Commit Graph

94 Commits

Author SHA1 Message Date
Al Viro 2c9ede55ec switch device_get_devnode() and ->devnode() to umode_t *
both callers of device_get_devnode() are only interested in lower 16bits
and nobody tries to return anything wider than 16bit anyway.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-01-03 22:54:55 -05:00
Paul Gortmaker 66300e66c6 drivers/char: Add export.h for EXPORT_SYMBOL/THIS_MODULE as required
They will need it called out explicitly in the near future due
to a module.h usage cleanup that removes its implicit presence
everywhere.

Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2011-10-31 19:31:41 -04:00
Andrew Morton 70a5f52165 kmsg: properly support writev to avoid interleaved printk lines fix
make `len' size_t, avoid multiple-assignments.

Cc: Kay Sievers <kay.sievers@vrfy.org>
Cc: Lennart Poettering <lennart@poettering.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-04-19 17:00:48 -07:00
Kay Sievers 7e5b58bcbc printk: /dev/kmsg - properly support writev() to avoid interleaved printk() lines
printk: /dev/kmsg - properly support writev() to avoid interleaved printk lines

We should avoid calling printk() in a loop, when we pass a single
string to /dev/kmsg with writev().

Cc: Lennart Poettering <lennart@poettering.net>
Signed-off-by: Kay Sievers <kay.sievers@vrfy.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-04-19 16:59:58 -07:00
Changli Gao cfaf346cb2 drivers/char/mem.c: clean up the code
Reduce the lines of code and simplify the logic.

Signed-off-by: Changli Gao <xiaosuo@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-03-23 19:46:40 -07:00
KAMEZAWA Hiroyuki 4a3956c790 vfs: introduce FMODE_UNSIGNED_OFFSET for allowing negative f_pos
Now, rw_verify_area() checsk f_pos is negative or not.  And if negative,
returns -EINVAL.

But, some special files as /dev/(k)mem and /proc/<pid>/mem etc..  has
negative offsets.  And we can't do any access via read/write to the
file(device).

So introduce FMODE_UNSIGNED_OFFSET to allow negative file offsets.

Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2010-10-25 21:18:21 -04:00
Linus Torvalds 092e0e7e52 Merge branch 'llseek' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/bkl
* 'llseek' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/bkl:
  vfs: make no_llseek the default
  vfs: don't use BKL in default_llseek
  llseek: automatically add .llseek fop
  libfs: use generic_file_llseek for simple_attr
  mac80211: disallow seeks in minstrel debug code
  lirc: make chardev nonseekable
  viotape: use noop_llseek
  raw: use explicit llseek file operations
  ibmasmfs: use generic_file_llseek
  spufs: use llseek in all file operations
  arm/omap: use generic_file_llseek in iommu_debug
  lkdtm: use generic_file_llseek in debugfs
  net/wireless: use generic_file_llseek in debugfs
  drm: use noop_llseek
2010-10-22 10:52:56 -07:00
Arnd Bergmann 6038f373a3 llseek: automatically add .llseek fop
All file_operations should get a .llseek operation so we can make
nonseekable_open the default for future file operations without a
.llseek pointer.

The three cases that we can automatically detect are no_llseek, seq_lseek
and default_llseek. For cases where we can we can automatically prove that
the file offset is always ignored, we use noop_llseek, which maintains
the current behavior of not returning an error from a seek.

New drivers should normally not use noop_llseek but instead use no_llseek
and call nonseekable_open at open time.  Existing drivers can be converted
to do the same when the maintainer knows for certain that no user code
relies on calling seek on the device file.

The generated code is often incorrectly indented and right now contains
comments that clarify for each added line why a specific variant was
chosen. In the version that gets submitted upstream, the comments will
be gone and I will manually fix the indentation, because there does not
seem to be a way to do that using coccinelle.

Some amount of new code is currently sitting in linux-next that should get
the same modifications, which I will do at the end of the merge window.

Many thanks to Julia Lawall for helping me learn to write a semantic
patch that does all this.

===== begin semantic patch =====
// This adds an llseek= method to all file operations,
// as a preparation for making no_llseek the default.
//
// The rules are
// - use no_llseek explicitly if we do nonseekable_open
// - use seq_lseek for sequential files
// - use default_llseek if we know we access f_pos
// - use noop_llseek if we know we don't access f_pos,
//   but we still want to allow users to call lseek
//
@ open1 exists @
identifier nested_open;
@@
nested_open(...)
{
<+...
nonseekable_open(...)
...+>
}

@ open exists@
identifier open_f;
identifier i, f;
identifier open1.nested_open;
@@
int open_f(struct inode *i, struct file *f)
{
<+...
(
nonseekable_open(...)
|
nested_open(...)
)
...+>
}

@ read disable optional_qualifier exists @
identifier read_f;
identifier f, p, s, off;
type ssize_t, size_t, loff_t;
expression E;
identifier func;
@@
ssize_t read_f(struct file *f, char *p, size_t s, loff_t *off)
{
<+...
(
   *off = E
|
   *off += E
|
   func(..., off, ...)
|
   E = *off
)
...+>
}

@ read_no_fpos disable optional_qualifier exists @
identifier read_f;
identifier f, p, s, off;
type ssize_t, size_t, loff_t;
@@
ssize_t read_f(struct file *f, char *p, size_t s, loff_t *off)
{
... when != off
}

@ write @
identifier write_f;
identifier f, p, s, off;
type ssize_t, size_t, loff_t;
expression E;
identifier func;
@@
ssize_t write_f(struct file *f, const char *p, size_t s, loff_t *off)
{
<+...
(
  *off = E
|
  *off += E
|
  func(..., off, ...)
|
  E = *off
)
...+>
}

@ write_no_fpos @
identifier write_f;
identifier f, p, s, off;
type ssize_t, size_t, loff_t;
@@
ssize_t write_f(struct file *f, const char *p, size_t s, loff_t *off)
{
... when != off
}

@ fops0 @
identifier fops;
@@
struct file_operations fops = {
 ...
};

@ has_llseek depends on fops0 @
identifier fops0.fops;
identifier llseek_f;
@@
struct file_operations fops = {
...
 .llseek = llseek_f,
...
};

@ has_read depends on fops0 @
identifier fops0.fops;
identifier read_f;
@@
struct file_operations fops = {
...
 .read = read_f,
...
};

@ has_write depends on fops0 @
identifier fops0.fops;
identifier write_f;
@@
struct file_operations fops = {
...
 .write = write_f,
...
};

@ has_open depends on fops0 @
identifier fops0.fops;
identifier open_f;
@@
struct file_operations fops = {
...
 .open = open_f,
...
};

// use no_llseek if we call nonseekable_open
////////////////////////////////////////////
@ nonseekable1 depends on !has_llseek && has_open @
identifier fops0.fops;
identifier nso ~= "nonseekable_open";
@@
struct file_operations fops = {
...  .open = nso, ...
+.llseek = no_llseek, /* nonseekable */
};

@ nonseekable2 depends on !has_llseek @
identifier fops0.fops;
identifier open.open_f;
@@
struct file_operations fops = {
...  .open = open_f, ...
+.llseek = no_llseek, /* open uses nonseekable */
};

// use seq_lseek for sequential files
/////////////////////////////////////
@ seq depends on !has_llseek @
identifier fops0.fops;
identifier sr ~= "seq_read";
@@
struct file_operations fops = {
...  .read = sr, ...
+.llseek = seq_lseek, /* we have seq_read */
};

// use default_llseek if there is a readdir
///////////////////////////////////////////
@ fops1 depends on !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
identifier fops0.fops;
identifier readdir_e;
@@
// any other fop is used that changes pos
struct file_operations fops = {
... .readdir = readdir_e, ...
+.llseek = default_llseek, /* readdir is present */
};

// use default_llseek if at least one of read/write touches f_pos
/////////////////////////////////////////////////////////////////
@ fops2 depends on !fops1 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
identifier fops0.fops;
identifier read.read_f;
@@
// read fops use offset
struct file_operations fops = {
... .read = read_f, ...
+.llseek = default_llseek, /* read accesses f_pos */
};

@ fops3 depends on !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
identifier fops0.fops;
identifier write.write_f;
@@
// write fops use offset
struct file_operations fops = {
... .write = write_f, ...
+	.llseek = default_llseek, /* write accesses f_pos */
};

// Use noop_llseek if neither read nor write accesses f_pos
///////////////////////////////////////////////////////////

@ fops4 depends on !fops1 && !fops2 && !fops3 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
identifier fops0.fops;
identifier read_no_fpos.read_f;
identifier write_no_fpos.write_f;
@@
// write fops use offset
struct file_operations fops = {
...
 .write = write_f,
 .read = read_f,
...
+.llseek = noop_llseek, /* read and write both use no f_pos */
};

@ depends on has_write && !has_read && !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
identifier fops0.fops;
identifier write_no_fpos.write_f;
@@
struct file_operations fops = {
... .write = write_f, ...
+.llseek = noop_llseek, /* write uses no f_pos */
};

@ depends on has_read && !has_write && !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
identifier fops0.fops;
identifier read_no_fpos.read_f;
@@
struct file_operations fops = {
... .read = read_f, ...
+.llseek = noop_llseek, /* read uses no f_pos */
};

@ depends on !has_read && !has_write && !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
identifier fops0.fops;
@@
struct file_operations fops = {
...
+.llseek = noop_llseek, /* no read or write fn */
};
===== End semantic patch =====

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Cc: Julia Lawall <julia@diku.dk>
Cc: Christoph Hellwig <hch@infradead.org>
2010-10-15 15:53:27 +02:00
Jan Kara 371d217ee1 char: Mark /dev/zero and /dev/kmem as not capable of writeback
These devices don't do any writeback but their device inodes still can get
dirty so mark bdi appropriately so that bdi code does the right thing and files
inodes to lists of bdi carrying the device inodes.

Cc: stable@kernel.org
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
2010-09-22 09:48:47 +02:00
David Howells 31d1d48e19 Fix init ordering of /dev/console vs callers of modprobe
Make /dev/console get initialised before any initialisation routine that
invokes modprobe because if modprobe fails, it's going to want to open
/dev/console, presumably to write an error message to.

The problem with that is that if the /dev/console driver is not yet
initialised, the chardev handler will call request_module() to invoke
modprobe, which will fail, because we never compile /dev/console as a
module.

This will lead to a modprobe loop, showing the following in the kernel
log:

	request_module: runaway loop modprobe char-major-5-1
	request_module: runaway loop modprobe char-major-5-1
	request_module: runaway loop modprobe char-major-5-1
	request_module: runaway loop modprobe char-major-5-1
	request_module: runaway loop modprobe char-major-5-1

This can happen, for example, when the built in md5 module can't find
the built in cryptomgr module (because the latter fails to initialise).
The md5 module comes before the call to tty_init(), presumably because
'crypto' comes before 'drivers' alphabetically.

Fix this by calling tty_init() from chrdev_init().

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-08-06 09:17:02 -07:00
David Howells ea56f411ec frv: hide uncached_access() when pgprot_noncached is not #defined
Hide uncached_access() when pgprot_noncached is not #defined.  This prevents
the following warning:

	  CC      drivers/char/mem.o
	drivers/char/mem.c:229: warning: 'uncached_access' defined but not used

Repairs d7d4d849b4 ("drivers/char/mem.c:
cleanups").

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-04-07 08:38:05 -07:00
Eric Dumazet ee5d2acd5c /dev/mem: allow rewinding
commit dcefafb6 ("/dev/mem: dont allow seek to last page") inadvertently
disabled rewinding on /dev/mem.

This broke x86info for example.

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Acked-by: Wu Fengguang <fengguang.wu@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-04-07 08:38:04 -07:00
Anton Blanchard 6e191f7bb0 devmem: handle class_create() failure
I hit this when we had a bug in IDR for a few days.  Basically sysfs would
fail to create new inodes since it uses an IDR and therefore class_create
would fail.

While we are unlikely to see this fail we may as well handle it instead of
oopsing.

Signed-off-by: Anton Blanchard <anton@samba.org>
Reviewed-by: Wu Fengguang <fengguang.wu@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-04-07 08:38:03 -07:00
Andrew Morton d7d4d849b4 drivers/char/mem.c: cleanups
- fix switch statement layout

- fix whitespace stuff

- fix comment layout

- remove unneeded inlining

- use __weak

- remove trailing whitespace

- move uncached_access() inside `#ifndef __HAVE_PHYS_MEM_ACCESS_PROT' - it
  is otherwise unused.

Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-03-12 15:52:35 -08:00
Wu Fengguang dcefafb6ac /dev/mem: dont allow seek to last page
So as to return a uniform error -EOVERFLOW instead of a random one:

# kmem-seek 0xfffffffffffffff0
seek /dev/kmem: Device or resource busy
# kmem-seek 0xfffffffffffffff1
seek /dev/kmem: Block device required

Suggested by OGAWA Hirofumi.

Cc: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-03-12 15:52:35 -08:00
Wu Fengguang c85e9a97c4 devmem: fix kmem write bug on memory holes
write_kmem() used to assume vwrite() always return the full buffer length.
However now vwrite() could return 0 to indicate memory hole.  This
creates a bug that "buf" is not advanced accordingly.

Fix it to simply ignore the return value, hence the memory hole.

Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Christoph Lameter <cl@linux-foundation.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Tejun Heo <tj@kernel.org>
Cc: Nick Piggin <npiggin@suse.de>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-02-02 18:11:22 -08:00
KAMEZAWA Hiroyuki 325fda71d0 devmem: check vmalloc address on kmem read/write
Otherwise vmalloc_to_page() will BUG().

This also makes the kmem read/write implementation aligned with mem(4):
"References to nonexistent locations cause errors to be returned." Here we
return -ENXIO (inspired by Hugh) if no bytes have been transfered to/from
user space, otherwise return partial read/write results.

Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
Cc: Greg Kroah-Hartman <gregkh@suse.de>
Cc: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-02-02 18:11:22 -08:00
Wu Fengguang ee32398fda /dev/mem: remove redundant parameter from do_write_kmem()
Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Avi Kivity <avi@qumranet.com>
Cc: Greg Kroah-Hartman <gregkh@suse.de>
Cc: Johannes Berg <johannes@sipsolutions.net>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Cc: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-12-15 08:53:12 -08:00
Wu Fengguang 80ad89a0ce /dev/mem: remove the "written" variable in write_kmem()
Also rename "len" to "sz". No behavior change.

Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Avi Kivity <avi@qumranet.com>
Cc: Greg Kroah-Hartman <gregkh@suse.de>
Cc: Johannes Berg <johannes@sipsolutions.net>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Cc: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-12-15 08:53:11 -08:00
Wu Fengguang 7fabaddd09 /dev/mem: make size_inside_page() logic straight
Also convert more size_inside_page() users.

Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Avi Kivity <avi@qumranet.com>
Cc: Greg Kroah-Hartman <gregkh@suse.de>
Cc: Johannes Berg <johannes@sipsolutions.net>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Cc: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-12-15 08:53:11 -08:00
Wu Fengguang fa29e97bb8 /dev/mem: cleanup unxlate_dev_mem_ptr() calls
No behaviour change.

[akpm@linux-foundation.org: cleanuplets]
[akpm@linux-foundation.org: remove unused `ret']
Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
Acked-by: Andi Kleen <ak@linux.intel.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Cc: Greg Kroah-Hartman <gregkh@suse.de>
Cc: Mark Brown <broonie@opensource.wolfsonmicro.com>
Cc: Johannes Berg <johannes@sipsolutions.net>
Cc: Avi Kivity <avi@qumranet.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-12-15 08:53:11 -08:00
Wu Fengguang f222318e9c /dev/mem: introduce size_inside_page()
Introduce size_inside_page() to replace duplicate /dev/mem code.

Also apply it to /dev/kmem, whose alignment logic was buggy.

Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
Acked-by: Andi Kleen <ak@linux.intel.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Cc: Greg Kroah-Hartman <gregkh@suse.de>
Cc: Mark Brown <broonie@opensource.wolfsonmicro.com>
Cc: Johannes Berg <johannes@sipsolutions.net>
Cc: Avi Kivity <avi@qumranet.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-12-15 08:53:11 -08:00
Wu Fengguang 4ea2f43f28 /dev/mem: remove redundant test on len
The len test in write_kmem() is always true, so can be reduced.

Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
Acked-by: Andi Kleen <ak@linux.intel.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Cc: Greg Kroah-Hartman <gregkh@suse.de>
Cc: Mark Brown <broonie@opensource.wolfsonmicro.com>
Cc: Johannes Berg <johannes@sipsolutions.net>
Cc: Avi Kivity <avi@qumranet.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-12-15 08:53:11 -08:00
Christoph Hellwig 6b2f3d1f76 vfs: Implement proper O_SYNC semantics
While Linux provided an O_SYNC flag basically since day 1, it took until
Linux 2.4.0-test12pre2 to actually get it implemented for filesystems,
since that day we had generic_osync_around with only minor changes and the
great "For now, when the user asks for O_SYNC, we'll actually give
O_DSYNC" comment.  This patch intends to actually give us real O_SYNC
semantics in addition to the O_DSYNC semantics.  After Jan's O_SYNC
patches which are required before this patch it's actually surprisingly
simple, we just need to figure out when to set the datasync flag to
vfs_fsync_range and when not.

This patch renames the existing O_SYNC flag to O_DSYNC while keeping it's
numerical value to keep binary compatibility, and adds a new real O_SYNC
flag.  To guarantee backwards compatiblity it is defined as expanding to
both the O_DSYNC and the new additional binary flag (__O_SYNC) to make
sure we are backwards-compatible when compiled against the new headers.

This also means that all places that don't care about the differences can
just check O_DSYNC and get the right behaviour for O_SYNC, too - only
places that actuall care need to check __O_SYNC in addition.  Drivers and
network filesystems have been updated in a fail safe way to always do the
full sync magic if O_DSYNC is set.  The few places setting O_SYNC for
lower layers are kept that way for now to stay failsafe.

We enforce that O_DSYNC is set when __O_SYNC is set early in the open path
to make sure we always get these sane options.

Note that parisc really screwed up their headers as they already define a
O_DSYNC that has always been a no-op.  We try to repair it by using it for
the new O_DSYNC and redefinining O_SYNC to send both the traditional
O_SYNC numerical value _and_ the O_DSYNC one.

Cc: Richard Henderson <rth@twiddle.net>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: Grant Grundler <grundler@parisc-linux.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Andreas Dilger <adilger@sun.com>
Acked-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Acked-by: Kyle McMartin <kyle@mcmartin.ca>
Acked-by: Ulrich Drepper <drepper@redhat.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Jan Kara <jack@suse.cz>
2009-12-10 15:02:50 +01:00
Linus Torvalds 4ef58d4e2a Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial: (42 commits)
  tree-wide: fix misspelling of "definition" in comments
  reiserfs: fix misspelling of "journaled"
  doc: Fix a typo in slub.txt.
  inotify: remove superfluous return code check
  hdlc: spelling fix in find_pvc() comment
  doc: fix regulator docs cut-and-pasteism
  mtd: Fix comment in Kconfig
  doc: Fix IRQ chip docs
  tree-wide: fix assorted typos all over the place
  drivers/ata/libata-sff.c: comment spelling fixes
  fix typos/grammos in Documentation/edac.txt
  sysctl: add missing comments
  fs/debugfs/inode.c: fix comment typos
  sgivwfb: Make use of ARRAY_SIZE.
  sky2: fix sky2_link_down copy/paste comment error
  tree-wide: fix typos "couter" -> "counter"
  tree-wide: fix typos "offest" -> "offset"
  fix kerneldoc for set_irq_msi()
  spidev: fix double "of of" in comment
  comment typo fix: sybsystem -> subsystem
  ...
2009-12-09 19:43:33 -08:00
André Goddard Rosa af901ca181 tree-wide: fix assorted typos all over the place
That is "success", "unknown", "through", "performance", "[re|un]mapping"
, "access", "default", "reasonable", "[con]currently", "temperature"
, "channel", "[un]used", "application", "example","hierarchy", "therefore"
, "[over|under]flow", "contiguous", "threshold", "enough" and others.

Signed-off-by: André Goddard Rosa <andre.goddard@gmail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2009-12-04 15:39:55 +01:00
Frederic Weisbecker 205153aa40 mem_class: Drop the bkl from memory_open()
The generic open callback for the mem class devices is "protected" by
the bkl.

Let's look at the datas manipulated inside memory_open:

- inode and file: safe
- the devlist: safe because it is constant
- the memdev classes inside this array are safe too (constant)

After we find out which memdev file operation we need to use, we call
its open callback. Depending on the targeted memdev, we call either
open_port() that doesn't manipulate any racy data (just a capable()
check), or we call nothing.

So it's safe to remove the big kernel lock there.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <1255113062-5835-1-git-send-email-fweisbec@gmail.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2009-10-14 17:36:49 +02:00
Alexey Dobriyan f0f37e2f77 const: mark struct vm_struct_operations
* mark struct vm_area_struct::vm_ops as const
* mark vm_ops in AGP code

But leave TTM code alone, something is fishy there with global vm_ops
being used.

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-09-27 11:39:25 -07:00
Nikanth Karthikesan bb521c5de0 /dev/zero: avoid repeated access_ok() checks
In read_zero, we check for access_ok() once for the count bytes.  It is
unnecessarily checked again in clear_user.  Use __clear_user, which does
not check for access_ok().

Signed-off-by: Nikanth Karthikesan <knikanth@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-09-24 07:21:03 -07:00
Kay Sievers e454cea20b Driver-Core: extend devnode callbacks to provide permissions
This allows subsytems to provide devtmpfs with non-default permissions
for the device node. Instead of the default mode of 0600, null, zero,
random, urandom, full, tty, ptmx now have a mode of 0666, which allows
non-privileged processes to access standard device nodes in case no
other userspace process applies the expected permissions.

This also fixes a wrong assignment in pktcdvd and a checkpatch.pl complain.

Signed-off-by: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2009-09-19 12:50:38 -07:00
Jin Dongming 162dd42124 mem_class: fix bug
When I build and boot -next on fedora 10, I can not login anymore.
When I input the user name and password, the system does not output
any message and requires user to input the user name and password
again and again.

I find the patch which caused this problem with "GIT BISECT" command.
And the patch is
    commit 7c4b7daa1878972ed0137c95f23569124bd6e2b1
    "mem_class: use minor as index instead of searching the array".

Though I don't know the real reason why user could not login, I
confirmed the patch I made as following could resolve the problem on
fedora 10.

Signed-off-by: Jin Dongming <jin.dongming@np.css.fujitsu.com>
Acked-by: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2009-09-15 09:50:47 -07:00
Kay Sievers 389e0cb9a1 mem_class: use minor as index instead of searching the array
Declare the device list with the minor numbers as the index, which saves us from
searching for a matching list entry. Remove old devfs permissions declaration.

Signed-off-by: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2009-09-15 09:50:47 -07:00
Jens Axboe d993831fa7 writeback: add name to backing_dev_info
This enables us to track who does what and print info. Its main use
is catching dirty inodes on the default_backing_dev_info, so we can
fix that up.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-09-11 09:20:26 +02:00
Adriano dos Santos Fernandes d6f47befdd drivers/char/mem.c: memory_open() cleanup: lookup minor device number from devlist
memory_open() ignores devlist and does a switch for each item, duplicating
code and conditional definitions.

Clean it up by adding backing_dev_info to devlist and use it to lookup for
the minor device.

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Adriano dos Santos Fernandes <adrianosf@uol.com.br>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-06-18 13:03:54 -07:00
Linus Torvalds 2b83868723 Make /dev/zero reads interruptible by signals
This helps with bad latencies for large reads from /dev/zero, but might
conceivably break some application that "knows" that a read of /dev/zero
cannot return early.  So do this early in the merge window to give us
maximal test coverage, even if the patch is totally trivial.

Obviously, no well-behaved application should ever depend on the read
being uninterruptible, but hey, bugs happen.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-06-09 20:40:25 -07:00
Salman Qazi 730c586ad5 drivers/char/mem.c: avoid OOM lockup during large reads from /dev/zero
While running 20 parallel instances of dd as follows:

  #!/bin/bash
  for i in `seq 1 20`; do
           dd if=/dev/zero of=/export/hda3/dd_$i bs=1073741824 count=1 &
  done
  wait

on a 16G machine, we noticed that rather than just killing the processes,
the entire kernel went down.  Stracing dd reveals that it first does an
mmap2, which makes 1GB worth of zero page mappings.  Then it performs a
read on those pages from /dev/zero, and finally it performs a write.

The machine died during the reads.  Looking at the code, it was noticed
that /dev/zero's read operation had been changed by
557ed1fa26 ("remove ZERO_PAGE") from giving
zero page mappings to actually zeroing the page.

The zeroing of the pages causes physical pages to be allocated to the
process.  But, when the process exhausts all the memory that it can, the
kernel cannot kill it, as it is still in the kernel mode allocating more
memory.  Consequently, the kernel eventually crashes.

To fix this, I propose that when a fatal signal is pending during
/dev/zero read operation, we simply return and let the user process die.

Signed-off-by: Salman Qazi <sqazi@google.com>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
[ Modified error return and comment trivially.  - Linus]
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-06-04 15:20:39 -07:00
Suresh Siddha 0c3c8a1836 x86, PAT: Remove duplicate memtype reserve in devmem mmap
/dev/mem mmap code was doing memtype reserve/free for a while now.
Recently we added memtype tracking in remap_pfn_range, and /dev/mem mmap
uses it indirectly. So, we don't need seperate tracking in /dev/mem code
any more. That means another ~100 lines of code removed :-).

Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
LKML-Reference: <20090409212709.085210000@intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-04-10 13:55:48 +02:00
KOSAKI Motohiro 69beeb1d34 mm: make vread() and vwrite() declaration
Sparse output following warnings.

mm/vmalloc.c:1436:6: warning: symbol 'vread' was not declared. Should it be static?
mm/vmalloc.c:1474:6: warning: symbol 'vwrite' was not declared. Should it be static?

However, it is used by /dev/kmem. fixed here.

Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-01-06 15:59:05 -08:00
Greg Kroah-Hartman 03457cd455 device create: char: convert device_create_drvdata to device_create
Now that device_create() has been audited, rename things back to the
original call to be sane.

Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2008-10-16 09:24:42 -07:00
Rik van Riel 7ae8ed5053 use generic_access_phys for /dev/mem mappings
Use generic_access_phys as the access_process_vm access function for
/dev/mem mappings.  This makes it possible to debug the X server.

[akpm@linux-foundation.org: repair all the architectures which broke]
Signed-off-by: Rik van Riel <riel@redhat.com>
Cc: Benjamin Herrensmidt <benh@kernel.crashing.org>
Cc: Dave Airlie <airlied@linux.ie>
Cc: Hugh Dickins <hugh@veritas.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-07-24 10:47:15 -07:00
Greg Kroah-Hartman 47aa5793f7 device create: char: convert device_create to device_create_drvdata
device_create() is race-prone, so use the race-free
device_create_drvdata() instead as device_create() is going away.

Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2008-07-21 21:54:41 -07:00
Ingo Molnar d092633bff Subject: devmem, x86: fix rename of CONFIG_NONPROMISC_DEVMEM
From: Arjan van de Ven <arjan@infradead.org>
Date: Sat, 19 Jul 2008 15:47:17 -0700

CONFIG_NONPROMISC_DEVMEM was a rather confusing name - but renaming it
to CONFIG_PROMISC_DEVMEM causes problems on architectures that do not
support this feature; this patch renames it to CONFIG_STRICT_DEVMEM,
so that architectures can opt-in into it.

( the polarity of the option is still the same as it was originally; it
  needs to be for now to not break architectures that don't have the
  infastructure yet to support this feature)

Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Cc: "V.Radhakrishnan" <rk@atr-labs.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
---
2008-07-20 08:35:55 +02:00
Ingo Molnar 64d206d896 x86: rename CONFIG_NONPROMISC_DEVMEM to CONFIG_PROMISC_DEVMEM
Linus observed:

> The real bug is that we shouldn't have "double negatives", and
> certainly not negative config options. Making that "promiscuous
> /dev/mem" option a negated thing as a config option was bad.

right ... lets rename this option. There should never be a negation
in config options.

[ that reminds me of CONFIG_SCHED_NO_NO_OMIT_FRAME_POINTER, but that
  is for another commit ;-) ]

Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-07-18 00:28:57 +02:00
Jonathan Corbet 1f439647a4 mem: cdev lock_kernel() pushdown
It's really hard to tell if this is necessary - lots of weird
magic happens by way of map_devmem()

Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2008-06-20 14:05:48 -06:00
Arjan van de Ven b781ecb6a3 make /dev/kmem a config option
Make /dev/kmem a config option; /dev/kmem is VERY rarely used, and when
used, it's generally for no good (rootkits tend to be the most common
users).  With this config option, users have the choice to disable
/dev/kmem, saving some size as well.

A patch to disable /dev/kmem has been in the Fedora and RHEL kernels for
4+ years now without any known problems or legit users of /dev/kmem.

[akpm@linux-foundation.org: make CONFIG_DEVKMEM default to y]
Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-29 08:05:59 -07:00
venkatesh.pallipadi@intel.com e7f260a276 x86: PAT use reserve free memtype in mmap of /dev/mem
Use reserve_memtype and free_memtype wrappers for /dev/mem mmaps. The memtype
is slightly complicated here, given that we have to support existing X mappings.
We fallback on UC_MINUS for that.

Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-04-24 23:40:47 +02:00
venkatesh.pallipadi@intel.com f0970c13b6 x86: PAT phys_mem_access_prot_allowed for dev/mem mmap
Introduce phys_mem_access_prot_allowed(), which checks whether the mapping
is possible, without any conflicts and returns success or failure based on that.
phys_mem_access_prot() by itself does not allow failure case. This ability
to return error is needed for PAT where we may have aliasing conflicts.

x86 setup __HAVE_PHYS_MEM_ACCESS_PROT and move x86 specific code out of
/dev/mem into arch specific area.

Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-04-24 23:40:47 +02:00
venkatesh.pallipadi@intel.com e045fb2a98 x86: PAT avoid aliasing in /dev/mem read/write
Add xlate and unxlate around /dev/mem read/write. This sets up the mapping
that can be used for /dev/mem read and write without aliasing worries.

Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-04-24 23:40:47 +02:00
Venki Pallipadi e2beb3eae6 devmem: add range_is_allowed() check to mmap of /dev/mem
Earlier patch that introduced CONFIG_NONPROMISC_DEVMEM, did the
range_is_allowed() check only for read and write. Add range_is_allowed()
check to mmap of /dev/mem as well.

Changes the paramaters of range_is_allowed() to pfn and size to handle
more than 32 bits of physical address on 32 bit arch cleanly.

Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-04-24 23:40:47 +02:00
Arjan van de Ven ae531c26c5 x86: introduce /dev/mem restrictions with a config option
This patch introduces a restriction on /dev/mem: Only non-memory can be
read or written unless the newly introduced config option is set.

The X server needs access to /dev/mem for the PCI space, but it doesn't need
access to memory; both the file permissions and SELinux permissions of /dev/mem
just make X effectively super-super powerful. With the exception of the
BIOS area, there's just no valid app that uses /dev/mem on actual memory.
Other popular users of /dev/mem are rootkits and the like.
(note: mmap access of memory via /dev/mem was already not allowed since
a really long time)

People who want to use /dev/mem for kernel debugging can enable the config
option.

The restrictions of this patch have been in the Fedora and RHEL kernels for
at least 4 years without any problems.

Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-04-24 23:40:47 +02:00