From 34cc0b338a61de3eee3a2bfcaf4f9d6e9fae091a Mon Sep 17 00:00:00 2001 From: Jesper Dangaard Brouer Date: Thu, 14 May 2020 12:49:33 +0200 Subject: xdp: Xdp_frame add member frame_sz and handle in convert_to_xdp_frame MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Use hole in struct xdp_frame, when adding member frame_sz, which keeps same sizeof struct (32 bytes) Drivers ixgbe and sfc had bug cases where the necessary/expected tailroom was not reserved. This can lead to some hard to catch memory corruption issues. Having the drivers frame_sz this can be detected when packet length/end via xdp->data_end exceed the xdp_data_hard_end pointer, which accounts for the reserved the tailroom. When detecting this driver issue, simply fail the conversion with NULL, which results in feedback to driver (failing xdp_do_redirect()) causing driver to drop packet. Given the lack of consistent XDP stats, this can be hard to troubleshoot. And given this is a driver bug, we want to generate some more noise in form of a WARN stack dump (to ID the driver code that inlined convert_to_xdp_frame). Inlining the WARN macro is problematic, because it adds an asm instruction (on Intel CPUs ud2) what influence instruction cache prefetching. Thus, introduce xdp_warn and macro XDP_WARN, to avoid this and at the same time make identifying the function and line of this inlined function easier. Signed-off-by: Jesper Dangaard Brouer Signed-off-by: Alexei Starovoitov Acked-by: Toke Høiland-Jørgensen Link: https://lore.kernel.org/bpf/158945337313.97035.10015729316710496600.stgit@firesoul --- net/core/xdp.c | 8 ++++++++ 1 file changed, 8 insertions(+) (limited to 'net/core/xdp.c') diff --git a/net/core/xdp.c b/net/core/xdp.c index 4c7ea85486af..490b8f5fa8ee 100644 --- a/net/core/xdp.c +++ b/net/core/xdp.c @@ -11,6 +11,7 @@ #include #include #include +#include #include #include @@ -496,3 +497,10 @@ struct xdp_frame *xdp_convert_zc_to_xdp_frame(struct xdp_buff *xdp) return xdpf; } EXPORT_SYMBOL_GPL(xdp_convert_zc_to_xdp_frame); + +/* Used by XDP_WARN macro, to avoid inlining WARN() in fast-path */ +void xdp_warn(const char *msg, const char *func, const int line) +{ + WARN(1, "XDP_WARN: %s(line:%d): %s\n", func, line, msg); +}; +EXPORT_SYMBOL_GPL(xdp_warn); -- cgit v1.2.3 From 2b43470add8c8ff1e1ee28dffc5c5df97e955d09 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Bj=C3=B6rn=20T=C3=B6pel?= Date: Wed, 20 May 2020 21:20:53 +0200 Subject: xsk: Introduce AF_XDP buffer allocation API MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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 Signed-off-by: Maxim Mikityanskiy Signed-off-by: Alexei Starovoitov Link: https://lore.kernel.org/bpf/20200520192103.355233-6-bjorn.topel@gmail.com --- net/core/xdp.c | 14 ++++++++++---- 1 file changed, 10 insertions(+), 4 deletions(-) (limited to 'net/core/xdp.c') diff --git a/net/core/xdp.c b/net/core/xdp.c index 490b8f5fa8ee..f0ce8b195193 100644 --- a/net/core/xdp.c +++ b/net/core/xdp.c @@ -17,6 +17,7 @@ #include #include /* struct xdp_mem_allocator */ #include +#include #define REG_STATE_NEW 0x0 #define REG_STATE_REGISTERED 0x1 @@ -361,7 +362,7 @@ EXPORT_SYMBOL_GPL(xdp_rxq_info_reg_mem_model); * of xdp_frames/pages in those cases. */ static void __xdp_return(void *data, struct xdp_mem_info *mem, bool napi_direct, - unsigned long handle) + unsigned long handle, struct xdp_buff *xdp) { struct xdp_mem_allocator *xa; struct page *page; @@ -390,6 +391,11 @@ static void __xdp_return(void *data, struct xdp_mem_info *mem, bool napi_direct, xa = rhashtable_lookup(mem_id_ht, &mem->id, mem_id_rht_params); xa->zc_alloc->free(xa->zc_alloc, handle); rcu_read_unlock(); + break; + case MEM_TYPE_XSK_BUFF_POOL: + /* NB! Only valid from an xdp_buff! */ + xsk_buff_free(xdp); + break; default: /* Not possible, checked in xdp_rxq_info_reg_mem_model() */ break; @@ -398,19 +404,19 @@ static void __xdp_return(void *data, struct xdp_mem_info *mem, bool napi_direct, void xdp_return_frame(struct xdp_frame *xdpf) { - __xdp_return(xdpf->data, &xdpf->mem, false, 0); + __xdp_return(xdpf->data, &xdpf->mem, false, 0, NULL); } EXPORT_SYMBOL_GPL(xdp_return_frame); void xdp_return_frame_rx_napi(struct xdp_frame *xdpf) { - __xdp_return(xdpf->data, &xdpf->mem, true, 0); + __xdp_return(xdpf->data, &xdpf->mem, true, 0, NULL); } EXPORT_SYMBOL_GPL(xdp_return_frame_rx_napi); void xdp_return_buff(struct xdp_buff *xdp) { - __xdp_return(xdp->data, &xdp->rxq->mem, true, xdp->handle); + __xdp_return(xdp->data, &xdp->rxq->mem, true, xdp->handle, xdp); } EXPORT_SYMBOL_GPL(xdp_return_buff); -- cgit v1.2.3 From 0807892ecb35734b7ce6f7c29b078f1b60151c94 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Bj=C3=B6rn=20T=C3=B6pel?= Date: Wed, 20 May 2020 21:21:00 +0200 Subject: xsk: Remove MEM_TYPE_ZERO_COPY and corresponding code MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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 Signed-off-by: Alexei Starovoitov Link: https://lore.kernel.org/bpf/20200520192103.355233-13-bjorn.topel@gmail.com --- net/core/xdp.c | 42 +++++------------------------------------- 1 file changed, 5 insertions(+), 37 deletions(-) (limited to 'net/core/xdp.c') diff --git a/net/core/xdp.c b/net/core/xdp.c index f0ce8b195193..a8c2f243367d 100644 --- a/net/core/xdp.c +++ b/net/core/xdp.c @@ -110,27 +110,6 @@ static void mem_allocator_disconnect(void *allocator) mutex_unlock(&mem_id_lock); } -static void mem_id_disconnect(int id) -{ - struct xdp_mem_allocator *xa; - - mutex_lock(&mem_id_lock); - - xa = rhashtable_lookup_fast(mem_id_ht, &id, mem_id_rht_params); - if (!xa) { - mutex_unlock(&mem_id_lock); - WARN(1, "Request remove non-existing id(%d), driver bug?", id); - return; - } - - trace_mem_disconnect(xa); - - if (!rhashtable_remove_fast(mem_id_ht, &xa->node, mem_id_rht_params)) - call_rcu(&xa->rcu, __xdp_mem_allocator_rcu_free); - - mutex_unlock(&mem_id_lock); -} - void xdp_rxq_info_unreg_mem_model(struct xdp_rxq_info *xdp_rxq) { struct xdp_mem_allocator *xa; @@ -144,9 +123,6 @@ void xdp_rxq_info_unreg_mem_model(struct xdp_rxq_info *xdp_rxq) if (id == 0) return; - if (xdp_rxq->mem.type == MEM_TYPE_ZERO_COPY) - return mem_id_disconnect(id); - if (xdp_rxq->mem.type == MEM_TYPE_PAGE_POOL) { rcu_read_lock(); xa = rhashtable_lookup(mem_id_ht, &id, mem_id_rht_params); @@ -302,7 +278,7 @@ int xdp_rxq_info_reg_mem_model(struct xdp_rxq_info *xdp_rxq, xdp_rxq->mem.type = type; if (!allocator) { - if (type == MEM_TYPE_PAGE_POOL || type == MEM_TYPE_ZERO_COPY) + if (type == MEM_TYPE_PAGE_POOL) return -EINVAL; /* Setup time check page_pool req */ return 0; } @@ -362,7 +338,7 @@ EXPORT_SYMBOL_GPL(xdp_rxq_info_reg_mem_model); * of xdp_frames/pages in those cases. */ static void __xdp_return(void *data, struct xdp_mem_info *mem, bool napi_direct, - unsigned long handle, struct xdp_buff *xdp) + struct xdp_buff *xdp) { struct xdp_mem_allocator *xa; struct page *page; @@ -384,14 +360,6 @@ static void __xdp_return(void *data, struct xdp_mem_info *mem, bool napi_direct, page = virt_to_page(data); /* Assumes order0 page*/ put_page(page); break; - case MEM_TYPE_ZERO_COPY: - /* NB! Only valid from an xdp_buff! */ - rcu_read_lock(); - /* mem->id is valid, checked in xdp_rxq_info_reg_mem_model() */ - xa = rhashtable_lookup(mem_id_ht, &mem->id, mem_id_rht_params); - xa->zc_alloc->free(xa->zc_alloc, handle); - rcu_read_unlock(); - break; case MEM_TYPE_XSK_BUFF_POOL: /* NB! Only valid from an xdp_buff! */ xsk_buff_free(xdp); @@ -404,19 +372,19 @@ static void __xdp_return(void *data, struct xdp_mem_info *mem, bool napi_direct, void xdp_return_frame(struct xdp_frame *xdpf) { - __xdp_return(xdpf->data, &xdpf->mem, false, 0, NULL); + __xdp_return(xdpf->data, &xdpf->mem, false, NULL); } EXPORT_SYMBOL_GPL(xdp_return_frame); void xdp_return_frame_rx_napi(struct xdp_frame *xdpf) { - __xdp_return(xdpf->data, &xdpf->mem, true, 0, NULL); + __xdp_return(xdpf->data, &xdpf->mem, true, NULL); } EXPORT_SYMBOL_GPL(xdp_return_frame_rx_napi); void xdp_return_buff(struct xdp_buff *xdp) { - __xdp_return(xdp->data, &xdp->rxq->mem, true, xdp->handle, xdp); + __xdp_return(xdp->data, &xdp->rxq->mem, true, xdp); } EXPORT_SYMBOL_GPL(xdp_return_buff); -- cgit v1.2.3 From 82c41671ca4f597b6ff05bd5d118161deec26e07 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Bj=C3=B6rn=20T=C3=B6pel?= Date: Wed, 20 May 2020 21:21:01 +0200 Subject: xdp: Simplify xdp_return_{frame, frame_rx_napi, buff} MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The xdp_return_{frame,frame_rx_napi,buff} function are never used, except in xdp_convert_zc_to_xdp_frame(), by the MEM_TYPE_XSK_BUFF_POOL memory type. To simplify and reduce code, change so that xdp_convert_zc_to_xdp_frame() calls xsk_buff_free() directly since the type is know, and remove MEM_TYPE_XSK_BUFF_POOL from the switch statement in __xdp_return() function. Suggested-by: Maxim Mikityanskiy Signed-off-by: Björn Töpel Signed-off-by: Alexei Starovoitov Link: https://lore.kernel.org/bpf/20200520192103.355233-14-bjorn.topel@gmail.com --- net/core/xdp.c | 21 +++++++++------------ 1 file changed, 9 insertions(+), 12 deletions(-) (limited to 'net/core/xdp.c') diff --git a/net/core/xdp.c b/net/core/xdp.c index a8c2f243367d..90f44f382115 100644 --- a/net/core/xdp.c +++ b/net/core/xdp.c @@ -335,10 +335,11 @@ EXPORT_SYMBOL_GPL(xdp_rxq_info_reg_mem_model); * scenarios (e.g. queue full), it is possible to return the xdp_frame * while still leveraging this protection. The @napi_direct boolean * is used for those calls sites. Thus, allowing for faster recycling - * of xdp_frames/pages in those cases. + * of xdp_frames/pages in those cases. This path is never used by the + * MEM_TYPE_XSK_BUFF_POOL memory type, so it's explicitly not part of + * the switch-statement. */ -static void __xdp_return(void *data, struct xdp_mem_info *mem, bool napi_direct, - struct xdp_buff *xdp) +static void __xdp_return(void *data, struct xdp_mem_info *mem, bool napi_direct) { struct xdp_mem_allocator *xa; struct page *page; @@ -360,33 +361,29 @@ static void __xdp_return(void *data, struct xdp_mem_info *mem, bool napi_direct, page = virt_to_page(data); /* Assumes order0 page*/ put_page(page); break; - case MEM_TYPE_XSK_BUFF_POOL: - /* NB! Only valid from an xdp_buff! */ - xsk_buff_free(xdp); - break; default: /* Not possible, checked in xdp_rxq_info_reg_mem_model() */ + WARN(1, "Incorrect XDP memory type (%d) usage", mem->type); break; } } void xdp_return_frame(struct xdp_frame *xdpf) { - __xdp_return(xdpf->data, &xdpf->mem, false, NULL); + __xdp_return(xdpf->data, &xdpf->mem, false); } EXPORT_SYMBOL_GPL(xdp_return_frame); void xdp_return_frame_rx_napi(struct xdp_frame *xdpf) { - __xdp_return(xdpf->data, &xdpf->mem, true, NULL); + __xdp_return(xdpf->data, &xdpf->mem, true); } EXPORT_SYMBOL_GPL(xdp_return_frame_rx_napi); void xdp_return_buff(struct xdp_buff *xdp) { - __xdp_return(xdp->data, &xdp->rxq->mem, true, xdp); + __xdp_return(xdp->data, &xdp->rxq->mem, true); } -EXPORT_SYMBOL_GPL(xdp_return_buff); /* Only called for MEM_TYPE_PAGE_POOL see xdp.h */ void __xdp_release_frame(void *data, struct xdp_mem_info *mem) @@ -467,7 +464,7 @@ struct xdp_frame *xdp_convert_zc_to_xdp_frame(struct xdp_buff *xdp) xdpf->metasize = metasize; xdpf->mem.type = MEM_TYPE_PAGE_ORDER0; - xdp_return_buff(xdp); + xsk_buff_free(xdp); return xdpf; } EXPORT_SYMBOL_GPL(xdp_convert_zc_to_xdp_frame); -- cgit v1.2.3