From 5febf432df1cfa5b25d99b54c32103fafbdd0eb9 Mon Sep 17 00:00:00 2001 From: Miguel Ojeda Date: Sun, 16 Aug 2026 15:32:33 +0200 Subject: kbuild: rust: keep Rust objects out of Clang LTO with inline helpers Under `CONFIG_LTO_CLANG` + `CONFIG_RUST_INLINE_HELPERS`, one may hit `objtool` errors such as: vmlinux.o: error: objtool: _R..._3Gsp4boot+0xd6a: can't find jump dest instruction at .text._R..._3Gsp4boot+0x1dfd The reason is that in such builds, the Clang invocation that compiles the combined Rust plus helpers bitcode emits LLVM bitcode (again) -- the final code generation happens in the linker's LTO step, which the `-mllvm` trap options passed to Clang do not reach. This, in turn, means that unreachable traps are missing, and the impossible paths do not merely fallthrough to the next symbol, but past the end of their own section, since LTO builds place each function in its own section. Thus filter `CC_FLAGS_LTO` out of the Clang invocation, so that it always emits machine code directly, with the traps in place. Assisted-by: LLM Cc: Gary Guo Cc: Boqun Feng Cc: Alice Ryhl Cc: Matthew Maurer Cc: Josh Poimboeuf Cc: Peter Zijlstra Cc: stable@vger.kernel.org Fixes: 3a2486cc1da5 ("kbuild: rust: provide an option to inline C helpers into Rust") Acked-by: Gary Guo Link: https://patch.msgid.link/20260816133233.197500-2-ojeda@kernel.org Signed-off-by: Miguel Ojeda --- net/ceph/msgpool.c | 94 ++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 94 insertions(+) create mode 100644 net/ceph/msgpool.c (limited to 'net/ceph/msgpool.c') diff --git a/net/ceph/msgpool.c b/net/ceph/msgpool.c new file mode 100644 index 000000000..e3ecb80cd --- /dev/null +++ b/net/ceph/msgpool.c @@ -0,0 +1,94 @@ +// SPDX-License-Identifier: GPL-2.0 +#include + +#include +#include +#include +#include + +#include +#include + +static void *msgpool_alloc(gfp_t gfp_mask, void *arg) +{ + struct ceph_msgpool *pool = arg; + struct ceph_msg *msg; + + msg = ceph_msg_new2(pool->type, pool->front_len, pool->max_data_items, + gfp_mask, true); + if (!msg) { + dout("msgpool_alloc %s failed\n", pool->name); + } else { + dout("msgpool_alloc %s %p\n", pool->name, msg); + msg->pool = pool; + } + return msg; +} + +static void msgpool_free(void *element, void *arg) +{ + struct ceph_msgpool *pool = arg; + struct ceph_msg *msg = element; + + dout("msgpool_release %s %p\n", pool->name, msg); + msg->pool = NULL; + ceph_msg_put(msg); +} + +int ceph_msgpool_init(struct ceph_msgpool *pool, int type, + int front_len, int max_data_items, int size, + const char *name) +{ + dout("msgpool %s init\n", name); + pool->type = type; + pool->front_len = front_len; + pool->max_data_items = max_data_items; + pool->pool = mempool_create(size, msgpool_alloc, msgpool_free, pool); + if (!pool->pool) + return -ENOMEM; + pool->name = name; + return 0; +} + +void ceph_msgpool_destroy(struct ceph_msgpool *pool) +{ + dout("msgpool %s destroy\n", pool->name); + mempool_destroy(pool->pool); +} + +struct ceph_msg *ceph_msgpool_get(struct ceph_msgpool *pool, int front_len, + int max_data_items) +{ + struct ceph_msg *msg; + + if (front_len > pool->front_len || + max_data_items > pool->max_data_items) { + pr_warn_ratelimited("%s need %d/%d, pool %s has %d/%d\n", + __func__, front_len, max_data_items, pool->name, + pool->front_len, pool->max_data_items); + WARN_ON_ONCE(1); + + /* try to alloc a fresh message */ + return ceph_msg_new2(pool->type, front_len, max_data_items, + GFP_NOFS, false); + } + + msg = mempool_alloc(pool->pool, GFP_NOFS); + dout("msgpool_get %s %p\n", pool->name, msg); + return msg; +} + +void ceph_msgpool_put(struct ceph_msgpool *pool, struct ceph_msg *msg) +{ + dout("msgpool_put %s %p\n", pool->name, msg); + + /* reset msg front_len; user may have changed it */ + msg->front.iov_len = pool->front_len; + msg->hdr.front_len = cpu_to_le32(pool->front_len); + + msg->data_length = 0; + msg->num_data_items = 0; + + kref_init(&msg->kref); /* retake single ref */ + mempool_free(msg, pool->pool); +} -- cgit v1.3.1