cpu_relax() is documented in volatile-considered-harmful.txt to be a
memory barrier. However, everyone with the exception of Blackfin and
possibly ia64 defines cpu_relax() to be a compiler barrier.
Make the documentation reflect the general concensus.
Linus sayeth:
: I don't think it was ever the intention that it would be seen as anything
: but a compiler barrier, although it is obviously implied that it might
: well perform some per-architecture actions that have "memory barrier-like"
: semantics.
:
: After all, the whole and only point of the "cpu_relax()" thing is to tell
: the CPU that we're busy-looping on some event.
:
: And that "event" might be (and often is) about reading the same memory
: location over and over until it changes to what we want it to be. So it's
: quite possible that on various architectures the "cpu_relax()" could be
: about making sure that such a tight loop on loads doesn't starve cache
: transactions, for example - and as such look a bit like a memory barrier
: from a CPU standpoint.
:
: But it's not meant to have any kind of architectural memory ordering
: semantics as far as the kernel is concerned - those must come from other
: sources.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Cc: <linux-arch@vger.kernel.org>
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core-2.6:
driver core: numa: fix BUILD_BUG_ON for node_read_distance
driver-core: document ERR_PTR() return values
kobject: documentation: Update to refer to kset-example.c.
sysdev: the cpu probe/release attributes should be sysdev_class_attributes
kobject: documentation: Fix erroneous example in kobject doc.
driver-core: fix missing kernel-doc in firmware_class
Driver core: Early platform kernel-doc update
sysfs: fix sysfs lockdep warning in mlx4 code
sysfs: fix sysfs lockdep warning in infiniband code
sysfs: fix sysfs lockdep warning in ipmi code
sysfs: Initialised pci bus legacy_mem field before use
sysfs: use sysfs_bin_attr_init in firmware class driver
* git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb-2.6: (45 commits)
USB: gadget/multi: cdc_do_config: remove redundant check
usb: r8a66597-hcd: fix removed from an attached hub
USB: xhci: Make endpoint interval debugging clearer.
USB: Fix usb_fill_int_urb for SuperSpeed devices
USB: cp210x: Remove double usb_control_msg from cp210x_set_config
USB: Remove last bit of CONFIG_USB_BERRY_CHARGE
USB: gadget: add gadget controller number for s3c-hsotg driver
USB: ftdi_sio: Fix locking for change_speed() function
USB: g_mass_storage: fixed module name in Kconfig
USB: gadget: f_mass_storage::fsg_bind(): fix error handling
USB: g_mass_storage: fix section mismatch warnings
USB: gadget: fix Blackfin builds after gadget cleansing
USB: goku_udc: remove potential null dereference
USB: option.c: Add Pirelli VID/PID and indicate Pirelli's modem interface is 0xff
USB: serial: Fix module name typo for qcaux Kconfig entry.
usb: cdc-wdm: Fix deadlock between write and resume
usb: cdc-wdm: Fix order in disconnect and fix locking
usb: cdc-wdm:Fix loss of data due to autosuspend
usb: cdc-wdm: Fix submission of URB after suspension
usb: cdc-wdm: Fix race between disconnect and debug messages
...
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/sage/ceph-client: (205 commits)
ceph: update for write_inode API change
ceph: reset osd after relevant messages timed out
ceph: fix flush_dirty_caps race with caps migration
ceph: include migrating caps in issued set
ceph: fix osdmap decoding when pools include (removed) snaps
ceph: return EBADF if waiting for caps on closed file
ceph: set osd request message front length correctly
ceph: reset front len on return to msgpool; BUG on mismatched front iov
ceph: fix snaptrace decoding on cap migration between mds
ceph: use single osd op reply msg
ceph: reset bits on connection close
ceph: remove bogus mds forward warning
ceph: remove fragile __map_osds optimization
ceph: fix connection fault STANDBY check
ceph: invalidate_authorizer without con->mutex held
ceph: don't clobber write return value when using O_SYNC
ceph: fix client_request_forward decoding
ceph: drop messages on unregistered mds sessions; cleanup
ceph: fix comments, locking in destroy_inode
ceph: move dereference after NULL test
...
Fix trivial conflicts in Documentation/ioctl/ioctl-number.txt
The name used in the documentation doesn't match reality.
Signed-off-by: Oliver Neukum <neukum@b1-systems.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Replace uio_mem example for kobjects with uio_map, since the uio_mem
struct no longer contains a kobject.
Signed-off-by: Robert P. J. Day <rpjday@crashcourse.ca>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Fix Makefiles so that Documentation/networking/timestamping/timestamping.c
will build when using the CONFIG_BUILD_DOCSRC kconfig option.
(timestamping.c does not build currently with its simple Makefile.)
Also fix printf format warnings.
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Cc: Patrick Ohly <patrick.ohly@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Now that we check for physically present processors before blindly
evaluating _PDC, we no longer need to maintain a DMI opt-in table
nor a kernel param.
Acked-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: Alex Chiang <achiang@hp.com>
Signed-off-by: Len Brown <len.brown@intel.com>
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial: (56 commits)
doc: fix typo in comment explaining rb_tree usage
Remove fs/ntfs/ChangeLog
doc: fix console doc typo
doc: cpuset: Update the cpuset flag file
Fix of spelling in arch/sparc/kernel/leon_kernel.c no longer needed
Remove drivers/parport/ChangeLog
Remove drivers/char/ChangeLog
doc: typo - Table 1-2 should refer to "status", not "statm"
tree-wide: fix typos "ass?o[sc]iac?te" -> "associate" in comments
No need to patch AMD-provided drivers/gpu/drm/radeon/atombios.h
devres/irq: Fix devm_irq_match comment
Remove reference to kthread_create_on_cpu
tree-wide: Assorted spelling fixes
tree-wide: fix 'lenght' typo in comments and code
drm/kms: fix spelling in error message
doc: capitalization and other minor fixes in pnp doc
devres: typo fix s/dev/devm/
Remove redundant trailing semicolons from macros
fix typo "definetly" -> "definitely" in comment
tree-wide: s/widht/width/g typo in comments
...
Fix trivial conflict in Documentation/laptops/00-INDEX
* 'for-linus' of master.kernel.org:/home/rmk/linux-2.6-arm: (370 commits)
ARM: S3C2443: Add set_rate and round_rate calls for armdiv clock
ARM: S3C2443: Remove #if 0 for clk_mpll
ARM: S3C2443: Update notes on MPLLREF clock
ARM: S3C2443: Further clksrc-clk conversions
ARM: S3C2443: Change to using plat-samsung clksrc-clk implementation
USB: Fix s3c-hsotg build following Samsung platform header moves
ARM: S3C64XX: Reintroduce unconditional build of audio device
ARM: 5961/1: ux500: fix CLKRST addresses
ARM: 5977/1: arm: Enable backtrace printing on oops when PC is corrupted
ASoC: Fix S3C64xx IIS driver for Samsung header reorg
ARM: S3C2440: Fix plat-s3c24xx move of s3c2440/s3c2442 support
[ARM] pxa: fix typo in mxm8x10.h
[ARM] pxa/raumfeld: set GPIO drive bits for LED pins
[ARM] pxa/zeus: Add support for mcp2515 CAN bus
[ARM] pxa/zeus: Add support for onboard max6369 watchdog
[ARM] pxa/zeus: Add Eurotech as the manufacturer
[ARM] pxa/zeus: Correct the USB host initialisation flags
[ARM] pxa/zeus: Allow usage of 8250-compatible UART in uncompress
[ARM] pxa: refactor uncompress.h for non-PXA uarts
[ARM] mmp2: fix incorrect calling of chip->mask_ack() for 2nd level cascaded IRQs
...
- replace the PCI DMA API (i.e. pci_dma_*) with the generic DMA API.
- make the document more generic (use the PCI specific explanation as
an example).
[akpm@linux-foundation.org: fix things Randy noticed]
Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
Cc: "David S. Miller" <davem@davemloft.net>
Reviewed-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Adds the following macros:
DECLARE_DMA_UNMAP_ADDR(ADDR_NAME)
DECLARE_DMA_UNMAP_LEN(LEN_NAME)
dma_unmap_addr(PTR, ADDR_NAME)
dma_unmap_addr_set(PTR, ADDR_NAME, VAL)
dma_unmap_len(PTR, LEN_NAME)
dma_unmap_len_set(PTR, LEN_NAME, VAL)
The API corresponds to the pci_unmap state API. We'll move to this new
generic API from the PCI specific API in the long term. As
include/asm-generic/pci-dma-compat.h does, the pci_unmap API simply calls
the new generic API for some time.
Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Cc: James Bottomley <James.Bottomley@suse.de>
Cc: David S. Miller <davem@davemloft.net>
Cc: Jesse Barnes <jbarnes@virtuousgeek.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
dma_sync_single_for_cpu/for_device supports a partial sync so there is no
point to have dma_sync_single_range (also dma_sync_single was obsoleted
long ago, replaced with dma_sync_single_for_cpu/for_device).
There is no user of dma_sync_single_range() in mainline and only Alpha
architecture supports dma_sync_single_range(). So it's unlikely that
someone out of the tree uses it.
Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Acked-by: David Miller <davem@davemloft.net>
Acked-by: James Bottomley <James.Bottomley@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
David Howells
KOSAKI Motohiro
FUJITA Tomonori
Greg Thelen
Russell King
Linus Torvalds
Oliver Neukum
Robert P. J. Day
David S. Miller
Randy Dunlap
Len Brown
Alex Chiang
Rodolfo Giometti