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 command "cdrecord dev=/dev/uba x.iso" prints nasty garbage if a blank
is not in the drive. This happens because drivers have to set req->errors
separately from just returning zero uptodate with end_that_request_first,
end_that_request_last. These functions only set error in BIO, but sg_io()
ignores it.
Since we're on it, let cdrecord access a device when ->changed is set.
It's useful if someone wants to know device capabilities without burning
anything.
Signed-Off-By: Pete Zaitcev <zaitcev@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Remove some silly messages and cast in stone "temporary" messages which
we keep around. Also, I am hesitant to remove the initialization retries
without having the hardware to test (anyone who was at KS04 has a spare?)
Signed-off-by: Pete Zaitcev <zaitcev@yahoo.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
<zaitcev> I am taling about this: "if (disk->flags & GENHD_FL_UP) del_gendisk(disk);"
<zaitcev> If del_gendisk() undoes add_disk() like viro just said, why is it conditional?
<viro> huh?
<viro> add_disk() sets the damn flag
<zaitcev> So, I should not need to check ever
<viro> so the above is "if I've called add_disk(), call gendisk()"
<viro> which might be what you want, of course
<viro> but usually you know if you'd done add_disk() on that puppy anyway
In ub, nobody upstream should ever see half-constructed disks before
they were passed to add_disk. To that end, only add the struct lun to
the list on the path of no return. With that fix in place, we do
not need to test GENHD_FL_UP.
Signed-off-by: Pete Zaitcev <zaitcev@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Remove the check for NULL which makes no sense. Suggested by Al.
Signed-off-by: Pete Zaitcev <zaitcev@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
In kernel 2.6.16, if a mounted storage device is removed, an oops happens
because ub supplies an interface device (and kobject) to the block layer,
but neglects to pin it. And apparently, the block layer expects its users
to pin device structures.
The code in ub was broken this way for years. But the bug was exposed only
by 2.6.16 when it started to call block_uevent on close, which traverses
device structures (kobjects actually).
Signed-off-by: Pete Zaitcev <zaitcev@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Matt mentioned that a very old ZIP-100 actually does need this, but I am
yet to see anyone who actually has one still working and uses ub with it.
He/she must be a retrocomputing geek, who can easily bias it to usb-storage
with libusual, if needed. Meanwhile, common folks have trouble with poorly
designed USB keys and some el-cheapo European music players. I think we
better drop this for now.
Signed-off-by: Pete Zaitcev <zaitcev@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Remove the "diag" file from the sysfs. The usbmon is good enough these days
so I do not need this feature anymore. Also, sysfs is a pain. Al Viro caught
a race in this, which I thought too bothersome to fix.
Signed-off-by: Pete Zaitcev <zaitcev@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
The first_open was long overdue for removal, but I wanted to keep this
separate for other changes in case of regressions.
Signed-off-by: Pete Zaitcev <zaitcev@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
For crying out loud, they have devices which do not like port resets.
So, do what usb-storage does and try both bulk and port resets.
We start with a port reset (which usb-storage does at the end of transport),
then do a Bulk reset, then a port reset again. This seems to work for me.
The code is getting dirtier and dirtier here, but I swear that I'll
do something about it (see those two new XXX). Honest.
Signed-off-by: Pete Zaitcev <zaitcev@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
If SCSI commands are submitted while other commands are still processed,
the dispatch loop turns, and we stop the work_timer. Then, if URB fails
to complete, ub hangs until the device is unplugged.
This does not happen often, becase we only allow one SCSI command per
block device, but does happen (on multi-LUN devices, for example).
The fix is to stop timer only when we actually going to change the state.
The nicest code would be to have the timer stopped in URB callback, but
this is impossible, because it can be called from inside a timer, through
the urb_unlink. Then we get BUG in timer.c:cascade(). So, we do it a
little dirtier.
Signed-off-by: Pete Zaitcev <zaitcev@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
The blk_cleanup_queue does not necesserily destroy the queue. When we
destroy the corresponding ub_dev, it may leave the queue spinlock pointer
dangling.
This patch moves spinlocks from ub_dev to static memory. The locking
scheme is not changed. These spinlocks are still separate from the ub_lock.
Signed-off-by: Pete Zaitcev <zaitcev@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
add @uptodate argument to end_that_request_last() and @error
to rq_end_io_fn(). there's no generic way to pass error code
to request completion function, making generic error handling
of non-fs request difficult (rq->errors is driver-specific and
each driver uses it differently). this patch adds @uptodate
to end_that_request_last() and @error to rq_end_io_fn().
for fs requests, this doesn't really matter, so just using the
same uptodate argument used in the last call to
end_that_request_first() should suffice. imho, this can also
help the generic command-carrying request jens is working on.
Signed-off-by: tejun heo <htejun@gmail.com>
Signed-Off-By: Jens Axboe <axboe@suse.de>
Implement command retries and resets in ub. It is advantageous for users
to know if their devices are getting bad. However, failing every I/O
is not practical if you have a external USB enclosure with a hard drive.
Signed-off-by: Pete Zaitcev <zaitcev@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This patch adds a shim driver libusual, which routes devices between
usb-storage and ub according to the common table, based on unusual_devs.h.
The help and example syntax is in Kconfig.
Signed-off-by: Pete Zaitcev <zaitcev@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
When building on a 64-bit platform, gcc produces a warning
"cast of a pointer to an integer of a different size".
The scatterlist.offset on the LHS is unsigned int, so I used
that originally.
Signed-off-by: Pete Zaitcev <zaitcev@yahoo.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
drivers/block/ub.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
This code appears to be more trouble than it's worth, considering that
no normal users reload drivers. So, we comment it for now. It is not
removed outright for the benefit of hackers (that is, myself).
Signed-off-by: Pete Zaitcev <zaitcev@yahoo.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This patch fixes a few problems with ub and cleans up a couple of things:
- Bump UB_MAX_REQ_SG, this allows to burn CDs
- Drop initialization of urb.transfer_flags,
now that URB_UNLINK_ASYNC is gone
- Add forgotten processing of stalls at GetMaxLUN
- Remove a few more P3-tagged printks whose time has come
- Correct comment about ZIP-100
Signed-off-by: Pete Zaitcev <zaitcev@yahoo.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
drivers/block/ub.c | 53 +++++++++++++++++++++++++++--------------------------
1 file changed, 27 insertions(+), 26 deletions(-)
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>
Back out Axboe-style quasi-S/G and replace it with one command and
repeated URBs. This is similar to what usb-storage does, only instead
of a few URBs allocated together, one URB is reused.
Jens's idea was very nice, but it collapsed when I had to support
packet commads for CD burning. I cannot issue two or more packet
commands where application expected only one.
However, burning does not work completely yet. The cdrecord starts,
recognizes the device, then aborts without writing a TOC.
Signed-off-by: Pete Zaitcev <zaitcev@yahoo.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
When Al Viro saw the ub.c, he observed that it was a proof positive of
Linus not reading patches anymore: names like fo_ob_ar_ba_2 used to
cause serious fireworks. In my defence, any good scheme can be pushed
to the realm of absurd if pushed far enough.
Signed-off-by: Pete Zaitcev <zaitcev@yahoo.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Evidently, Yani Ioannou's display is wider than mine.
Signed-off-by: Pete Zaitcev <zaitcev@yahoo.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This the quasi-S/G patch for ub as suggested by Jens Axboe at OLS and
implemented that night before 4 a.m. Surprisingly, it worked right away...
Alas, I had to skip some OLS partying, but it was for the good cause.
Now the speed of ub is quite acceptable even on partitions with small
block size.
The ub does not really support S/G. Instead, it just tells the block
layer that it does. Then, most of the time, the block layer merges
requests and passes single-segmnent requests down to ub; everything
works as before. Very rarely ub gets an unmerged S/G request. In such
case, it issues several commands to the device.
I added a small array of counters to monitor the merging (sg_stat).
This may be dropped later.
Signed-off-by: Pete Zaitcev <zaitcev@yahoo.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This patch fixes a microcode lockup in my CD-ROM adapters when a blank CD
is inserted. However, do not try to burn CDs yet! I'm pretty sure that
trying it will end in coasters.
- Fix a few cases where we were unable to resynchronize with replies
for previous commands. The main thing is to keep reading replies
in case of a stall. This is done with the new state CLRRS.
- Since I am forgetting the basic state machine already, document it.
- Move counter increments in the looping path in its own function.
- Fix a harmless buglet in case CSW read fails to submit: do not
override state.
- Implement the Alan Stern's idea for adaptive signature checking.
Signed-off-by: Pete Zaitcev <zaitcev@yahoo.com>
Cc: Greg KH <greg@kroah.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This smoothes two imperfections:
- Increase number of LUNs per device from 4 to 9. The best solution
would be to remove this limit altogether, but that has to wait until
the time when more than 26 hosts are allowed.
- Replace mdelay with msleep in a probing routine.
Signed-off-by: Pete Zaitcev <zaitcev@yahoo.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
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!
David Howells