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Fix NULL pointer dereference during execution of Internal commands,
where gdth only allocates scp, but not scp->sense_buffer. The rest of
the code assumes that sense_buffer is allocated, which leads to a kernel
oops e.g. on reboot (during cache flush).
Signed-off-by: Sven Schnelle <svens@stackframe.org>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
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The recent patch named:
[SCSI] gdth: !use_sg cleanup and use of scsi accessors
has done a bad job in handling internal commands issued by gdth_execute().
Internal commands are issued with device gdth_cmd_str ready made directly
to the card, without any mapping or translations of scsi commands. So here
I added a gdth_cmd_str pointer to the gdth_cmndinfo private structure which
is then copied directly to host.
following this patch is a cleanup that removes the home cooked accessors
and reverts them to regular scsi_cmnd accessors. Since they are not used
anymore. After review maybe the 2 patches should be squashed together.
FIXME: There is still a problem with gdth_get_info(). as reported there
is a WARN_ON trigerd in dma_free_coherent() when doing:
$ cat /proc/sys/gdth/0
Signed-off-by: Boaz Harrosh <bharrosh@panasas.com>
Tested-by: Joerg Dorchain: <joerg@dorchain.net>
Tested-by: Stefan Priebe <s.priebe@allied-internet.ag>
Tested-by: Jon Chelton <jchelton@ffpglobal.com>
Cc: Stable Tree <stable@kernel.org>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
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gdth_exit would first remove all cards then stop the timer
and would not sync with the timer function. This caused a crash
in gdth_timer() when module was unloaded.
So del_timer_sync the timer before we delete the cards.
also the reboot notifier function would crash. So clean
that up and fix the crashes.
Signed-off-by: Boaz Harrosh <bharrosh@panasas.com>
Tested-by: Joerg Dorchain: <joerg@dorchain.net>
Tested-by: Stefan Priebe <s.priebe@allied-internet.ag>
Tested-by: Jon Chelton <jchelton@ffpglobal.com>
Cc: Stable Tree <stable@kernel.org>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
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Fix compilation warning in gdth.c, which was using the deprecated
pci_find_device.
drivers/scsi/gdth.c:645: warning: 'pci_find_device' is deprecated (declared at include/linux/pci.h:495)
Changing it to use pci_get_device, instead.
Signed-off-by: Sergio Luis <sergio@larces.uece.br>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
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The patch: "gdth: switch to modern scsi host registration"
missed one simple fact when moving a way from scsi_module.c.
That is to call scsi_scan_host() on the probed host.
With this the gdth driver from 2.6.24 is again able to
see drives and boot.
Signed-off-by: Boaz Harrosh <bharrosh@panasas.com>
Tested-by: Joerg Dorchain <joerg@dorchain.net>
Tested-by: Stefan Priebe <s.priebe@allied-internet.ag>
Tested-by: Jon Chelton <jchelton@ffpglobal.com>
Cc: Stable Tree <stable@kernel.org>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
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Neither gdth_get_status() nor __gdth_interrupt() need their 'irq' argument,
so remove it.
[akpm@linux-foundation.org: coding style fixes]
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
Acked-by: Boaz Harrosh <bharrosh@panasas.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
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* master.kernel.org:/pub/scm/linux/kernel/git/jejb/scsi-misc-2.6: (39 commits)
[SCSI] qla2xxx: Update version number to 8.02.00-k5.
[SCSI] qla2xxx: Correct display of ISP serial-number.
[SCSI] qla2xxx: Correct residual-count handling discrepancies during UNDERRUN handling.
[SCSI] qla2xxx: Make driver (mostly) legacy I/O port free.
[SCSI] qla2xxx: Fix issue where final flash-segment updates were falling into the slow-path write handler.
[SCSI] qla2xxx: Handle unaligned sector writes during NVRAM/VPD updates.
[SCSI] qla2xxx: Defer explicit interrupt-polling processing to init-time scenarios.
[SCSI] qla2xxx: Resync with latest HBA SSID specification -- 2.2u.
[SCSI] sym53c8xx: Remove sym_xpt_async_sent_bdr
[SCSI] sym53c8xx: Remove pci_dev pointer from sym_shcb
[SCSI] sym53c8xx: Make interrupt handler capable of returning IRQ_NONE
[SCSI] sym53c8xx: Get rid of IRQ_FMT and IRQ_PRM
[SCSI] sym53c8xx: Use scmd_printk where appropriate
[SCSI] sym53c8xx: Simplify DAC DMA handling
[SCSI] sym53c8xx: Remove tag_ctrl module parameter
[SCSI] sym53c8xx: Remove io_ws, mmio_ws and ram_ws elements
[SCSI] sym53c8xx: Remove ->device_id
[SCSI] sym53c8xx: Use pdev->revision
[SCSI] sym53c8xx: PCI Error Recovery support
[SCSI] sym53c8xx: Stop overriding scsi_done
...
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Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
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This patch fixes the following build warnings:
WARNING: vmlinux.o(.text+0xbcffdb): Section mismatch: reference to .init.text.20:gdth_search_drives (between 'gdth_pci_probe_one' and 'gdth_start_timeout')
WARNING: vmlinux.o(.text+0xbd0102): Section mismatch: reference to .init.text.20:gdth_enable_int (between 'gdth_pci_probe_one' and 'gdth_start_timeout')
Signed-off-by: Adrian Bunk <bunk@kernel.org>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>
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If the gdth module is loaded (or compiled in), the gdth_timeout function
gets started even if no actual gdth controllers are found b the probing.
That ends up not only being unnecessary, but also causes a crash due to
the function blindly just trying to pick the first entry off the
"gdth_instances" list, and accessing it - which obviously doesn't work
if the list is empty!
Noticed by Ingo Molnar.
Tested-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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drivers/scsi/gdth.c: In function ‘gdth_search_dev’:
drivers/scsi/gdth.c:646: warning: ‘pci_find_device’ is deprecated
(declared at include/linux/pci.h:482)
drivers/scsi/gdth.c: In function ‘gdth_init_isa’:
drivers/scsi/gdth.c:857: error: ‘gdth_irq_tab’ undeclared (first use in
this function)
drivers/scsi/gdth.c:857: error: (Each undeclared identifier is reported
only once
drivers/scsi/gdth.c:857: error: for each function it appears in.)
drivers/scsi/gdth.c: In function ‘gdth_copy_internal_data’:
drivers/scsi/gdth.c:2362: warning: unused variable ‘sg’
Looking into the code I notice that gdth_irq_tab is not declared with
CONFIG_ISA=y and !CONFIG_EISA.
The values seem to be same in 2.6.23 (I am not sure why it has been put
with #ifdefs in -mm) so I have just modified the #ifdef to take care of
CONFIG_ISA as well.
Signed-off-by: Dhaval Giani <dhaval@linux.vnet.ibm.com>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>
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gdth_execute() will issue an internal, none scsi-standard commands
onto __gdth_queuecommand(). Since it is not recommended to set
struct scsi_cmnd IO members in llds, gdth now uses internal IO
members for IO. In the case of gdth_execute() these members will be
set properly. In case the command was issued from scsi-ml
(by gdth_queuecommand) they will be set from scsi IO accessors.
* define gdth IO accessors and use them throughout the driver.
* use an sg-of-one in gdth_execute() and fix gdth_special_cmd()
accordingly.
* Clean the not use_sg code path and company
Signed-off-by Boaz Harrosh <bharrosh@panasas.com>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>
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- Cleanup the rest of the scsi_cmnd->SCp members and move them
to gdth_cmndinfo:
SCp.this_residual => priority
SCp.buffers_residual => timeout
SCp.Status => status and dma_dir
SCp.Message => info
SCp.have_data_in => volatile wait_for_completion
SCp.sent_command => OpCode
SCp.phase => phase
- Two more members will be naturally removed in the !use_sg cleanup
TODO: What is the meaning of gdth_cmndinfo.phase? (rhetorically)
Signed-off-by Boaz Harrosh <bharrosh@panasas.com>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>
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- scsi_cmnd and specifically ->SCp of, where heavily abused
with internal meaning members and flags. So introduce a new
struct gdth_cmndinfo, put it on ->host_scribble and define a
gdth_cmnd_priv() accessor to retrieve it from a scsi_cmnd.
- The structure now holds two members:
internal_command - replaces the IS_GDTH_INTERNAL_CMD() croft.
sense_paddr - which was a 64-bit spanning on 2 32-bit members of SCp.
More overloaded members from SCp and scsi_cmnd will be moved in a later
patch (For easy review).
- Split up gdth_queuecommand to an additional internal_function. The later
is the one called by gdth_execute(). This will be more evident later in
the scsi accessors patch, but it also facilitates in the differentiation
between internal_command and external. And the setup of gdth_cmndinfo of
each command.
Signed-off-by Boaz Harrosh <bharrosh@panasas.com>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>
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- Places like Initialization and Reset that Just loop on all devices can
use the link list with the list_for_each_entry macro.
But the io_ctrl from user mode now suffers performance-wise because
code has to do a sequential search for the requested host number.
I have isolated this search in a gdth_find_ha(int hanum) member
for future enhancement if needed.
Signed-off-by Boaz Harrosh <bharrosh@panasas.com>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>
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- Use scsi_add_host and friends and track instances ourselves. And
generally modernize the driver's structure.
- TODO: Next we can remove the controller table
- TODO: Fix use of deprecated pci_find_device()
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Boaz Harrosh <bharrosh@panasas.com>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>
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- gdth_get_status() returns a single device interrupt IStatus
- gdth_interrupt split to __gdth_interrupt() that receives
flags if is called from gdth_wait().
- Use dev_id passed from kernel and do not loop on all
controllers.
- gdth_wait(), get read of all global variables and call the new
__gdth_interrupt with these variables on the stack
Signed-off-by Boaz Harrosh <bharrosh@panasas.com>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>
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- Based on same patch from Christoph Hellwig <hch@lst.de>
- Get rid of all the indirection in the Scsi_Host private data and always
put the gdth_ha_str directly into it.
- Change all internal functions prototype to recieve an "gdth_ha_str *ha"
pointer directlly and kill all that redundent access to the "gdth_ctr_tab[]"
controller-table.
Signed-off-by: Boaz Harrosh <bharrosh@panasas.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>
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The virt_ctr option allows to register a new scsi_host for each bus
on the raid controller. This non-default option makes no sense with
the current scsi code and prevents cleaning up the host registration,
so remove it.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Boaz Harrosh <bharrosh@panasas.com>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>
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shuffle scsi_host_template members such that they appear in the
order in which they are defined in the header. this makes is easier
to verify when initializers are missing members.
Signed-off-by: Jeff Garzik <jeff@garzik.org>
Signed-off-by: Boaz Harrosh <bharrosh@panasas.com>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>
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They are direct equivalents to {read,write}[bwl].
Signed-off-by: Jeff Garzik <jeff@garzik.org>
Signed-off-by: Boaz Harrosh <bharrosh@panasas.com>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>
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* Remove in-source changelog. It's archived permanently in git and
various kernel archives, and changelogs should exist purely in git.
* Remove 2.4.x kernel support. It is an active obstacle to
modernizing this driver, at this point. This includes killing
gdth_kcompat.h which is 100% redundant in modern kernels.
Signed-off-by: Jeff Garzik <jeff@garzik.org>
Signed-off-by: Boaz Harrosh <bharrosh@panasas.com>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>
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Split out per-device pci probing and put it under proper CONFIG_PCI.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Boaz Harrosh <bharrosh@panasas.com>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>
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Split eisa probing into it's own helper, and do proper error unwinding.
Protect EISA probind by the proper CONFIG_EISA symbol.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Boaz Harrosh <bharrosh@panasas.com>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>
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(note: this is ontop of Jeff's pci cleanup patch)
Split out isa probing into a helper of it's own. Error handling is
cleaned up, but errors are not propagated yet. Also enclose the isa
probe under the proper CONFIG_ISA symbol instead of the !IA64 hack.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Boaz Harrosh <bharrosh@panasas.com>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>
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Rather than having internal commands abuse scsi_done to call
gdth_scsi_done, have all the places that use to call scsi_done directly
call gdth_scsi_done, which now checks whether the command was internal,
and calls scsi_done if not.
Signed-off-by: Matthew Wilcox <willy@linux.intel.com>
Signed-off-by: Boaz Harrosh <bharrosh@panasas.com>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>
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The ->done member was being used to mark commands as being internal.
I decided to put a magic number in ->underflow instead. I believe this
to be safe as no current user of ->underflow has any of the bottom 9
bits set.
Signed-off-by: Matthew Wilcox <willy@linux.intel.com>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>
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In NCR_D700, a4000t, aic7xxx_old, bvme6000, dpt_i2o, gdth, lpfc,
megaraid, mvme16x osst, pluto, qla2xxx, zorro7xx
Signed-off-by: Mariusz Kozlowski <m.kozlowski@tuxland.pl>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>
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This patch
* removes struct members that duplicate pci_dev members
* replaces ha->stype usage with ha->pdev->device usage where feasible
Signed-off-by: Jeff Garzik <jeff@garzik.org>
Acked-by: Christoph Hellwig <hch@lst.de>
Acked-by: Achim Leubner <Achim_Leubner@adaptec.com>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>
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Fix misspelled "spin_lock_irqrestore" to read "spin_unlock_irqrestore"
instead.
Presumably, GDTH_RTC doesn't get used a lot.
Signed-off-by: Robert P. J. Day <rpjday@mindspring.com>
Acked-by: Achim Leubner <achim_leubner@adaptec.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>
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Labeling a variable as __attribute_used__ is ambiguous: it means
__attribute__((unused)) for gcc <3.4 and __attribute__((used)) for gcc >=3.4.
There is no such thing as labeling a variable as __attribute__((used)). We
assume that we're simply suppressing a warning here if gdthtable[] is declared
but unreferenced.
Acked-by: Achim Leubner <achim_leubner@adaptec.com>
Signed-off-by: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>
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Recent alterations to the gdth_fill_raw_cmd() path no longer set the
sg_ranz field for zero transfer commands. However, this field is used
lower down in the function to initialise ha->cmd_len to the size of
the firmware packet. If this uninitialised field contains a bogus
value, ha->cmd_len can become much larger than the actual firmware
packet and end up oopsing in gdth_copy_cmd() as it tries to copy this
huge packet to the device (usually because it runs into an unallocated
page).
The fix is to initialise the sg_ranz field to zero at the start of
gdth_fill_raw_cmd().
Signed-off-by: Joerg Dorchain <joerg@dorchain.net>
Acked-by: "Leubner, Achim" <Achim_Leubner@adaptec.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>
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After Al Viro (finally) succeeded in removing the sched.h #include in module.h
recently, it makes sense again to remove other superfluous sched.h includes.
There are quite a lot of files which include it but don't actually need
anything defined in there. Presumably these includes were once needed for
macros that used to live in sched.h, but moved to other header files in the
course of cleaning it up.
To ease the pain, this time I did not fiddle with any header files and only
removed #includes from .c-files, which tend to cause less trouble.
Compile tested against 2.6.20-rc2 and 2.6.20-rc2-mm2 (with offsets) on alpha,
arm, i386, ia64, mips, powerpc, and x86_64 with allnoconfig, defconfig,
allmodconfig, and allyesconfig as well as a few randconfigs on x86_64 and all
configs in arch/arm/configs on arm. I also checked that no new warnings were
introduced by the patch (actually, some warnings are removed that were emitted
by unnecessarily included header files).
Signed-off-by: Tim Schmielau <tim@physik3.uni-rostock.de>
Acked-by: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Many struct file_operations in the kernel can be "const". Marking them const
moves these to the .rodata section, which avoids false sharing with potential
dirty data. In addition it'll catch accidental writes at compile time to
these shared resources.
Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Fix uses of "&&" where "&" was obviously intended instead.
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>
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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)
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All on stack DECLARE_COMPLETIONs should be replaced by:
DECLARE_COMPLETION_ONSTACK
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: Ingo Molnar <mingo@elte.hu>
Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: James Bottomley <James.Bottomley@steeleye.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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With Achim patch the last user (gdth) is switched away from scsi_request
so we an kill it now. Also disables some code in i2o_scsi that was
broken since the sg driver stopped using scsi_requests.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>
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Use ARRAY_SIZE macro instead of sizeof(x)/sizeof(x[0]) and remove
duplicates of the macro.
Signed-off-by: Tobias Klauser <tklauser@nuerscht.ch>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>
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Initial pass at converting the gdth driver away from the scsi_request
interface so that the request interface can be removed post 2.6.18
without breaking gdth. Based on changes from Christoph Hellwig
<hch@lst.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>
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Various scsi drivers use scsi_cmnd.buffer and scsi_cmnd.bufflen in their
queuecommand functions. Those fields are internal storage for the
midlayer only and are used to restore the original payload after
request_buffer and request_bufflen have been overwritten for EH. Using
the buffer and bufflen fields means they do very broken things in error
handling.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>
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Replace all occurences of 0xff.. in calls to function pci_set_dma_mask()
and pci_set_consistant_dma_mask() with the corresponding DMA_xBIT_MASK from
linux/dma-mapping.h.
Signed-off-by: Matthias Gehre <M.Gehre@gmx.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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The kernel's implementation of notifier chains is unsafe. There is no
protection against entries being added to or removed from a chain while the
chain is in use. The issues were discussed in this thread:
http://marc.theaimsgroup.com/?l=linux-kernel&m=113018709002036&w=2
We noticed that notifier chains in the kernel fall into two basic usage
classes:
"Blocking" chains are always called from a process context
and the callout routines are allowed to sleep;
"Atomic" chains can be called from an atomic context and
the callout routines are not allowed to sleep.
We decided to codify this distinction and make it part of the API. Therefore
this set of patches introduces three new, parallel APIs: one for blocking
notifiers, one for atomic notifiers, and one for "raw" notifiers (which is
really just the old API under a new name). New kinds of data structures are
used for the heads of the chains, and new routines are defined for
registration, unregistration, and calling a chain. The three APIs are
explained in include/linux/notifier.h and their implementation is in
kernel/sys.c.
With atomic and blocking chains, the implementation guarantees that the chain
links will not be corrupted and that chain callers will not get messed up by
entries being added or removed. For raw chains the implementation provides no
guarantees at all; users of this API must provide their own protections. (The
idea was that situations may come up where the assumptions of the atomic and
blocking APIs are not appropriate, so it should be possible for users to
handle these things in their own way.)
There are some limitations, which should not be too hard to live with. For
atomic/blocking chains, registration and unregistration must always be done in
a process context since the chain is protected by a mutex/rwsem. Also, a
callout routine for a non-raw chain must not try to register or unregister
entries on its own chain. (This did happen in a couple of places and the code
had to be changed to avoid it.)
Since atomic chains may be called from within an NMI handler, they cannot use
spinlocks for synchronization. Instead we use RCU. The overhead falls almost
entirely in the unregister routine, which is okay since unregistration is much
less frequent that calling a chain.
Here is the list of chains that we adjusted and their classifications. None
of them use the raw API, so for the moment it is only a placeholder.
ATOMIC CHAINS
-------------
arch/i386/kernel/traps.c: i386die_chain
arch/ia64/kernel/traps.c: ia64die_chain
arch/powerpc/kernel/traps.c: powerpc_die_chain
arch/sparc64/kernel/traps.c: sparc64die_chain
arch/x86_64/kernel/traps.c: die_chain
drivers/char/ipmi/ipmi_si_intf.c: xaction_notifier_list
kernel/panic.c: panic_notifier_list
kernel/profile.c: task_free_notifier
net/bluetooth/hci_core.c: hci_notifier
net/ipv4/netfilter/ip_conntrack_core.c: ip_conntrack_chain
net/ipv4/netfilter/ip_conntrack_core.c: ip_conntrack_expect_chain
net/ipv6/addrconf.c: inet6addr_chain
net/netfilter/nf_conntrack_core.c: nf_conntrack_chain
net/netfilter/nf_conntrack_core.c: nf_conntrack_expect_chain
net/netlink/af_netlink.c: netlink_chain
BLOCKING CHAINS
---------------
arch/powerpc/platforms/pseries/reconfig.c: pSeries_reconfig_chain
arch/s390/kernel/process.c: idle_chain
arch/x86_64/kernel/process.c idle_notifier
drivers/base/memory.c: memory_chain
drivers/cpufreq/cpufreq.c cpufreq_policy_notifier_list
drivers/cpufreq/cpufreq.c cpufreq_transition_notifier_list
drivers/macintosh/adb.c: adb_client_list
drivers/macintosh/via-pmu.c sleep_notifier_list
drivers/macintosh/via-pmu68k.c sleep_notifier_list
drivers/macintosh/windfarm_core.c wf_client_list
drivers/usb/core/notify.c usb_notifier_list
drivers/video/fbmem.c fb_notifier_list
kernel/cpu.c cpu_chain
kernel/module.c module_notify_list
kernel/profile.c munmap_notifier
kernel/profile.c task_exit_notifier
kernel/sys.c reboot_notifier_list
net/core/dev.c netdev_chain
net/decnet/dn_dev.c: dnaddr_chain
net/ipv4/devinet.c: inetaddr_chain
It's possible that some of these classifications are wrong. If they are,
please let us know or submit a patch to fix them. Note that any chain that
gets called very frequently should be atomic, because the rwsem read-locking
used for blocking chains is very likely to incur cache misses on SMP systems.
(However, if the chain's callout routines may sleep then the chain cannot be
atomic.)
The patch set was written by Alan Stern and Chandra Seetharaman, incorporating
material written by Keith Owens and suggestions from Paul McKenney and Andrew
Morton.
[jes@sgi.com: restructure the notifier chain initialization macros]
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Chandra Seetharaman <sekharan@us.ibm.com>
Signed-off-by: Jes Sorensen <jes@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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Don't map zero-length requests in gdth, zome architectures don't like
that in their dma mapping routines.
[ I'm pretty sure Jens posted this before, but for some reason it got
forgotten --hch ]
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>
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Signed-off-by: Adrian Bunk <bunk@stusta.de>
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Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>
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Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>
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scsi_add_host is the proper place to set the device, but people copy
the scsi_set_device usage from older drivers again and again.
note that this leaves some legacy drivers like qlogicisp/qlogicfc
without pci association in sysfs, but they're scheduled to go away soon
anyway.
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>
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Drivers need not implement a hook that returns FAILED, and does nothing
else, since the SCSI midlayer code will do that for us.
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>
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