/proc/vmcore: fix seeking

commit c227e69028473c7c7994a9b0a2cc0034f3f7e0fe upstream.

Commit 73296bc611 ("procfs: Use generic_file_llseek in /proc/vmcore")
broke seeking on /proc/vmcore.  This changes it back to use default_llseek
in order to restore the original behaviour.

The problem with generic_file_llseek is that it only allows seeks up to
inode->i_sb->s_maxbytes, which is zero on procfs and some other virtual
file systems.  We should merge generic_file_llseek and default_llseek some
day and clean this up in a proper way, but for 2.6.35/36, reverting vmcore
is the safer solution.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Reported-by: CAI Qian <caiqian@redhat.com>
Tested-by: CAI Qian <caiqian@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/fs/proc/vmcore.c b/fs/proc/vmcore.c
index 91c817ff02c3847a874e1e99f7638b1148869a77..2367fb3f70bc6ba468ab0ccb628b5b88fabac955 100644 (file)
--- a/fs/proc/vmcore.c
+++ b/fs/proc/vmcore.c
@@ -163,7 +163,7 @@ static ssize_t read_vmcore(struct file *file, char __user *buffer,
 
 static const struct file_operations proc_vmcore_operations = {
        .read           = read_vmcore,
-       .llseek         = generic_file_llseek,
+       .llseek         = default_llseek,
 };
 
 static struct vmcore* __init get_new_element(void)