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2024-01-25xsk: fix usage of multi-buffer BPF helpers for ZC XDPMaciej Fijalkowski1-0/+26
Currently when packet is shrunk via bpf_xdp_adjust_tail() and memory type is set to MEM_TYPE_XSK_BUFF_POOL, null ptr dereference happens: [1136314.192256] BUG: kernel NULL pointer dereference, address: 0000000000000034 [1136314.203943] #PF: supervisor read access in kernel mode [1136314.213768] #PF: error_code(0x0000) - not-present page [1136314.223550] PGD 0 P4D 0 [1136314.230684] Oops: 0000 [#1] PREEMPT SMP NOPTI [1136314.239621] CPU: 8 PID: 54203 Comm: xdpsock Not tainted 6.6.0+ #257 [1136314.250469] Hardware name: Intel Corporation S2600WFT/S2600WFT, BIOS SE5C620.86B.02.01.0008.031920191559 03/19/2019 [1136314.265615] RIP: 0010:__xdp_return+0x6c/0x210 [1136314.274653] Code: ad 00 48 8b 47 08 49 89 f8 a8 01 0f 85 9b 01 00 00 0f 1f 44 00 00 f0 41 ff 48 34 75 32 4c 89 c7 e9 79 cd 80 ff 83 fe 03 75 17 <f6> 41 34 01 0f 85 02 01 00 00 48 89 cf e9 22 cc 1e 00 e9 3d d2 86 [1136314.302907] RSP: 0018:ffffc900089f8db0 EFLAGS: 00010246 [1136314.312967] RAX: ffffc9003168aed0 RBX: ffff8881c3300000 RCX: 0000000000000000 [1136314.324953] RDX: 0000000000000000 RSI: 0000000000000003 RDI: ffffc9003168c000 [1136314.336929] RBP: 0000000000000ae0 R08: 0000000000000002 R09: 0000000000010000 [1136314.348844] R10: ffffc9000e495000 R11: 0000000000000040 R12: 0000000000000001 [1136314.360706] R13: 0000000000000524 R14: ffffc9003168aec0 R15: 0000000000000001 [1136314.373298] FS: 00007f8df8bbcb80(0000) GS:ffff8897e0e00000(0000) knlGS:0000000000000000 [1136314.386105] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [1136314.396532] CR2: 0000000000000034 CR3: 00000001aa912002 CR4: 00000000007706f0 [1136314.408377] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [1136314.420173] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [1136314.431890] PKRU: 55555554 [1136314.439143] Call Trace: [1136314.446058] <IRQ> [1136314.452465] ? __die+0x20/0x70 [1136314.459881] ? page_fault_oops+0x15b/0x440 [1136314.468305] ? exc_page_fault+0x6a/0x150 [1136314.476491] ? asm_exc_page_fault+0x22/0x30 [1136314.484927] ? __xdp_return+0x6c/0x210 [1136314.492863] bpf_xdp_adjust_tail+0x155/0x1d0 [1136314.501269] bpf_prog_ccc47ae29d3b6570_xdp_sock_prog+0x15/0x60 [1136314.511263] ice_clean_rx_irq_zc+0x206/0xc60 [ice] [1136314.520222] ? ice_xmit_zc+0x6e/0x150 [ice] [1136314.528506] ice_napi_poll+0x467/0x670 [ice] [1136314.536858] ? ttwu_do_activate.constprop.0+0x8f/0x1a0 [1136314.546010] __napi_poll+0x29/0x1b0 [1136314.553462] net_rx_action+0x133/0x270 [1136314.561619] __do_softirq+0xbe/0x28e [1136314.569303] do_softirq+0x3f/0x60 This comes from __xdp_return() call with xdp_buff argument passed as NULL which is supposed to be consumed by xsk_buff_free() call. To address this properly, in ZC case, a node that represents the frag being removed has to be pulled out of xskb_list. Introduce appropriate xsk helpers to do such node operation and use them accordingly within bpf_xdp_adjust_tail(). Fixes: 24ea50127ecf ("xsk: support mbuf on ZC RX") Acked-by: Magnus Karlsson <magnus.karlsson@intel.com> # For the xsk header part Signed-off-by: Maciej Fijalkowski <maciej.fijalkowski@intel.com> Link: https://lore.kernel.org/r/20240124191602.566724-4-maciej.fijalkowski@intel.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2024-01-25xsk: make xsk_buff_pool responsible for clearing xdp_buff::flagsMaciej Fijalkowski1-0/+1
XDP multi-buffer support introduced XDP_FLAGS_HAS_FRAGS flag that is used by drivers to notify data path whether xdp_buff contains fragments or not. Data path looks up mentioned flag on first buffer that occupies the linear part of xdp_buff, so drivers only modify it there. This is sufficient for SKB and XDP_DRV modes as usually xdp_buff is allocated on stack or it resides within struct representing driver's queue and fragments are carried via skb_frag_t structs. IOW, we are dealing with only one xdp_buff. ZC mode though relies on list of xdp_buff structs that is carried via xsk_buff_pool::xskb_list, so ZC data path has to make sure that fragments do *not* have XDP_FLAGS_HAS_FRAGS set. Otherwise, xsk_buff_free() could misbehave if it would be executed against xdp_buff that carries a frag with XDP_FLAGS_HAS_FRAGS flag set. Such scenario can take place when within supplied XDP program bpf_xdp_adjust_tail() is used with negative offset that would in turn release the tail fragment from multi-buffer frame. Calling xsk_buff_free() on tail fragment with XDP_FLAGS_HAS_FRAGS would result in releasing all the nodes from xskb_list that were produced by driver before XDP program execution, which is not what is intended - only tail fragment should be deleted from xskb_list and then it should be put onto xsk_buff_pool::free_list. Such multi-buffer frame will never make it up to user space, so from AF_XDP application POV there would be no traffic running, however due to free_list getting constantly new nodes, driver will be able to feed HW Rx queue with recycled buffers. Bottom line is that instead of traffic being redirected to user space, it would be continuously dropped. To fix this, let us clear the mentioned flag on xsk_buff_pool side during xdp_buff initialization, which is what should have been done right from the start of XSK multi-buffer support. Fixes: 1bbc04de607b ("ice: xsk: add RX multi-buffer support") Fixes: 1c9ba9c14658 ("i40e: xsk: add RX multi-buffer support") Fixes: 24ea50127ecf ("xsk: support mbuf on ZC RX") Signed-off-by: Maciej Fijalkowski <maciej.fijalkowski@intel.com> Link: https://lore.kernel.org/r/20240124191602.566724-3-maciej.fijalkowski@intel.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2024-01-03xsk: make struct xsk_cb_desc available outside CONFIG_XDP_SOCKETSVladimir Oltean1-2/+2
The ice driver fails to build when CONFIG_XDP_SOCKETS is disabled. drivers/net/ethernet/intel/ice/ice_base.c:533:21: error: variable has incomplete type 'struct xsk_cb_desc' struct xsk_cb_desc desc = {}; ^ include/net/xsk_buff_pool.h:15:8: note: forward declaration of 'struct xsk_cb_desc' struct xsk_cb_desc; ^ Fixes: d68d707dcbbf ("ice: Support XDP hints in AF_XDP ZC mode") Closes: https://lore.kernel.org/netdev/8b76dad3-8847-475b-aa17-613c9c978f7a@infradead.org/ Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com> Acked-by: Larysa Zaremba <larysa.zaremba@intel.com> Reviewed-by: Maciej Fijalkowski <maciej.fijalkowski@intel.com> Acked-by: Randy Dunlap <rdunlap@infradead.org> Tested-by: Randy Dunlap <rdunlap@infradead.org> # build-tested Link: https://lore.kernel.org/r/20231219110205.1289506-1-vladimir.oltean@nxp.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2023-12-14xsk: add functions to fill control bufferMaciej Fijalkowski1-0/+17
Commit 94ecc5ca4dbf ("xsk: Add cb area to struct xdp_buff_xsk") has added a buffer for custom data to xdp_buff_xsk. Particularly, this memory is used for data, consumed by XDP hints kfuncs. It does not always change on a per-packet basis and some parts can be set for example, at the same time as RX queue info. Add functions to fill all cbs in xsk_buff_pool with the same metadata. Signed-off-by: Maciej Fijalkowski <maciej.fijalkowski@intel.com> Signed-off-by: Larysa Zaremba <larysa.zaremba@intel.com> Acked-by: Magnus Karlsson <magnus.karlsson@intel.com> Link: https://lore.kernel.org/r/20231205210847.28460-8-larysa.zaremba@intel.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2023-11-30xsk: Validate xsk_tx_metadata flagsStanislav Fomichev1-1/+22
Accept only the flags that the kernel knows about to make sure we can extend this field in the future. Note that only in XDP_COPY mode we propagate the error signal back to the user (via sendmsg). For zerocopy mode we silently skip the metadata for the descriptors that have wrong flags (since we process the descriptors deep in the driver). Signed-off-by: Stanislav Fomichev <sdf@google.com> Link: https://lore.kernel.org/r/20231127190319.1190813-8-sdf@google.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2023-11-30xsk: Add TX timestamp and TX checksum offload supportStanislav Fomichev1-0/+13
This change actually defines the (initial) metadata layout that should be used by AF_XDP userspace (xsk_tx_metadata). The first field is flags which requests appropriate offloads, followed by the offload-specific fields. The supported per-device offloads are exported via netlink (new xsk-flags). The offloads themselves are still implemented in a bit of a framework-y fashion that's left from my initial kfunc attempt. I'm introducing new xsk_tx_metadata_ops which drivers are supposed to implement. The drivers are also supposed to call xsk_tx_metadata_request/xsk_tx_metadata_complete in the right places. Since xsk_tx_metadata_{request,_complete} are static inline, we don't incur any extra overhead doing indirect calls. The benefit of this scheme is as follows: - keeps all metadata layout parsing away from driver code - makes it easy to grep and see which drivers implement what - don't need any extra flags to maintain to keep track of what offloads are implemented; if the callback is implemented - the offload is supported (used by netlink reporting code) Two offloads are defined right now: 1. XDP_TXMD_FLAGS_CHECKSUM: skb-style csum_start+csum_offset 2. XDP_TXMD_FLAGS_TIMESTAMP: writes TX timestamp back into metadata area upon completion (tx_timestamp field) XDP_TXMD_FLAGS_TIMESTAMP is also implemented for XDP_COPY mode: it writes SW timestamp from the skb destructor (note I'm reusing hwtstamps to pass metadata pointer). The struct is forward-compatible and can be extended in the future by appending more fields. Reviewed-by: Song Yoong Siang <yoong.siang.song@intel.com> Signed-off-by: Stanislav Fomichev <sdf@google.com> Acked-by: Jakub Kicinski <kuba@kernel.org> Link: https://lore.kernel.org/r/20231127190319.1190813-3-sdf@google.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2023-07-19xsk: support mbuf on ZC RXMaciej Fijalkowski1-0/+44
Given that skb_shared_info relies on skb_frag_t, in order to support xskb chaining, introduce xdp_buff_xsk::xskb_list_node and xsk_buff_pool::xskb_list. This is needed so ZC drivers can add frags as xskb nodes which will make it possible to handle it both when producing AF_XDP Rx descriptors as well as freeing/recycling all the frags that a single frame carries. Speaking of latter, update xsk_buff_free() to take care of list nodes. For the former (adding as frags), introduce xsk_buff_add_frag() for ZC drivers usage that is going to be used to add a frag to xskb list from pool. xsk_buff_get_frag() will be utilized by XDP_TX and, on contrary, will return xdp_buff. One of the previous patches added a wrapper for ZC Rx so implement xskb list walk and production of Rx descriptors there. On bind() path, bail out if socket wants to use ZC multi-buffer but underlying netdev does not support it. Signed-off-by: Maciej Fijalkowski <maciej.fijalkowski@intel.com> Link: https://lore.kernel.org/r/20230719132421.584801-12-maciej.fijalkowski@intel.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2023-07-19xsk: allow core/drivers to test EOP bitMaciej Fijalkowski1-0/+10
Drivers are used to check for EOP bit whereas AF_XDP operates on inverted logic - user space indicates that current frag is not the last one and packet continues. For AF_XDP core needs, add xp_mb_desc() that will simply test XDP_PKT_CONTD from xdp_desc::options, but in order to preserve drivers default behavior, introduce an interface for ZC drivers that will negate xp_mb_desc() result and therefore make it easier to test EOP bit from during production of HW Tx descriptors. Signed-off-by: Maciej Fijalkowski <maciej.fijalkowski@intel.com> Link: https://lore.kernel.org/r/20230719132421.584801-8-maciej.fijalkowski@intel.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2023-06-19xsk: Remove unused inline function xsk_buff_discard()YueHaibing1-4/+0
commit f2f167583601 ("xsk: Remove unused xsk_buff_discard") left behind this, remove it. Signed-off-by: YueHaibing <yuehaibing@huawei.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Reviewed-by: Simon Horman <simon.horman@corigine.com> Acked-by: Maciej Fijalkowski <maciej.fijalkowski@intel.com> Link: https://lore.kernel.org/bpf/20230616062800.30780-1-yuehaibing@huawei.com
2022-09-30xsk: Remove unused xsk_buff_discardMaxim Mikityanskiy1-7/+0
The previous commit removed the last usage of xsk_buff_discard in mlx5e, so the function that is no longer used can be removed. Signed-off-by: Maxim Mikityanskiy <maximmi@nvidia.com> Reviewed-by: Tariq Toukan <tariqt@nvidia.com> CC: "Björn Töpel" <bjorn@kernel.org> CC: Magnus Karlsson <magnus.karlsson@intel.com> CC: Maciej Fijalkowski <maciej.fijalkowski@intel.com> Signed-off-by: Saeed Mahameed <saeedm@nvidia.com> Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-09-30xsk: Expose min chunk size to driversMaxim Mikityanskiy1-0/+3
Drivers should be aware of the range of valid UMEM chunk sizes to be able to allocate their internal structures of an appropriate size. It will be used by mlx5e in the following patches. Signed-off-by: Maxim Mikityanskiy <maximmi@nvidia.com> Reviewed-by: Tariq Toukan <tariqt@nvidia.com> CC: "Björn Töpel" <bjorn@kernel.org> CC: Magnus Karlsson <magnus.karlsson@intel.com> CC: Maciej Fijalkowski <maciej.fijalkowski@intel.com> Signed-off-by: Saeed Mahameed <saeedm@nvidia.com> Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-08-03Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/netPaolo Abeni1-0/+11
Conflicts: net/ax25/af_ax25.c d7c4c9e075f8c ("ax25: fix incorrect dev_tracker usage") d62607c3fe459 ("net: rename reference+tracking helpers") drivers/net/netdevsim/fib.c 180a6a3ee60a ("netdevsim: fib: Fix reference count leak on route deletion failure") 012ec02ae441 ("netdevsim: convert driver to use unlocked devlink API during init/fini") Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2022-08-02net/mlx5e: xsk: Discard unaligned XSK frames on striding RQMaxim Mikityanskiy1-0/+11
Striding RQ uses MTT page mapping, where each page corresponds to an XSK frame. MTT pages have alignment requirements, and XSK frames don't have any alignment guarantees in the unaligned mode. Frames with improper alignment must be discarded, otherwise the packet data will be written at a wrong address. Fixes: 282c0c798f8e ("net/mlx5e: Allow XSK frames smaller than a page") Signed-off-by: Maxim Mikityanskiy <maximmi@nvidia.com> Reviewed-by: Tariq Toukan <tariqt@nvidia.com> Reviewed-by: Saeed Mahameed <saeedm@nvidia.com> Reviewed-by: Maciej Fijalkowski <maciej.fijalkowski@intel.com> Link: https://lore.kernel.org/r/20220729121356.3990867-1-maximmi@nvidia.com Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2022-07-14xsk: Mark napi_id on sendmsg()Maciej Fijalkowski1-0/+14
When application runs in busy poll mode and does not receive a single packet but only sends them, it is currently impossible to get into napi_busy_loop() as napi_id is only marked on Rx side in xsk_rcv_check(). In there, napi_id is being taken from xdp_rxq_info carried by xdp_buff. From Tx perspective, we do not have access to it. What we have handy is the xsk pool. Xsk pool works on a pool of internal xdp_buff wrappers called xdp_buff_xsk. AF_XDP ZC enabled drivers call xp_set_rxq_info() so each of xdp_buff_xsk has a valid pointer to xdp_rxq_info of underlying queue. Therefore, on Tx side, napi_id can be pulled from xs->pool->heads[0].xdp.rxq->napi_id. Hide this pointer chase under helper function, xsk_pool_get_napi_id(). Do this only for sockets working in ZC mode as otherwise rxq pointers would not be initialized. Signed-off-by: Maciej Fijalkowski <maciej.fijalkowski@intel.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Magnus Karlsson <magnus.karlsson@intel.com> Link: https://lore.kernel.org/bpf/20220707130842.49408-1-maciej.fijalkowski@intel.com
2022-01-27i40e: xsk: Move tmp desc array from driver to poolMagnus Karlsson1-3/+2
Move desc_array from the driver to the pool. The reason behind this is that we can then reuse this array as a temporary storage for descriptors in all zero-copy drivers that use the batched interface. This will make it easier to add batching to more drivers. i40e is the only driver that has a batched Tx zero-copy implementation, so no need to touch any other driver. Signed-off-by: Magnus Karlsson <magnus.karlsson@intel.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Reviewed-by: Alexander Lobakin <alexandr.lobakin@intel.com> Link: https://lore.kernel.org/bpf/20220125160446.78976-6-maciej.fijalkowski@intel.com
2021-09-28xsk: Batched buffer allocation for the poolMagnus Karlsson1-0/+22
Add a new driver interface xsk_buff_alloc_batch() offering batched buffer allocations to improve performance. The new interface takes three arguments: the buffer pool to allocated from, a pointer to an array of struct xdp_buff pointers which will contain pointers to the allocated xdp_buffs, and an unsigned integer specifying the max number of buffers to allocate. The return value is the actual number of buffers that the allocator managed to allocate and it will be in the range 0 <= N <= max, where max is the third parameter to the function. u32 xsk_buff_alloc_batch(struct xsk_buff_pool *pool, struct xdp_buff **xdp, u32 max); A second driver interface is also introduced that need to be used in conjunction with xsk_buff_alloc_batch(). It is a helper that sets the size of struct xdp_buff and is used by the NIC Rx irq routine when receiving a packet. This helper sets the three struct members data, data_meta, and data_end. The two first ones is in the xsk_buff_alloc() case set in the allocation routine and data_end is set when a packet is received in the receive irq function. This unfortunately leads to worse performance since the xdp_buff is touched twice with a long time period in between leading to an extra cache miss. Instead, we fill out the xdp_buff with all 3 fields at one single point in time in the driver, when the size of the packet is known. Hence this helper. Note that the driver has to use this helper (or set all three fields itself) when using xsk_buff_alloc_batch(). xsk_buff_alloc() works as before and does not require this. void xsk_buff_set_size(struct xdp_buff *xdp, u32 size); Signed-off-by: Magnus Karlsson <magnus.karlsson@intel.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/bpf/20210922075613.12186-3-magnus.karlsson@gmail.com
2020-11-18xsk: Introduce batched Tx descriptor interfacesMagnus Karlsson1-0/+7
Introduce batched descriptor interfaces in the xsk core code for the Tx path to be used in the driver to write a code path with higher performance. This interface will be used by the i40e driver in the next patch. Though other drivers would likely benefit from this new interface too. Note that batching is only implemented for the common case when there is only one socket bound to the same device and queue id. When this is not the case, we fall back to the old non-batched version of the function. Signed-off-by: Magnus Karlsson <magnus.karlsson@intel.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: John Fastabend <john.fastabend@gmail.com> Link: https://lore.kernel.org/bpf/1605525167-14450-5-git-send-email-magnus.karlsson@gmail.com
2020-08-31xsk: i40e: ice: ixgbe: mlx5: Test for dma_need_sync earlier for better ↵Magnus Karlsson1-2/+5
performance Test for dma_need_sync earlier to increase performance. xsk_buff_dma_sync_for_cpu() takes an xdp_buff as parameter and from that the xsk_buff_pool reference is dug out. Perf shows that this dereference causes a lot of cache misses. But as the buffer pool is now sent down to the driver at zero-copy initialization time, we might as well use this pointer directly, instead of going via the xsk_buff and we can do so already in xsk_buff_dma_sync_for_cpu() instead of in xp_dma_sync_for_cpu. This gets rid of these cache misses. Throughput increases with 3% for the xdpsock l2fwd sample application on my machine. Signed-off-by: Magnus Karlsson <magnus.karlsson@intel.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Björn Töpel <bjorn.topel@intel.com> Link: https://lore.kernel.org/bpf/1598603189-32145-11-git-send-email-magnus.karlsson@intel.com
2020-08-31xsk: i40e: ice: ixgbe: mlx5: Rename xsk zero-copy driver interfacesMagnus Karlsson1-55/+59
Rename the AF_XDP zero-copy driver interface functions to better reflect what they do after the replacement of umems with buffer pools in the previous commit. Mostly it is about replacing the umem name from the function names with xsk_buff and also have them take the a buffer pool pointer instead of a umem. The various ring functions have also been renamed in the process so that they have the same naming convention as the internal functions in xsk_queue.h. This so that it will be clearer what they do and also for consistency. Signed-off-by: Magnus Karlsson <magnus.karlsson@intel.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Björn Töpel <bjorn.topel@intel.com> Link: https://lore.kernel.org/bpf/1598603189-32145-3-git-send-email-magnus.karlsson@intel.com
2020-08-31xsk: i40e: ice: ixgbe: mlx5: Pass buffer pool to driver instead of umemMagnus Karlsson1-3/+4
Replace the explicit umem reference passed to the driver in AF_XDP zero-copy mode with the buffer pool instead. This in preparation for extending the functionality of the zero-copy mode so that umems can be shared between queues on the same netdev and also between netdevs. In this commit, only an umem reference has been added to the buffer pool struct. But later commits will add other entities to it. These are going to be entities that are different between different queue ids and netdevs even though the umem is shared between them. Signed-off-by: Magnus Karlsson <magnus.karlsson@intel.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Björn Töpel <bjorn.topel@intel.com> Link: https://lore.kernel.org/bpf/1598603189-32145-2-git-send-email-magnus.karlsson@intel.com
2020-05-22xsk: Remove MEM_TYPE_ZERO_COPY and corresponding codeBjörn Töpel1-149/+0
There are no users of MEM_TYPE_ZERO_COPY. Remove all corresponding code, including the "handle" member of struct xdp_buff. rfc->v1: Fixed spelling in commit message. (Björn) Signed-off-by: Björn Töpel <bjorn.topel@intel.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20200520192103.355233-13-bjorn.topel@gmail.com
2020-05-22xsk: Introduce AF_XDP buffer allocation APIBjörn Töpel1-0/+164
In order to simplify AF_XDP zero-copy enablement for NIC driver developers, a new AF_XDP buffer allocation API is added. The implementation is based on a single core (single producer/consumer) buffer pool for the AF_XDP UMEM. A buffer is allocated using the xsk_buff_alloc() function, and returned using xsk_buff_free(). If a buffer is disassociated with the pool, e.g. when a buffer is passed to an AF_XDP socket, a buffer is said to be released. Currently, the release function is only used by the AF_XDP internals and not visible to the driver. Drivers using this API should register the XDP memory model with the new MEM_TYPE_XSK_BUFF_POOL type. The API is defined in net/xdp_sock_drv.h. The buffer type is struct xdp_buff, and follows the lifetime of regular xdp_buffs, i.e. the lifetime of an xdp_buff is restricted to a NAPI context. In other words, the API is not replacing xdp_frames. In addition to introducing the API and implementations, the AF_XDP core is migrated to use the new APIs. rfc->v1: Fixed build errors/warnings for m68k and riscv. (kbuild test robot) Added headroom/chunk size getter. (Maxim/Björn) v1->v2: Swapped SoBs. (Maxim) v2->v3: Initialize struct xdp_buff member frame_sz. (Björn) Add API to query the DMA address of a frame. (Maxim) Do DMA sync for CPU till the end of the frame to handle possible growth (frame_sz). (Maxim) Signed-off-by: Björn Töpel <bjorn.topel@intel.com> Signed-off-by: Maxim Mikityanskiy <maximmi@mellanox.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20200520192103.355233-6-bjorn.topel@gmail.com
2020-05-22xsk: Move driver interface to xdp_sock_drv.hMagnus Karlsson1-0/+217
Move the AF_XDP zero-copy driver interface to its own include file called xdp_sock_drv.h. This, hopefully, will make it more clear for NIC driver implementors to know what functions to use for zero-copy support. v4->v5: Fix -Wmissing-prototypes by include header file. (Jakub) Signed-off-by: Magnus Karlsson <magnus.karlsson@intel.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20200520192103.355233-4-bjorn.topel@gmail.com