diff options
| -rw-r--r-- | kernel/proc.c | 21 |
1 files 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); } } } |