This reverts commit cb26a31157.
It mysteriously causes NetworkManager to not find the wireless device
for me. As far as I can tell, Tejun *meant* for this commit to not make
any semantic changes, but there clearly are some. So revert it, taking
into account some of the calling convention changes that happened in
this area in subsequent commits.
Cc: Tejun Heo <tj@kernel.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
sysfs_assoc_lock is an odd piece of locking. In general, whoever owns
a kobject is responsible for synchronizing sysfs operations and sysfs
proper assumes that, for example, removal won't race with any other
operation; however, this doesn't work for symlinking because an entity
performing symlink doesn't usually own the target kobject and thus has
no control over its removal.
sysfs_assoc_lock synchronizes symlink operations against kobj->sd
disassociation so that symlink code doesn't end up dereferencing
already freed sysfs_dirent by racing with removal of the target
kobject.
This is quite obscure and the generic name of the lock and lack of
comments make it difficult to understand its role. Let's rename it to
sysfs_symlink_target_lock and add comments explaining what's going on.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
13c589d5b0 ("sysfs: use seq_file when reading regular files")
converted regular sysfs files to use seq_file. The commit substituted
generic_file_llseek() with seq_lseek() for llseek implementation.
Before the change, all regular sysfs files were allowed to seek to any
position in [0, PAGE_SIZE] as the file size is always PAGE_SIZE and
generic_file_llseek() allows any seeking inside the range under file
size; however, seq_lseek()'s behavior is different. It traverses the
output by repeatedly invoking ->show() until it reaches the target
offset or traversal indicates EOF. As seq_files are fully dynamic and
may not end at all, it doesn't support seeking from the end
(SEEK_END).
Apparently, there are userland tools which uses SEEK_END to discover
the buffer size to use and the switch to seq_lseek() disturbs them as
SEEK_END fails with -EINVAL.
The only benefits of using seq_lseek() instead of
generic_file_llseek() are
* Early failure. If traversing to certain file position should fail,
seq_lseek() will report such failures on lseek(2) instead of the
following read/write operations.
* EOF detection. While SEEK_END is not supported, SEEK_SET/CUR +
large offset can be used to detect eof - eof at the time of the seek
anyway as the file size may change dynamically.
Both aren't necessary for sysfs or prospect kernfs users. Revert to
genefic_file_llseek() and preserve the original behavior.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Link: https://lkml.kernel.org/r/20131031114358.GA5551@osiris
Tested-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Both POSIX.1-2008 and Linux Programmer's Manual have a dedicated return
error code for a case, when a file doesn't support mmap(), it's ENODEV.
This change replaces overloaded EINVAL with ENODEV in a situation
described above for sysfs binary files.
Signed-off-by: Vladimir Zapolskiy <vladimir_zapolskiy@mentor.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Separate out sysfs_warn_dup() out of sysfs_add_one(). This will help
separating out the core sysfs functionalities into kernfs so that it
can be used by non-sysfs users too.
This doesn't make any functional changes.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Most removal related logic is implemented in fs/sysfs/dir.c. Move
sysfs_hash_and_remove() to fs/sysfs/dir.c so that __sysfs_remove()
doesn't have to be public.
This is pure relocation.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
sysfs_get_dentry() has been gone for years now. Remove the left-over
prototype.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
ignore_lockdep is currently honored only for regular files. There's
no reason to ignore it for bin files. Update sysfs_ignore_lockdep()
so that bin_attr.attr.ignore_lockdep works too.
While this doesn't have any in-kernel user, this unifies the behaviors
between regular and bin files and will help later changes.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
3124eb1679 ("sysfs: merge regular and bin file handling") folded bin
file handling into regular file handling. Among other things, bin
file now shares the same open path including sysfs_open_dirent
association using sysfs_dirent->s_attr.open. This is buggy because
->s_bin_attr lives in the same union and doesn't have the field. This
bug doesn't trigger because sysfs_elem_bin_attr doesn't have an active
field at the conflicting position. It does have a field "buffers" but
it isn't used anymore.
This patch collapses sysfs_elem_bin_attr into sysfs_elem_attr so that
the bin_attr is accessed through ->s_attr.bin_attr which lives with
->s_attr.attr in an anonymous union. The code paths already assume
bin_attr contains attr as the first element, so this doesn't add any
more assumptions while making it explicit that the two types are
handled together.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Before patch(sysfs: prepare path write for unified regular / bin
file handling), when size of bin file is zero, writting still can
continue, but this patch changes the behaviour.
The worse thing is that firmware loader is broken by this patch,
and user space application can't write to firmware bin file any more
because both firmware loader and drivers can't know at advance how
large the firmware file is and have to set its initialized size as
zero.
This patch fixes the problem and keeps behaviour of writting to bin
as before.
Reported-by: Lothar Waßmann <LW@karo-electronics.de>
Tested-by: Lothar Waßmann <LW@karo-electronics.de>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Ming Lei <ming.lei@canonical.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
While looking at the code, I noticed that bin_attribute read() and write()
ops copy the inode size into an int for futher comparisons.
Some bin_attributes can be fairly large. For example, pci creates some for
BARs set to the BAR size and giant BARs are around the corner, so this is
going to break something somewhere eventually.
Let's use the right type.
[adjust for seqfile conversions, only needed for bin_read() - gkh]
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
375b611e60 ("sysfs: remove sysfs_buffer->ops") introduced
sysfs_file_ops() which determines the associated file operation of a
given sysfs_dirent. As file ops access should be protected by an
active reference, the new function includes a lockdep assertion on the
sysfs_dirent; unfortunately, I forgot to take attr->ignore_lockdep
flag into account and the lockdep assertion trips spuriously for files
which opt out from active reference lockdep checking.
# cat /sys/devices/pci0000:00/0000:00:01.2/usb1/authorized
------------[ cut here ]------------
WARNING: CPU: 1 PID: 540 at /work/os/work/fs/sysfs/file.c:79 sysfs_file_ops+0x4e/0x60()
Modules linked in:
CPU: 1 PID: 540 Comm: cat Not tainted 3.11.0-work+ #3
Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
0000000000000009 ffff880016205c08 ffffffff81ca0131 0000000000000000
ffff880016205c40 ffffffff81096d0d ffff8800166cb898 ffff8800166f6f60
ffffffff8125a220 ffff880011ab1ec0 ffff88000aff0c78 ffff880016205c50
Call Trace:
[<ffffffff81ca0131>] dump_stack+0x4e/0x82
[<ffffffff81096d0d>] warn_slowpath_common+0x7d/0xa0
[<ffffffff81096dea>] warn_slowpath_null+0x1a/0x20
[<ffffffff8125994e>] sysfs_file_ops+0x4e/0x60
[<ffffffff8125a274>] sysfs_open_file+0x54/0x300
[<ffffffff811df612>] do_dentry_open.isra.17+0x182/0x280
[<ffffffff811df820>] finish_open+0x30/0x40
[<ffffffff811f0623>] do_last+0x503/0xd90
[<ffffffff811f0f6b>] path_openat+0xbb/0x6d0
[<ffffffff811f23ba>] do_filp_open+0x3a/0x90
[<ffffffff811e09a9>] do_sys_open+0x129/0x220
[<ffffffff811e0abe>] SyS_open+0x1e/0x20
[<ffffffff81caf3c2>] system_call_fastpath+0x16/0x1b
---[ end trace aa48096b111dafdb ]---
Rename fs/sysfs/dir.c::ignore_lockdep() to sysfs_ignore_lockdep() and
move it to fs/sysfs/sysfs.h and make sysfs_file_ops() skip lockdep
assertion if sysfs_ignore_lockdep() is true.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
With the previous changes, sysfs regular file code is ready to handle
bin files too. This patch makes bin files share the regular file
path.
* sysfs_create/remove_bin_file() are moved to fs/sysfs/file.c.
* sysfs_init_inode() is updated to use the new sysfs_bin_operations
instead of bin_fops for bin files.
* fs/sysfs/bin.c and the related pieces are removed.
This patch shouldn't introduce any behavior difference to bin file
accesses.
Overall, this unification reduces the amount of duplicate logic, makes
behaviors more consistent and paves the road for building simpler and
more versatile interface which will allow other subsystems to make use
of sysfs for their pseudo filesystems.
v2: Stale fs/sysfs/bin.c reference dropped from
Documentation/DocBook/filesystems.tmpl. Reported by kbuild test
robot.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Kay Sievers <kay@vrfy.org>
Cc: kbuild test robot <fengguang.wu@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
sysfs bin file handling will be merged into the regular file support.
This patch prepares the open path.
This patch updates sysfs_open_file() such that it can handle both
regular and bin files.
This is a preparation and the new bin file path isn't used yet.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
sysfs bin file handling will be merged into the regular file support.
This patch copies mmap support from bin so that fs/sysfs/file.c can
handle mmapping bin files.
The code is copied mostly verbatim with the following updates.
* ->mmapped and ->vm_ops are added to sysfs_open_file and bin_buffer
references are replaced with sysfs_open_file ones.
* Symbols are prefixed with sysfs_.
* sysfs_unmap_bin_file() grabs sysfs_open_dirent and traverses
->files. Invocation of this function is added to
sysfs_addrm_finish().
* sysfs_bin_mmap() is added to sysfs_bin_operations.
This is a preparation and the new mmap path isn't used yet.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
sysfs bin file handling will be merged into the regular file support.
This patch prepares the read path.
Copy fs/sysfs/bin.c::read() to fs/sysfs/file.c and make it use
sysfs_open_file instead of bin_buffer. The function is identical copy
except for the use of sysfs_open_file.
The new function is added to sysfs_bin_operations. This isn't used
yet but will eventually replace fs/sysfs/bin.c.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
sysfs bin file handling will be merged into the regular file support.
This patch prepares the write path.
bin file write is almost identical to regular file write except that
the write length is capped by the inode size and @off is passed to the
write method. This patch adds bin file handling to sysfs_write_file()
so that it can handle both regular and bin files.
A new file_operations struct sysfs_bin_operations is added, which
currently only hosts sysfs_write_file() and generic_file_llseek().
This isn't used yet but will eventually replace fs/sysfs/bin.c.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
read() is simple enough and fill_read() being in a separate function
doesn't add anything. Let's collapse it into read(). This will make
merging bin file handling with regular file.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
After b31ca3f5df ("sysfs: fix deadlock"), bin read() first writes
data to bb->buffer and bounces it to a transient kernel buffer which
is then copied out to userland. The double bouncing doesn't add
anything. Let's just use the transient buffer directly.
While at it, rename @temp to @buf for clarity.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
sysfs read path implements its own buffering scheme between userland
and kernel callbacks, which essentially is a degenerate duplicate of
seq_file. This patch replaces the custom read buffering
implementation in sysfs with seq_file.
While the amount of code reduction is small, this reduces low level
hairiness and enables future development of a new versatile API based
on seq_file so that sysfs features can be shared with other
subsystems.
As write path was already converted to not use sysfs_open_file->page,
this patch makes ->page and ->count unused and removes them.
Userland behavior remains the same except for some extreme corner
cases - e.g. sysfs will now regenerate the content each time a file is
read after a non-contiguous seek whereas the original code would keep
using the same content. While this is a userland visible behavior
change, it is extremely unlikely to be noticeable and brings sysfs
behavior closer to that of procfs.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Kay Sievers <kay@vrfy.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
There isn't much to be gained by keeping around kernel buffer while a
file is open especially as the read path planned to be converted to
use seq_file and won't use the buffer. This patch makes
sysfs_write_file() use per-write transient buffer instead of
sysfs_open_file->page.
This simplifies the write path, enables removing sysfs_open_file->page
once read path is updated and will help merging bin file write path
which already requires the use of a transient buffer due to a locking
order issue.
As the function comments of flush_write_buffer() and
sysfs_write_buffer() are being updated anyway, reformat them so that
they're more conventional.
v2: Use min_t() instead of min() in sysfs_write_file() to avoid build
warning on arm. Reported by build test robot.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: kbuild test robot <fengguang.wu@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
sysfs will be converted to use seq_file for read path, which will make
it difficult to pass around multiple pointers directly. This patch
adds sysfs_open_file->sd and ->file so that we can reach all the
necessary data structures from sysfs_open_file.
flush_write_buffer() is updated to drop @dentry which was used to
discover the sysfs_dirent as it's now available through
sysfs_open_file->sd.
This patch doesn't cause any behavior difference.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
sysfs read path will be converted to use seq_file which will handle
buffering making sysfs_buffer a misnomer. Rename sysfs_buffer to
sysfs_open_file, and sysfs_open_dirent->buffers to ->files.
This path is pure rename.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Add a separate mutex to protect sysfs_open_dirent->buffers list. This
will allow performing sleepable operations while traversing
sysfs_buffers, which will be renamed to sysfs_open_file.
Note that currently sysfs_open_dirent->buffers list isn't being used
for anything and this patch doesn't make any functional difference.
It will be used to merge regular and bin file supports.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Currently, sysfs_ops is fetched during sysfs_open_file() and cached in
sysfs_buffer->ops to be used while the file is open. This patch
removes the caching and makes each operation directly fetch sysfs_ops.
This patch doesn't introduce any behavior difference and is to prepare
for merging regular and bin file supports.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Linus Torvalds
Tejun Heo
Vladimir Zapolskiy
Ming Lei
Benjamin Herrenschmidt