We need to figure out what userspace programs are expecting from this
driver, so log them so we can try to get it right.
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This is for the Symbol 6608 barcode scanner in a fake "HID" mode.
Thanks to Dalibor Grgec for working with me to get this to start to work
properly.
Cc: Dalibor Grgec <dalibor.grgec@zemris.fer.hr>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Currently, the driver only supports PCI and PPC_OF but there are
boards like ARM RealView where this is a platform device. The patch adds
the necessary functions and registration to the isp1760-if.c file and
modifies the corresponding Makefile and Kconfig to be able to use this
driver even if PCI and PPC_OF are not enabled.
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: Sebastian Siewior <bigeasy@linutronix.de>
Cc: Russell King <rmk@arm.linux.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
The patch changes the prototype of the isp1760_register() function to use
predefined types like phys_addr_t and resource_size_t rather than u64
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: Sebastian Siewior <bigeasy@linutronix.de>
Cc: Russell King <rmk@arm.linux.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This patch (as1204) adds a software retry mechanism to ehci-hcd. It
gets invoked when the driver encounters transaction errors on an
asynchronous endpoint. On many systems, hardware deficiencies cause
such errors to occur if one device is unplugged while the host is
communicating with another device. With the patch, the failed
transactions are retried and generally succeed the second or third
time through.
This is based on code originally written by Koichiro Saito.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Tested by: Koichiro Saito <Saito.Koichiro@adniss.jp>
CC: David Brownell <david-b@pacbell.net>
Cc: stable <stable@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
commit 64a87b24: [SCSI] Let scsi_cmnd->cmnd use request->cmd buffer
changed the scsi_eh_prep_cmnd logic by making it clear
the ->cmnd buffer. But the sat to cypress atacb translation supposed
the ->cmnd buffer wasn't modified.
This patch makes it set the ->cmnd buffer after scsi_eh_prep_cmnd call.
The problem and a fix was reported by Matthieu CASTET <castet.matthieu@free.fr>
It also removes all the hackery fiddling of scsi_cmnd and scsi_eh_save by
requesting from scsi_eh_prep_cmnd to prepare a read into ->sense_buffer,
which is much more suitable a buffer for HW transfers, then after the command
execution the regs read is copied into regs buffer before actual preparation
of sense_buffer.
Also fix an alien comment character to my utf-8 editor.
Signed-off-by: Boaz Harrosh <bharrosh@panasas.com>
Signed-off-by: Matthieu CASTET <castet.matthieu@free.fr>
Cc: stable <stable@kernel.org>
Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
Cc: Matthew Dharm <mdharm-kernel@one-eyed-alien.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This patch (as1205) moves timer_action() from ehci.h to ehci-hcd.c and
makes it out-of-line. Over the years it has grown too big to be inline
any more.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Acked-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Remove old comments about USB_EHCI_HCD.
Cc: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
A USB-serial converter device is plugged into a system, and a process
opens it's device node. If the device is physically removed whilst the
process still has its device node open, then other processes can
sucessfully open the now non-existent device's node. I would expect
that open() on a device that has been physically removed should return
ENODEV.
This is manifesting itself with getty on my system. I do the following:
1. set up inittab to spawn getty on ttyUSB0, eg:
T1:23:respawn:/sbin/getty -L ttyUSB0 115200 vt100
2. Plug in USB-serial converter cable
3. Wait for a login prompt on a terminal program attached to the serial
cable
4. Login
5. Pull the USB-serial converter cable from the box
6. getty doesn't realise that ttyUSB0 no longer exists as /dev/ttyUSB0
can still be opened.
7. Re-insert the USB-serial converter cable
8. You should no longer get a login prompt over the serial cable, as
the the USB-serial cable now shows up as /dev/ttyUSB1, and getty is
trying to talk to /dev/ttyUSB0.
The attached patch will cause open("/dev/ttyUSB0", O_RDONLY) to return
ENODEV after the USB-serial converter has been pulled. The patch was
created against 2.6.28.1. I can supply it against something else if
needs be. It is fairly simple, so should be OK.
I am using a pl2303 device, although I don't think that makes any
difference.
From: James Woodcock <James.Woodcock@ACULAB.COM>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This removes the fallback to the generic method. It is cleaner to
explicitely request it. Introducing this was my mistake. This will
be solved by an explicit test and the driver being allowed to request
what it needs to be done upon resumption.
Signed-off-by: Oliver Neukum <oneukum@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
338b67b0c1 removed the info macro and
replaced its uses with dev_info. This patch does so for
usb-skeleton.c, which was missed.
Signed-off-by: Matt Kraai <kraai@ftbfs.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Make lines about usb_storage depending on SCSI visible when configuring the
kernel in a 80x25 console
Signed-off-by: Borislav Petkov <petkovbb@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This lets userspace determine what the state of the RTS line is, which
is what is needed to properly handle data flow for this device (it
raises RTS when there is data to be sent from it.)
Cc: Kees Stoop <kees.stoop@opticon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
NOP transceiver is used by all the usb transceiver which are mostly
autonomous and doesn't require any programming or which are built
into the usb ip itself.NOP transceiver only allocates the memory
for struct xceiv and calls otg_set_transceiver() so function call
to otg_get_transceiver() will return a valid transceiver.
NOP transceiver device should be registered by calling
usb_nop_xceiv_register() from platform files.
Signed-off-by: Ajay Kumar Gupta <ajay.gupta@ti.com>
Cc: Felipe Balbi <felipe.balbi@nokia.com>
Cc: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Remove some pointless messages from the FTDI serial driver;
I found these filling up syslog on one system. Also remove
a pointless "break" after a "return" in the same area.
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
According to kerneljanitors todo list all printk calls (beginning
a new line) should have an according KERN_* constant.
Those are the missing peaces here for the usb subsystem.
Signed-off-by: Frank Seidel <frank@f-seidel.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This patch makes use of the generic method if a serial driver provides
no implementation. This simplifies implementing suspend/resume support
in serial drivers.
Signed-off-by: Oliver Neukum <oneukum@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This exports a symbol for usb_serial_generic_resume, so that modules can
use it.
Signed-off-by: Oliver Neukum <oneukum@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This removes an unnecessary check for autoresume from the generic
resume method. The check has been obsoleted by the now delayed
increase of the usage counter which makes the error this check prevented
impossible. This change allows drivers which only use the bulk read URB
the use of the generic method even if they support autosuspend.
Signed-off-by: Oliver Neukum <oneukum@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This patch introduces a flag into the usb serial layer to tell drivers
that their URBs are killed due to suspension. That is necessary to let
drivers know whether they should report an error back.
Signed-off-by: Oliver Neukum <oneukum@suse.de>
Hi Greg,
this is for 2.6.30. Patches to use this in drivers are under development.
Regards
Oliver
With a postfix decrement count will reach -1 rather than 0,
so the warning will not be issued.
Signed-off-by: Roel Kluin <roel.kluin@gmail.com>
Acked-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
this does the standard support for suspend/resume for the opticon
driver.
Signed-off-by: Oliver Neukum <oneukum@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This patch implements suspend and resume methods for the
option driver. With my hardware I can even suspend the system
and keep up a connection for a short time.
Signed-off-by: Oliver Neukum <oneukum@suse.de>
Signed-Off-By: Matthias Urlichs <smurf@smurf.noris.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Workaround of hw bug in IMX UDC.
This bug causes wrong handling of CFG_CHG interrupt.
Workaround is documented inline source code.
Signed-off-by: Darius Augulis <augulis.darius@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Fix small bugs and add some omptimization in IMX UDC Gadget.
Signed-off-by: Darius Augulis <augulis.darius@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Fixup of Werner Cornelius patch to the ch341 USB-serial driver, which adds:
- support all baudrates, not just a hard-coded set
- support for controlling DTR, RTS and CTS
Features still missing:
- character length other than 8 bits
- parity settings
- break control
I adapted his patch for the new usb_serial API introduced in 2.6.25-git8 by
Alan Cox on 22 July 2008. Non-compliance to the new API was a reason for
refusing a similar patch from Tollef Fog Heen.
Usage example by Tollef Fog Heen :
TEMPer USB thermometer <http://err.no/src/TEMPer.c>
Signed-off-by: Werner Cornelius <Werner.Cornelius@cornelius-consult.de>
Signed-off-by: Boris Hajduk <boris@hajduk.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This set of patches introduces calls to the following set of functions:
usb_endpoint_dir_in(epd)
usb_endpoint_dir_out(epd)
usb_endpoint_is_bulk_in(epd)
usb_endpoint_is_bulk_out(epd)
usb_endpoint_is_int_in(epd)
usb_endpoint_is_int_out(epd)
usb_endpoint_num(epd)
usb_endpoint_type(epd)
usb_endpoint_xfer_bulk(epd)
usb_endpoint_xfer_control(epd)
usb_endpoint_xfer_int(epd)
usb_endpoint_xfer_isoc(epd)
In some cases, introducing one of these functions is not possible, and it
just replaces an explicit integer value by one of the following constants:
USB_ENDPOINT_XFER_BULK
USB_ENDPOINT_XFER_CONTROL
USB_ENDPOINT_XFER_INT
USB_ENDPOINT_XFER_ISOC
An extract of the semantic patch that makes these changes is as follows:
(http://www.emn.fr/x-info/coccinelle/)
// <smpl>
@r1@ struct usb_endpoint_descriptor *epd; @@
- ((epd->bmAttributes & \(USB_ENDPOINT_XFERTYPE_MASK\|3\)) ==
- \(USB_ENDPOINT_XFER_CONTROL\|0\))
+ usb_endpoint_xfer_control(epd)
@r5@ struct usb_endpoint_descriptor *epd; @@
- ((epd->bEndpointAddress & \(USB_ENDPOINT_DIR_MASK\|0x80\)) ==
- \(USB_DIR_IN\|0x80\))
+ usb_endpoint_dir_in(epd)
@inc@
@@
#include <linux/usb.h>
@depends on !inc && (r1||r5)@
@@
+ #include <linux/usb.h>
#include <linux/usb/...>
// </smpl>
Signed-off-by: Julia Lawall <julia@diku.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
priv is checked not to be NULL near the beginning of the function and not
changed subsequently, making the test redundant.
A simplified version of the semantic patch that makes this change is as
follows: (http://www.emn.fr/x-info/coccinelle/)
// <smpl>
@r exists@
local idexpression x;
expression E;
position p1,p2;
@@
if (x@p1 == NULL || ...) { ... when forall
return ...; }
... when != \(x=E\|x--\|x++\|--x\|++x\|x-=E\|x+=E\|x|=E\|x&=E\|&x\)
(
x@p2 == NULL
|
x@p2 != NULL
)
// another path to the test that is not through p1?
@s exists@
local idexpression r.x;
position r.p1,r.p2;
@@
... when != x@p1
(
x@p2 == NULL
|
x@p2 != NULL
)
@fix depends on !s@
position r.p1,r.p2;
expression x,E;
statement S1,S2;
@@
(
- if ((x@p2 != NULL) || ...)
S1
|
- if ((x@p2 == NULL) && ...) S1
|
- BUG_ON(x@p2 == NULL);
)
// </smpl>
Signed-off-by: Julia Lawall <julia@diku.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This set of patches introduces calls to the following set of functions:
usb_endpoint_dir_in(epd)
usb_endpoint_dir_out(epd)
usb_endpoint_is_bulk_in(epd)
usb_endpoint_is_bulk_out(epd)
usb_endpoint_is_int_in(epd)
usb_endpoint_is_int_out(epd)
usb_endpoint_num(epd)
usb_endpoint_type(epd)
usb_endpoint_xfer_bulk(epd)
usb_endpoint_xfer_control(epd)
usb_endpoint_xfer_int(epd)
usb_endpoint_xfer_isoc(epd)
In some cases, introducing one of these functions is not possible, and it
just replaces an explicit integer value by one of the following constants:
USB_ENDPOINT_XFER_BULK
USB_ENDPOINT_XFER_CONTROL
USB_ENDPOINT_XFER_INT
USB_ENDPOINT_XFER_ISOC
An extract of the semantic patch that makes these changes is as follows:
(http://www.emn.fr/x-info/coccinelle/)
// <smpl>
@r1@ struct usb_endpoint_descriptor *epd; @@
- ((epd->bmAttributes & \(USB_ENDPOINT_XFERTYPE_MASK\|3\)) ==
- \(USB_ENDPOINT_XFER_CONTROL\|0\))
+ usb_endpoint_xfer_control(epd)
@r5@ struct usb_endpoint_descriptor *epd; @@
- ((epd->bEndpointAddress & \(USB_ENDPOINT_DIR_MASK\|0x80\)) ==
- \(USB_DIR_IN\|0x80\))
+ usb_endpoint_dir_in(epd)
@inc@
@@
#include <linux/usb.h>
@depends on !inc && (r1||r5)@
@@
+ #include <linux/usb.h>
#include <linux/usb/...>
// </smpl>
Signed-off-by: Julia Lawall <julia@diku.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
The functions:
usb_endpoint_dir_in(epd)
usb_endpoint_dir_out(epd)
usb_endpoint_is_bulk_in(epd)
usb_endpoint_is_bulk_out(epd)
usb_endpoint_is_int_in(epd)
usb_endpoint_is_int_out(epd)
usb_endpoint_is_isoc_in(epd)
usb_endpoint_is_isoc_out(epd)
usb_endpoint_num(epd)
usb_endpoint_type(epd)
usb_endpoint_xfer_bulk(epd)
usb_endpoint_xfer_control(epd)
usb_endpoint_xfer_int(epd)
usb_endpoint_xfer_isoc(epd)
are moved from include/linux/usb.h to include/linux/usb/ch9.h.
include/linux/usb/ch9.h makes more sense for these functions because they
only depend on constants that are defined in this file.
Signed-off-by: Julia Lawall <julia@diku.dk>
Acked-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Add the vbus_draw() callback to inform the transceiver, if
it exists, how much current may be drawn. The decision is
taken on gadget driver side using the configuration chosen
by the host and its bMaxPower field. Some systems can use
the host's VBUS supply to augment or recharge a battery.
(There's also a default of 100 mA for unconfigured devices,
or 8 mA if they're OTG devices.)
Signed-off-by: Robert Jarzmik <robert.jarzmik@free.fr>
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
When a transceiver driver is used, no automatic udc enable
is done. The transceiver (OTG or not) should :
- take care of VBus sensing
- call usb_gadget_vbus_connect()
- call usb_gadget_vbus_disconnect()
The pullup should remain within this driver's management,
either by gpio_pullup of udc_command() fields.
Signed-off-by: Robert Jarzmik <robert.jarzmik@free.fr>
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
On vbus_session() call, optionally activate D+ pullup
resistor and enable the udc, or deactivate D+ pullup
resistor and disable the udc.
It is intentional to not handle any VBus sense related irq.
An external transceiver driver (like gpio_vbus) should
catch VBus sense signal, and call usb_gadget_vbus_connect()
or usb_gadget_vbus_disconnect().
Signed-off-by: Robert Jarzmik <robert.jarzmik@free.fr>
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Prepare pxa27x_udc to handle usb D+ pullup properly : it
should connect the pullup resistor and disconnect it only
if no external transceiver is handling it.
[ dbrownell@users.sourceforge.net: kerneldoc and gpio fixes ]
Signed-off-by: Robert Jarzmik <robert.jarzmik@free.fr>
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Call usb_gadget_vbus_connect() and ...disconnect() from a
workqueue rather than from an irq handler, allowing msleep()
calls in vbus_session. Update kerneldoc to match.
[ dbrownell@users.sourceforge.net: more kerneldoc updates ]
Signed-off-by: Robert Jarzmik <robert.jarzmik@free.fr>
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
The usblp in 2.6.18 polled for status regardless if we actually needed it.
At some point I dropped it, to save the batteries if nothing else.
As it turned out, printers exist (e.g. Canon BJC-3000) that need prodding
this way or else they stop. This patch restores the old behaviour.
If you want to save battery, don't leave jobs in the print queue.
I tested this on my printers by printing and examining usbmon traces
to make sure status is being requested and printers continue to print.
Tuomas Jäntti verified the fix on BJC-3000.
Signed-off-by: Pete Zaitcev <zaitcev@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This patch (as1203) increases the max_sector limit for USB tape
drives. By default usb-storage sets max_sectors to 240 (i.e., 120 KB)
for all devices. But tape drives need a higher limit, since tapes can
and do have very large block sizes. Without the ability to transfer
an entire large block in a single command, such tapes can't be used.
This fixes Bugzilla #12207.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Reported-and-tested-by: Phil Mitchell <philipm@sybase.com>
Cc: stable <stable@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Restore some code that was wrongly dropped from the RNDIS
driver, and caused interop problems observed with OpenMoko.
The issue is with hardware which needs help conforming to part
of the USB 2.0 spec (section 8.5.3.2); some can automagically
send a ZLP in response to an unexpected IN, but not all chips
will do that. We don't need to check the packet length ourselves
the way earlier code did, since the UDC must already check it.
But we do need to tell the UDC when it must force a short packet
termination of the data stage.
(Based on a patch from Aric D. Blumer <aric at sdgsystems.com>)
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Cc: stable <stable@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Apparently the Configuration and Interface strings aren't used as
often as the Vendor, Product, and Serial strings. In at least one
device (a Saitek Cyborg Gold 3D joystick), attempts to read the
Configuration string cause the device to stop responding to Control
requests.
This patch (as1226) adds a quirks flag, telling the kernel not to
read a device's Configuration or Interface strings, together with a
new quirk for the offending joystick.
Reported-by: Melchior FRANZ <melchior.franz@gmail.com>
Tested-by: Melchior FRANZ <melchior.franz@gmail.com>
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Cc: stable <stable@kernel.org> [2.6.28 and 2.6.29, nothing earlier]
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
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>
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>
* 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
...
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>
