scftorture: Count single_rpc offline failures in statistics outputgrafted

scf_torture_stats_print() aggregates each invoker thread's counters
into a local scf_statistics structure before printing, but the
n_single_rpc_ofl field is missing from the aggregation loop.  As a
result, the "single_rpc_ofl" value printed in the statistics line is
always zero, even when smp_call_function_single() invocations for the
RPC test have failed due to offline CPUs and been counted by the
invoker threads.

Add the missing accumulation so that the printed value reflects the
actual counts.

Signed-off-by: Joel Fernandes <joelagnelf@nvidia.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>

1 files changed, 209 insertions, 0 deletions

diff --git a/fs/smb/server/compress.c b/fs/smb/server/compress.c
new file mode 100644
index 000000000..f8cf515b9
--- /dev/null
+++ b/fs/smb/server/compress.c
@@ -0,0 +1,209 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * SMB2 compression support for ksmbd.
+ *
+ * Receive and send SMB 3.1.1 compression transforms using the common helpers.
+ *
+ * Copyright (C) 2026 Namjae Jeon <linkinjeon@kernel.org>
+ */
+#include <linux/slab.h>
+
+#include "compress.h"
+#include "smb_common.h"
+#include "../common/compress/lz77.h"
+
+#define SMB_COMPRESS_MIN_LEN	PAGE_SIZE
+
+/**
+ * ksmbd_decompress_request() - replace a compressed request with its SMB2 PDU
+ * @conn: connection which owns the current RFC1002 request buffer
+ *
+ * Derive the uncompressed size from the transform variant, enforce ksmbd's
+ * normal message limits, and ask the common decoder to validate every payload.
+ * On success, replace conn->request_buf with a regular RFC1002-framed SMB2
+ * message so the rest of the request path needs no compression awareness.
+ *
+ * Return: 0 on success, otherwise a negative errno.
+ */
+int ksmbd_decompress_request(struct ksmbd_conn *conn)
+{
+	struct smb2_compression_hdr *hdr;
+	unsigned int pdu_size = get_rfc1002_len(conn->request_buf);
+	u32 orig_size, offset, out_size;
+	u32 max_allowed_pdu_size;
+	char *buf, *out;
+	int rc;
+
+	if (pdu_size < sizeof(struct smb2_compression_hdr))
+		return -EINVAL;
+
+	if (conn->dialect != SMB311_PROT_ID ||
+	    conn->compress_algorithm == SMB3_COMPRESS_NONE)
+		return -EINVAL;
+
+	hdr = smb_get_msg(conn->request_buf);
+	if (hdr->ProtocolId != SMB2_COMPRESSION_TRANSFORM_ID)
+		return -EINVAL;
+
+	orig_size = le32_to_cpu(hdr->OriginalCompressedSegmentSize);
+	if (hdr->Flags == cpu_to_le16(SMB2_COMPRESSION_FLAG_CHAINED)) {
+		out_size = orig_size;
+	} else {
+		offset = le32_to_cpu(hdr->Offset);
+		if (offset > pdu_size - sizeof(*hdr) ||
+		    check_add_overflow(orig_size, offset, &out_size))
+			return -EINVAL;
+	}
+
+	max_allowed_pdu_size = SMB3_MAX_MSGSIZE + conn->vals->max_write_size;
+	if (out_size > max_allowed_pdu_size ||
+	    out_size > MAX_STREAM_PROT_LEN)
+		return -EINVAL;
+
+	out = kvmalloc(out_size + 4 + 1, KSMBD_DEFAULT_GFP);
+	if (!out)
+		return -ENOMEM;
+
+	buf = (char *)hdr;
+	*(__be32 *)out = cpu_to_be32(out_size);
+	rc = smb_compression_decompress(conn->compress_algorithm,
+					conn->compress_chained,
+					buf, pdu_size, out + 4, out_size);
+	if (rc) {
+		kvfree(out);
+		return rc;
+	}
+
+	kvfree(conn->request_buf);
+	conn->request_buf = out;
+	return 0;
+}
+
+/**
+ * ksmbd_compress_response() - compress an eligible ksmbd response
+ * @work: request work item containing the response iov
+ *
+ * Compression transforms describe one contiguous SMB2 message, while ksmbd
+ * builds responses from multiple iov entries. Flatten the response first,
+ * produce the negotiated transform, and replace the response iov only when the
+ * result is smaller than the original message.
+ *
+ * Encrypted and compound responses are intentionally left unchanged. The
+ * caller may still continue sending the original response when this function
+ * returns zero.
+ *
+ * Return: 1 if the response was replaced, 0 if compression was skipped, or a
+ * negative errno on failure.
+ */
+int ksmbd_compress_response(struct ksmbd_work *work)
+{
+	struct smb2_compression_hdr *chdr;
+	struct smb2_hdr *req_hdr;
+	u32 src_len, dst_len, compressed_pdu_len, max_dst_len;
+	u8 *src = NULL, *out = NULL, *p;
+	int i, rc;
+
+	if (!work->compress_response || work->encrypted ||
+	    work->conn->compress_algorithm != SMB3_COMPRESS_LZ77)
+		return 0;
+
+	req_hdr = smb_get_msg(work->request_buf);
+	if (req_hdr->NextCommand || work->next_smb2_rcv_hdr_off ||
+	    work->next_smb2_rsp_hdr_off)
+		return 0;
+
+	src_len = get_rfc1002_len(work->iov[0].iov_base);
+	if (src_len < SMB_COMPRESS_MIN_LEN)
+		return 0;
+
+	src = kvmalloc(src_len, KSMBD_DEFAULT_GFP);
+	if (!src)
+		return -ENOMEM;
+
+	p = src;
+	/* iov[0] contains only the RFC1002 length; the SMB2 PDU starts at iov[1]. */
+	for (i = 1; i < work->iov_cnt; i++) {
+		if (work->iov[i].iov_len > src + src_len - p) {
+			rc = -EINVAL;
+			goto out;
+		}
+		memcpy(p, work->iov[i].iov_base, work->iov[i].iov_len);
+		p += work->iov[i].iov_len;
+	}
+	if (p != src + src_len) {
+		rc = -EINVAL;
+		goto out;
+	}
+
+	max_dst_len = smb_lz77_compressed_alloc_size(src_len) +
+		sizeof(struct smb2_compression_hdr) +
+		3 * sizeof(struct smb2_compression_payload_hdr) +
+		2 * sizeof(struct smb2_compression_pattern_v1);
+	out = kvzalloc(sizeof(__be32) + max_dst_len,
+		       KSMBD_DEFAULT_GFP);
+	if (!out) {
+		rc = -ENOMEM;
+		goto out;
+	}
+
+	if (work->conn->compress_chained) {
+		dst_len = max_dst_len;
+		rc = smb_compression_compress_chained(SMB3_COMPRESS_LZ77,
+						      work->conn->compress_pattern,
+						      src, src_len,
+						      out + sizeof(__be32),
+						      &dst_len);
+		if (rc == -EMSGSIZE || dst_len >= src_len) {
+			rc = 0;
+			goto out;
+		}
+		if (rc)
+			goto out;
+		compressed_pdu_len = dst_len;
+	} else {
+		/*
+		 * Peers which did not negotiate chained compression still use
+		 * the original 16-byte unchained transform format.
+		 */
+		dst_len = smb_lz77_compressed_alloc_size(src_len);
+		rc = smb_lz77_compress(src, src_len,
+				       out + sizeof(__be32) + sizeof(*chdr),
+				       &dst_len);
+		if (rc == -EMSGSIZE ||
+		    dst_len + sizeof(*chdr) >= src_len) {
+			rc = 0;
+			goto out;
+		}
+		if (rc)
+			goto out;
+
+		compressed_pdu_len = sizeof(*chdr) + dst_len;
+		chdr = (struct smb2_compression_hdr *)(out + sizeof(__be32));
+		chdr->ProtocolId = SMB2_COMPRESSION_TRANSFORM_ID;
+		chdr->OriginalCompressedSegmentSize = cpu_to_le32(src_len);
+		chdr->CompressionAlgorithm = SMB3_COMPRESS_LZ77;
+		chdr->Flags = cpu_to_le16(SMB2_COMPRESSION_FLAG_NONE);
+		chdr->Offset = 0;
+	}
+
+	*(__be32 *)out = cpu_to_be32(compressed_pdu_len);
+
+	/*
+	 * Keep the transform in work->compress_buf until send completion.
+	 * Existing response iovs can then be replaced without changing their
+	 * individual ownership rules.
+	 */
+	work->compress_buf = out;
+	work->iov[0].iov_base = out;
+	work->iov[0].iov_len = sizeof(__be32);
+	work->iov[1].iov_base = out + sizeof(__be32);
+	work->iov[1].iov_len = compressed_pdu_len;
+	work->iov_cnt = 2;
+	work->iov_idx = 1;
+	out = NULL;
+	rc = 1;
+out:
+	kvfree(out);
+	kvfree(src);
+	return rc;
+}