- 08 Jan, 2018 19 commits
-
-
Ido Schimmel authored
Check that IPv4 and IPv6 react the same when the carrier of a netdev is toggled. Local routes should not be affected by this, whereas unicast routes should. Signed-off-by:
Ido Schimmel <idosch@mellanox.com> Acked-by:
David Ahern <dsahern@gmail.com> Signed-off-by:
David S. Miller <davem@davemloft.net>
-
Ido Schimmel authored
Check that IPv4 and IPv6 react the same when a netdev is being put administratively down. Signed-off-by:
-
Ido Schimmel authored
Add test cases to check that IPv4 and IPv6 react to a netdev being unregistered as expected. Signed-off-by:
-
Ido Schimmel authored
By default, IPv6 deletes nexthops from a multipath route when the nexthop device is put administratively down. This differs from IPv4 where the nexthops are kept, but marked with the RTNH_F_DEAD flag. A multipath route is flushed when all of its nexthops become dead. Align IPv6 with IPv4 and have it conform to the same guidelines. In case the multipath route needs to be flushed, its siblings are flushed one by one. Otherwise, the nexthops are marked with the appropriate flags and the tree walker is instructed to skip all the siblings. As explained in previous patches, care is taken to update the sernum of the affected tree nodes, so as to prevent the use of wrong dst entries. Signed-off-by:
-
Ido Schimmel authored
The next patch is going to allow dead routes to remain in the FIB tree in certain situations. When this happens we need to be sure to bump the sernum of the nodes where these are stored so that potential copies cached in sockets are invalidated. The function that performs this update assumes the table lock is not taken when it is invoked, but that will not be the case when it is invoked by the tree walker. Have the function assume the lock is taken and make the single caller take the lock itself. Signed-off-by:
-
Ido Schimmel authored
We are going to allow dead routes to stay in the FIB tree (e.g., when they are part of a multipath route, directly connected route with no carrier) and revive them when their nexthop device gains carrier or when it is put administratively up. This is equivalent to the addition of the route to the FIB tree and we should therefore take care of updating the sernum of all the parent nodes of the node where the route is stored. Otherwise, we risk sockets caching and using sub-optimal dst entries. Export the function that performs the above, so that it could be invoked from fib6_ifup() later on. Signed-off-by:
-
Ido Schimmel authored
As explained in previous patch, fib6_ifdown() needs to consider the state of all the sibling routes when a multipath route is traversed. This is done by evaluating all the siblings when the first sibling in a multipath route is traversed. If the multipath route does not need to be flushed (e.g., not all siblings are dead), then we should just skip the multipath route as our work is done. Have the tree walker jump to the last sibling when it is determined that the multipath route needs to be skipped. Signed-off-by:
-
Ido Schimmel authored
When routes that are a part of a multipath route are evaluated by fib6_ifdown() in response to NETDEV_DOWN and NETDEV_UNREGISTER events the state of their sibling routes is not considered. This will change in subsequent patches in order to align IPv6 with IPv4's behavior. For example, when the last sibling in a multipath route becomes dead, the entire multipath route needs to be removed. To prevent the tree walker from re-evaluating all the sibling routes each time, we can simply evaluate them once - when the first sibling is traversed. If we determine the entire multipath route needs to be removed, then the 'should_flush' bit is set in all the siblings, which will cause the walker to flush them when it traverses them. Signed-off-by:
-
Ido Schimmel authored
Up until now the RTNH_F_DEAD flag was only reported in route dump when the 'ignore_routes_with_linkdown' sysctl was set. This is expected as dead routes were flushed otherwise. The reliance on this sysctl is going to be removed, so we need to report the flag regardless of the sysctl's value. Signed-off-by:
-
Ido Schimmel authored
Currently, dead routes are only present in the routing tables in case the 'ignore_routes_with_linkdown' sysctl is set. Otherwise, they are flushed. Subsequent patches are going to remove the reliance on this sysctl and make IPv6 more consistent with IPv4. Before this is done, we need to make sure dead routes are skipped during route lookup, so as to not cause packet loss. Signed-off-by:
-
Ido Schimmel authored
Similar to previous patch, there is no need to check for the carrier of the nexthop device when dumping the route and we can instead check for the presence of the RTNH_F_LINKDOWN flag. Signed-off-by:
-
Ido Schimmel authored
Now that the RTNH_F_LINKDOWN flag is set in nexthops, we can avoid the need to dereference the nexthop device and check its carrier and instead check for the presence of the flag. Signed-off-by:
-
Ido Schimmel authored
It is valid to install routes with a nexthop device that does not have a carrier, so we need to make sure they're marked accordingly. As explained in the previous patch, host and anycast routes are never marked with the 'linkdown' flag. Note that reject routes are unaffected, as these use the loopback device which always has a carrier. Signed-off-by:
-
Ido Schimmel authored
Similar to IPv4, when the carrier of a netdev changes we should toggle the 'linkdown' flag on all the nexthops using it as their nexthop device. This will later allow us to test for the presence of this flag during route lookup and dump. Up until commit 4832c30d ("net: ipv6: put host and anycast routes on device with address") host and anycast routes used the loopback netdev as their nexthop device and thus were not marked with the 'linkdown' flag. The patch preserves this behavior and allows one to ping the local address even when the nexthop device does not have a carrier and the 'ignore_routes_with_linkdown' sysctl is set. Signed-off-by:
-
Ido Schimmel authored
To make IPv6 more in line with IPv4 we need to be able to respond differently to different netdev events. For example, when a netdev is unregistered all the routes using it as their nexthop device should be flushed, whereas when the netdev's carrier changes only the 'linkdown' flag should be toggled. Currently, this is not possible, as the function that traverses the routing tables is not aware of the triggering event. Propagate the triggering event down, so that it could be used in later patches. Signed-off-by:
-
Ido Schimmel authored
Previous patch marked nexthops with the 'dead' and 'linkdown' flags. Clear these flags when the netdev comes back up. Signed-off-by:
-
Ido Schimmel authored
When a netdev is put administratively down or unregistered all the nexthops using it as their nexthop device should be marked with the 'dead' and 'linkdown' flags. Currently, when a route is dumped its nexthop device is tested and the flags are set accordingly. A similar check is performed during route lookup. Instead, we can simply mark the nexthops based on netdev events and avoid checking the netdev's state during route dump and lookup. Signed-off-by:
-
Ido Schimmel authored
By the time fib6_net_exit() is executed all the netdevs in the namespace have been either unregistered or pushed back to the default namespace. That is because pernet subsys operations are always ordered before pernet device operations and therefore invoked after them during namespace dismantle. Thus, all the routing tables in the namespace are empty by the time fib6_net_exit() is invoked and the call to rt6_ifdown() can be removed. This allows us to simplify the condition in fib6_ifdown() as it's only ever called with an actual netdev. Signed-off-by:
-
git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-nextDavid S. Miller authored
Daniel Borkmann says: ==================== pull-request: bpf-next 2018-01-07 The following pull-request contains BPF updates for your *net-next* tree. The main changes are: 1) Add a start of a framework for extending struct xdp_buff without having the overhead of populating every data at runtime. Idea is to have a new per-queue struct xdp_rxq_info that holds read mostly data (currently that is, queue number and a pointer to the corresponding netdev) which is set up during rxqueue config time. When a XDP program is invoked, struct xdp_buff holds a pointer to struct xdp_rxq_info that the BPF program can then walk. The user facing BPF program that uses struct xdp_md for context can use these members directly, and the verifier rewrites context access transparently by walking the xdp_rxq_info and net_device pointers to load the data, from Jesper. 2) Redo the reporting of offload device information to user space such that it works in combination with network namespaces. The latter is reported through a device/inode tuple as similarly done in other subsystems as well (e.g. perf) in order to identify the namespace. For this to work, ns_get_path() has been generalized such that the namespace can be retrieved not only from a specific task (perf case), but also from a callback where we deduce the netns (ns_common) from a netdevice. bpftool support using the new uapi info and extensive test cases for test_offload.py in BPF selftests have been added as well, from Jakub. 3) Add two bpftool improvements: i) properly report the bpftool version such that it corresponds to the version from the kernel source tree. So pick the right linux/version.h from the source tree instead of the installed one. ii) fix bpftool and also bpf_jit_disasm build with bintutils >= 2.9. The reason for the build breakage is that binutils library changed the function signature to select the disassembler. Given this is needed in multiple tools, add a proper feature detection to the tools/build/features infrastructure, from Roman. 4) Implement the BPF syscall command BPF_MAP_GET_NEXT_KEY for the stacktrace map. It is currently unimplemented, but there are use cases where user space needs to walk all stacktrace map entries e.g. for dumping or deleting map entries w/o having to close and recreate the map. Add BPF selftests along with it, from Yonghong. 5) Few follow-up cleanups for the bpftool cgroup code: i) rename the cgroup 'list' command into 'show' as we have it for other subcommands as well, ii) then alias the 'show' command such that 'list' is accepted which is also common practice in iproute2, and iii) remove couple of newlines from error messages using p_err(), from Jakub. 6) Two follow-up cleanups to sockmap code: i) remove the unused bpf_compute_data_end_sk_skb() function and ii) only build the sockmap infrastructure when CONFIG_INET is enabled since it's only aware of TCP sockets at this time, from John. ==================== Signed-off-by:
-
- 06 Jan, 2018 3 commits
-
-
Daniel Borkmann authored
Yonghong Song says: ==================== The patch set implements bpf syscall command BPF_MAP_GET_NEXT_KEY for stacktrace map. Patch #1 is the core implementation and Patch #2 implements a bpf test at tools/testing/selftests/bpf directory. Please see individual patch comments for details. Changelog: v1 -> v2: - For invalid key (key pointer is non-NULL), sets next_key to be the first valid key. ==================== Signed-off-by:Daniel Borkmann <daniel@iogearbox.net>
-
Yonghong Song authored
Added a bpf selftest in test_progs at tools directory for stacktrace. The test will populate a hashtable map and a stacktrace map at the same time with the same key, stackid. The user space will compare both maps, using BPF_MAP_LOOKUP_ELEM command and BPF_MAP_GET_NEXT_KEY command, to ensure that both have the same set of keys. Signed-off-by:
Yonghong Song <yhs@fb.com> Signed-off-by:
-
Yonghong Song authored
Currently, bpf syscall command BPF_MAP_GET_NEXT_KEY is not supported for stacktrace map. However, there are use cases where user space wants to enumerate all stacktrace map entries where BPF_MAP_GET_NEXT_KEY command will be really helpful. In addition, if user space wants to delete all map entries in order to save memory and does not want to close the map file descriptor, BPF_MAP_GET_NEXT_KEY may help improve performance if map entries are sparsely populated. The implementation has similar behavior for BPF_MAP_GET_NEXT_KEY implementation in hashtab. If user provides a NULL key pointer or an invalid key, the first key is returned. Otherwise, the first valid key after the input parameter "key" is returned, or -ENOENT if no valid key can be found. Signed-off-by:
-
- 05 Jan, 2018 18 commits
-
-
Alexei Starovoitov authored
Jesper Dangaard Brouer says: ==================== V4: * Added reviewers/acks to patches * Fix patch desc in i40e that got out-of-sync with code * Add SPDX license headers for the two new files added in patch 14 V3: * Fixed bug in virtio_net driver * Removed export of xdp_rxq_info_init() V2: * Changed API exposed to drivers - Removed invocation of "init" in drivers, and only call "reg" (Suggested by Saeed) - Allow "reg" to fail and handle this in drivers (Suggested by David Ahern) * Removed the SINKQ qtype, instead allow to register as "unused" * Also fixed some drivers during testing on actual HW (noted in patches) There is a need for XDP to know more about the RX-queue a given XDP frames have arrived on. For both the XDP bpf-prog and kernel side. Instead of extending struct xdp_buff each time new info is needed, this patchset takes a different approach. Struct xdp_buff is only extended with a pointer to a struct xdp_rxq_info (allowing for easier extending this later). This xdp_rxq_info contains information related to how the driver have setup the individual RX-queue's. This is read-mostly information, and all xdp_buff frames (in drivers napi_poll) point to the same xdp_rxq_info (per RX-queue). We stress this data/cache-line is for read-mostly info. This is NOT for dynamic per packet info, use the data_meta for such use-cases. This patchset start out small, and only expose ingress_ifindex and the RX-queue index to the XDP/BPF program. Access to tangible info like the ingress ifindex and RX queue index, is fairly easy to comprehent. The other future use-cases could allow XDP frames to be recycled back to the originating device driver, by providing info on RX device and queue number. As XDP doesn't have driver feature flags, and eBPF code due to bpf-tail-calls cannot determine that XDP driver invoke it, this patchset have to update every driver that support XDP. For driver developers (review individual driver patches!): The xdp_rxq_info is tied to the drivers RX-ring(s). Whenever a RX-ring modification require (temporary) stopping RX frames, then the xdp_rxq_info should (likely) also be unregistred and re-registered, especially if reallocating the pages in the ring. Make sure ethtool set_channels does the right thing. When replacing XDP prog, if and only if RX-ring need to be changed, then also re-register the xdp_rxq_info. I'm Cc'ing the individual driver patches to the registered maintainers. Testing: I've only tested the NIC drivers I have hardware for. The general test procedure is to (DUT = Device Under Test): (1) run pktgen script pktgen_sample04_many_flows.sh (against DUT) (2) run samples/bpf program xdp_rxq_info --dev $DEV (on DUT) (3) runtime modify number of NIC queues via ethtool -L (on DUT) (4) runtime modify number of NIC ring-size via ethtool -G (on DUT) Patch based on git tree bpf-next (at commit fb982666): https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next.git/ ==================== Signed-off-by:Alexei Starovoitov <ast@kernel.org>
-
Jesper Dangaard Brouer authored
This sample program can be used for monitoring and reporting how many packets per sec (pps) are received per NIC RX queue index and which CPU processed the packet. In itself it is a useful tool for quickly identifying RSS imbalance issues, see below. The default XDP action is XDP_PASS in-order to provide a monitor mode. For benchmarking purposes it is possible to specify other XDP actions on the cmdline --action. Output below shows an imbalance RSS case where most RXQ's deliver to CPU-0 while CPU-2 only get packets from a single RXQ. Looking at things from a CPU level the two CPUs are processing approx the same amount, BUT looking at the rx_queue_index levels it is clear that RXQ-2 receive much better service, than other RXQs which all share CPU-0. Running XDP on dev:i40e1 (ifindex:3) action:XDP_PASS XDP stats CPU pps issue-pps XDP-RX CPU 0 900,473 0 XDP-RX CPU 2 906,921 0 XDP-RX CPU total 1,807,395 RXQ stats RXQ:CPU pps issue-pps rx_queue_index 0:0 180,098 0 rx_queue_index 0:sum 180,098 rx_queue_index 1:0 180,098 0 rx_queue_index 1:sum 180,098 rx_queue_index 2:2 906,921 0 rx_queue_index 2:sum 906,921 rx_queue_index 3:0 180,098 0 rx_queue_index 3:sum 180,098 rx_queue_index 4:0 180,082 0 rx_queue_index 4:sum 180,082 rx_queue_index 5:0 180,093 0 rx_queue_index 5:sum 180,093 Signed-off-by:
Jesper Dangaard Brouer <brouer@redhat.com> Signed-off-by:
-
Jesper Dangaard Brouer authored
Now all XDP driver have been updated to setup xdp_rxq_info and assign this to xdp_buff->rxq. Thus, it is now safe to enable access to some of the xdp_rxq_info struct members. This patch extend xdp_md and expose UAPI to userspace for ingress_ifindex and rx_queue_index. Access happens via bpf instruction rewrite, that load data directly from struct xdp_rxq_info. * ingress_ifindex map to xdp_rxq_info->dev->ifindex * rx_queue_index map to xdp_rxq_info->queue_index Signed-off-by:
John Fastabend <john.fastabend@gmail.com> Signed-off-by:
-
Jesper Dangaard Brouer authored
Hook points for xdp_rxq_info: * reg : netif_alloc_rx_queues * unreg: netif_free_rx_queues The net_device have some members (num_rx_queues + real_num_rx_queues) and data-area (dev->_rx with struct netdev_rx_queue's) that were primarily used for exporting information about RPS (CONFIG_RPS) queues to sysfs (CONFIG_SYSFS). For generic XDP extend struct netdev_rx_queue with the xdp_rxq_info, and remove some of the CONFIG_SYSFS ifdefs. Signed-off-by:
-
Jesper Dangaard Brouer authored
The virtio_net driver doesn't dynamically change the RX-ring queue layout and backing pages, but instead reject XDP setup if all the conditions for XDP is not meet. Thus, the xdp_rxq_info also remains fairly static. This allow us to simply add the reg/unreg to net_device open/close functions. Driver hook points for xdp_rxq_info: * reg : virtnet_open * unreg: virtnet_close V3: - bugfix, also setup xdp.rxq in receive_mergeable() - Tested bpf-sample prog inside guest on a virtio_net device Cc: "Michael S. Tsirkin" <mst@redhat.com> Cc: Jason Wang <jasowang@redhat.com> Cc: virtualization@lists.linux-foundation.org Signed-off-by:
Jason Wang <jasowang@redhat.com> Signed-off-by:
-
Jesper Dangaard Brouer authored
Driver hook points for xdp_rxq_info: * reg : tun_attach * unreg: __tun_detach I've done some manual testing of this tun driver, but I would appriciate good review and someone else running their use-case tests, as I'm not 100% sure I understand the tfile->detached semantics. V2: Removed the skb_array_cleanup() call from V1 by request from Jason Wang. Cc: Jason Wang <jasowang@redhat.com> Cc: "Michael S. Tsirkin" <mst@redhat.com> Cc: Willem de Bruijn <willemb@google.com> Signed-off-by:
-
Jesper Dangaard Brouer authored
This driver uses a bool scheme for "enable"/"disable" when setting up different resources. Thus, the hook points for xdp_rxq_info is done in the same function call nicvf_rcv_queue_config(). This is activated through enable/disable via nicvf_config_data_transfer(), which is tied into nicvf_stop()/nicvf_open(). Extending driver packet handler call-path nicvf_rcv_pkt_handler() with a pointer to the given struct rcv_queue, in-order to access the xdp_rxq_info data area (in nicvf_xdp_rx()). V2: Driver have no proper error path for failed XDP RX-queue info reg, as nicvf_rcv_queue_config is a void function. Cc: linux-arm-kernel@lists.infradead.org Cc: Sunil Goutham <sgoutham@cavium.com> Cc: Robert Richter <rric@kernel.org> Signed-off-by:
-
Jesper Dangaard Brouer authored
Driver hook points for xdp_rxq_info: * reg : nfp_net_rx_ring_alloc * unreg: nfp_net_rx_ring_free In struct nfp_net_rx_ring moved member @size into a hole on 64-bit. Thus, the size remaines the same after adding member @xdp_rxq. Cc: oss-drivers@netronome.com Cc: Jakub Kicinski <jakub.kicinski@netronome.com> Cc: Simon Horman <simon.horman@netronome.com> Signed-off-by:
-
Jesper Dangaard Brouer authored
Driver hook points for xdp_rxq_info: * reg : bnxt_alloc_rx_rings * unreg: bnxt_free_rx_rings This driver should be updated to re-register when changing allocation mode of RX rings. Tested on actual hardware. Cc: Andy Gospodarek <andy@greyhouse.net> Cc: Michael Chan <michael.chan@broadcom.com> Signed-off-by:
-
Jesper Dangaard Brouer authored
Driver hook points for xdp_rxq_info: * reg : mlx4_en_create_rx_ring * unreg: mlx4_en_destroy_rx_ring Tested on actual hardware. Cc: Tariq Toukan <tariqt@mellanox.com> Signed-off-by:
Tariq Toukan <tariqt@mellanox.com> Signed-off-by:
-
Jesper Dangaard Brouer authored
The driver code qede_free_fp_array() depend on kfree() can be called with a NULL pointer. This stems from the qede_alloc_fp_array() function which either (kz)alloc memory for fp->txq or fp->rxq. This also simplifies error handling code in case of memory allocation failures, but xdp_rxq_info_unreg need to know the difference. Introduce xdp_rxq_info_is_reg() to handle if a memory allocation fails and detect this is the failure path by seeing that xdp_rxq_info was not registred yet, which first happens after successful alloaction in qede_init_fp(). Driver hook points for xdp_rxq_info: * reg : qede_init_fp * unreg: qede_free_fp_array Tested on actual hardware with samples/bpf program. V2: Driver have no proper error path for failed XDP RX-queue info reg, as qede_init_fp() is a void function. Cc: everest-linux-l2@cavium.com Cc: Ariel Elior <Ariel.Elior@cavium.com> Signed-off-by:
-
Jesper Dangaard Brouer authored
Driver hook points for xdp_rxq_info: * reg : ixgbe_setup_rx_resources() * unreg: ixgbe_free_rx_resources() Tested on actual hardware. V2: Fix ixgbe_set_ringparam, clear xdp_rxq_info in temp_ring Cc: intel-wired-lan@lists.osuosl.org Cc: Jeff Kirsher <jeffrey.t.kirsher@intel.com> Cc: Alexander Duyck <alexander.duyck@gmail.com> Signed-off-by:
-
Jesper Dangaard Brouer authored
The i40e driver has a special "FDIR" RX-ring (I40E_VSI_FDIR) which is a sideband channel for configuring/updating the flow director tables. This (i40e_vsi_)type does not invoke XDP-ebpf code. As suggested by Björn (V2): Instead of marking this I40E_VSI_FDIR RX-ring a special case, reverse the logic and only select RX-rings of type I40E_VSI_MAIN to register xdp_rxq_info's for. Driver hook points for xdp_rxq_info: * reg : i40e_setup_rx_descriptors (via i40e_vsi_setup_rx_resources) * unreg: i40e_free_rx_resources (via i40e_vsi_free_rx_resources) Tested on actual hardware with samples/bpf program. V2: Fixed bug in i40e_set_ringparam (memset zero) + match on I40E_VSI_MAIN. V4: Update patch desc that got out-of-sync with code. Cc: intel-wired-lan@lists.osuosl.org Cc: Björn Töpel <bjorn.topel@intel.com> Cc: Jeff Kirsher <jeffrey.t.kirsher@intel.com> Cc: Paul Menzel <pmenzel@molgen.mpg.de> Signed-off-by:
Paul Menzel <pmenzel@molgen.mpg.de> Acked-by:
-
Jesper Dangaard Brouer authored
The mlx5 driver have a special drop-RQ queue (one per interface) that simply drops all incoming traffic. It helps driver keep other HW objects (flow steering) alive upon down/up operations. It is temporarily pointed by flow steering objects during the interface setup, and when interface is down. It lacks many fields that are set in a regular RQ (for example its state is never switched to MLX5_RQC_STATE_RDY). (Thanks to Tariq Toukan for explanation). The XDP RX-queue info for this drop-RQ marked as unused, which allow us to use the same takedown/free code path as other RX-queues. Driver hook points for xdp_rxq_info: * reg : mlx5e_alloc_rq() * unused: mlx5e_alloc_drop_rq() * unreg : mlx5e_free_rq() Tested on actual hardware with samples/bpf program Cc: Saeed Mahameed <saeedm@mellanox.com> Cc: Matan Barak <matanb@mellanox.com> Cc: Tariq Toukan <tariqt@mellanox.com> Signed-off-by:
-
Jesper Dangaard Brouer authored
This patch only introduce the core data structures and API functions. All XDP enabled drivers must use the API before this info can used. There is a need for XDP to know more about the RX-queue a given XDP frames have arrived on. For both the XDP bpf-prog and kernel side. Instead of extending xdp_buff each time new info is needed, the patch creates a separate read-mostly struct xdp_rxq_info, that contains this info. We stress this data/cache-line is for read-only info. This is NOT for dynamic per packet info, use the data_meta for such use-cases. The performance advantage is this info can be setup at RX-ring init time, instead of updating N-members in xdp_buff. A possible (driver level) micro optimization is that xdp_buff->rxq assignment could be done once per XDP/NAPI loop. The extra pointer deref only happens for program needing access to this info (thus, no slowdown to existing use-cases). Signed-off-by:
-
Jakub Kicinski authored
We currently always pass all multicast traffic through. Only set L2MC when actually needed. Since the driver was not making use of the capability to filter out mcast frames, some FW projects don't implement it any more. Don't warn users if capability is not present (like we do for promisc flag). The lack of L2MC capability is assumed to mean all multicast traffic goes through. Signed-off-by:
Jakub Kicinski <jakub.kicinski@netronome.com> Signed-off-by:
Simon Horman <simon.horman@netronome.com> Signed-off-by:
-
David S. Miller authored
Sowmini Varadhan says: ==================== rds: use RCU between work-enqueue and connection teardown This patchset follows up on the root-cause mentioned in https://www.spinics.net/lists/netdev/msg472849.html Patch1 implements some code refactoring that was suggeseted as an enhancement in http://patchwork.ozlabs.org/patch/843157/ It replaces the c_destroy_in_prog bit in rds_connection with an atomically managed flag in rds_conn_path. Patch2 builds on Patch1 and uses RCU to make sure that work is only enqueued if the connection destroy is not already in progress: the test-flag-and-enqueue is done under rcu_read_lock, while destroy first sets the flag, uses synchronize_rcu to wait for existing reader threads to complete, and then starts all the work-cancellation. Since I have not been able to reproduce the original stack traces reported by syszbot, and these are fixes for a race condition that are based on code-inspection I am not marking these as reported-by at this time. ==================== Signed-off-by:
-
Sowmini Varadhan authored
rds_sendmsg() can enqueue work on cp_send_w from process context, but it should not enqueue this work if connection teardown has commenced (else we risk enquing work after rds_conn_path_destroy() has assumed that all work has been cancelled/flushed). Similarly some other functions like rds_cong_queue_updates and rds_tcp_data_ready are called in softirq context, and may end up enqueuing work on rds_wq after rds_conn_path_destroy() has assumed that all workqs are quiesced. Check the RDS_DESTROY_PENDING bit and use rcu synchronization to avoid all these races. Signed-off-by:
Sowmini Varadhan <sowmini.varadhan@oracle.com> Acked-by:
Santosh Shilimkar <santosh.shilimkar@oracle.com> Signed-off-by:
-
