Commit Graph

132604 Commits

Author SHA1 Message Date
Ming Lei
b23530ebc3 driver core: remove polling for driver_probe_done(v5)
This patch removes 100ms polling for driver_probe_done in
wait_for_device_probe(), and uses wait_event() instead.
Removing polling in fs initialization may lead to
a faster boot.

This patch also changes the return type of wait_for_device_done()
from int to void.

This patch is against Arjan's patch in linux-next tree.

Signed-off-by: Ming Lei <tom.leiming@gmail.com>
Acked-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Reviewed-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2009-03-24 16:38:25 -07:00
Eric W. Biederman
04256b4a8f sysfs: reference sysfs_dirent from sysfs inodes
The sysfs_dirent serves as both an inode and a directory entry
for sysfs.  To prevent the sysfs inode numbers from being freed
prematurely hold a reference to sysfs_dirent from the sysfs inode.

[akpm@linux-foundation.org: add comment]
Signed-off-by: Eric W. Biederman <ebiederm@aristanetworks.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2009-03-24 16:38:25 -07:00
Alex Chiang
425cb02912 sysfs: sysfs_add_one WARNs with full path to duplicate filename
sysfs: sysfs_add_one WARNs with full path to duplicate filename

As a debugging aid, it can be useful to know the full path to a
duplicate file being created in sysfs.

We now will display warnings such as:

	sysfs: cannot create duplicate filename '/foo'

when attempting to create multiple files named 'foo' in the sysfs
root, or:

	sysfs: cannot create duplicate filename '/bus/pci/slots/5/foo'

when attempting to create multiple files named 'foo' under a
given directory in sysfs.

The path displayed is always a relative path to sysfs_root. The
leading '/' in the path name refers to the sysfs_root mount
point, and should not be confused with the "real" '/'.

Thanks to Alex Williamson for essentially writing sysfs_pathname.

Cc: Alex Williamson <alex.williamson@hp.com>
Signed-off-by: Alex Chiang <achiang@hp.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2009-03-24 16:38:25 -07:00
Dave Young
f48f3febb2 driver-core: do not register a driver with bus_type not registered
If the bus_type is not registerd, driver_register to that bus will cause oops.

I found this bug when test built-in usb serial drivers (ie. aircable driver)
with 'nousb' cmdline params.

In this patch:
1. set the bus->p=NULL when bus_register failed and unregisterd.
2. if bus->p is NULL, driver_register BUG_ON will be triggered.

Signed-off-by: Dave Young <hidave.darkstar@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2009-03-24 16:38:25 -07:00
Geert Uytterhoeven
e5779a583d scsi/m68k: Kill NCR_700_detect() warnings
The patch from Ming Lei <tom.leiming@gmail.com> entitled:
    platform driver: fix incorrect use of 'platform_bus_type' with 'struct devic
introduced the following warnings on m68k, as `dev' is now a `struct
platform_device *' instead of a `struct device *':

| drivers/scsi/a4000t.c:64: warning: passing argument 3 of 'NCR_700_detect' from incompatible pointer type
| drivers/scsi/mvme16x_scsi.c:67: warning: passing argument 3 of 'NCR_700_detect' from incompatible pointer type
| drivers/scsi/bvme6000_scsi.c:61: warning: passing argument 3 of 'NCR_700_detect' from incompatible pointer type

I think the below is missing (untested on real hardware).

Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Ming Lei <tom.leiming@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2009-03-24 16:38:25 -07:00
Ming Lei
7a192ec334 platform driver: fix incorrect use of 'platform_bus_type' with 'struct device_driver'
This patch fixes the bug reported in
	http://bugzilla.kernel.org/show_bug.cgi?id=11681.

"Lots of device drivers register a 'struct device_driver' with
the '.bus' member set to '&platform_bus_type'. This is wrong,
since the platform_bus functions expect the 'struct device_driver'
to be wrapped up in a 'struct platform_driver' which provides
some additional callbacks (like suspend_late, resume_early).
The effect may be that platform_suspend_late() uses bogus data
outside the device_driver struct as a pointer pointer to the
device driver's suspend_late() function or other hard to
reproduce failures."(Lothar Wassmann)

Signed-off-by: Ming Lei <tom.leiming@gmail.com>
Acked-by: Henrique de Moraes Holschuh <hmh@hmh.eng.br>
Acked-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2009-03-24 16:38:25 -07:00
Ian Abbott
6da2d377bb UIO: Take offset into account when determining number of pages that can be mapped
If a UIO memory region does not start on a page boundary but straddles one,
the number of actual pages that overlap the memory region may be calculated
incorrectly because the offset isn't taken into account.  If userspace sets
the mmap length to offset+size, it may fail with -EINVAL if UIO thinks it's
trying to allocate too many pages.

Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Cc: Hans J. Koch <hjk@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2009-03-24 16:38:25 -07:00
Brandon Philips
1bafeb378e uio: add the uio_aec driver
UIO driver for the Adrienne Electronics Corporation PCI time code
device.

This device differs from other UIO devices since it uses I/O ports instead of
memory mapped I/O. In order to make it possible for UIO to work with this
device a utility, uioport, can be used to read and write the ports.

uioport is designed to be a setuid program and checks the permissions of
the /dev/uio* node and if the user has write permissions it will use
iopl and out*/in* to access the device.

[1] git clone git://ifup.org/philips/uioport.git

Signed-off-by: Brandon Philips <brandon@ifup.org>
Signed-off-by: Hans J. Koch <hjk@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2009-03-24 16:38:24 -07:00
Hans J. Koch
8205779114 UIO: Add name attributes for mappings and port regions
If a UIO device has several memory mappings, it can be difficult for userspace
to find the right one. The situation becomes even worse if the UIO driver can
handle different versions of a card that have different numbers of mappings.
Benedikt Spranger has such cards and pointed this out to me. Thanks, Bene!

To address this problem, this patch adds "name" sysfs attributes for each
mapping. Userspace can use these to clearly identify each mapping. The name
string is optional. If a driver doesn't set it, an empty string will be
returned, so this patch won't break existing drivers.

The same problem exists for port region information, so a "name" attribute is
added there, too.

Signed-off-by: Hans J. Koch <hjk@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2009-03-24 16:38:24 -07:00
Eric Miao
57fee4a58f platform: introduce module id table for platform devices
Now platform_device is being widely used on SoC processors where the
peripherals are attached to the system bus, which is simple enough.

However, silicon IPs for these SoCs are usually shared heavily across
a family of processors, even products from different companies.  This
makes the original simple driver name based matching insufficient, or
simply not straight-forward.

Introduce a module id table for platform devices, and makes it clear
that a platform driver is able to support some shared IP and handle
slight differences across different platforms (by 'driver_data').
Module alias is handled automatically when a MODULE_DEVICE_TABLE()
is defined.

To not disturb the current platform drivers too much, the matched id
entry is recorded and can be retrieved by platform_get_device_id().

Signed-off-by: Eric Miao <eric.miao@marvell.com>
Cc: Kay Sievers <kay.sievers@vrfy.org>
Cc: Ben Dooks <ben-linux@fluff.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2009-03-24 16:38:24 -07:00
Eric Miao
71b3e0c1ad platform: make better use of to_platform_{device,driver}() macros
This helps the code look more consistent and cleaner.

Signed-off-by: Eric Miao <eric.miao@marvell.com>
Cc: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2009-03-24 16:38:24 -07:00
Ming Lei
49b420a13f driver core: check bus->match without holding device lock
This patch moves bus->match out from driver_probe_device and
does not hold device lock to check the match between a device
and a driver.

The idea has been verified by the commit 6cd4958609,
which leads to a faster boot. But the commit 6cd4958609 has
the following drawbacks: 1),only does the quick check in
the path of __driver_attach->driver_probe_device, not in other
paths; 2),for a matched device and driver, check the same match
twice. It is a waste of cpu ,especially for some drivers with long
device id table (eg. usb-storage driver).

This patch adds a helper of driver_match_device to check the match
in all paths, and testes the match only once.

Signed-off-by: Ming Lei <tom.leiming@gmail.com>
Acked-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2009-03-24 16:38:24 -07:00
Eric W. Biederman
4a67a1bc0b sysfs: Take sysfs_mutex when fetching the root inode.
sysfs_get_inode ultimately calls sysfs_count_nlink when the a
directory inode is fectched.  sysfs_count_nlink needs to be
called under the sysfs_mutex to guard against the unlikely
but possible scenario that the root directory is changing
as we are counting the number entries in it, and just in
general to be consistent.

Signed-off-by: Eric W. Biederman <ebiederm@aristanetworks.com>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2009-03-24 16:38:24 -07:00
Qinghuang Feng
8231f2f99a SYSFS: use standard magic.h for sysfs
SYSFS_MAGIC has been added into magic.h, so only use that definition
in magic.h to avoid potential consistency problem.

Signed-off-by: Qinghuang Feng <qhfeng.kernel@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2009-03-24 16:38:24 -07:00
Kay Sievers
1fa5ae857b driver core: get rid of struct device's bus_id string array
Now that all users of bus_id is gone, we can remove it from struct
device.

Signed-off-by: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2009-03-24 16:38:23 -07:00
Sachin Sant
6866ac9db0 USB: FHCI: use dev_name() in place of bus_id.
Replace references to bus_id with dev_name() to fix fhci driver build break.

drivers/usb/host/fhci-hcd.c:586: error: struct device has no member named bus_id
drivers/usb/host/fhci-hcd.c:653: error: struct device has no member named bus_id
drivers/usb/host/fhci-dbg.c:111: error: struct device has no member named bus_id

Signed-off-by: Sachin Sant <sachinp@in.ibm.com>
Acked-by: Anton Vorontsov <avorontsov@ru.mvista.com>
Cc: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2009-03-24 16:38:23 -07:00
Greg Kroah-Hartman
54ca5412b5 PS3: replace bus_id usage
These simple debug statments should be using dev_dbg() instead of
accessing bus_id directly (or they should use device_name).

As bus_id is going away, this patch is necessary.

Acked-by: Geoff Levand <geoffrey.levand@am.sony.com>
Cc: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2009-03-24 16:38:23 -07:00
Kay Sievers
5df5852446 usb: struct device - replace bus_id with dev_name(), dev_set_name()
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Kay Sievers <kay.sievers@vrfy.org>
2009-03-24 16:38:23 -07:00
Kay Sievers
2c0f3e96f3 wimax: struct device - replace bus_id with dev_name(), dev_set_name()
Cc: inaky.perez-gonzalez@intel.com
Cc: linux-wimax@intel.com
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Kay Sievers <kay.sievers@vrfy.org>
2009-03-24 16:38:23 -07:00
Kay Sievers
b2bf61f23f mfd: struct device - replace bus_id with dev_name(), dev_set_name()
Cc: sameo@openedhand.com
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Kay Sievers <kay.sievers@vrfy.org>
2009-03-24 16:38:23 -07:00
Kay Sievers
cf43f4ab3a mca: struct device - replace bus_id with dev_name(), dev_set_name()
Cc: James.Bottomley@HansenPartnership.com
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Kay Sievers <kay.sievers@vrfy.org>
2009-03-24 16:38:23 -07:00
Kay Sievers
3e274bd02b gpio: struct device - replace bus_id with dev_name(), dev_set_name()
Cc: Michael Buesch <mb@bu3sch.de>
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Kay Sievers <kay.sievers@vrfy.org>
2009-03-24 16:38:23 -07:00
Kay Sievers
e537b2453c eisa: struct device - replace bus_id with dev_name(), dev_set_name()
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Kay Sievers <kay.sievers@vrfy.org>
2009-03-24 16:38:22 -07:00
Kay Sievers
dfbc90196d dma: struct device - replace bus_id with dev_name(), dev_set_name()
Cc: Dan Williams <dan.j.williams@intel.com>
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Kay Sievers <kay.sievers@vrfy.org>
2009-03-24 16:38:22 -07:00
Kay Sievers
9591463af7 dio: struct device - replace bus_id with dev_name(), dev_set_name()
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Kay Sievers <kay.sievers@vrfy.org>
2009-03-24 16:38:22 -07:00
Kay Sievers
9d6b4c82bf amba: struct device - replace bus_id with dev_name(), dev_set_name()
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Kay Sievers <kay.sievers@vrfy.org>
2009-03-24 16:38:22 -07:00
Kay Sievers
c3ef01ce4f v4l: struct device - replace bus_id with dev_name(), dev_set_name()
Cc: mchehab@infradead.org
Cc: linux-media@vger.kernel.org
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Kay Sievers <kay.sievers@vrfy.org>
2009-03-24 16:38:22 -07:00
Kay Sievers
2ead054cd2 drm: struct device - replace bus_id with dev_name(), dev_set_name()
Cc: airlied@linux.ie
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Kay Sievers <kay.sievers@vrfy.org>
2009-03-24 16:38:22 -07:00
Kay Sievers
c23135573f net: struct device - replace bus_id with dev_name(), dev_set_name()
Cc: davem@davemloft.net
Cc: netdev@vger.kernel.org
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Kay Sievers <kay.sievers@vrfy.org>
2009-03-24 16:38:22 -07:00
Kay Sievers
744bcb13d3 rtc: struct device - replace bus_id with dev_name(), dev_set_name()
Cc: a.zummo@towertech.it
Cc: rtc-linux@googlegroups.com
Signed-off-by: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Alessandro Zummo <a.zummo@towertech.it>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2009-03-24 16:38:22 -07:00
Kay Sievers
f2fecec51a pcmcia: struct device - replace bus_id with dev_name(), dev_set_name()
Cc: Dominik Brodowski <linux@dominikbrodowski.net>
Cc: linux-pcmcia@lists.infradead.org
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Kay Sievers <kay.sievers@vrfy.org>
2009-03-24 16:38:22 -07:00
Kay Sievers
df388556d7 tc: struct device - replace bus_id with dev_name(), dev_set_name()
Cc: macro@linux-mips.org
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Kay Sievers <kay.sievers@vrfy.org>
2009-03-24 16:38:22 -07:00
Kay Sievers
1692713ee9 sh: struct device - replace bus_id with dev_name(), dev_set_name()
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Kay Sievers <kay.sievers@vrfy.org>
2009-03-24 16:38:21 -07:00
Kay Sievers
65a212dd71 serial: struct device - replace bus_id with dev_name(), dev_set_name()
Cc: davem@davemloft.net
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Kay Sievers <kay.sievers@vrfy.org>
2009-03-24 16:38:21 -07:00
Kay Sievers
1173960b0e s390: struct device - replace bus_id with dev_name(), dev_set_name()
Cc: schwidefsky@de.ibm.com
Cc: linux-s390@vger.kernel.org
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Kay Sievers <kay.sievers@vrfy.org>
2009-03-24 16:38:21 -07:00
Kay Sievers
37f105448e rapidio: struct device - replace bus_id with dev_name(), dev_set_name()
Cc: mporter@kernel.crashing.org
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Kay Sievers <kay.sievers@vrfy.org>
2009-03-24 16:38:21 -07:00
Kay Sievers
54cc6954a4 pci: struct device - replace bus_id with dev_name(), dev_set_name()
Cc: jbarnes@virtuousgeek.org
Cc: linux-pci@vger.kernel.org
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Kay Sievers <kay.sievers@vrfy.org>
2009-03-24 16:38:21 -07:00
Kay Sievers
c36f1e3301 mtd: struct device - replace bus_id with dev_name(), dev_set_name()
Cc: dwmw2@infradead.org
Cc: linux-mtd@lists.infradead.org
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Kay Sievers <kay.sievers@vrfy.org>
2009-03-24 16:38:21 -07:00
Kay Sievers
48f8151ea6 mmc: struct device - replace bus_id with dev_name(), dev_set_name()
Cc: drzeus-mmc@drzeus.cx
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Kay Sievers <kay.sievers@vrfy.org>
2009-03-24 16:38:21 -07:00
Kay Sievers
2796872c40 zorro: struct device - replace bus_id with dev_name(), dev_set_name()
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Kay Sievers <kay.sievers@vrfy.org>
2009-03-24 16:38:21 -07:00
Kay Sievers
7ad33e7485 video: struct device - replace bus_id with dev_name(), dev_set_name()
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Kay Sievers <kay.sievers@vrfy.org>
2009-03-24 16:38:21 -07:00
Kay Sievers
6c7377ab68 spi: struct device - replace bus_id with dev_name(), dev_set_name()
Cc: dbrownell@users.sourceforge.net
Cc: spi-devel-general@lists.sourceforge.net
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Kay Sievers <kay.sievers@vrfy.org>
2009-03-24 16:38:21 -07:00
Kay Sievers
031d551859 edac: struct device - replace bus_id with dev_name(), dev_set_name()
Cc: dougthompson@xmission.com
Cc: bluesmoke-devel@lists.sourceforge.net
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Kay Sievers <kay.sievers@vrfy.org>
2009-03-24 16:38:21 -07:00
Linus Torvalds
8e0ee43bc2 Linux 2.6.29 2009-03-23 16:12:14 -07:00
Kyle McMartin
003086497f Build with -fno-dwarf2-cfi-asm
With a sufficiently new compiler and binutils, code which wasn't
previously generating .eh_frame sections has begun to.  Certain
architectures (powerpc, in this case) may generate unexpected relocation
formats in response to this, preventing modules from loading.

While the new relocation types should probably be handled, revert to the
previous behaviour with regards to generation of .eh_frame sections.

(This was reported against Fedora, which appears to be the only distro
doing any building against gcc-4.4 at present: RH bz#486545.)

Signed-off-by: Kyle McMartin <kyle@redhat.com>
Acked-by: Roland McGrath <roland@redhat.com>
Cc: Alexandre Oliva <aoliva@redhat.com>
Cc: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-03-23 14:21:26 -07:00
Jody McIntyre
1db4b2d221 trivial: fix orphan dates in ext2 documentation
Revert the change to the orphan dates of Windows 95, DOS, compression.
Add a new orphan date for OS/2.

Signed-off-by: Jody McIntyre <scjody@sun.com>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-03-23 14:21:26 -07:00
Linus Torvalds
d56ffd38a9 Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-2.6
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-2.6: (32 commits)
  ucc_geth: Fix oops when using fixed-link support
  dm9000: locking bugfix
  net: update dnet.c for bus_id removal
  dnet: DNET should depend on HAS_IOMEM
  dca: add missing copyright/license headers
  nl80211: Check that function pointer != NULL before using it
  sungem: missing net_device_ops
  be2net: fix to restore vlan ids into BE2 during a IF DOWN->UP cycle
  be2net: replenish when posting to rx-queue is starved in out of mem conditions
  bas_gigaset: correctly allocate USB interrupt transfer buffer
  smsc911x: reset last known duplex and carrier on open
  sh_eth: Fix mistake of the address of SH7763
  sh_eth: Change handling of IRQ
  netns: oops in ip[6]_frag_reasm incrementing stats
  net: kfree(napi->skb) => kfree_skb
  net: fix sctp breakage
  ipv6: fix display of local and remote sit endpoints
  net: Document /proc/sys/net/core/netdev_budget
  tulip: fix crash on iface up with shirq debug
  virtio_net: Make virtio_net support carrier detection
  ...
2009-03-23 09:25:58 -07:00
Linus Torvalds
12a37b5e2c Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/sparc-2.6
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/sparc-2.6:
  sparc64: Fix crash with /proc/iomem
  sparc64: Reschedule KGDB capture to a software interrupt.
  sbus: Auto-load openprom module when device opened.
2009-03-23 09:25:24 -07:00
Miklos Szeredi
53da1d9456 fix ptrace slowness
This patch fixes bug #12208:

  Bug-Entry       : http://bugzilla.kernel.org/show_bug.cgi?id=12208
  Subject         : uml is very slow on 2.6.28 host

This turned out to be not a scheduler regression, but an already
existing problem in ptrace being triggered by subtle scheduler
changes.

The problem is this:

 - task A is ptracing task B
 - task B stops on a trace event
 - task A is woken up and preempts task B
 - task A calls ptrace on task B, which does ptrace_check_attach()
 - this calls wait_task_inactive(), which sees that task B is still on the runq
 - task A goes to sleep for a jiffy
 - ...

Since UML does lots of the above sequences, those jiffies quickly add
up to make it slow as hell.

This patch solves this by not rescheduling in read_unlock() after
ptrace_stop() has woken up the tracer.

Thanks to Oleg Nesterov and Ingo Molnar for the feedback.

Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
CC: stable@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-03-23 09:22:31 -07:00
Linus Torvalds
b0dcb4a91d Merge branch 'merge' of git://git.kernel.org/pub/scm/linux/kernel/git/galak/powerpc
* 'merge' of git://git.kernel.org/pub/scm/linux/kernel/git/galak/powerpc:
  powerpc/mm: Fix Respect _PAGE_COHERENT on classic ppc32 SW TLB load machines
2009-03-23 08:03:09 -07:00