From 4ce3a5fa21bc1ecda7b833a0f8fb05cdcd6d3a67 Mon Sep 17 00:00:00 2001
From: Robert Morris <rtm@csail.mit.edu>
Date: Sun, 7 Jul 2019 14:57:16 -0400
Subject: [PATCH] nits

---
 kernel/proc.c | 21 +++++++++++----------
 1 file changed, 11 insertions(+), 10 deletions(-)

diff --git a/kernel/proc.c b/kernel/proc.c
index cfb3262..44bacc2 100644
--- a/kernel/proc.c
+++ b/kernel/proc.c
@@ -76,8 +76,9 @@ allocpid() {
 
 //PAGEBREAK: 32
 // Look in the process table for an UNUSED proc.
-// If found, change state to EMBRYO and initialize
-// state required to run in the kernel.
+// If found, change state to EMBRYO, initialize
+// state required to run in the kernel,
+// and return with p->lock held.
 // Otherwise return 0.
 static struct proc*
 allocproc(void)
@@ -124,7 +125,7 @@ found:
 
 // free a proc structure and the data hanging from it,
 // including user pages.
-// the proc lock must be held.
+// p->lock must be held.
 static void
 freeproc(struct proc *p)
 {
@@ -259,6 +260,7 @@ fork(void)
   // Copy user memory from parent to child.
   if(uvmcopy(p->pagetable, np->pagetable, p->sz) < 0){
     freeproc(np);
+    release(&np->lock);
     return -1;
   }
   np->sz = p->sz;
@@ -290,9 +292,10 @@ fork(void)
 
 // Pass p's abandoned children to init. p and p's parent
 // are locked.
-void reparent(struct proc *p, struct proc *parent) {
+void
+reparent(struct proc *p, struct proc *parent) {
   struct proc *pp;
-  int init_is_my_parent = (p->parent == initproc);
+  int child_of_init = (p->parent == initproc);
 
   for(pp = ptable.proc; pp < &ptable.proc[NPROC]; pp++){
     if (pp != p && pp != parent) {
@@ -300,10 +303,10 @@ void reparent(struct proc *p, struct proc *parent) {
       if(pp->parent == p){
         pp->parent = initproc;
         if(pp->state == ZOMBIE) {
-          if(!init_is_my_parent)
+          if(!child_of_init)
             acquire(&initproc->lock);
           wakeup1(initproc);
-          if(!init_is_my_parent)
+          if(!child_of_init)
             release(&initproc->lock);
         }
       }
@@ -431,10 +434,8 @@ scheduler(void)
         // Process is done running for now.
         // It should have changed its p->state before coming back.
         c->proc = 0;
-        release(&p->lock);
-      } else {
-        release(&p->lock);
       }
+      release(&p->lock);
     }
   }
 }