scripts/specialize-patch: Rebuild filtered hunks

scripts/specialize-patch

@@ -613,21 +613,48 @@ function reset_hunk_state_variables() {
 function dump_lines() {
   # Detect empty hunks
   first_modif = -1
+  last_modif = -1
   for (i = 0; i < lines; i++)
   {
     if (line[i] ~ "^[+-]")
     {
-      first_modif = i
-      break
+      if (first_modif < 0)
+        first_modif = i
+      last_modif = i
     }
   }
 
   # Dump line[] as a hunk, but only if the hunk is not empty.
   if (first_modif >= 0)
   {
-    if (h[0] != "")
-      printf "@@ -%d,%d +%d,%d @@%s\n",h[1],h[2]-lines_less_deleted,h[3],h[4]-lines_less_added,h[5]
-    for (i = 0; i < lines; i++) {
+    # Restore standard unified diff context after discarding added lines.
+    first_line = first_modif > context_lines ? first_modif - context_lines : 0
+    last_line = last_modif + context_lines < lines ? \
+      last_modif + context_lines : lines - 1
+
+    if (h[0] != "") {
+      old_start = h[1]
+      new_start = h[3] + new_line_adjustment
+      for (i = 0; i < first_line; i++) {
+        if (line[i] !~ "^\\+" && line[i] !~ "^\\\\")
+          old_start++
+        if (line[i] !~ "^-" && line[i] !~ "^\\\\")
+          new_start++
+      }
+
+      old_count = 0
+      new_count = 0
+      for (i = first_line; i <= last_line; i++) {
+        if (line[i] !~ "^\\+" && line[i] !~ "^\\\\")
+          old_count++
+        if (line[i] !~ "^-" && line[i] !~ "^\\\\")
+          new_count++
+      }
+
+      printf "@@ -%d,%d +%d,%d @@%s\n", old_start, old_count, \
+        new_start, new_count, h[5]
+    }
+    for (i = first_line; i <= last_line; i++) {
       modifier = (LINUX_VERSION_CODE < version_code("4.19.0") &&
                   (RHEL_MAJOR == "" ||
                    RHEL_MAJOR * 256 + RHEL_MINOR < 7 * 256 + 7 ||
@@ -638,6 +665,9 @@ function dump_lines() {
       print line[i]
     }
   }
+
+  if (h[0] != "")
+    new_line_adjustment += lines_less_deleted - lines_less_added
 }
 
 BEGIN {
@@ -660,18 +690,21 @@ BEGIN {
   if (config_tcp_zero_copy_transfer_completion_notification_undefined != 0 && config_tcp_zero_copy_transfer_completion_notification_undefined != 1)
     config_tcp_zero_copy_transfer_completion_notification_undefined = 0
   # Variable initialization.
+  context_lines = 3
   process_file = 0
   reset_hunk_state_variables()
 }
 
 
 {
   if (match($0, "^diff[ \t]+[^ \t]+[ \t]+[^ \t]+[ \t]+([^ \t]+)$", filename) \
+      || match($0, "^---[ \t]+([^ \t]+)[ \t]+", filename) \
       || match($0, "^\\+\\+\\+[ \t]+([^ \t]+)[ \t]+", filename))
   {
     # Start of new file.
     dump_lines()
     reset_hunk_state_variables()
+    new_line_adjustment = 0
     process_file = match(filename[1], "\\.[ch]$") != 0 &&
       match(filename[1], "drivers/scsi/qla2xxx/") == 0
   }

scripts/test-specialize-patch

@@ -0,0 +1,116 @@
+#!/bin/bash
+
+set -euo pipefail
+
+script_dir="$(cd -- "$(dirname -- "${BASH_SOURCE[0]}")" && pwd)"
+scst_dir="$(dirname -- "$script_dir")"
+test_dir="$(mktemp -d)"
+
+trap 'rm -rf -- "$test_dir"' EXIT
+
+mkdir -p "$test_dir/orig"
+
+cat > "$test_dir/orig/qla.h" <<'EOF'
+/* SPDX-License-Identifier: GPL-2.0 */
+#if !defined(_TRACE_QLA_H_) || defined(TRACE_HEADER_MULTI_READ)
+#define _TRACE_QLA_H_
+
+#include <linux/tracepoint.h>
+
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM qla
+
+#define QLA_MSG_MAX 256
+
+#pragma GCC diagnostic push
+#ifndef __clang__
+#pragma GCC diagnostic ignored "-Wsuggest-attribute=format"
+#endif
+
+DECLARE_EVENT_CLASS(qla_log_event,
+	TP_PROTO(const char *buf,
+		struct va_format *vaf),
+
+	TP_ARGS(buf, vaf),
+
+	TP_STRUCT__entry(
+		__string(buf, buf)
+		__vstring(msg, vaf->fmt, vaf->va)
+	),
+	TP_fast_assign(
+		__assign_str(buf);
+		__assign_vstr(msg, vaf->fmt, vaf->va);
+	),
+
+	TP_printk("%s %s", __get_str(buf), __get_str(msg))
+);
+
+#pragma GCC diagnostic pop
+
+DEFINE_EVENT(qla_log_event, ql_dbg_log,
+	TP_PROTO(const char *buf, struct va_format *vaf),
+	TP_ARGS(buf, vaf)
+);
+
+#endif /* _TRACE_QLA_H */
+
+#define TRACE_INCLUDE_FILE qla
+
+#include <trace/define_trace.h>
+EOF
+
+if diff -up "$test_dir/orig/qla.h" \
+  "$scst_dir/qla2x00t-32gbit/include/trace/events/qla.h" \
+  > "$test_dir/qla.raw.patch"; then
+  echo "Error: qla.h test inputs do not differ." >&2
+  exit 1
+else
+  diff_status=$?
+  if [ "$diff_status" -gt 1 ]; then
+    exit "$diff_status"
+  fi
+fi
+
+for kernel_version in 7.1 7.2; do
+  mkdir -p "$test_dir/linux-$kernel_version/include/trace/events"
+  cp "$test_dir/orig/qla.h" \
+    "$test_dir/linux-$kernel_version/include/trace/events/qla.h"
+
+  sed -e "s:^--- [^ ]*:--- linux-$kernel_version/include/trace/events/qla.h:" \
+    -e "s:^+++ [^ ]*:+++ linux-$kernel_version/include/trace/events/qla.h:" \
+    < "$test_dir/qla.raw.patch" > "$test_dir/qla-$kernel_version.patch"
+
+  cat >> "$test_dir/qla-$kernel_version.patch" <<EOF
+--- linux-$kernel_version/drivers/scst/next.c 2026-08-26 00:00:00.000000000 +0300
++++ linux-$kernel_version/drivers/scst/next.c 2026-08-26 00:00:00.000000000 +0300
+@@ -1,1 +1,1 @@
+-old
++new
+EOF
+
+  mkdir -p "$test_dir/linux-$kernel_version/drivers/scst"
+  echo old > "$test_dir/linux-$kernel_version/drivers/scst/next.c"
+
+  "$script_dir/specialize-patch" -v delete_disabled_code=1 \
+    -v kernel_version="$kernel_version" -v SCST_IO_CONTEXT=0 \
+    < "$test_dir/qla-$kernel_version.patch" \
+    > "$test_dir/qla-$kernel_version.specialized.patch"
+
+  grep -qF '@@ -9,8 +9,8 @@' \
+    "$test_dir/qla-$kernel_version.specialized.patch"
+  grep -qF '@@ -32,13 +32,15 @@' \
+    "$test_dir/qla-$kernel_version.specialized.patch"
+
+  patch --dry-run -f -s -p0 -d "$test_dir" \
+    < "$test_dir/qla-$kernel_version.specialized.patch"
+
+  "$script_dir/specialize-patch" -v blank_deleted_code=1 \
+    -v kernel_version="$kernel_version" -v SCST_IO_CONTEXT=0 \
+    < "$test_dir/qla-$kernel_version.patch" \
+    > "$test_dir/qla-$kernel_version.specialized-n.patch"
+
+  patch --dry-run -f -s -p0 -d "$test_dir" \
+    < "$test_dir/qla-$kernel_version.specialized-n.patch"
+done
+
+echo "specialize-patch qla.h regression: PASS"