1. 15 Sep, 2021 3 commits
  2. 14 Sep, 2021 4 commits
    • Eric Dumazet's avatar
      Revert "Revert "ipv4: fix memory leaks in ip_cmsg_send() callers"" · d198b277
      Eric Dumazet authored
      This reverts commit d7807a9a.
      
      As mentioned in https://lkml.org/lkml/2021/9/13/1819
      5 years old commit 91948309 ("ipv4: fix memory leaks in ip_cmsg_send() callers")
      was a correct fix.
      
        ip_cmsg_send() can loop over multiple cmsghdr()
      
        If IP_RETOPTS has been successful, but following cmsghdr generates an error,
        we do not free ipc.ok
      
        If IP_RETOPTS is not successful, we have freed the allocated temporary space,
        not the one currently in ipc.opt.
      
      Sure, code could be refactored, but let's not bring back old bugs.
      
      Fixes: d7807a9a ("Revert "ipv4: fix memory leaks in ip_cmsg_send() callers"")
      Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
      Cc: Yajun Deng <yajun.deng@linux.dev>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      d198b277
    • zhenggy's avatar
      tcp: fix tp->undo_retrans accounting in tcp_sacktag_one() · 4f884f39
      zhenggy authored
      Commit 10d3be56 ("tcp-tso: do not split TSO packets at retransmit
      time") may directly retrans a multiple segments TSO/GSO packet without
      split, Since this commit, we can no longer assume that a retransmitted
      packet is a single segment.
      
      This patch fixes the tp->undo_retrans accounting in tcp_sacktag_one()
      that use the actual segments(pcount) of the retransmitted packet.
      
      Before that commit (10d3be56), the assumption underlying the
      tp->undo_retrans-- seems correct.
      
      Fixes: 10d3be56 ("tcp-tso: do not split TSO packets at retransmit time")
      Signed-off-by: default avatarzhenggy <zhenggy@chinatelecom.cn>
      Reviewed-by: default avatarEric Dumazet <edumazet@google.com>
      Acked-by: default avatarYuchung Cheng <ycheng@google.com>
      Acked-by: default avatarNeal Cardwell <ncardwell@google.com>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      4f884f39
    • David S. Miller's avatar
      Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf · 2865ba82
      David S. Miller authored
      Daniel Borkmann says:
      
      ====================
      pull-request: bpf 2021-09-14
      
      The following pull-request contains BPF updates for your *net* tree.
      
      We've added 7 non-merge commits during the last 13 day(s) which contain
      a total of 18 files changed, 334 insertions(+), 193 deletions(-).
      
      The main changes are:
      
      1) Fix mmap_lock lockdep splat in BPF stack map's build_id lookup, from Yonghong Song.
      
      2) Fix BPF cgroup v2 program bypass upon net_cls/prio activation, from Daniel Borkmann.
      
      3) Fix kvcalloc() BTF line info splat on oversized allocation attempts, from Bixuan Cui.
      
      4) Fix BPF selftest build of task_pt_regs test for arm64/s390, from Jean-Philippe Brucker.
      
      5) Fix BPF's disasm.{c,h} to dual-license so that it is aligned with bpftool given the former
         is a build dependency for the latter, from Daniel Borkmann with ACKs from contributors.
      ====================
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      2865ba82
    • Eric Dumazet's avatar
      net-caif: avoid user-triggerable WARN_ON(1) · 550ac9c1
      Eric Dumazet authored
      syszbot triggers this warning, which looks something
      we can easily prevent.
      
      If we initialize priv->list_field in chnl_net_init(),
      then always use list_del_init(), we can remove robust_list_del()
      completely.
      
      WARNING: CPU: 0 PID: 3233 at net/caif/chnl_net.c:67 robust_list_del net/caif/chnl_net.c:67 [inline]
      WARNING: CPU: 0 PID: 3233 at net/caif/chnl_net.c:67 chnl_net_uninit+0xc9/0x2e0 net/caif/chnl_net.c:375
      Modules linked in:
      CPU: 0 PID: 3233 Comm: syz-executor.3 Not tainted 5.14.0-syzkaller #0
      Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
      RIP: 0010:robust_list_del net/caif/chnl_net.c:67 [inline]
      RIP: 0010:chnl_net_uninit+0xc9/0x2e0 net/caif/chnl_net.c:375
      Code: 89 eb e8 3a a3 ba f8 48 89 d8 48 c1 e8 03 42 80 3c 28 00 0f 85 bf 01 00 00 48 81 fb 00 14 4e 8d 48 8b 2b 75 d0 e8 17 a3 ba f8 <0f> 0b 5b 5d 41 5c 41 5d e9 0a a3 ba f8 4c 89 e3 e8 02 a3 ba f8 4c
      RSP: 0018:ffffc90009067248 EFLAGS: 00010202
      RAX: 0000000000008780 RBX: ffffffff8d4e1400 RCX: ffffc9000fd34000
      RDX: 0000000000040000 RSI: ffffffff88bb6e49 RDI: 0000000000000003
      RBP: ffff88802cd9ee08 R08: 0000000000000000 R09: ffffffff8d0e6647
      R10: ffffffff88bb6dc2 R11: 0000000000000000 R12: ffff88803791ae08
      R13: dffffc0000000000 R14: 00000000e600ffce R15: ffff888073ed3480
      FS:  00007fed10fa0700(0000) GS:ffff8880b9d00000(0000) knlGS:0000000000000000
      CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
      CR2: 0000001b2c322000 CR3: 00000000164a6000 CR4: 00000000001506e0
      DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
      DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
      Call Trace:
       register_netdevice+0xadf/0x1500 net/core/dev.c:10347
       ipcaif_newlink+0x4c/0x260 net/caif/chnl_net.c:468
       __rtnl_newlink+0x106d/0x1750 net/core/rtnetlink.c:3458
       rtnl_newlink+0x64/0xa0 net/core/rtnetlink.c:3506
       rtnetlink_rcv_msg+0x413/0xb80 net/core/rtnetlink.c:5572
       netlink_rcv_skb+0x153/0x420 net/netlink/af_netlink.c:2504
       netlink_unicast_kernel net/netlink/af_netlink.c:1314 [inline]
       netlink_unicast+0x533/0x7d0 net/netlink/af_netlink.c:1340
       netlink_sendmsg+0x86d/0xdb0 net/netlink/af_netlink.c:1929
       sock_sendmsg_nosec net/socket.c:704 [inline]
       sock_sendmsg+0xcf/0x120 net/socket.c:724
       __sys_sendto+0x21c/0x320 net/socket.c:2036
       __do_sys_sendto net/socket.c:2048 [inline]
       __se_sys_sendto net/socket.c:2044 [inline]
       __x64_sys_sendto+0xdd/0x1b0 net/socket.c:2044
       do_syscall_x64 arch/x86/entry/common.c:50 [inline]
       do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
       entry_SYSCALL_64_after_hwframe+0x44/0xae
      
      Fixes: cc36a070 ("net-caif: add CAIF netdevice")
      Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      550ac9c1
  3. 13 Sep, 2021 20 commits
  4. 12 Sep, 2021 3 commits
  5. 11 Sep, 2021 1 commit
    • Jesper Nilsson's avatar
      net: stmmac: allow CSR clock of 300MHz · 08dad2f4
      Jesper Nilsson authored
      The Synopsys Ethernet IP uses the CSR clock as a base clock for MDC.
      The divisor used is set in the MAC_MDIO_Address register field CR
      (Clock Rate)
      
      The divisor is there to change the CSR clock into a clock that falls
      below the IEEE 802.3 specified max frequency of 2.5MHz.
      
      If the CSR clock is 300MHz, the code falls back to using the reset
      value in the MAC_MDIO_Address register, as described in the comment
      above this code.
      
      However, 300MHz is actually an allowed value and the proper divider
      can be estimated quite easily (it's just 1Hz difference!)
      
      A CSR frequency of 300MHz with the maximum clock rate value of 0x5
      (STMMAC_CSR_250_300M, a divisor of 124) gives somewhere around
      ~2.42MHz which is below the IEEE 802.3 specified maximum.
      
      For the ARTPEC-8 SoC, the CSR clock is this problematic 300MHz,
      and unfortunately, the reset-value of the MAC_MDIO_Address CR field
      is 0x0.
      
      This leads to a clock rate of zero and a divisor of 42, and gives an
      MDC frequency of ~7.14MHz.
      
      Allow CSR clock of 300MHz by making the comparison inclusive.
      Signed-off-by: default avatarJesper Nilsson <jesper.nilsson@axis.com>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      08dad2f4
  6. 10 Sep, 2021 6 commits
    • Yonghong Song's avatar
      bpf, mm: Fix lockdep warning triggered by stack_map_get_build_id_offset() · 2f1aaf3e
      Yonghong Song authored
      Currently the bpf selftest "get_stack_raw_tp" triggered the warning:
      
        [ 1411.304463] WARNING: CPU: 3 PID: 140 at include/linux/mmap_lock.h:164 find_vma+0x47/0xa0
        [ 1411.304469] Modules linked in: bpf_testmod(O) [last unloaded: bpf_testmod]
        [ 1411.304476] CPU: 3 PID: 140 Comm: systemd-journal Tainted: G        W  O      5.14.0+ #53
        [ 1411.304479] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.14.0-0-g155821a1990b-prebuilt.qemu.org 04/01/2014
        [ 1411.304481] RIP: 0010:find_vma+0x47/0xa0
        [ 1411.304484] Code: de 48 89 ef e8 ba f5 fe ff 48 85 c0 74 2e 48 83 c4 08 5b 5d c3 48 8d bf 28 01 00 00 be ff ff ff ff e8 2d 9f d8 00 85 c0 75 d4 <0f> 0b 48 89 de 48 8
        [ 1411.304487] RSP: 0018:ffffabd440403db8 EFLAGS: 00010246
        [ 1411.304490] RAX: 0000000000000000 RBX: 00007f00ad80a0e0 RCX: 0000000000000000
        [ 1411.304492] RDX: 0000000000000001 RSI: ffffffff9776b144 RDI: ffffffff977e1b0e
        [ 1411.304494] RBP: ffff9cf5c2f50000 R08: ffff9cf5c3eb25d8 R09: 00000000fffffffe
        [ 1411.304496] R10: 0000000000000001 R11: 00000000ef974e19 R12: ffff9cf5c39ae0e0
        [ 1411.304498] R13: 0000000000000000 R14: 0000000000000000 R15: ffff9cf5c39ae0e0
        [ 1411.304501] FS:  00007f00ae754780(0000) GS:ffff9cf5fba00000(0000) knlGS:0000000000000000
        [ 1411.304504] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
        [ 1411.304506] CR2: 000000003e34343c CR3: 0000000103a98005 CR4: 0000000000370ee0
        [ 1411.304508] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
        [ 1411.304510] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
        [ 1411.304512] Call Trace:
        [ 1411.304517]  stack_map_get_build_id_offset+0x17c/0x260
        [ 1411.304528]  __bpf_get_stack+0x18f/0x230
        [ 1411.304541]  bpf_get_stack_raw_tp+0x5a/0x70
        [ 1411.305752] RAX: 0000000000000000 RBX: 5541f689495641d7 RCX: 0000000000000000
        [ 1411.305756] RDX: 0000000000000001 RSI: ffffffff9776b144 RDI: ffffffff977e1b0e
        [ 1411.305758] RBP: ffff9cf5c02b2f40 R08: ffff9cf5ca7606c0 R09: ffffcbd43ee02c04
        [ 1411.306978]  bpf_prog_32007c34f7726d29_bpf_prog1+0xaf/0xd9c
        [ 1411.307861] R10: 0000000000000001 R11: 0000000000000044 R12: ffff9cf5c2ef60e0
        [ 1411.307865] R13: 0000000000000005 R14: 0000000000000000 R15: ffff9cf5c2ef6108
        [ 1411.309074]  bpf_trace_run2+0x8f/0x1a0
        [ 1411.309891] FS:  00007ff485141700(0000) GS:ffff9cf5fae00000(0000) knlGS:0000000000000000
        [ 1411.309896] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
        [ 1411.311221]  syscall_trace_enter.isra.20+0x161/0x1f0
        [ 1411.311600] CR2: 00007ff48514d90e CR3: 0000000107114001 CR4: 0000000000370ef0
        [ 1411.312291]  do_syscall_64+0x15/0x80
        [ 1411.312941] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
        [ 1411.313803]  entry_SYSCALL_64_after_hwframe+0x44/0xae
        [ 1411.314223] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
        [ 1411.315082] RIP: 0033:0x7f00ad80a0e0
        [ 1411.315626] Call Trace:
        [ 1411.315632]  stack_map_get_build_id_offset+0x17c/0x260
      
      To reproduce, first build `test_progs` binary:
      
        make -C tools/testing/selftests/bpf -j60
      
      and then run the binary at tools/testing/selftests/bpf directory:
      
        ./test_progs -t get_stack_raw_tp
      
      The warning is due to commit 5b78ed24 ("mm/pagemap: add mmap_assert_locked()
      annotations to find_vma*()") which added mmap_assert_locked() in find_vma()
      function. The mmap_assert_locked() function asserts that mm->mmap_lock needs
      to be held. But this is not the case for bpf_get_stack() or bpf_get_stackid()
      helper (kernel/bpf/stackmap.c), which uses mmap_read_trylock_non_owner()
      instead. Since mm->mmap_lock is not held in bpf_get_stack[id]() use case,
      the above warning is emitted during test run.
      
      This patch fixed the issue by (1). using mmap_read_trylock() instead of
      mmap_read_trylock_non_owner() to satisfy lockdep checking in find_vma(), and
      (2). droping lockdep for mmap_lock right before the irq_work_queue(). The
      function mmap_read_trylock_non_owner() is also removed since after this
      patch nobody calls it any more.
      
      Fixes: 5b78ed24 ("mm/pagemap: add mmap_assert_locked() annotations to find_vma*()")
      Suggested-by: default avatarJason Gunthorpe <jgg@ziepe.ca>
      Signed-off-by: default avatarYonghong Song <yhs@fb.com>
      Signed-off-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
      Reviewed-by: default avatarLiam R. Howlett <Liam.Howlett@oracle.com>
      Cc: Luigi Rizzo <lrizzo@google.com>
      Cc: Jason Gunthorpe <jgg@ziepe.ca>
      Cc: linux-mm@kvack.org
      Link: https://lore.kernel.org/bpf/20210909155000.1610299-1-yhs@fb.com
      2f1aaf3e
    • Colin Ian King's avatar
      qlcnic: Remove redundant initialization of variable ret · 666eb96d
      Colin Ian King authored
      The variable ret is being initialized with a value that is never read, it
      is being updated later on. The assignment is redundant and can be removed.
      
      Addresses-Coverity: ("Unused value")
      Signed-off-by: default avatarColin Ian King <colin.king@canonical.com>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      666eb96d
    • Shai Malin's avatar
      qed: Handle management FW error · 20e100f5
      Shai Malin authored
      Handle MFW (management FW) error response in order to avoid a crash
      during recovery flows.
      
      Changes from v1:
      - Add "Fixes tag".
      
      Fixes: tag 5e7ba042 ("qed: Fix reading stale configuration information")
      Signed-off-by: default avatarAriel Elior <aelior@marvell.com>
      Signed-off-by: default avatarShai Malin <smalin@marvell.com>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      20e100f5
    • Baruch Siach's avatar
      net/packet: clarify source of pr_*() messages · dc41c4a9
      Baruch Siach authored
      Add pr_fmt macro to spell out the source of messages in prefix.
      
      Before this patch:
      
        packet size is too long (1543 > 1518)
      
      With this patch:
      
        af_packet: packet size is too long (1543 > 1518)
      Signed-off-by: default avatarBaruch Siach <baruch@tkos.co.il>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      dc41c4a9
    • Florian Fainelli's avatar
      r6040: Restore MDIO clock frequency after MAC reset · e3f0cc1a
      Florian Fainelli authored
      A number of users have reported that they were not able to get the PHY
      to successfully link up, especially after commit c36757eb ("net:
      phy: consider AN_RESTART status when reading link status") where we
      stopped reading just BMSR, but we also read BMCR to determine the link
      status.
      
      Andrius at NetBSD did a wonderful job at debugging the problem
      and found out that the MDIO bus clock frequency would be incorrectly set
      back to its default value which would prevent the MDIO bus controller
      from reading PHY registers properly. Back when we only read BMSR, if we
      read all 1s, we could falsely indicate a link status, though in general
      there is a cable plugged in, so this went unnoticed. After a second read
      of BMCR was added, a wrong read will lead to the inability to determine
      a link UP condition which is when it started to be visibly broken, even
      if it was long before that.
      
      The fix consists in restoring the value of the MD_CSR register that was
      set prior to the MAC reset.
      
      Link: http://gnats.netbsd.org/cgi-bin/query-pr-single.pl?number=53494
      Fixes: 90f750a8 ("r6040: consolidate MAC reset to its own function")
      Reported-by: default avatarAndrius V <vezhlys@gmail.com>
      Reported-by: default avatarDarek Strugacz <darek.strugacz@op.pl>
      Tested-by: default avatarDarek Strugacz <darek.strugacz@op.pl>
      Signed-off-by: default avatarFlorian Fainelli <f.fainelli@gmail.com>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      e3f0cc1a
    • Dave Ertman's avatar
      ice: Correctly deal with PFs that do not support RDMA · bfe84435
      Dave Ertman authored
      There are two cases where the current PF does not support RDMA
      functionality.  The first is if the NVM loaded on the device is set
      to not support RDMA (common_caps.rdma is false).  The second is if
      the kernel bonding driver has included the current PF in an active
      link aggregate.
      
      When the driver has determined that this PF does not support RDMA, then
      auxiliary devices should not be created on the auxiliary bus.  Without
      a device on the auxiliary bus, even if the irdma driver is present, there
      will be no RDMA activity attempted on this PF.
      
      Currently, in the reset flow, an attempt to create auxiliary devices is
      performed without regard to the ability of the PF.  There needs to be a
      check in ice_aux_plug_dev (as the central point that creates auxiliary
      devices) to see if the PF is in a state to support the functionality.
      
      When disabling and re-enabling RDMA due to the inclusion/removal of the PF
      in a link aggregate, we also need to set/clear the bit which controls
      auxiliary device creation so that a reset recovery in a link aggregate
      situation doesn't try to create auxiliary devices when it shouldn't.
      
      Fixes: f9f5301e ("ice: Register auxiliary device to provide RDMA")
      Reported-by: default avatarYongxin Liu <yongxin.liu@windriver.com>
      Signed-off-by: default avatarDave Ertman <david.m.ertman@intel.com>
      Signed-off-by: default avatarTony Nguyen <anthony.l.nguyen@intel.com>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      bfe84435
  7. 09 Sep, 2021 3 commits
    • Guenter Roeck's avatar
      net: ni65: Avoid typecast of pointer to u32 · e0119126
      Guenter Roeck authored
      Building alpha:allmodconfig results in the following error.
      
      drivers/net/ethernet/amd/ni65.c: In function 'ni65_stop_start':
      drivers/net/ethernet/amd/ni65.c:751:37: error:
      	cast from pointer to integer of different size
      		buffer[i] = (u32) isa_bus_to_virt(tmdp->u.buffer);
      
      'buffer[]' is declared as unsigned long, so replace the typecast to u32
      with a typecast to unsigned long to fix the problem.
      
      Cc: Arnd Bergmann <arnd@kernel.org>
      Signed-off-by: default avatarGuenter Roeck <linux@roeck-us.net>
      Acked-by: default avatarArnd Bergmann <arnd@arndb.de>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      e0119126
    • David S. Miller's avatar
      Merge branch 'sfx-xdp-fallback-tx-queues' · e3a843f9
      David S. Miller authored
      Íñigo Huguet says:
      
      ====================
      sfc: fallback for lack of xdp tx queues
      
      If there are not enough hardware resources to allocate one tx queue per
      CPU for XDP, XDP_TX and XDP_REDIRECT actions were unavailable, and using
      them resulted each time with the packet being drop and this message in
      the logs: XDP TX failed (-22)
      
      These patches implement 2 fallback solutions for 2 different situations
      that might happen:
      1. There are not enough free resources for all the tx queues, but there
         are some free resources available
      2. There are not enough free resources at all for tx queues.
      
      Both solutions are based in sharing tx queues, using __netif_tx_lock for
      synchronization. In the second case, as there are not XDP TX queues to
      share, network stack queues are used instead, but since we're taking
      __netif_tx_lock, concurrent access to the queues is correctly protected.
      
      The solution for this second case might affect performance both of XDP
      traffic and normal traffice due to lock contention if both are used
      intensively. That's why I call it a "last resort" fallback: it's not a
      desirable situation, but at least we have XDP TX working.
      
      Some tests has shown good results and indicate that the non-fallback
      case is not being damaged by this changes. They are also promising for
      the fallback cases. This is the test:
      1. From another machine, send high amount of packets with pktgen, script
         samples/pktgen/pktgen_sample04_many_flows.sh
      2. In the tested machine, run samples/bpf/xdp_rxq_info with arguments
         "-a XDP_TX --swapmac" and see the results
      3. In the tested machine, run also pktgen_sample04 to create high TX
         normal traffic, and see how xdp_rxq_info results vary
      
      Note that this test doesn't check the worst situations for the fallback
      solutions because XDP_TX will only be executed from the same CPUs that
      are processed by sfc, and not from every CPU in the system, so the
      performance drop due to the highest locking contention doesn't happen.
      I'd like to test that, as well, but I don't have access right now to a
      proper environment.
      
      Test results:
      
      Without doing TX:
      Before changes: ~2,900,000 pps
      After changes, 1 queues/core: ~2,900,000 pps
      After changes, 2 queues/core: ~2,900,000 pps
      After changes, 8 queues/core: ~2,900,000 pps
      After changes, borrowing from network stack: ~2,900,000 pps
      
      With multiflow TX at the same time:
      Before changes: ~1,700,000 - 2,900,000 pps
      After changes, 1 queues/core: ~1,700,000 - 2,900,000 pps
      After changes, 2 queues/core: ~1,700,000 pps
      After changes, 8 queues/core: ~1,700,000 pps
      After changes, borrowing from network stack: 1,150,000 pps
      
      Sporadic "XDP TX failed (-5)" warnings are shown when running xdp program
      and pktgen simultaneously. This was expected because XDP doesn't have any
      buffering system if the NIC is under very high pressure. Thousands of
      these warnings are shown in the case of borrowing net stack queues. As I
      said before, this was also expected.
      ====================
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      e3a843f9
    • Íñigo Huguet's avatar
      sfc: last resort fallback for lack of xdp tx queues · 6215b608
      Íñigo Huguet authored
      Previous patch addressed the situation of having some free resources for
      xdp tx but not enough for one tx queue per CPU. This patch address the
      worst case of not having resources at all for xdp tx.
      
      Instead of using queues dedicated to xdp, normal queues used by network
      stack are shared for both cases, using __netif_tx_lock for
      synchronization. Also queue stop/restart must be considered in the xdp
      path to avoid freezing the queue.
      
      This is not the ideal situation we might want to be, and a performance
      penalty is expected both for normal and xdp traffic, but at least XDP
      will work in all possible situations (with a warning in the logs),
      improving a bit the pain of not knowing in what situations we can use it
      and in what situations we cannot.
      Signed-off-by: default avatarÍñigo Huguet <ihuguet@redhat.com>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      6215b608