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 biggest change is that ata_host_set is renamed to ata_host.
* ata_host_set => ata_host
* ata_probe_ent->host_flags => ata_probe_ent->port_flags
* ata_probe_ent->host_set_flags => ata_probe_ent->_host_flags
* ata_host_stats => ata_port_stats
* ata_port->host => ata_port->scsi_host
* ata_port->host_set => ata_port->host
* ata_port_info->host_flags => ata_port_info->flags
* ata_(.*)host_set(.*)\(\) => ata_\1host\2()
The leading underscore in ata_probe_ent->_host_flags is to avoid
reusing ->host_flags for different purpose. Currently, the only user
of the field is libata-bmdma.c and probe_ent itself is scheduled to be
removed.
ata_port->host is reused for different purpose but this field is used
inside libata core proper and of different type.
Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
pdc_adma was overlooked and broken by the irq-pio patch:
Only HSM_ST_LAST interrupts should be delivered to this LLDD.
Adding ATA_FLAG_PIO_POLLING to pdc_adma fixes the problem (temporarily),
before we convert the irq handler of pdc_adma to handle all interrupts.
Signed-off-by: Albert Lee <albertcc@tw.ibm.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
pdc_adma use libata-core PIO path but were left out
during ->data_xfer conversion. Initialize with proper callbacks.
This patch is against the current libata-dev#ALL. Controllers which
implement their own PIO HSM (ahci and sil24) don't need ->data_xfer, so the
above two are the only drivers which were left out during conversion.
From: "Barry K. Nathan" <barryn@pobox.com>
Signed-off-by: Barry K. Nathan <barryn@pobox.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
Overriding the whole EH code is a per-transport, not per-host thing.
Move ->eh_strategy_handler to the transport class, same as
->eh_timed_out.
Downside is that scsi_host_alloc can't check for the total lack of EH
anymore, but the transition period from old EH where we needed it is
long gone already.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
Rename ATA_FLAG_PORT_DISABLED to ATA_FLAG_DISABLED for consistency.
(ATA_FLAG_* are always about ports).
Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
SCSI midlayer has moved hostt->eh_timed_out to transport template. As
libata doesn't need full-blown transport support yet, implement
minimal transport for libata. No transport class or whatsoever, just
empty transport template with ->eh_timed_out hook.
Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>
The previous dev->max_sectors patch made sht->max_sectors meaningless.
Kill all initializations of sht->max_sectors.
Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Jeff Garzik <jgarzik@pobox.com>
Return AC_ERR_* mask from issue fuctions instead of 0/-1. This
enables things like failing a qc with AC_ERR_HSM when the device
doesn't set DRDY when the qc is about to be issued.
Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Jeff Garzik <jgarzik@pobox.com>
- remove err_mask from the parameter list of the complete functions
- move err_mask to ata_queued_cmd
- initialize qc->err_mask when needed
- for each function call to ata_qc_complete(), replace the err_mask parameter with qc->err_mask.
Signed-off-by: Albert Lee <albertcc@tw.ibm.com>
===============
Signed-off-by: Jeff Garzik <jgarzik@pobox.com>
The second argument to ata_qc_complete() was being used for two
purposes: communicate the ATA Status register to the completion
function, and indicate an error. On legacy PCI IDE hardware, the latter
is often implicit in the former. On more modern hardware, the driver
often completely emulated a Status register value, passing ATA_ERR as an
indication that something went wrong.
Now that previous code changes have eliminated the need to use drv_stat
arg to communicate the ATA Status register value, we can convert it to a
mask of possible error classes.
This will lead to more flexible error handling in the future.
We want ->tf_read() to get a complete snapshot of all taskfile
registers, without requiring the callers to manually call
ata_chk_status() and ata_chk_err() themselves.
This also fixes a minor bug in sata_vsc where the lower bits of the
feature register were incorrectly placed in the HOB (high order bits)
portion of struct ata_taskfile.
David Howells