linux/fs/sysfs
NeilBrown 4ef67a8c95 sysfs/kernfs: make read requests on pre-alloc files use the buffer.
To match the previous patch which used the pre-alloc buffer for
writes, this patch causes reads to use the same buffer.
This is not strictly necessary as the current seq_read() will allocate
on first read, so user-space can trigger the required pre-alloc.  But
consistency is valuable.

The read function is somewhat simpler than seq_read() and, for example,
does not support reading from an offset into the file: reads must be
at the start of the file.

As seq_read() does not use the prealloc buffer, ->seq_show is
incompatible with ->prealloc and caused an EINVAL return from open().
sysfs code which calls into kernfs always chooses the correct function.

As the buffer is shared with writes and other reads, the mutex is
extended to cover the copy_to_user.

Signed-off-by: NeilBrown <neilb@suse.de>
Reviewed-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-11-07 10:54:38 -08:00
..
Kconfig kernfs: add CONFIG_KERNFS 2014-02-07 16:08:57 -08:00
Makefile sysfs, kernfs: move inode code to fs/kernfs/inode.c 2013-11-29 17:55:10 -08:00
dir.c kernfs: implement kernfs_get_parent(), kernfs_name/path() and friends 2014-02-07 16:05:35 -08:00
file.c sysfs/kernfs: make read requests on pre-alloc files use the buffer. 2014-11-07 10:54:38 -08:00
group.c sysfs: fix attribute_group bin file path on removal 2014-05-27 14:33:17 -07:00
mount.c kernfs: move the last knowledge of sysfs out from kernfs 2014-05-27 14:33:17 -07:00
symlink.c kernfs: s/sysfs/kernfs/ in constants 2013-12-11 17:39:20 -08:00
sysfs.h kernfs: s/sysfs_dirent/kernfs_node/ and rename its friends accordingly 2013-12-11 15:28:36 -08:00