge branch 'ieee802154-for-davem-2018-08-06' of ↵David S. Miller
git://git.kernel.org/pub/scm/linux/kernel/git/sschmidt/wpan-next Stefan Schmidt says: ==================== pull-request: ieee802154-next 2018-08-06 An update from ieee802154 for *net-next* Romuald added a socket option to get the LQI value of the received datagram. Alexander added a new hardware simulation driver modelled after hwsim of the wireless people. It allows runtime configuration for new nodes and edges over a netlink interface (a config utlity is making its way into wpan-tools). We also have three fixes in here. One from Colin which is more of a cleanup and two from Alex fixing tailroom and single frame space problems. I would normally put the last two into my fixes tree, but given we are already in -rc8 I simply put them here and added a cc: stable to them. ==================== Signed-off-by: David S. Miller <davem@davemloft.net>
2018-08-06ipv4: frags: precedence bug in ip_expire()Dan Carpenter
We accidentally removed the parentheses here, but they are required because '!' has higher precedence than '&'. Fixes: fa0f527358bd ("ip: use rb trees for IP frag queue.") Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-08-06net: avoid unnecessary sock_flag() check when enable timestampYafang Shao
The sock_flag() check is alreay inside sock_enable_timestamp(), so it is unnecessary checking it in the caller. void sock_enable_timestamp(struct sock *sk, int flag) { if (!sock_flag(sk, flag)) { ... } } Signed-off-by: Yafang Shao <laoar.shao@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>