Maintain a per-CPU global "struct pt_regs *" variable which can be used instead
of passing regs around manually through all ~1800 interrupt handlers in the
Linux kernel.
The regs pointer is used in few places, but it potentially costs both stack
space and code to pass it around. On the FRV arch, removing the regs parameter
from all the genirq function results in a 20% speed up of the IRQ exit path
(ie: from leaving timer_interrupt() to leaving do_IRQ()).
Where appropriate, an arch may override the generic storage facility and do
something different with the variable. On FRV, for instance, the address is
maintained in GR28 at all times inside the kernel as part of general exception
handling.
Having looked over the code, it appears that the parameter may be handed down
through up to twenty or so layers of functions. Consider a USB character
device attached to a USB hub, attached to a USB controller that posts its
interrupts through a cascaded auxiliary interrupt controller. A character
device driver may want to pass regs to the sysrq handler through the input
layer which adds another few layers of parameter passing.
I've build this code with allyesconfig for x86_64 and i386. I've runtested the
main part of the code on FRV and i386, though I can't test most of the drivers.
I've also done partial conversion for powerpc and MIPS - these at least compile
with minimal configurations.
This will affect all archs. Mostly the changes should be relatively easy.
Take do_IRQ(), store the regs pointer at the beginning, saving the old one:
struct pt_regs *old_regs = set_irq_regs(regs);
And put the old one back at the end:
set_irq_regs(old_regs);
Don't pass regs through to generic_handle_irq() or __do_IRQ().
In timer_interrupt(), this sort of change will be necessary:
- update_process_times(user_mode(regs));
- profile_tick(CPU_PROFILING, regs);
+ update_process_times(user_mode(get_irq_regs()));
+ profile_tick(CPU_PROFILING);
I'd like to move update_process_times()'s use of get_irq_regs() into itself,
except that i386, alone of the archs, uses something other than user_mode().
Some notes on the interrupt handling in the drivers:
(*) input_dev() is now gone entirely. The regs pointer is no longer stored in
the input_dev struct.
(*) finish_unlinks() in drivers/usb/host/ohci-q.c needs checking. It does
something different depending on whether it's been supplied with a regs
pointer or not.
(*) Various IRQ handler function pointers have been moved to type
irq_handler_t.
Signed-Off-By: David Howells <dhowells@redhat.com>
(cherry picked from 1b16e7ac850969f38b375e511e3fa2f474a33867 commit)
The purpose of this patch is to split off the case when a device does
not reply on the lower level (which is reported by HC hardware), and
a case when the device accepted the request, but does not reply at
upper level. This redefinition allows to diagnose issues easier,
without asking the user if the -110 happened "immediately".
The usbmon splits such cases already thanks to its timestamp, but
it's not always available.
I adjusted all drivers which I found affected (by searching for "urb").
Out of tree drivers may suffer a little bit, but I do not expect much
breakage. At worst they may print a few messages.
Signed-off-by: Pete Zaitcev <zaitcev@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
We all failed to notice that Franck's recent update to usb-storage allowed
an URB to complete after its context data was no longer valid. This patch
(as746) makes the driver wait for the URB to complete whenever there's a
timeout.
Although timeouts in usb-storage are relatively uncommon, they do occur.
Without this patch the code in 2.6.18-rc1 will fault within an interrupt
handler, which is not nice at all.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Cc: Greg KH <greg@kroah.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This patch (as701) modifies usb-storage to take advantage of the new
usb_reset_composite_device() API. Now we will be able to safely request
port resets even if other drivers are bound to a mass-storage device.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This patch uses completion timeout instead of a timer to implement
a timeout when submitting an URB.
It also put the task in interruptible state instead of an
uninterruptible one while waiting for the completion.
Signed-off-by: Franck Bui-Huu <vagabon.xyz@gmail.com>
Signed-off-by: Matthew Dharm <mdharm-usb@one-eyed-alien.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This patch is from Alan Stern (as560). It has been rediffed against a
current tree.
This patch allocates a separate buffer for usb-storage to use when
auto-sensing. Up to now we have been using the sense buffer embedded in a
scsi_cmnd struct, which is dangerous on hosts that (a) don't do
cache-coherent DMA or (b) have DMA alignment restrictions.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Matthew Dharm <mdharm-usb@one-eyed-alien.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This patch is originally from Alan Stern (as557). It has been re-diffed
against a current tree, and I also corrected a minor merging error.
Some time ago we introduced a delay before device scanning, because many
devices do not like to receive SCSI commands right after enumeration.
Now it turns out there's a device that doesn't like to receive
Get-Max-LUN right after enumeration either. Accordingly this patch
delays the Get-Max-LUN request until the beginning of the scanning
procedure. This fixes Bugzilla entry #5010.
Three things are worth noting. First, I removed the locking code from
usb_stor_acquire_resources. It's not needed, because the locking is to
protect against disconnect events and acquire_resources is only called
during probe (so the disconnect routine can't be called). Second, I
initialized to 0 the buffer used for the Get-Max-LUN response. It's not
really necessary, but it will prevent random values from showing up in
the debugging log when the request fails. Third, I added a test against
the SINGLE_LUN flag. This will allow us to use the flag to indicate
Bulk-only devices that can't handle Get-Max-LUN.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Matthew Dharm <mdharm-usb@one-eyed-alien.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
29 July 2005, Cambridge, MA:
This afternoon Alan Stern submitted a patch to remove the URB_ASYNC_UNLINK
flag from the Linux kernel. Mr. Stern explained, "This flag is a relic
from an earlier, less-well-designed system. For over a year it hasn't
been used for anything other than printing warning messages."
An anonymous spokesman for the Linux kernel development community
commented, "This is exactly the sort of thing we see happening all the
time. As the kernel evolves, support for old techniques and old code can
be jettisoned and replaced by newer, better approaches. Proprietary
operating systems do not have the freedom or flexibility to change so
quickly."
Mr. Stern, a staff member at Harvard University's Rowland Institute who
works on Linux only as a hobby, noted that the patch (labelled as548) did
not update two files, keyspan.c and option.c, in the USB drivers' "serial"
subdirectory. "Those files need more extensive changes," he remarked.
"They examine the status field of several URBs at times when they're not
supposed to. That will need to be fixed before the URB_ASYNC_UNLINK flag
is removed."
Greg Kroah-Hartman, the kernel maintainer responsible for overseeing all
of Linux's USB drivers, did not respond to our inquiries or return our
calls. His only comment was "Applied, thanks."
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This patch started life as as531 from Alan Stern. It has been rediffed
against the latest tree.
The SCSI people have deprecated the use of scsi_cmnd.serial_number for
anything other than printk. Worse than that, the SCSI core doesn't
always increment the number (when the error handler is running, for
example). So this patch creates a locally-stored value for use in
bulk-only tags. The net result is a simplification, since we no longer
have to save & restore the serial_number value while autosensing.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Matthew Dharm <mdharm-usb@one-eyed-alien.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This patch causes a port reset whenever there's a transport error or abort.
If that fails it reverts back to doing a mass-storage device reset. It
started life as as497 and was rediffed by me.
This makes error recovery a lot quicker and more reliable.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Matthew Dharm <mdharm-usb@one-eyed-alien.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This patch does two things to help reset recovery. It started life as
as496 and was rediffed by me.
First, the patch checks the result of a CLEAR_HALT request and doesn't reset the
endpoint's data toggle unless the request succeeded.
Second, it reduces the timeout for a device reset from 20 seconds to 5
seconds.
If all goes well, then I've finally figured quilt out and this patch should
apply cleanly.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Matthew Dharm <mdharm-usb@one-eyed-alien.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This patch changes the delay for the US_FL_GO_SLOW patch from 110us to 125.
Some delays need this extra delay includign Jan De Luyck's drive which spawned
the original increase from 110 to 110us. 125 is a microframe, so this delay
seems to make sense more than just be a random delay (thanks to David Brownell
for pointing that out after my original patch).
Signed-off-by: Phil Dibowitz <phil@ipom.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Index: gregkh-2.6/drivers/usb/storage/transport.c
===================================================================
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
