From abf847a083888bbed4260ecacf849ea19f23e810 Mon Sep 17 00:00:00 2001
From: Frans Kaashoek <kaashoek@mit.edu>
Date: Tue, 31 Jan 2017 17:47:16 -0500
Subject: Start of an experiment to remove the use of gs for cpu local
 variables.

---
 sysfile.c | 14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

(limited to 'sysfile.c')

diff --git a/sysfile.c b/sysfile.c
index 98e8c43..fae6960 100644
--- a/sysfile.c
+++ b/sysfile.c
@@ -26,7 +26,7 @@ argfd(int n, int *pfd, struct file **pf)
 
   if(argint(n, &fd) < 0)
     return -1;
-  if(fd < 0 || fd >= NOFILE || (f=proc->ofile[fd]) == 0)
+  if(fd < 0 || fd >= NOFILE || (f=myproc()->ofile[fd]) == 0)
     return -1;
   if(pfd)
     *pfd = fd;
@@ -43,8 +43,8 @@ fdalloc(struct file *f)
   int fd;
 
   for(fd = 0; fd < NOFILE; fd++){
-    if(proc->ofile[fd] == 0){
-      proc->ofile[fd] = f;
+    if(myproc()->ofile[fd] == 0){
+      myproc()->ofile[fd] = f;
       return fd;
     }
   }
@@ -97,7 +97,7 @@ sys_close(void)
 
   if(argfd(0, &fd, &f) < 0)
     return -1;
-  proc->ofile[fd] = 0;
+  myproc()->ofile[fd] = 0;
   fileclose(f);
   return 0;
 }
@@ -386,9 +386,9 @@ sys_chdir(void)
     return -1;
   }
   iunlock(ip);
-  iput(proc->cwd);
+  iput(myproc()->cwd);
   end_op();
-  proc->cwd = ip;
+  myproc()->cwd = ip;
   return 0;
 }
 
@@ -432,7 +432,7 @@ sys_pipe(void)
   fd0 = -1;
   if((fd0 = fdalloc(rf)) < 0 || (fd1 = fdalloc(wf)) < 0){
     if(fd0 >= 0)
-      proc->ofile[fd0] = 0;
+      myproc()->ofile[fd0] = 0;
     fileclose(rf);
     fileclose(wf);
     return -1;
-- 
cgit v1.2.3


From fbb4c0944422f860484142010bb9f366f3e87bf8 Mon Sep 17 00:00:00 2001
From: Frans Kaashoek <kaashoek@mit.edu>
Date: Tue, 31 Jan 2017 20:21:14 -0500
Subject: Read curproc from cpu structure, but be careful because after a
 schedule event myproc() points to a different thread.

   myproc();
   sched();
   myproc();  // this proc maybe different than the one before sched

Thus, in a function that operates on one thread better to retrieve the
current process once at the start of the function.
---
 sysfile.c | 12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)

(limited to 'sysfile.c')

diff --git a/sysfile.c b/sysfile.c
index fae6960..87e508b 100644
--- a/sysfile.c
+++ b/sysfile.c
@@ -41,10 +41,11 @@ static int
 fdalloc(struct file *f)
 {
   int fd;
+  struct proc *curproc = myproc();
 
   for(fd = 0; fd < NOFILE; fd++){
-    if(myproc()->ofile[fd] == 0){
-      myproc()->ofile[fd] = f;
+    if(curproc->ofile[fd] == 0){
+      curproc->ofile[fd] = f;
       return fd;
     }
   }
@@ -373,7 +374,8 @@ sys_chdir(void)
 {
   char *path;
   struct inode *ip;
-
+  struct proc *curproc = myproc();
+  
   begin_op();
   if(argstr(0, &path) < 0 || (ip = namei(path)) == 0){
     end_op();
@@ -386,9 +388,9 @@ sys_chdir(void)
     return -1;
   }
   iunlock(ip);
-  iput(myproc()->cwd);
+  iput(curproc->cwd);
   end_op();
-  myproc()->cwd = ip;
+  curproc->cwd = ip;
   return 0;
 }
 
-- 
cgit v1.2.3