commit b835996f628eadb55c5fb222ba46fe9395bf73c7
author Dipankar Sarma <dipankar@in.ibm.com> Fri Sep 09 13:04:14 2005 -0700
committer Linus Torvalds <torvalds@g5.osdl.org> Fri Sep 09 13:57:55 2005 -0700
tree d63d80585d197e1ffc299af4a0034049790fb197
parent ab2af1f5005069321c5d130f09cce577b03f43ef

[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>

arch/sparc64/solaris/ioctl.c

diff --git a/arch/sparc64/solaris/ioctl.c b/arch/sparc64/solaris/ioctl.c
index 3747664..be0a054 100644
--- a/arch/sparc64/solaris/ioctl.c
+++ b/arch/sparc64/solaris/ioctl.c
@@ -24,6 +24,7 @@
 #include <linux/netdevice.h>
 #include <linux/mtio.h>
 #include <linux/time.h>
+#include <linux/rcupdate.h>
 #include <linux/compat.h>
 
 #include <net/sock.h>
@@ -295,16 +296,16 @@
 	struct inode *ino;
 	struct fdtable *fdt;
 	/* I wonder which of these tests are superfluous... --patrik */
-	spin_lock(&current->files->file_lock);
+	rcu_read_lock();
 	fdt = files_fdtable(current->files);
 	if (! fdt->fd[fd] ||
 	    ! fdt->fd[fd]->f_dentry ||
 	    ! (ino = fdt->fd[fd]->f_dentry->d_inode) ||
 	    ! S_ISSOCK(ino->i_mode)) {
-		spin_unlock(&current->files->file_lock);
+		rcu_read_unlock();
 		return TBADF;
 	}
-	spin_unlock(&current->files->file_lock);
+	rcu_read_unlock();
 	
 	switch (cmd & 0xff) {
 	case 109: /* SI_SOCKPARAMS */