[PATCH 1/2] BKL: Remove BKL from default_llseek()

Jan Blunck
2009-11-18T16:07:37Z

Using the BKL in llseek() does not protect the inode's i_size from
modification since the i_size is protected by a seqlock nowadays. Since
default_llseek() is already using the i_size_read() wrapper it is not the
BKL which is serializing the access here.
The access to file->f_pos is not protected by the BKL either since its
access in vfs_write()/vfs_read() is not protected by any lock. If the BKL
is not protecting anything here it can clearly get removed.

Signed-off-by: Jan Blunck <jblunck@suse.de>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Frédéric Weisbecker <fweisbec@gmail.com>
Cc: John Kacur <jkacur@redhat.com>
---
fs/read_write.c | 2 --
1 files changed, 0 insertions(+), 2 deletions(-)

diff --git a/fs/read_write.c b/fs/read_write.c
index 3ac2898..0e491cc 100644
--- a/fs/read_write.c
+++ b/fs/read_write.c
@@ -107,7 +107,6 @@ loff_t default_llseek(struct file *file, loff_t offset, int origin)
{
loff_t retval;

- lock_kernel();
switch (origin) {
case SEEK_END:
offset += i_size_read(file->f_path.dentry->d_inode);
@@ -128,7 +127,6 @@ loff_t default_llseek(struct file *file, loff_t offset, int origin)
retval = offset;
}
out:
- unlock_kernel();
return retval;
}
EXPORT_SYMBOL(default_llseek);
--
1.6.4.2