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2019-10-28net: add READ_ONCE() annotation in __skb_wait_for_more_packets()Eric Dumazet1-1/+1
__skb_wait_for_more_packets() can be called while other cpus can feed packets to the socket receive queue. KCSAN reported : BUG: KCSAN: data-race in __skb_wait_for_more_packets / __udp_enqueue_schedule_skb write to 0xffff888102e40b58 of 8 bytes by interrupt on cpu 0: __skb_insert include/linux/skbuff.h:1852 [inline] __skb_queue_before include/linux/skbuff.h:1958 [inline] __skb_queue_tail include/linux/skbuff.h:1991 [inline] __udp_enqueue_schedule_skb+0x2d7/0x410 net/ipv4/udp.c:1470 __udp_queue_rcv_skb net/ipv4/udp.c:1940 [inline] udp_queue_rcv_one_skb+0x7bd/0xc70 net/ipv4/udp.c:2057 udp_queue_rcv_skb+0xb5/0x400 net/ipv4/udp.c:2074 udp_unicast_rcv_skb.isra.0+0x7e/0x1c0 net/ipv4/udp.c:2233 __udp4_lib_rcv+0xa44/0x17c0 net/ipv4/udp.c:2300 udp_rcv+0x2b/0x40 net/ipv4/udp.c:2470 ip_protocol_deliver_rcu+0x4d/0x420 net/ipv4/ip_input.c:204 ip_local_deliver_finish+0x110/0x140 net/ipv4/ip_input.c:231 NF_HOOK include/linux/netfilter.h:305 [inline] NF_HOOK include/linux/netfilter.h:299 [inline] ip_local_deliver+0x133/0x210 net/ipv4/ip_input.c:252 dst_input include/net/dst.h:442 [inline] ip_rcv_finish+0x121/0x160 net/ipv4/ip_input.c:413 NF_HOOK include/linux/netfilter.h:305 [inline] NF_HOOK include/linux/netfilter.h:299 [inline] ip_rcv+0x18f/0x1a0 net/ipv4/ip_input.c:523 __netif_receive_skb_one_core+0xa7/0xe0 net/core/dev.c:5010 __netif_receive_skb+0x37/0xf0 net/core/dev.c:5124 process_backlog+0x1d3/0x420 net/core/dev.c:5955 read to 0xffff888102e40b58 of 8 bytes by task 13035 on cpu 1: __skb_wait_for_more_packets+0xfa/0x320 net/core/datagram.c:100 __skb_recv_udp+0x374/0x500 net/ipv4/udp.c:1683 udp_recvmsg+0xe1/0xb10 net/ipv4/udp.c:1712 inet_recvmsg+0xbb/0x250 net/ipv4/af_inet.c:838 sock_recvmsg_nosec+0x5c/0x70 net/socket.c:871 ___sys_recvmsg+0x1a0/0x3e0 net/socket.c:2480 do_recvmmsg+0x19a/0x5c0 net/socket.c:2601 __sys_recvmmsg+0x1ef/0x200 net/socket.c:2680 __do_sys_recvmmsg net/socket.c:2703 [inline] __se_sys_recvmmsg net/socket.c:2696 [inline] __x64_sys_recvmmsg+0x89/0xb0 net/socket.c:2696 do_syscall_64+0xcc/0x370 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x44/0xa9 Reported by Kernel Concurrency Sanitizer on: CPU: 1 PID: 13035 Comm: syz-executor.3 Not tainted 5.4.0-rc3+ #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Signed-off-by: Eric Dumazet <edumazet@google.com> Reported-by: syzbot <syzkaller@googlegroups.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2019-10-28net: use skb_queue_empty_lockless() in busy poll contextsEric Dumazet1-1/+1
Busy polling usually runs without locks. Let's use skb_queue_empty_lockless() instead of skb_queue_empty() Also uses READ_ONCE() in __skb_try_recv_datagram() to address a similar potential problem. Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2019-10-28net: use skb_queue_empty_lockless() in poll() handlersEric Dumazet1-2/+2
Many poll() handlers are lockless. Using skb_queue_empty_lockless() instead of skb_queue_empty() is more appropriate. Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2019-10-13tcp: annotate sk->sk_wmem_queued lockless readsEric Dumazet1-1/+1
For the sake of tcp_poll(), there are few places where we fetch sk->sk_wmem_queued while this field can change from IRQ or other cpu. We need to add READ_ONCE() annotations, and also make sure write sides use corresponding WRITE_ONCE() to avoid store-tearing. sk_wmem_queued_add() helper is added so that we can in the future convert to ADD_ONCE() or equivalent if/when available. Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2019-07-30net: Use skb_frag_off accessorsJonathan Lemon1-3/+3
Use accessor functions for skb fragment's page_offset instead of direct references, in preparation for bvec conversion. Signed-off-by: Jonathan Lemon <jonathan.lemon@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2019-04-08datagram: remove rendundant 'peeked' argumentPaolo Abeni1-11/+8
After commit a297569fe00a ("net/udp: do not touch skb->peeked unless really needed") the 'peeked' argument of __skb_try_recv_datagram() and friends is always equal to !!'flags & MSG_PEEK'. Since such argument is really a boolean info, and the callers have already 'flags & MSG_PEEK' handy, we can remove it and clean-up the code a bit. Signed-off-by: Paolo Abeni <pabeni@redhat.com> Acked-by: Willem de Bruijn <willemb@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2019-04-05Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/netDavid S. Miller1-1/+1
Minor comment merge conflict in mlx5. Staging driver has a fixup due to the skb->xmit_more changes in 'net-next', but was removed in 'net'. Signed-off-by: David S. Miller <davem@davemloft.net>
2019-03-27net: datagram: fix unbounded loop in __skb_try_recv_datagram()Paolo Abeni1-1/+1
Christoph reported a stall while peeking datagram with an offset when busy polling is enabled. __skb_try_recv_datagram() uses as the loop termination condition 'queue empty'. When peeking, the socket queue can be not empty, even when no additional packets are received. Address the issue explicitly checking for receive queue changes, as currently done by __skb_wait_for_more_packets(). Fixes: 2b5cd0dfa384 ("net: Change return type of sk_busy_loop from bool to void") Reported-and-tested-by: Christoph Paasch <cpaasch@apple.com> Signed-off-by: Paolo Abeni <pabeni@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2019-03-27net/core: Allow the compiler to verify declaration and definition consistencyBart Van Assche1-0/+2
Instead of declaring a function in a .c file, declare it in a header file and include that header file from the source files that define and that use the function. That allows the compiler to verify consistency of declaration and definition. See also commit 52267790ef52 ("sock: add MSG_ZEROCOPY") # v4.14. Cc: Willem de Bruijn <willemb@google.com> Signed-off-by: Bart Van Assche <bvanassche@acm.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2019-03-19datagram: Make __skb_datagram_iter staticYueHaibing1-4/+4
Fix sparse warning: net/core/datagram.c:411:5: warning: symbol '__skb_datagram_iter' was not declared. Should it be static? Signed-off-by: YueHaibing <yuehaibing@huawei.com> Reviewed-by: Sagi Grimberg <sagi@grimberg.me> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-12-28Merge tag 'for-4.21/block-20181221' of git://git.kernel.dk/linux-blockLinus Torvalds1-95/+64
Pull block updates from Jens Axboe: "This is the main pull request for block/storage for 4.21. Larger than usual, it was a busy round with lots of goodies queued up. Most notable is the removal of the old IO stack, which has been a long time coming. No new features for a while, everything coming in this week has all been fixes for things that were previously merged. This contains: - Use atomic counters instead of semaphores for mtip32xx (Arnd) - Cleanup of the mtip32xx request setup (Christoph) - Fix for circular locking dependency in loop (Jan, Tetsuo) - bcache (Coly, Guoju, Shenghui) * Optimizations for writeback caching * Various fixes and improvements - nvme (Chaitanya, Christoph, Sagi, Jay, me, Keith) * host and target support for NVMe over TCP * Error log page support * Support for separate read/write/poll queues * Much improved polling * discard OOM fallback * Tracepoint improvements - lightnvm (Hans, Hua, Igor, Matias, Javier) * Igor added packed metadata to pblk. Now drives without metadata per LBA can be used as well. * Fix from Geert on uninitialized value on chunk metadata reads. * Fixes from Hans and Javier to pblk recovery and write path. * Fix from Hua Su to fix a race condition in the pblk recovery code. * Scan optimization added to pblk recovery from Zhoujie. * Small geometry cleanup from me. - Conversion of the last few drivers that used the legacy path to blk-mq (me) - Removal of legacy IO path in SCSI (me, Christoph) - Removal of legacy IO stack and schedulers (me) - Support for much better polling, now without interrupts at all. blk-mq adds support for multiple queue maps, which enables us to have a map per type. This in turn enables nvme to have separate completion queues for polling, which can then be interrupt-less. Also means we're ready for async polled IO, which is hopefully coming in the next release. - Killing of (now) unused block exports (Christoph) - Unification of the blk-rq-qos and blk-wbt wait handling (Josef) - Support for zoned testing with null_blk (Masato) - sx8 conversion to per-host tag sets (Christoph) - IO priority improvements (Damien) - mq-deadline zoned fix (Damien) - Ref count blkcg series (Dennis) - Lots of blk-mq improvements and speedups (me) - sbitmap scalability improvements (me) - Make core inflight IO accounting per-cpu (Mikulas) - Export timeout setting in sysfs (Weiping) - Cleanup the direct issue path (Jianchao) - Export blk-wbt internals in block debugfs for easier debugging (Ming) - Lots of other fixes and improvements" * tag 'for-4.21/block-20181221' of git://git.kernel.dk/linux-block: (364 commits) kyber: use sbitmap add_wait_queue/list_del wait helpers sbitmap: add helpers for add/del wait queue handling block: save irq state in blkg_lookup_create() dm: don't reuse bio for flushes nvme-pci: trace SQ status on completions nvme-rdma: implement polling queue map nvme-fabrics: allow user to pass in nr_poll_queues nvme-fabrics: allow nvmf_connect_io_queue to poll nvme-core: optionally poll sync commands block: make request_to_qc_t public nvme-tcp: fix spelling mistake "attepmpt" -> "attempt" nvme-tcp: fix endianess annotations nvmet-tcp: fix endianess annotations nvme-pci: refactor nvme_poll_irqdisable to make sparse happy nvme-pci: only set nr_maps to 2 if poll queues are supported nvmet: use a macro for default error location nvmet: fix comparison of a u16 with -1 blk-mq: enable IO poll if .nr_queues of type poll > 0 blk-mq: change blk_mq_queue_busy() to blk_mq_queue_inflight() blk-mq: skip zero-queue maps in blk_mq_map_swqueue ...
2018-12-13datagram: introduce skb_copy_and_hash_datagram_iter helperSagi Grimberg1-1/+19
Introduce a helper to copy datagram into an iovec iterator but also update a predefined hash. This is useful for consumers of skb_copy_datagram_iter to also support inflight data digest without having to finish to copy and only then traverse the iovec and calculate the digest hash. Acked-by: David S. Miller <davem@davemloft.net> Signed-off-by: Sagi Grimberg <sagi@lightbitslabs.com> Signed-off-by: Christoph Hellwig <hch@lst.de>
2018-12-13datagram: consolidate datagram copy to iter helpersSagi Grimberg1-94/+42
skb_copy_datagram_iter and skb_copy_and_csum_datagram are essentialy the same but with a couple of differences: The first is the copy operation used which either a simple copy or a csum_and_copy, and the second are the behavior on the "short copy" path where simply copy needs to return the number of bytes successfully copied while csum_and_copy needs to fault immediately as the checksum is partial. Introduce __skb_datagram_iter that additionally accepts: 1. copy operation function pointer 2. private data that goes with the copy operation 3. fault_short flag to indicate the action on short copy Suggested-by: David S. Miller <davem@davemloft.net> Acked-by: David S. Miller <davem@davemloft.net> Signed-off-by: Sagi Grimberg <sagi@lightbitslabs.com> Signed-off-by: Christoph Hellwig <hch@lst.de>
2018-12-13datagram: open-code copy_page_to_iterSagi Grimberg1-3/+6
This will be useful to consolidate skb_copy_and_hash_datagram_iter and skb_copy_and_csum_datagram to a single code path. Acked-by: David S. Miller <davem@davemloft.net> Signed-off-by: Sagi Grimberg <sagi@lightbitslabs.com> Signed-off-by: Christoph Hellwig <hch@lst.de>
2018-11-15net: dump more useful information in netdev_rx_csum_fault()Cong Wang1-1/+1
Currently netdev_rx_csum_fault() only shows a device name, we need more information about the skb for debugging csum failures. Sample output: ens3: hw csum failure dev features: 0x0000000000014b89 skb len=84 data_len=0 pkt_type=0 gso_size=0 gso_type=0 nr_frags=0 ip_summed=0 csum=0 csum_complete_sw=0 csum_valid=0 csum_level=0 Note, I use pr_err() just to be consistent with the existing one. Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-11-08net: move __skb_checksum_complete*() to skbuff.cCong Wang1-43/+0
__skb_checksum_complete_head() and __skb_checksum_complete() are both declared in skbuff.h, they fit better in skbuff.c than datagram.c. Cc: Stefano Brivio <sbrivio@redhat.com> Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-10-24net: udp: fix handling of CHECKSUM_COMPLETE packetsSean Tranchetti1-2/+3
Current handling of CHECKSUM_COMPLETE packets by the UDP stack is incorrect for any packet that has an incorrect checksum value. udp4/6_csum_init() will both make a call to __skb_checksum_validate_complete() to initialize/validate the csum field when receiving a CHECKSUM_COMPLETE packet. When this packet fails validation, skb->csum will be overwritten with the pseudoheader checksum so the packet can be fully validated by software, but the skb->ip_summed value will be left as CHECKSUM_COMPLETE so that way the stack can later warn the user about their hardware spewing bad checksums. Unfortunately, leaving the SKB in this state can cause problems later on in the checksum calculation. Since the the packet is still marked as CHECKSUM_COMPLETE, udp_csum_pull_header() will SUBTRACT the checksum of the UDP header from skb->csum instead of adding it, leaving us with a garbage value in that field. Once we try to copy the packet to userspace in the udp4/6_recvmsg(), we'll make a call to skb_copy_and_csum_datagram_msg() to checksum the packet data and add it in the garbage skb->csum value to perform our final validation check. Since the value we're validating is not the proper checksum, it's possible that the folded value could come out to 0, causing us not to drop the packet. Instead, we believe that the packet was checksummed incorrectly by hardware since skb->ip_summed is still CHECKSUM_COMPLETE, and we attempt to warn the user with netdev_rx_csum_fault(skb->dev); Unfortunately, since this is the UDP path, skb->dev has been overwritten by skb->dev_scratch and is no longer a valid pointer, so we end up reading invalid memory. This patch addresses this problem in two ways: 1) Do not use the dev pointer when calling netdev_rx_csum_fault() from skb_copy_and_csum_datagram_msg(). Since this gets called from the UDP path where skb->dev has been overwritten, we have no way of knowing if the pointer is still valid. Also for the sake of consistency with the other uses of netdev_rx_csum_fault(), don't attempt to call it if the packet was checksummed by software. 2) Add better CHECKSUM_COMPLETE handling to udp4/6_csum_init(). If we receive a packet that's CHECKSUM_COMPLETE that fails verification (i.e. skb->csum_valid == 0), check who performed the calculation. It's possible that the checksum was done in software by the network stack earlier (such as Netfilter's CONNTRACK module), and if that says the checksum is bad, we can drop the packet immediately instead of waiting until we try and copy it to userspace. Otherwise, we need to mark the SKB as CHECKSUM_NONE, since the skb->csum field no longer contains the full packet checksum after the call to __skb_checksum_validate_complete(). Fixes: e6afc8ace6dd ("udp: remove headers from UDP packets before queueing") Fixes: c84d949057ca ("udp: copy skb->truesize in the first cache line") Cc: Sam Kumar <samanthakumar@google.com> Cc: Eric Dumazet <edumazet@google.com> Signed-off-by: Sean Tranchetti <stranche@codeaurora.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-10-23Revert "net: simplify sock_poll_wait"Karsten Graul1-1/+1
This reverts commit dd979b4df817e9976f18fb6f9d134d6bc4a3c317. This broke tcp_poll for SMC fallback: An AF_SMC socket establishes an internal TCP socket for the initial handshake with the remote peer. Whenever the SMC connection can not be established this TCP socket is used as a fallback. All socket operations on the SMC socket are then forwarded to the TCP socket. In case of poll, the file->private_data pointer references the SMC socket because the TCP socket has no file assigned. This causes tcp_poll to wait on the wrong socket. Signed-off-by: Karsten Graul <kgraul@linux.ibm.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-07-30net: simplify sock_poll_waitChristoph Hellwig1-1/+1
The wait_address argument is always directly derived from the filp argument, so remove it. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-06-28Revert changes to convert to ->poll_mask() and aio IOCB_CMD_POLLLinus Torvalds1-4/+9
The poll() changes were not well thought out, and completely unexplained. They also caused a huge performance regression, because "->poll()" was no longer a trivial file operation that just called down to the underlying file operations, but instead did at least two indirect calls. Indirect calls are sadly slow now with the Spectre mitigation, but the performance problem could at least be largely mitigated by changing the "->get_poll_head()" operation to just have a per-file-descriptor pointer to the poll head instead. That gets rid of one of the new indirections. But that doesn't fix the new complexity that is completely unwarranted for the regular case. The (undocumented) reason for the poll() changes was some alleged AIO poll race fixing, but we don't make the common case slower and more complex for some uncommon special case, so this all really needs way more explanations and most likely a fundamental redesign. [ This revert is a revert of about 30 different commits, not reverted individually because that would just be unnecessarily messy - Linus ] Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Christoph Hellwig <hch@lst.de> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-05-26net: convert datagram_poll users tp ->poll_maskChristoph Hellwig1-9/+4
Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-02-11vfs: do bulk POLL* -> EPOLL* replacementLinus Torvalds1-8/+8
This is the mindless scripted replacement of kernel use of POLL* variables as described by Al, done by this script: for V in IN OUT PRI ERR RDNORM RDBAND WRNORM WRBAND HUP RDHUP NVAL MSG; do L=`git grep -l -w POLL$V | grep -v '^t' | grep -v /um/ | grep -v '^sa' | grep -v '/poll.h$'|grep -v '^D'` for f in $L; do sed -i "-es/^\([^\"]*\)\(\<POLL$V\>\)/\\1E\\2/" $f; done done with de-mangling cleanups yet to come. NOTE! On almost all architectures, the EPOLL* constants have the same values as the POLL* constants do. But they keyword here is "almost". For various bad reasons they aren't the same, and epoll() doesn't actually work quite correctly in some cases due to this on Sparc et al. The next patch from Al will sort out the final differences, and we should be all done. Scripted-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-11-27net: annotate ->poll() instancesAl Viro1-2/+2
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2017-11-27annotate poll-related wait keysAl Viro1-3/+1
__poll_t is also used as wait key in some waitqueues. Verify that wait_..._poll() gets __poll_t as key and provide a helper for wakeup functions to get back to that __poll_t value. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2017-11-04Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/netDavid S. Miller1-0/+1
Files removed in 'net-next' had their license header updated in 'net'. We take the remove from 'net-next'. Signed-off-by: David S. Miller <davem@davemloft.net>
2017-11-02License cleanup: add SPDX GPL-2.0 license identifier to files with no licenseGreg Kroah-Hartman1-0/+1
Many source files in the tree are missing licensing information, which makes it harder for compliance tools to determine the correct license. By default all files without license information are under the default license of the kernel, which is GPL version 2. Update the files which contain no license information with the 'GPL-2.0' SPDX license identifier. The SPDX identifier is a legally binding shorthand, which can be used instead of the full boiler plate text. This patch is based on work done by Thomas Gleixner and Kate Stewart and Philippe Ombredanne. How this work was done: Patches were generated and checked against linux-4.14-rc6 for a subset of the use cases: - file had no licensing information it it. - file was a */uapi/* one with no licensing information in it, - file was a */uapi/* one with existing licensing information, Further patches will be generated in subsequent months to fix up cases where non-standard license headers were used, and references to license had to be inferred by heuristics based on keywords. The analysis to determine which SPDX License Identifier to be applied to a file was done in a spreadsheet of side by side results from of the output of two independent scanners (ScanCode & Windriver) producing SPDX tag:value files created by Philippe Ombredanne. Philippe prepared the base worksheet, and did an initial spot review of a few 1000 files. The 4.13 kernel was the starting point of the analysis with 60,537 files assessed. Kate Stewart did a file by file comparison of the scanner results in the spreadsheet to determine which SPDX license identifier(s) to be applied to the file. She confirmed any determination that was not immediately clear with lawyers working with the Linux Foundation. Criteria used to select files for SPDX license identifier tagging was: - Files considered eligible had to be source code files. - Make and config files were included as candidates if they contained >5 lines of source - File already had some variant of a license header in it (even if <5 lines). All documentation files were explicitly excluded. The following heuristics were used to determine which SPDX license identifiers to apply. - when both scanners couldn't find any license traces, file was considered to have no license information in it, and the top level COPYING file license applied. For non */uapi/* files that summary was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 11139 and resulted in the first patch in this series. If that file was a */uapi/* path one, it was "GPL-2.0 WITH Linux-syscall-note" otherwise it was "GPL-2.0". Results of that was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 WITH Linux-syscall-note 930 and resulted in the second patch in this series. - if a file had some form of licensing information in it, and was one of the */uapi/* ones, it was denoted with the Linux-syscall-note if any GPL family license was found in the file or had no licensing in it (per prior point). Results summary: SPDX license identifier # files ---------------------------------------------------|------ GPL-2.0 WITH Linux-syscall-note 270 GPL-2.0+ WITH Linux-syscall-note 169 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) 21 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) 17 LGPL-2.1+ WITH Linux-syscall-note 15 GPL-1.0+ WITH Linux-syscall-note 14 ((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause) 5 LGPL-2.0+ WITH Linux-syscall-note 4 LGPL-2.1 WITH Linux-syscall-note 3 ((GPL-2.0 WITH Linux-syscall-note) OR MIT) 3 ((GPL-2.0 WITH Linux-syscall-note) AND MIT) 1 and that resulted in the third patch in this series. - when the two scanners agreed on the detected license(s), that became the concluded license(s). - when there was disagreement between the two scanners (one detected a license but the other didn't, or they both detected different licenses) a manual inspection of the file occurred. - In most cases a manual inspection of the information in the file resulted in a clear resolution of the license that should apply (and which scanner probably needed to revisit its heuristics). - When it was not immediately clear, the license identifier was confirmed with lawyers working with the Linux Foundation. - If there was any question as to the appropriate license identifier, the file was flagged for further research and to be revisited later in time. In total, over 70 hours of logged manual review was done on the spreadsheet to determine the SPDX license identifiers to apply to the source files by Kate, Philippe, Thomas and, in some cases, confirmation by lawyers working with the Linux Foundation. Kate also obtained a third independent scan of the 4.13 code base from FOSSology, and compared selected files where the other two scanners disagreed against that SPDX file, to see if there was new insights. The Windriver scanner is based on an older version of FOSSology in part, so they are related. Thomas did random spot checks in about 500 files from the spreadsheets for the uapi headers and agreed with SPDX license identifier in the files he inspected. For the non-uapi files Thomas did random spot checks in about 15000 files. In initial set of patches against 4.14-rc6, 3 files were found to have copy/paste license identifier errors, and have been fixed to reflect the correct identifier. Additionally Philippe spent 10 hours this week doing a detailed manual inspection and review of the 12,461 patched files from the initial patch version early this week with: - a full scancode scan run, collecting the matched texts, detected license ids and scores - reviewing anything where there was a license detected (about 500+ files) to ensure that the applied SPDX license was correct - reviewing anything where there was no detection but the patch license was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied SPDX license was correct This produced a worksheet with 20 files needing minor correction. This worksheet was then exported into 3 different .csv files for the different types of files to be modified. These .csv files were then reviewed by Greg. Thomas wrote a script to parse the csv files and add the proper SPDX tag to the file, in the format that the file expected. This script was further refined by Greg based on the output to detect more types of files automatically and to distinguish between header and source .c files (which need different comment types.) Finally Greg ran the script using the .csv files to generate the patches. Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org> Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-09-26datagram: Remove redundant unlikely()Tobias Klauser1-1/+1
IS_ERR() already implies unlikely(), so it can be omitted. Signed-off-by: Tobias Klauser <tklauser@distanz.ch> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-09-01Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/netDavid S. Miller1-1/+1
Three cases of simple overlapping changes. Signed-off-by: David S. Miller <davem@davemloft.net>
2017-08-22udp: on peeking bad csum, drop packets even if not at headEric Dumazet1-1/+1
When peeking, if a bad csum is discovered, the skb is unlinked from the queue with __sk_queue_drop_skb and the peek operation restarted. __sk_queue_drop_skb only drops packets that match the queue head. This fails if the skb was found after the head, using SO_PEEK_OFF socket option. This causes an infinite loop. We MUST drop this problematic skb, and we can simply check if skb was already removed by another thread, by looking at skb->next : This pointer is set to NULL by the __skb_unlink() operation, that might have happened only under the spinlock protection. Many thanks to syzkaller team (and particularly Dmitry Vyukov who provided us nice C reproducers exhibiting the lockup) and Willem de Bruijn who provided first version for this patch and a test program. Fixes: 627d2d6b5500 ("udp: enable MSG_PEEK at non-zero offset") Signed-off-by: Eric Dumazet <edumazet@google.com> Reported-by: Dmitry Vyukov <dvyukov@google.com> Cc: Willem de Bruijn <willemb@google.com> Acked-by: Paolo Abeni <pabeni@redhat.com> Acked-by: Willem de Bruijn <willemb@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-08-21Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/netDavid S. Miller1-3/+9
2017-08-18datagram: When peeking datagrams with offset < 0 don't skip empty skbsMatthew Dawson1-3/+9
Due to commit e6afc8ace6dd5cef5e812f26c72579da8806f5ac ("udp: remove headers from UDP packets before queueing"), when udp packets are being peeked the requested extra offset is always 0 as there is no need to skip the udp header. However, when the offset is 0 and the next skb is of length 0, it is only returned once. The behaviour can be seen with the following python script: from socket import *; f=socket(AF_INET6, SOCK_DGRAM | SOCK_NONBLOCK, 0); g=socket(AF_INET6, SOCK_DGRAM | SOCK_NONBLOCK, 0); f.bind(('::', 0)); addr=('::1', f.getsockname()[1]); g.sendto(b'', addr) g.sendto(b'b', addr) print(f.recvfrom(10, MSG_PEEK)); print(f.recvfrom(10, MSG_PEEK)); Where the expected output should be the empty string twice. Instead, make sk_peek_offset return negative values, and pass those values to __skb_try_recv_datagram/__skb_try_recv_from_queue. If the passed offset to __skb_try_recv_from_queue is negative, the checked skb is never skipped. __skb_try_recv_from_queue will then ensure the offset is reset back to 0 if a peek is requested without an offset, unless no packets are found. Also simplify the if condition in __skb_try_recv_from_queue. If _off is greater then 0, and off is greater then or equal to skb->len, then (_off || skb->len) must always be true assuming skb->len >= 0 is always true. Also remove a redundant check around a call to sk_peek_offset in af_unix.c, as it double checked if MSG_PEEK was set in the flags. V2: - Moved the negative fixup into __skb_try_recv_from_queue, and remove now redundant checks - Fix peeking in udp{,v6}_recvmsg to report the right value when the offset is 0 V3: - Marked new branch in __skb_try_recv_from_queue as unlikely. Signed-off-by: Matthew Dawson <matthew@mjdsystems.ca> Acked-by: Willem de Bruijn <willemb@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-08-03sock: add MSG_ZEROCOPYWillem de Bruijn1-21/+34
The kernel supports zerocopy sendmsg in virtio and tap. Expand the infrastructure to support other socket types. Introduce a completion notification channel over the socket error queue. Notifications are returned with ee_origin SO_EE_ORIGIN_ZEROCOPY. ee_errno is 0 to avoid blocking the send/recv path on receiving notifications. Add reference counting, to support the skb split, merge, resize and clone operations possible with SOCK_STREAM and other socket types. The patch does not yet modify any datapaths. Signed-off-by: Willem de Bruijn <willemb@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-07-12datagram: fix kernel-doc commentsstephen hemminger1-3/+3
An underscore in the kernel-doc comment section has special meaning and mis-use generates an errors. ./net/core/datagram.c:207: ERROR: Unknown target name: "msg". ./net/core/datagram.c:379: ERROR: Unknown target name: "msg". ./net/core/datagram.c:816: ERROR: Unknown target name: "t". Signed-off-by: Stephen Hemminger <sthemmin@microsoft.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-07-05Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-nextLinus Torvalds1-44/+56
Pull networking updates from David Miller: "Reasonably busy this cycle, but perhaps not as busy as in the 4.12 merge window: 1) Several optimizations for UDP processing under high load from Paolo Abeni. 2) Support pacing internally in TCP when using the sch_fq packet scheduler for this is not practical. From Eric Dumazet. 3) Support mutliple filter chains per qdisc, from Jiri Pirko. 4) Move to 1ms TCP timestamp clock, from Eric Dumazet. 5) Add batch dequeueing to vhost_net, from Jason Wang. 6) Flesh out more completely SCTP checksum offload support, from Davide Caratti. 7) More plumbing of extended netlink ACKs, from David Ahern, Pablo Neira Ayuso, and Matthias Schiffer. 8) Add devlink support to nfp driver, from Simon Horman. 9) Add RTM_F_FIB_MATCH flag to RTM_GETROUTE queries, from Roopa Prabhu. 10) Add stack depth tracking to BPF verifier and use this information in the various eBPF JITs. From Alexei Starovoitov. 11) Support XDP on qed device VFs, from Yuval Mintz. 12) Introduce BPF PROG ID for better introspection of installed BPF programs. From Martin KaFai Lau. 13) Add bpf_set_hash helper for TC bpf programs, from Daniel Borkmann. 14) For loads, allow narrower accesses in bpf verifier checking, from Yonghong Song. 15) Support MIPS in the BPF selftests and samples infrastructure, the MIPS eBPF JIT will be merged in via the MIPS GIT tree. From David Daney. 16) Support kernel based TLS, from Dave Watson and others. 17) Remove completely DST garbage collection, from Wei Wang. 18) Allow installing TCP MD5 rules using prefixes, from Ivan Delalande. 19) Add XDP support to Intel i40e driver, from Björn Töpel 20) Add support for TC flower offload in nfp driver, from Simon Horman, Pieter Jansen van Vuuren, Benjamin LaHaise, Jakub Kicinski, and Bert van Leeuwen. 21) IPSEC offloading support in mlx5, from Ilan Tayari. 22) Add HW PTP support to macb driver, from Rafal Ozieblo. 23) Networking refcount_t conversions, From Elena Reshetova. 24) Add sock_ops support to BPF, from Lawrence Brako. This is useful for tuning the TCP sockopt settings of a group of applications, currently via CGROUPs" * git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next: (1899 commits) net: phy: dp83867: add workaround for incorrect RX_CTRL pin strap dt-bindings: phy: dp83867: provide a workaround for incorrect RX_CTRL pin strap cxgb4: Support for get_ts_info ethtool method cxgb4: Add PTP Hardware Clock (PHC) support cxgb4: time stamping interface for PTP nfp: default to chained metadata prepend format nfp: remove legacy MAC address lookup nfp: improve order of interfaces in breakout mode net: macb: remove extraneous return when MACB_EXT_DESC is defined bpf: add missing break in for the TCP_BPF_SNDCWND_CLAMP case bpf: fix return in load_bpf_file mpls: fix rtm policy in mpls_getroute net, ax25: convert ax25_cb.refcount from atomic_t to refcount_t net, ax25: convert ax25_route.refcount from atomic_t to refcount_t net, ax25: convert ax25_uid_assoc.refcount from atomic_t to refcount_t net, sctp: convert sctp_ep_common.refcnt from atomic_t to refcount_t net, sctp: convert sctp_transport.refcnt from atomic_t to refcount_t net, sctp: convert sctp_chunk.refcnt from atomic_t to refcount_t net, sctp: convert sctp_datamsg.refcnt from atomic_t to refcount_t net, sctp: convert sctp_auth_bytes.refcnt from atomic_t to refcount_t ...
2017-07-03Merge tag 'docs-4.13' of git://git.lwn.net/linuxLinus Torvalds1-1/+1
Pull documentation updates from Jonathan Corbet: "There has been a fair amount of activity in the docs tree this time around. Highlights include: - Conversion of a bunch of security documentation into RST - The conversion of the remaining DocBook templates by The Amazing Mauro Machine. We can now drop the entire DocBook build chain. - The usual collection of fixes and minor updates" * tag 'docs-4.13' of git://git.lwn.net/linux: (90 commits) scripts/kernel-doc: handle DECLARE_HASHTABLE Documentation: atomic_ops.txt is core-api/atomic_ops.rst Docs: clean up some DocBook loose ends Make the main documentation title less Geocities Docs: Use kernel-figure in vidioc-g-selection.rst Docs: fix table problems in ras.rst Docs: Fix breakage with Sphinx 1.5 and upper Docs: Include the Latex "ifthen" package doc/kokr/howto: Only send regression fixes after -rc1 docs-rst: fix broken links to dynamic-debug-howto in kernel-parameters doc: Document suitability of IBM Verse for kernel development Doc: fix a markup error in coding-style.rst docs: driver-api: i2c: remove some outdated information Documentation: DMA API: fix a typo in a function name Docs: Insert missing space to separate link from text doc/ko_KR/memory-barriers: Update control-dependencies example Documentation, kbuild: fix typo "minimun" -> "minimum" docs: Fix some formatting issues in request-key.rst doc: ReSTify keys-trusted-encrypted.txt doc: ReSTify keys-request-key.txt ...
2017-07-01net: convert sock.sk_wmem_alloc from atomic_t to refcount_tReshetova, Elena1-1/+1
refcount_t type and corresponding API should be used instead of atomic_t when the variable is used as a reference counter. This allows to avoid accidental refcounter overflows that might lead to use-after-free situations. Signed-off-by: Elena Reshetova <elena.reshetova@intel.com> Signed-off-by: Hans Liljestrand <ishkamiel@gmail.com> Signed-off-by: Kees Cook <keescook@chromium.org> Signed-off-by: David Windsor <dwindsor@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-07-01net: convert sk_buff.users from atomic_t to refcount_tReshetova, Elena1-2/+2
refcount_t type and corresponding API should be used instead of atomic_t when the variable is used as a reference counter. This allows to avoid accidental refcounter overflows that might lead to use-after-free situations. Signed-off-by: Elena Reshetova <elena.reshetova@intel.com> Signed-off-by: Hans Liljestrand <ishkamiel@gmail.com> Signed-off-by: Kees Cook <keescook@chromium.org> Signed-off-by: David Windsor <dwindsor@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-06-20sched/wait: Rename wait_queue_t => wait_queue_entry_tIngo Molnar1-1/+1
Rename: wait_queue_t => wait_queue_entry_t 'wait_queue_t' was always a slight misnomer: its name implies that it's a "queue", but in reality it's a queue *entry*. The 'real' queue is the wait queue head, which had to carry the name. Start sorting this out by renaming it to 'wait_queue_entry_t'. This also allows the real structure name 'struct __wait_queue' to lose its double underscore and become 'struct wait_queue_entry', which is the more canonical nomenclature for such data types. Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-06-12net: factor out a helper to decrement the skb refcountPaolo Abeni1-3/+1
The same code is replicated in 3 different places; move it to a common helper. Signed-off-by: Paolo Abeni <pabeni@redhat.com> Acked-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-05-18net: fix __skb_try_recv_from_queue to return the old behaviorAndrey Vagin1-6/+8
This function has to return NULL on a error case, because there is a separate error variable. The offset has to be changed only if skb is returned v2: fix udp code to not use an extra variable Cc: Paolo Abeni <pabeni@redhat.com> Cc: Eric Dumazet <edumazet@google.com> Cc: David S. Miller <davem@davemloft.net> Fixes: 65101aeca522 ("net/sock: factor out dequeue/peek with offset cod") Signed-off-by: Andrei Vagin <avagin@openvz.org> Acked-by: Paolo Abeni <pabeni@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-05-16net/sock: factor out dequeue/peek with offset codePaolo Abeni1-39/+51
And update __sk_queue_drop_skb() to work on the specified queue. This will help the udp protocol to use an additional private rx queue in a later patch. Signed-off-by: Paolo Abeni <pabeni@redhat.com> Acked-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-05-16net: fix some identation issues at kernel-doc markupsMauro Carvalho Chehab1-1/+1
Sphinx is very pedantic with regards to identation and escape sequences: ./include/net/sock.h:1967: ERROR: Unexpected indentation. ./include/net/sock.h:1969: ERROR: Unexpected indentation. ./include/net/sock.h:1970: WARNING: Block quote ends without a blank line; unexpected unindent. ./include/net/sock.h:1971: WARNING: Block quote ends without a blank line; unexpected unindent. ./include/net/sock.h:2268: WARNING: Inline emphasis start-string without end-string. ./net/core/sock.c:2686: ERROR: Unexpected indentation. ./net/core/sock.c:2687: WARNING: Block quote ends without a blank line; unexpected unindent. ./net/core/datagram.c:182: WARNING: Inline emphasis start-string without end-string. ./include/linux/netdevice.h:1444: ERROR: Unexpected indentation. ./drivers/net/phy/phy.c:381: ERROR: Unexpected indentation. ./drivers/net/phy/phy.c:382: WARNING: Block quote ends without a blank line; unexpected unindent. - Fix spacing where needed; - Properly escape constants; - Use a literal block for a race description. No functional changes. Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
2017-05-02Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-nextLinus Torvalds1-2/+6
Pull networking updates from David Millar: "Here are some highlights from the 2065 networking commits that happened this development cycle: 1) XDP support for IXGBE (John Fastabend) and thunderx (Sunil Kowuri) 2) Add a generic XDP driver, so that anyone can test XDP even if they lack a networking device whose driver has explicit XDP support (me). 3) Sparc64 now has an eBPF JIT too (me) 4) Add a BPF program testing framework via BPF_PROG_TEST_RUN (Alexei Starovoitov) 5) Make netfitler network namespace teardown less expensive (Florian Westphal) 6) Add symmetric hashing support to nft_hash (Laura Garcia Liebana) 7) Implement NAPI and GRO in netvsc driver (Stephen Hemminger) 8) Support TC flower offload statistics in mlxsw (Arkadi Sharshevsky) 9) Multiqueue support in stmmac driver (Joao Pinto) 10) Remove TCP timewait recycling, it never really could possibly work well in the real world and timestamp randomization really zaps any hint of usability this feature had (Soheil Hassas Yeganeh) 11) Support level3 vs level4 ECMP route hashing in ipv4 (Nikolay Aleksandrov) 12) Add socket busy poll support to epoll (Sridhar Samudrala) 13) Netlink extended ACK support (Johannes Berg, Pablo Neira Ayuso, and several others) 14) IPSEC hw offload infrastructure (Steffen Klassert)" * git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next: (2065 commits) tipc: refactor function tipc_sk_recv_stream() tipc: refactor function tipc_sk_recvmsg() net: thunderx: Optimize page recycling for XDP net: thunderx: Support for XDP header adjustment net: thunderx: Add support for XDP_TX net: thunderx: Add support for XDP_DROP net: thunderx: Add basic XDP support net: thunderx: Cleanup receive buffer allocation net: thunderx: Optimize CQE_TX handling net: thunderx: Optimize RBDR descriptor handling net: thunderx: Support for page recycling ipx: call ipxitf_put() in ioctl error path net: sched: add helpers to handle extended actions qed*: Fix issues in the ptp filter config implementation. qede: Fix concurrency issue in PTP Tx path processing. stmmac: Add support for SIMATIC IOT2000 platform net: hns: fix ethtool_get_strings overflow in hns driver tcp: fix wraparound issue in tcp_lp bpf, arm64: fix jit branch offset related to ldimm64 bpf, arm64: implement jiting of BPF_XADD ...
2017-05-01iov_iter: don't revert iov buffer if csum errorDing Tianhong1-6/+7
The patch 327868212381 (make skb_copy_datagram_msg() et.al. preserve ->msg_iter on error) will revert the iov buffer if copy to iter failed, but it didn't copy any datagram if the skb_checksum_complete error, so no need to revert any data at this place. v2: Sabrina notice that return -EFAULT when checksum error is not correct here, it would confuse the caller about the return value, so fix it. Fixes: 327868212381 ("make skb_copy_datagram_msg() et.al. preserve->msg_iter on error") Cc: stable@vger.kernel.org # v4.11 Signed-off-by: Ding Tianhong <dingtianhong@huawei.com> Acked-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2017-04-15Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/netDavid S. Miller1-9/+14
Conflicts were simply overlapping changes. In the net/ipv4/route.c case the code had simply moved around a little bit and the same fix was made in both 'net' and 'net-next'. In the net/sched/sch_generic.c case a fix in 'net' happened at the same time that a new argument was added to qdisc_hash_add(). Signed-off-by: David S. Miller <davem@davemloft.net>
2017-04-02make skb_copy_datagram_msg() et.al. preserve ->msg_iter on errorAl Viro1-9/+14
Fixes the mess observed in e.g. rsync over a noisy link we'd been seeing since last Summer. What happens is that we copy part of a datagram before noticing a checksum mismatch. Datagram will be resent, all right, but we want the next try go into the same place, not after it... All this family of primitives (copy/checksum and copy a datagram into destination) is "all or nothing" sort of interface - either we get 0 (meaning that copy had been successful) or we get an error (and no way to tell how much had been copied before we ran into whatever error it had been). Make all of them leave iterator unadvanced in case of errors - all callers must be able to cope with that (an error might've been caught before the iterator had been advanced), it costs very little to arrange, it's safer for callers and actually fixes at least one bug in said callers. Cc: stable@vger.kernel.org Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2017-03-24net: Change return type of sk_busy_loop from bool to voidAlexander Duyck1-2/+6
checking the return value of sk_busy_loop. As there are only a few consumers of that data, and the data being checked for can be replaced with a check for !skb_queue_empty() we might as well just pull the code out of sk_busy_loop and place it in the spots that actually need it. Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com> Acked-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-02-07udp: properly cope with csum errorsEric Dumazet1-2/+6
Dmitry reported that UDP sockets being destroyed would trigger the WARN_ON(atomic_read(&sk->sk_rmem_alloc)); in inet_sock_destruct() It turns out we do not properly destroy skb(s) that have wrong UDP checksum. Thanks again to syzkaller team. Fixes : 7c13f97ffde6 ("udp: do fwd memory scheduling on dequeue") Reported-by: Dmitry Vyukov <dvyukov@google.com> Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Paolo Abeni <pabeni@redhat.com> Cc: Hannes Frederic Sowa <hannes@stressinduktion.org> Acked-by: Paolo Abeni <pabeni@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-12-24Replace <asm/uaccess.h> with <linux/uaccess.h> globallyLinus Torvalds1-1/+1
This was entirely automated, using the script by Al: PATT='^[[:blank:]]*#[[:blank:]]*include[[:blank:]]*<asm/uaccess.h>' sed -i -e "s!$PATT!#include <linux/uaccess.h>!" \ $(git grep -l "$PATT"|grep -v ^include/linux/uaccess.h) to do the replacement at the end of the merge window. Requested-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-12-06net/udp: do not touch skb->peeked unless really neededEric Dumazet1-9/+10
In UDP recvmsg() path we currently access 3 cache lines from an skb while holding receive queue lock, plus another one if packet is dequeued, since we need to change skb->next->prev 1st cache line (contains ->next/prev pointers, offsets 0x00 and 0x08) 2nd cache line (skb->len & skb->peeked, offsets 0x80 and 0x8e) 3rd cache line (skb->truesize/users, offsets 0xe0 and 0xe4) skb->peeked is only needed to make sure 0-length packets are properly handled while MSG_PEEK is operated. I had first the intent to remove skb->peeked but the "MSG_PEEK at non-zero offset" support added by Sam Kumar makes this not possible. This patch avoids one cache line miss during the locked section, when skb->len and skb->peeked do not have to be read. It also avoids the skb_set_peeked() cost for non empty UDP datagrams. Signed-off-by: Eric Dumazet <edumazet@google.com> Acked-by: Paolo Abeni <pabeni@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>