checkpatch: add qemu_bh_new/aio_bh_new checks

Advise authors to use the _guarded versions of the APIs, instead.

Signed-off-by: Alexander Bulekov <alxndr@bu.edu>
Reviewed-by: Darren Kenny <darren.kenny@oracle.com>
Message-Id: <20230427211013.2994127-4-alxndr@bu.edu>
Signed-off-by: Thomas Huth <thuth@redhat.com>

scripts/checkpatch.pl

@@ -2865,6 +2865,14 @@ sub process {
 		if ($line =~ /\bsignal\s*\(/ && !($line =~ /SIG_(?:IGN|DFL)/)) {
 			ERROR("use sigaction to establish signal handlers; signal is not portable\n" . $herecurr);
 		}
+# recommend qemu_bh_new_guarded instead of qemu_bh_new
+        if ($realfile =~ /.*\/hw\/.*/ && $line =~ /\bqemu_bh_new\s*\(/) {
+			ERROR("use qemu_bh_new_guarded() instead of qemu_bh_new() to avoid reentrancy problems\n" . $herecurr);
+		}
+# recommend aio_bh_new_guarded instead of aio_bh_new
+        if ($realfile =~ /.*\/hw\/.*/ && $line =~ /\baio_bh_new\s*\(/) {
+			ERROR("use aio_bh_new_guarded() instead of aio_bh_new() to avoid reentrancy problems\n" . $herecurr);
+		}
 # check for module_init(), use category-specific init macros explicitly please
 		if ($line =~ /^module_init\s*\(/) {
 			ERROR("please use block_init(), type_init() etc. instead of module_init()\n" . $herecurr);