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rmap's page_check_address descend without page_table_lock. First just
pte_offset_map in case there's no pte present worth locking for, then take
page_table_lock for the full check, and pass ptl back to caller in the same
style as pte_offset_map_lock. __xip_unmap, page_referenced_one and
try_to_unmap_one use pte_unmap_unlock. try_to_unmap_cluster also.
page_check_address reformatted to avoid progressive indentation. No use is
made of its one error code, return NULL when it fails.
Signed-off-by: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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Remove the page_table_lock from around the calls to unmap_vmas, and replace
the pte_offset_map in zap_pte_range by pte_offset_map_lock: all callers are
now safe to descend without page_table_lock.
Don't attempt fancy locking for hugepages, just take page_table_lock in
unmap_hugepage_range. Which makes zap_hugepage_range, and the hugetlb test in
zap_page_range, redundant: unmap_vmas calls unmap_hugepage_range anyway. Nor
does unmap_vmas have much use for its mm arg now.
The tlb_start_vma and tlb_end_vma in unmap_page_range are now called without
page_table_lock: if they're implemented at all, they typically come down to
flush_cache_range (usually done outside page_table_lock) and flush_tlb_range
(which we already audited for the mprotect case).
Signed-off-by: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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Second step in pushing down the page_table_lock. Remove the temporary
bridging hack from __pud_alloc, __pmd_alloc, __pte_alloc: expect callers not
to hold page_table_lock, whether it's on init_mm or a user mm; take
page_table_lock internally to check if a racing task already allocated.
Convert their callers from common code. But avoid coming back to change them
again later: instead of moving the spin_lock(&mm->page_table_lock) down,
switch over to new macros pte_alloc_map_lock and pte_unmap_unlock, which
encapsulate the mapping+locking and unlocking+unmapping together, and in the
end may use alternatives to the mm page_table_lock itself.
These callers all hold mmap_sem (some exclusively, some not), so at no level
can a page table be whipped away from beneath them; and pte_alloc uses the
"atomic" pmd_present to test whether it needs to allocate. It appears that on
all arches we can safely descend without page_table_lock.
Signed-off-by: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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It seems odd to me that, whereas pud_alloc and pmd_alloc test inline, only
calling out-of-line __pud_alloc __pmd_alloc if allocation needed,
pte_alloc_map and pte_alloc_kernel are entirely out-of-line. Though it does
add a little to kernel size, change them to macros testing inline, calling
__pte_alloc or __pte_alloc_kernel to allocate out-of-line. Mark none of them
as fastcalls, leave that to CONFIG_REGPARM or not.
It also seems more natural for the out-of-line functions to leave the offset
calculation and map to the inline, which has to do it anyway for the common
case. At least mremap move wants __pte_alloc without _map.
Macros rather than inline functions, certainly to avoid the header file issues
which arise from CONFIG_HIGHPTE needing kmap_types.h, but also in case any
architectures I haven't built would have other such problems.
Signed-off-by: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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First step in pushing down the page_table_lock. init_mm.page_table_lock has
been used throughout the architectures (usually for ioremap): not to serialize
kernel address space allocation (that's usually vmlist_lock), but because
pud_alloc,pmd_alloc,pte_alloc_kernel expect caller holds it.
Reverse that: don't lock or unlock init_mm.page_table_lock in any of the
architectures; instead rely on pud_alloc,pmd_alloc,pte_alloc_kernel to take
and drop it when allocating a new one, to check lest a racing task already
did. Similarly no page_table_lock in vmalloc's map_vm_area.
Some temporary ugliness in __pud_alloc and __pmd_alloc: since they also handle
user mms, which are converted only by a later patch, for now they have to lock
differently according to whether or not it's init_mm.
If sources get muddled, there's a danger that an arch source taking
init_mm.page_table_lock will be mixed with common source also taking it (or
neither take it). So break the rules and make another change, which should
break the build for such a mismatch: remove the redundant mm arg from
pte_alloc_kernel (ppc64 scrapped its distinct ioremap_mm in 2.6.13).
Exceptions: arm26 used pte_alloc_kernel on user mm, now pte_alloc_map; ia64
used pte_alloc_map on init_mm, now pte_alloc_kernel; parisc had bad args to
pmd_alloc and pte_alloc_kernel in unused USE_HPPA_IOREMAP code; ppc64
map_io_page forgot to unlock on failure; ppc mmu_mapin_ram and ppc64 im_free
took page_table_lock for no good reason.
Signed-off-by: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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ia64 has expand_backing_store function for growing its Register Backing Store
vma upwards. But more complete code for this purpose is found in the
CONFIG_STACK_GROWSUP part of mm/mmap.c. Uglify its #ifdefs further to provide
expand_upwards for ia64 as well as expand_stack for parisc.
The Register Backing Store vma should be marked VM_ACCOUNT. Implement the
intention of growing it only a page at a time, instead of passing an address
outside of the vma to handle_mm_fault, with unknown consequences.
Signed-off-by: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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Slight and timid rearrangement of mm_struct: hiwater_rss and hiwater_vm were
tacked on the end, but it seems better to keep them near _file_rss, _anon_rss
and total_vm, in the same cacheline on those arches verified.
There are likely to be more profitable rearrangements, but less obvious (is it
good or bad that saved_auxv[AT_VECTOR_SIZE] isolates cpu_vm_mask and context
from many others?), needing serious instrumentation.
Signed-off-by: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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update_mem_hiwater has attracted various criticisms, in particular from those
concerned with mm scalability. Originally it was called whenever rss or
total_vm got raised. Then many of those callsites were replaced by a timer
tick call from account_system_time. Now Frank van Maarseveen reports that to
be found inadequate. How about this? Works for Frank.
Replace update_mem_hiwater, a poor combination of two unrelated ops, by macros
update_hiwater_rss and update_hiwater_vm. Don't attempt to keep
mm->hiwater_rss up to date at timer tick, nor every time we raise rss (usually
by 1): those are hot paths. Do the opposite, update only when about to lower
rss (usually by many), or just before final accounting in do_exit. Handle
mm->hiwater_vm in the same way, though it's much less of an issue. Demand
that whoever collects these hiwater statistics do the work of taking the
maximum with rss or total_vm.
And there has been no collector of these hiwater statistics in the tree. The
new convention needs an example, so match Frank's usage by adding a VmPeak
line above VmSize to /proc/<pid>/status, and also a VmHWM line above VmRSS
(High-Water-Mark or High-Water-Memory).
There was a particular anomaly during mremap move, that hiwater_vm might be
captured too high. A fleeting such anomaly remains, but it's quickly
corrected now, whereas before it would stick.
What locking? None: if the app is racy then these statistics will be racy,
it's not worth any overhead to make them exact. But whenever it suits,
hiwater_vm is updated under exclusive mmap_sem, and hiwater_rss under
page_table_lock (for now) or with preemption disabled (later on): without
going to any trouble, minimize the time between reading current values and
updating, to minimize those occasions when a racing thread bumps a count up
and back down in between.
Signed-off-by: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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Remove PageReserved() calls from core code by tightening VM_RESERVED
handling in mm/ to cover PageReserved functionality.
PageReserved special casing is removed from get_page and put_page.
All setting and clearing of PageReserved is retained, and it is now flagged
in the page_alloc checks to help ensure we don't introduce any refcount
based freeing of Reserved pages.
MAP_PRIVATE, PROT_WRITE of VM_RESERVED regions is tentatively being
deprecated. We never completely handled it correctly anyway, and is be
reintroduced in future if required (Hugh has a proof of concept).
Once PageReserved() calls are removed from kernel/power/swsusp.c, and all
arch/ and driver code, the Set and Clear calls, and the PG_reserved bit can
be trivially removed.
Last real user of PageReserved is swsusp, which uses PageReserved to
determine whether a struct page points to valid memory or not. This still
needs to be addressed (a generic page_is_ram() should work).
A last caveat: the ZERO_PAGE is now refcounted and managed with rmap (and
thus mapcounted and count towards shared rss). These writes to the struct
page could cause excessive cacheline bouncing on big systems. There are a
number of ways this could be addressed if it is an issue.
Signed-off-by: Nick Piggin <npiggin@suse.de>
Refcount bug fix for filemap_xip.c
Signed-off-by: Carsten Otte <cotte@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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I was lazy when we added anon_rss, and chose to change as few places as
possible. So currently each anonymous page has to be counted twice, in rss
and in anon_rss. Which won't be so good if those are atomic counts in some
configurations.
Change that around: keep file_rss and anon_rss separately, and add them
together (with get_mm_rss macro) when the total is needed - reading two
atomics is much cheaper than updating two atomics. And update anon_rss
upfront, typically in memory.c, not tucked away in page_add_anon_rmap.
Signed-off-by: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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Divide remove_vm_struct into two parts: first anon_vma_unlink plus
unlink_file_vma, to unlink the vma from the list and tree by which rmap or
vmtruncate might find it; then remove_vma to close, fput and free.
The intention here is to do the anon_vma_unlink and unlink_file_vma earlier,
in free_pgtables before freeing any page tables: so we can be sure that any
page tables traversed by rmap and vmtruncate are stable (and other, ordinary
cases are stabilized by holding mmap_sem).
This will be crucial to traversing pgd,pud,pmd without page_table_lock. But
testing the split-out patch showed that lifting the page_table_lock is
symbiotically necessary to make this change - the lock ordering is wrong to
move those unlinks into free_pgtables while it's under ptlock.
Signed-off-by: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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The original vm_stat_account has fallen into disuse, with only one user, and
only one user of vm_stat_unaccount. It's easier to keep track if we convert
them all to __vm_stat_account, then free it from its __shackles.
Signed-off-by: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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The NUMA policy code predated nodemask_t so it used open coded bitmaps.
Convert everything to nodemask_t. Big patch, but shouldn't have any actual
behaviour changes (except I removed one unnecessary check against
node_online_map and one unnecessary BUG_ON)
Signed-off-by: "Andi Kleen" <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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Add sem_is_read/write_locked functions to the read/write semaphores, along the
same lines of the *_is_locked spinlock functions. The swap token tuning patch
uses sem_is_read_locked; sem_is_write_locked is added for completeness.
Signed-off-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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This patch adds
vmalloc_node(size, node) -> Allocate necessary memory on the specified node
and
get_vm_area_node(size, flags, node)
and the other functions that it depends on.
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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- converted to platform bus
- removed pci dependencies
- removed virt_to_phys/phys_to_virt calls
System now can root off of a disk.
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
diff --git a/Documentation/mips/AU1xxx_IDE.README b/Documentation/mips/AU1xxx_IDE.README
new file mode 100644
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Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
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master.kernel.org:/pub/scm/linux/kernel/git/jgarzik/netdev-2.6
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Expose faster ether compare for use by protocols and other
driver. And change name to be more consistent with other ether
address manipulation routines in same file
Signed-off-by: Stephen Hemminger <shemminger@osdl.org>
Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>
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With CONFIG_PM=n:
drivers/built-in.o(.text+0x1098c): In function `hub_thread':
drivers/usb/core/hub.c:2673: undefined reference to `.dpm_runtime_resume'
drivers/built-in.o(.text+0x10998):drivers/usb/core/hub.c:2674: undefined reference to `.dpm_runtime_resume'
Please, never ever ever put extern decls into .c files. Use the darn header
files :(
Cc: David Brownell <david-b@pacbell.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
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This patch (as592) makes a few small improvements to the way device
strings are handled, and it fixes some bugs in a couple of other sysfs
attribute routines. (Look at show_configuration_string() to see what I
mean.)
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
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I can't stand text lines that wrap-around in my 80-column windows. This
patch (as589) makes cosmetic changes to a couple of source files.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
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This revised patch (as587b) improves the implementation of USB endpoint
sysfs files. Instead of storing a whole bunch of attributes for every
single endpoint, each endpoint now gets its own kobject and they can
share a static list of attributes. The number of extra fields added to
struct usb_host_endpoint has been reduced from 4 to 1.
The bEndpointAddress field is retained even though it is redundant (it
repeats the same information as the attributes' directory name). The
code avoids calling kobject_register, to prevent generating unwanted
hotplug events.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
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This revised patch (as586b) makes usb-handoff permanently true and no
longer a kernel boot parameter. It also removes the piix3_usb quirk code;
that was nothing more than an early version of the USB handoff code
(written at a time when Intel's PIIX3 was about the only motherboard with
USB support). And it adds identifiers for the three PCI USB controller
classes to pci_ids.h.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
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Dell supplied me with the following test:
#include<stdio.h>
#include<errno.h>
#include<sys/ioctl.h>
#include<fcntl.h>
#include<linux/usbdevice_fs.h>
main(int argc,char*argv[])
{
struct usbdevfs_hub_portinfo hubPortInfo = {0};
struct usbdevfs_ioctl command = {0};
command.ifno = 0;
command.ioctl_code = USBDEVFS_HUB_PORTINFO;
command.data = (void*)&hubPortInfo;
int fd, ret;
if(argc != 2) {
fprintf(stderr,"Usage: %s /proc/bus/usb/<BusNo>/<HubID>\n",argv[0]);
fprintf(stderr,"Example: %s /proc/bus/usb/001/001\n",argv[0]);
exit(1);
}
errno = 0;
fd = open(argv[1],O_RDWR);
if(fd < 0) {
perror("open failed:");
exit(errno);
}
errno = 0;
ret = ioctl(fd,USBDEVFS_IOCTL,&command);
printf("IOCTL return status:%d\n",ret);
if(ret<0) {
perror("IOCTL failed:");
close(fd);
exit(3);
} else {
printf("IOCTL passed:Num of ports %d\n",hubPortInfo.nports);
close(fd);
exit(0);
}
return 0;
}
I have verified that it breaks if built in 32 bit mode on x86_64 and that
the patch below fixes it.
Signed-off-by: Pete Zaitcev <zaitcev@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
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This should let us get rid of all of the different hooks in the USB core for
when something has changed.
Also, some other parts of the kernel have wanted to know this kind of
information at times.
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
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When a USB device is put into suspend mode, the current drawn from VBUS
has to be less than 500 uA. Some transceivers need to be put into a
special power-saving mode to accomplish this, and won't have a separate
OTG driver handling that.
This adds a suspend method to the "otg_transceiver" struct -- misnamed,
it's not only for OTG -- and calls it from the OMAP UDC driver.
Signed-off-by: Juha Yrj?l? <juha.yrjola@nokia.com>
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
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The way we're looking at USB suspend lately doesn't expect drivers to
call usb_suspend_device() or usb_resume_device() directly; that'll
be implicit when no interfaces are in use.
This patch removes those APIs from visibility outside usbcore.
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
drivers/usb/core/hub.c | 12 ++++--------
drivers/usb/core/usb.h | 4 ++++
include/linux/usb.h | 5 -----
3 files changed, 8 insertions(+), 13 deletions(-)
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This saves a word from "struct device" ... there's a refcounting mechanism
stub that's rather ineffective (the values are never even tested!), which
can safely be deleted. With this patch it uses normal device refcounting,
so any potential users of the pm_parent mechanism will be more correct.
(That mechanism is actually unusable for now though; it does nothing.)
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
drivers/base/power/main.c | 26 +++-----------------------
include/linux/pm.h | 1 -
2 files changed, 3 insertions(+), 24 deletions(-)
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This patch removes the extra usb_suspend_device() parameter. The original
reason to pass that parameter was so that this routine could suspend any
active children. A previous patch removed that functionality ... leaving
no reason to pass the parameter. A close analogy is pci_set_power_state,
which doesn't need a pm_message_t either.
On the internal code path that comes through the driver model, the parameter
is now used to distinguish cases where USB devices need to "freeze" but not
suspend. It also checks for an error case that's accessible through sysfs:
attempting to suspend a device before its interfaces (or for hubs, ports).
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
drivers/usb/core/hub.c | 34 +++++++++++++++++++++-------------
drivers/usb/core/usb.c | 23 +++++++++++++++++++++--
drivers/usb/host/ehci-hcd.c | 2 +-
drivers/usb/host/isp116x-hcd.c | 2 +-
drivers/usb/host/ohci-pci.c | 2 +-
include/linux/usb.h | 2 +-
6 files changed, 46 insertions(+), 19 deletions(-)
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needed
Also fixes all drivers that set this field, and removes some other devfs
specfic USB logic.
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
drivers/usb/class/usblp.c | 3 +--
drivers/usb/core/file.c | 19 ++++---------------
drivers/usb/image/mdc800.c | 3 +--
drivers/usb/input/aiptek.c | 2 +-
drivers/usb/input/hiddev.c | 3 +--
drivers/usb/media/dabusb.c | 3 +--
drivers/usb/misc/auerswald.c | 3 +--
drivers/usb/misc/idmouse.c | 5 ++---
drivers/usb/misc/legousbtower.c | 5 ++---
drivers/usb/misc/rio500.c | 3 +--
drivers/usb/misc/sisusbvga/sisusb.c | 5 -----
drivers/usb/misc/usblcd.c | 9 ++++-----
drivers/usb/usb-skeleton.c | 3 +--
include/linux/usb.h | 7 ++-----
14 files changed, 22 insertions(+), 51 deletions(-)
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This patch adds endpoint information for both devices and interfaces to
sysfs. Previously it was only possible to get the endpoint information
from usbfs, and never possible to get any information on endpoint 0.
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
drivers/usb/core/sysfs.c | 195 ++++++++++++++++++++++++++++++++++++++++++++++-
include/linux/usb.h | 4
2 files changed, 197 insertions(+), 2 deletions(-)
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pci_ids.h cleanup: convert // comment to /* comment */
Signed-off-by: Grant Coady <gcoady@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
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I told you that the pci_ids.h cleanup was a bad idea ;)
Cc: Alan Cox <alan@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
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pci_ids.h cleanup: removed non-referenced symbols, compile tested
with 'make allmodconfig'
Signed-off-by: Grant Coady <gcoady@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
include/linux/pci_ids.h | 540 ------------------------------------------------
1 file changed, 540 deletions(-)
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pci_ids.h cleanup: remove duplicated entries and change some defines to
explicit value rather than in terms of another constant, preparation for
removing unused symbols
Signed-off-by: Grant Coady <gcoady@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
include/linux/pci_ids.h | 28 +++++++++-------------------
1 file changed, 9 insertions(+), 19 deletions(-)
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Some PCI adapters (eg. ipr scsi adapters) have an exposure today in that they
issue BIST to the adapter to reset the card. If, during the time it takes to
complete BIST, userspace attempts to access PCI config space, the host bus
bridge will master abort the access since the ipr adapter does not respond on
the PCI bus for a brief period of time when running BIST. On PPC64 hardware,
this master abort results in the host PCI bridge isolating that PCI device
from the rest of the system, making the device unusable until Linux is
rebooted. This patch is an attempt to close that exposure by introducing some
blocking code in the PCI code. When blocked, writes will be humored and reads
will return the cached value. Ben Herrenschmidt has also mentioned that he
plans to use this in PPC power management.
Signed-off-by: Brian King <brking@us.ibm.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
drivers/pci/access.c | 89 ++++++++++++++++++++++++++++++++++++++++++++++++
drivers/pci/pci-sysfs.c | 20 +++++-----
drivers/pci/pci.h | 7 +++
drivers/pci/proc.c | 28 +++++++--------
drivers/pci/syscall.c | 14 +++----
include/linux/pci.h | 7 +++
6 files changed, 134 insertions(+), 31 deletions(-)
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This is the start of adding hotplug-like support for i2c devices.
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
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The new SMBus PEC implementation doesn't support PEC emulation on
non-PEC non-I2C SMBus masters, so we can drop all related code.
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
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This is my rewrite of the SMBus PEC support. The original
implementation was known to have bugs (credits go to Hideki Iwamoto
for reporting many of them recently), and was incomplete due to a
conceptual limitation.
The rewrite affects only software PEC. Hardware PEC needs very little
code and is mostly untouched.
Technically, both implementations differ in that the original one
was emulating PEC in software by modifying the contents of an
i2c_smbus_data union (changing the transaction to a different type),
while the new one works one level lower, on i2c_msg structures (working
on message contents). Due to the definition of the i2c_smbus_data union,
not all SMBus transactions could be handled (at least not without
changing the definition of this union, which would break user-space
compatibility), and those which could had to be implemented
individually. At the opposite, adding PEC to an i2c_msg structure
can be done on any SMBus transaction with common code.
Advantages of the new implementation:
* It's about twice as small (from ~136 lines before to ~70 now, only
counting i2c-core, including blank and comment lines). The memory
used by i2c-core is down by ~640 bytes (~3.5%).
* Easier to validate, less tricky code. The code being common to all
transactions by design, the risk that a bug can stay uncovered is
lower.
* All SMBus transactions have PEC support in I2C emulation mode
(providing the non-PEC transaction is also implemented). Transactions
which have no emulation code right now will get PEC support for free
when they finally get implemented.
* Allows for code simplifications in header files and bus drivers
(patch follows).
Drawbacks (I guess there had to be at least one):
* PEC emulation for non-PEC capable non-I2C SMBus masters was dropped.
It was based on SMBus tricks and doesn't quite fit in the new design.
I don't think it's really a problem, as the benefit was certainly
not worth the additional complexity, but it's only fair that I at
least mention it.
Lastly, let's note that the new implementation does slightly affect
compatibility (both in kernel and user-space), but doesn't actually
break it. Some defines will be dropped, but the code can always be
changed in a way that will work with both the old and the new
implementations. It shouldn't be a problem as there doesn't seem to be
many users of SMBus PEC to date anyway.
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
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Discard I2C_FUNC_SMBUS_*_PEC defines. i2c clients are not supposed to
check for PEC support of i2c bus drivers on individual SMBus
transactions, and i2c bus drivers are not supposed to advertise them.
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
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Drop unused i2c-over-parallel-port i2c IDs:
* I2C_HW_B_LPC was never actually used as far as I could search.
* I2C_HW_B_ELV and I2C_HW_B_VELLE are no more used since the
introduction of the unified i2c-parport driver in Linux 2.6.2.
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
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New driver for the Xicor X1205 RTC chip.
Signed-off-by: Alessandro Zummo <alessandro.zummo@towertech.it>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
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Drop I2C_SMBUS_I2C_BLOCK_MAX, use I2C_SMBUS_BLOCK_MAX instead.
I2C_SMBUS_I2C_BLOCK_MAX has always been defined to the same value as
I2C_SMBUS_BLOCK_MAX, and this will never change: setting it to a lower
value would make no sense, setting it to a higher value would break
i2c_smbus_data compatibility. There is no point in changing
i2c_smbus_data to support larger block transactions in SMBus mode, as
no SMBus hardware supports more than 32 byte blocks. Thus, for larger
transactions, direct I2C transfers are the way to go.
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
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There are no more per-i2c-algorithm adapter max. Last time there were
was in July 1999.
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
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Delete 2 out-of-date, colliding ioctl defines. I2C_UDELAY and
I2C_MDELAY are supposed to be used by i2c-algo-bit, but actually
aren't (and I suspect never were). Moreover, their values are the same
as I2C_FUNCS and I2C_SLAVE_FORCE, respectively, which *are* widely
used.
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
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Fix a misplaced comment in i2c.h. Spotted by Hideki Iwamoto.
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
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