[PATCH] files: lock-free fd look-up

With the use of RCU in files structure, the look-up of files using fds can now
be lock-free.  The lookup is protected by rcu_read_lock()/rcu_read_unlock().
This patch changes the readers to use lock-free lookup.

Signed-off-by: Maneesh Soni <maneesh@in.ibm.com>
Signed-off-by: Ravikiran Thirumalai <kiran_th@gmail.com>
Signed-off-by: Dipankar Sarma <dipankar@in.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This commit is contained in:
Dipankar Sarma
2005-09-09 13:04:14 -07:00
committed by Linus Torvalds
parent ab2af1f500
commit b835996f62
9 changed files with 39 additions and 27 deletions

View File

@@ -14,6 +14,7 @@
#include <linux/syscalls.h>
#include <linux/tty.h>
#include <linux/file.h>
#include <linux/rcupdate.h>
#include <asm/uaccess.h>
#include <asm/ioctl.h>
@@ -33,7 +34,7 @@ static struct tty_struct *get_tty(int fd)
struct file *filp;
struct tty_struct *ttyp = NULL;
spin_lock(&current->files->file_lock);
rcu_read_lock();
filp = fcheck(fd);
if(filp && filp->private_data) {
ttyp = (struct tty_struct *) filp->private_data;
@@ -41,7 +42,7 @@ static struct tty_struct *get_tty(int fd)
if(ttyp->magic != TTY_MAGIC)
ttyp =NULL;
}
spin_unlock(&current->files->file_lock);
rcu_read_unlock();
return ttyp;
}