[PATCH] m68k: sys_ptrace cleanup

- create helper function singlestep_disable()
- move variable definitions to the top of the function
- use "out_eio" label as common error destination
- don't clear failure value for PTRACE_SETREGS/PTRACE_GETREGS

Signed-off-by: Roman Zippel <zippel@linux-m68k.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 64 insertions, 111 deletions

diff --git a/arch/m68k/kernel/ptrace.c b/arch/m68k/kernel/ptrace.c
index 9bb25ea78677..8ed1b01a6a87 100644
--- a/arch/m68k/kernel/ptrace.c
+++ b/arch/m68k/kernel/ptrace.c
@@ -103,48 +103,56 @@ static inline int put_reg(struct task_struct *task, int regno,
 }
 
 /*
- * Called by kernel/ptrace.c when detaching..
- *
  * Make sure the single step bit is not set.
  */
-void ptrace_disable(struct task_struct *child)
+static inline void singlestep_disable(struct task_struct *child)
 {
-        unsigned long tmp;
-        /* make sure the single step bit is not set. */
-        tmp = get_reg(child, PT_SR) & ~(TRACE_BITS << 16);
+        unsigned long tmp = get_reg(child, PT_SR) & ~(TRACE_BITS << 16);
         put_reg(child, PT_SR, tmp);
         child->thread.work.delayed_trace = 0;
+}
+
+/*
+ * Called by kernel/ptrace.c when detaching..
+ */
+void ptrace_disable(struct task_struct *child)
+{
+        singlestep_disable(child);
         child->thread.work.syscall_trace = 0;
 }
 
 asmlinkage int sys_ptrace(long request, long pid, long addr, long data)
 {
         struct task_struct *child;
-        int ret;
+        unsigned long tmp;
+        int i, ret = 0;
 
         lock_kernel();
-        ret = -EPERM;
         if (request == PTRACE_TRACEME) {
                 /* are we already being traced? */
-                if (current->ptrace & PT_PTRACED)
+                if (current->ptrace & PT_PTRACED) {
+                        ret = -EPERM;
                         goto out;
+                }
                 /* set the ptrace bit in the process flags. */
                 current->ptrace |= PT_PTRACED;
-                ret = 0;
                 goto out;
         }
-        ret = -ESRCH;
         read_lock(&tasklist_lock);
         child = find_task_by_pid(pid);
         if (child)
                 get_task_struct(child);
         read_unlock(&tasklist_lock);
-        if (!child)
+        if (unlikely(!child)) {
+                ret = -ESRCH;
                 goto out;
+        }
 
-        ret = -EPERM;
-        if (pid == 1)           /* you may not mess with init */
+        /* you may not mess with init */
+        if (unlikely(pid == 1)) {
+                ret = -EPERM;
                 goto out_tsk;
+        }
 
         if (request == PTRACE_ATTACH) {
                 ret = ptrace_attach(child);
@@ -152,86 +160,62 @@ asmlinkage int sys_ptrace(long request, long pid, long addr, long data)
         }
 
         ret = ptrace_check_attach(child, request == PTRACE_KILL);
-        if (ret < 0)
+        if (ret)
                 goto out_tsk;
 
         switch (request) {
         /* when I and D space are separate, these will need to be fixed. */
         case PTRACE_PEEKTEXT:   /* read word at location addr. */
-        case PTRACE_PEEKDATA: {
-                unsigned long tmp;
-                int copied;
-
-                copied = access_process_vm(child, addr, &tmp, sizeof(tmp), 0);
-                ret = -EIO;
-                if (copied != sizeof(tmp))
-                        break;
+        case PTRACE_PEEKDATA:
+                i = access_process_vm(child, addr, &tmp, sizeof(tmp), 0);
+                if (i != sizeof(tmp))
+                        goto out_eio;
                 ret = put_user(tmp, (unsigned long *)data);
                 break;
-        }
 
         /* read the word at location addr in the USER area. */
-        case PTRACE_PEEKUSR: {
-                unsigned long tmp;
-
-                ret = -EIO;
-                if ((addr & 3) || addr < 0 ||
-                    addr > sizeof(struct user) - 3)
-                        break;
+        case PTRACE_PEEKUSR:
+                if (addr & 3)
+                        goto out_eio;
+                addr >>= 2;     /* temporary hack. */
 
-                tmp = 0;  /* Default return condition */
-                addr = addr >> 2; /* temporary hack. */
-                ret = -EIO;
-                if (addr < 19) {
+                if (addr >= 0 && addr < 19) {
                         tmp = get_reg(child, addr);
                         if (addr == PT_SR)
                                 tmp >>= 16;
                 } else if (addr >= 21 && addr < 49) {
                         tmp = child->thread.fp[addr - 21];
-#ifdef CONFIG_M68KFPU_EMU
                         /* Convert internal fpu reg representation
                          * into long double format
                          */
                         if (FPU_IS_EMU && (addr < 45) && !(addr % 3))
                                 tmp = ((tmp & 0xffff0000) << 15) |
                                       ((tmp & 0x0000ffff) << 16);
-#endif
                 } else
                         break;
                 ret = put_user(tmp, (unsigned long *)data);
                 break;
-        }
 
         /* when I and D space are separate, this will have to be fixed. */
         case PTRACE_POKETEXT:   /* write the word at location addr. */
         case PTRACE_POKEDATA:
-                ret = 0;
-                if (access_process_vm(child, addr, &data, sizeof(data), 1) == sizeof(data))
-                        break;
-                ret = -EIO;
+                if (access_process_vm(child, addr, &data, sizeof(data), 1) != sizeof(data))
+                        goto out_eio;
                 break;
 
         case PTRACE_POKEUSR:    /* write the word at location addr in the USER area */
-                ret = -EIO;
-                if ((addr & 3) || addr < 0 ||
-                    addr > sizeof(struct user) - 3)
-                        break;
-
-                addr = addr >> 2; /* temporary hack. */
+                if (addr & 3)
+                        goto out_eio;
+                addr >>= 2;     /* temporary hack. */
 
                 if (addr == PT_SR) {
                         data &= SR_MASK;
                         data <<= 16;
                         data |= get_reg(child, PT_SR) & ~(SR_MASK << 16);
-                }
-                if (addr < 19) {
+                } else if (addr >= 0 && addr < 19) {
                         if (put_reg(child, addr, data))
-                                break;
-                        ret = 0;
-                        break;
-                }
-                if (addr >= 21 && addr < 48) {
-#ifdef CONFIG_M68KFPU_EMU
+                                goto out_eio;
+                } else if (addr >= 21 && addr < 48) {
                         /* Convert long double format
                          * into internal fpu reg representation
                          */
@@ -240,60 +224,42 @@ asmlinkage int sys_ptrace(long request, long pid, long addr, long data)
                                 data = (data & 0xffff0000) |
                                        ((data & 0x0000ffff) >> 1);
                         }
-#endif
                         child->thread.fp[addr - 21] = data;
-                        ret = 0;
-                }
+                } else
+                        goto out_eio;
                 break;
 
         case PTRACE_SYSCALL:    /* continue and stop at next (return from) syscall */
-        case PTRACE_CONT: {     /* restart after signal. */
-                long tmp;
-
-                ret = -EIO;
+        case PTRACE_CONT:       /* restart after signal. */
                 if (!valid_signal(data))
-                        break;
-                if (request == PTRACE_SYSCALL) {
+                        goto out_eio;
+
+                if (request == PTRACE_SYSCALL)
                         child->thread.work.syscall_trace = ~0;
-                } else {
+                else
                         child->thread.work.syscall_trace = 0;
-                }
                 child->exit_code = data;
-                /* make sure the single step bit is not set. */
-                tmp = get_reg(child, PT_SR) & ~(TRACE_BITS << 16);
-                put_reg(child, PT_SR, tmp);
-                child->thread.work.delayed_trace = 0;
+                singlestep_disable(child);
                 wake_up_process(child);
-                ret = 0;
                 break;
-        }
 
         /*
          * make the child exit.  Best I can do is send it a sigkill.
          * perhaps it should be put in the status that it wants to
          * exit.
          */
-        case PTRACE_KILL: {
-                long tmp;
-
-                ret = 0;
+        case PTRACE_KILL:
                 if (child->exit_state == EXIT_ZOMBIE) /* already dead */
                         break;
                 child->exit_code = SIGKILL;
-                /* make sure the single step bit is not set. */
-                tmp = get_reg(child, PT_SR) & ~(TRACE_BITS << 16);
-                put_reg(child, PT_SR, tmp);
-                child->thread.work.delayed_trace = 0;
+                singlestep_disable(child);
                 wake_up_process(child);
                 break;
-        }
-
-        case PTRACE_SINGLESTEP: {  /* set the trap flag. */
-                long tmp;
 
-                ret = -EIO;
+        case PTRACE_SINGLESTEP: /* set the trap flag. */
                 if (!valid_signal(data))
-                        break;
+                        goto out_eio;
+
                 child->thread.work.syscall_trace = 0;
                 tmp = get_reg(child, PT_SR) | (TRACE_BITS << 16);
                 put_reg(child, PT_SR, tmp);
@@ -302,39 +268,29 @@ asmlinkage int sys_ptrace(long request, long pid, long addr, long data)
                 child->exit_code = data;
                 /* give it a chance to run. */
                 wake_up_process(child);
-                ret = 0;
                 break;
-        }
 
         case PTRACE_DETACH:     /* detach a process that was attached. */
                 ret = ptrace_detach(child, data);
                 break;
 
-        case PTRACE_GETREGS: { /* Get all gp regs from the child. */
-                int i;
-                unsigned long tmp;
+        case PTRACE_GETREGS:    /* Get all gp regs from the child. */
                 for (i = 0; i < 19; i++) {
                         tmp = get_reg(child, i);
                         if (i == PT_SR)
                                 tmp >>= 16;
-                        if (put_user(tmp, (unsigned long *)data)) {
-                                ret = -EFAULT;
+                        ret = put_user(tmp, (unsigned long *)data);
+                        if (ret)
                                 break;
-                        }
                         data += sizeof(long);
                 }
-                ret = 0;
                 break;
-        }
 
-        case PTRACE_SETREGS: { /* Set all gp regs in the child. */
-                int i;
-                unsigned long tmp;
+        case PTRACE_SETREGS:    /* Set all gp regs in the child. */
                 for (i = 0; i < 19; i++) {
-                        if (get_user(tmp, (unsigned long *)data)) {
-                                ret = -EFAULT;
+                        ret = get_user(tmp, (unsigned long *)data);
+                        if (ret)
                                 break;
-                        }
                         if (i == PT_SR) {
                                 tmp &= SR_MASK;
                                 tmp <<= 16;
@@ -343,25 +299,19 @@ asmlinkage int sys_ptrace(long request, long pid, long addr, long data)
                         put_reg(child, i, tmp);
                         data += sizeof(long);
                 }
-                ret = 0;
                 break;
-        }
 
-        case PTRACE_GETFPREGS: { /* Get the child FPU state. */
-                ret = 0;
+        case PTRACE_GETFPREGS:  /* Get the child FPU state. */
                 if (copy_to_user((void *)data, &child->thread.fp,
                                  sizeof(struct user_m68kfp_struct)))
                         ret = -EFAULT;
                 break;
-        }
 
-        case PTRACE_SETFPREGS: { /* Set the child FPU state. */
-                ret = 0;
+        case PTRACE_SETFPREGS:  /* Set the child FPU state. */
                 if (copy_from_user(&child->thread.fp, (void *)data,
                                    sizeof(struct user_m68kfp_struct)))
                         ret = -EFAULT;
                 break;
-        }
 
         default:
                 ret = ptrace_request(child, request, addr, data);
@@ -372,6 +322,9 @@ out_tsk:
 out:
         unlock_kernel();
         return ret;
+out_eio:
+        ret = -EIO;
+        goto out_tsk;
 }
 
 asmlinkage void syscall_trace(void)