lib: dhry: fix sleeping allocations inside non-preemptable section

The Smatch static checker reports the following warnings:

    lib/dhry_run.c:38 dhry_benchmark() warn: sleeping in atomic context
    lib/dhry_run.c:43 dhry_benchmark() warn: sleeping in atomic context

Indeed, dhry() does sleeping allocations inside the non-preemptable
section delimited by get_cpu()/put_cpu().

Fix this by using atomic allocations instead.
Add error handling, as atomic these allocations may fail.

Link: https://lkml.kernel.org/r/bac6d517818a7cd8efe217c1ad649fffab9cc371.1688568764.git.geert+renesas@glider.be
Fixes: 13684e9 ("lib: dhry: fix unstable smp_processor_id(_) usage")
Reported-by: Dan Carpenter <[email protected]>
Closes: https://lore.kernel.org/r/[email protected]
Signed-off-by: Geert Uytterhoeven <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

Author: geertu

lib/dhry_1.c

@@ -139,8 +139,15 @@ int dhry(int n)
 
 	/* Initializations */
 
-	Next_Ptr_Glob = (Rec_Pointer)kzalloc(sizeof(Rec_Type), GFP_KERNEL);
-	Ptr_Glob = (Rec_Pointer)kzalloc(sizeof(Rec_Type), GFP_KERNEL);
+	Next_Ptr_Glob = (Rec_Pointer)kzalloc(sizeof(Rec_Type), GFP_ATOMIC);
+	if (!Next_Ptr_Glob)
+		return -ENOMEM;
+
+	Ptr_Glob = (Rec_Pointer)kzalloc(sizeof(Rec_Type), GFP_ATOMIC);
+	if (!Ptr_Glob) {
+		kfree(Next_Ptr_Glob);
+		return -ENOMEM;
+	}
 
 	Ptr_Glob->Ptr_Comp = Next_Ptr_Glob;
 	Ptr_Glob->Discr = Ident_1;