udc
13 Commits
| Author | SHA1 | Message | Date | |
|---|---|---|---|---|
lucaswei
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bac74c1ae4 |
Merge android-4.9-q (4.9.237) into android-msm-pixel-4.9-lts
Merge 4.9.237 into android-4.9-q
Linux 4.9.237
x86/defconfig: Enable CONFIG_USB_XHCI_HCD=y
powerpc/dma: Fix dma_map_ops::get_required_mask
ehci-hcd: Move include to keep CRC stable
serial: 8250_pci: Add Realtek 816a and 816b
Input: i8042 - add Entroware Proteus EL07R4 to nomux and reset lists
usblp: fix race between disconnect() and read()
USB: UAS: fix disconnect by unplugging a hub
* USB: quirks: Add USB_QUIRK_IGNORE_REMOTE_WAKEUP quirk for BYD zhaoxin notebook
drivers/usb/core/quirks.c
drm/mediatek: Add exception handing in mtk_drm_probe() if component init fail
MIPS: SNI: Fix spurious interrupts
fbcon: Fix user font detection test at fbcon_resize().
perf test: Free formats for perf pmu parse test
MIPS: SNI: Fix MIPS_L1_CACHE_SHIFT
Drivers: hv: vmbus: Add timeout to vmbus_wait_for_unload
clk: rockchip: Fix initialization of mux_pll_src_4plls_p
i2c: algo: pca: Reapply i2c bus settings after reset
rapidio: Replace 'select' DMAENGINES 'with depends on'
SUNRPC: stop printk reading past end of string
spi: spi-loopback-test: Fix out-of-bounds read
scsi: lpfc: Fix FLOGI/PLOGI receive race condition in pt2pt discovery
scsi: pm8001: Fix memleak in pm8001_exec_internal_task_abort
NFSv4.1 handle ERR_DELAY error reclaiming locking state on delegation recall
* net: handle the return value of pskb_carve_frag_list() correctly
net/core/skbuff.c
* gcov: add support for GCC 10.1
kernel/gcov/Kconfig
RDMA/rxe: Fix the parent sysfs read when the interface has 15 chars
IB/rxe: Remove a pointless indirection layer
* usb: Fix out of sync data toggle if a configured device is reconfigured
drivers/usb/core/message.c
USB: serial: option: add support for SIM7070/SIM7080/SIM7090 modules
USB: serial: ftdi_sio: add IDs for Xsens Mti USB converter
* usb: core: fix slab-out-of-bounds Read in read_descriptors
drivers/usb/core/sysfs.c
staging: greybus: audio: fix uninitialized value issue
video: fbdev: fix OOB read in vga_8planes_imageblit()
KVM: VMX: Don't freeze guest when event delivery causes an APIC-access exit
* vgacon: remove software scrollback support
drivers/video/console/Kconfig
fbcon: remove now unusued 'softback_lines' cursor() argument
fbcon: remove soft scrollback code
rbd: require global CAP_SYS_ADMIN for mapping and unmapping
scsi: target: iscsi: Fix hang in iscsit_access_np() when getting tpg->np_login_sem
scsi: target: iscsi: Fix data digest calculation
* regulator: push allocation in set_consumer_device_supply() out of lock
drivers/regulator/core.c
btrfs: fix wrong address when faulting in pages in the search ioctl
staging: wlan-ng: fix out of bounds read in prism2sta_probe_usb()
* USB: core: add helpers to retrieve endpoints
drivers/usb/core/usb.c
include/linux/usb.h
iio:accel:mma8452: Fix timestamp alignment and prevent data leak.
iio:accel:mma7455: Fix timestamp alignment and prevent data leak.
iio: accel: kxsd9: Fix alignment of local buffer.
iio:light:max44000 Fix timestamp alignment and prevent data leak.
iio:magnetometer:ak8975 Fix alignment and data leak issues.
drivers: iio: magnetometer: Fix sparse endianness warnings cast to restricted __be16
iio:adc:ti-adc081c Fix alignment and data leak issues
iio:adc:ina2xx Fix timestamp alignment issue.
iio:accel:bmc150-accel: Fix timestamp alignment and prevent data leak.
iio:light:ltr501 Fix timestamp alignment issue.
iio: adc: ti-ads1015: fix conversion when CONFIG_PM is not set
iio: adc: mcp3422: fix locking on error path
iio: adc: mcp3422: fix locking scope
* gcov: Disable gcov build with GCC 10
kernel/gcov/Kconfig
ALSA: hda: fix a runtime pm issue in SOF when integrated GPU is disabled
drivers/net/wan/hdlc_cisco: Add hard_header_len
irqchip/eznps: Fix build error for !ARC700 builds
xfs: initialize the shortform attr header padding entry
drivers/net/wan/lapbether: Set network_header before transmitting
ALSA: hda: Fix 2 channel swapping for Tegra
firestream: Fix memleak in fs_open
NFC: st95hf: Fix memleak in st95hf_in_send_cmd
drivers/net/wan/lapbether: Added needed_tailroom
scsi: libsas: Set data_dir as DMA_NONE if libata marks qc as NODATA
RDMA/rxe: Drop pointless checks in rxe_init_ports
RDMA/rxe: Fix memleak in rxe_mem_init_user
ARM: dts: socfpga: fix register entry for timer3 on Arria10
Merge 4.9.236 into android-4.9-q
Linux 4.9.236
* net: disable netpoll on fresh napis
net/core/dev.c
sctp: not disable bh in the whole sctp_get_port_local()
net: usb: dm9601: Add USB ID of Keenetic Plus DSL
* netlabel: fix problems with mapping removal
net/netlabel/netlabel_domainhash.c
bnxt: don't enable NAPI until rings are ready
net: ethernet: mlx4: Fix memory allocation in mlx4_buddy_init()
affs: fix basic permission bits to actually work
fs/affs: use octal for permissions
ALSA; firewire-tascam: exclude Tascam FE-8 from detection
* net: usb: Fix uninit-was-stored issue in asix_read_phy_addr()
drivers/net/usb/asix_common.c
* cfg80211: regulatory: reject invalid hints
net/wireless/reg.c
mm/hugetlb: fix a race between hugetlb sysctl handlers
checkpatch: fix the usage of capture group ( ... )
vfio/pci: Fix SR-IOV VF handling with MMIO blocking
* net: initialize fastreuse on inet_inherit_port
net/ipv4/inet_hashtables.c
* net: refactor bind_bucket fastreuse into helper
include/net/inet_connection_sock.h
net/ipv4/inet_connection_sock.c
* KVM: arm64: Set HCR_EL2.PTW to prevent AT taking synchronous exception
arch/arm64/include/asm/kvm_arm.h
* KVM: arm64: Survive synchronous exceptions caused by AT instructions
arch/arm64/include/asm/kvm_asm.h
KVM: arm64: Defer guest entry when an asynchronous exception is pending
* KVM: arm64: Add kvm_extable for vaxorcism code
arch/arm64/include/asm/kvm_asm.h
arch/arm64/kernel/vmlinux.lds.S
vfio-pci: Invalidate mmaps and block MMIO access on disabled memory
vfio-pci: Fault mmaps to enable vma tracking
vfio/type1: Support faulting PFNMAP vmas
* mm: slub: fix conversion of freelist_corrupted()
mm/slub.c
dm thin metadata: Avoid returning cmd->bm wild pointer on error
dm cache metadata: Avoid returning cmd->bm wild pointer on error
libata: implement ATA_HORKAGE_MAX_TRIM_128M and apply to Sandisks
* block: Move SECTOR_SIZE and SECTOR_SHIFT definitions into <linux/blkdev.h>
drivers/block/brd.c
drivers/block/zram/zram_drv.h
include/linux/blkdev.h
include/linux/device-mapper.h
include/uapi/linux/msdos_fs.h
* block: allow for_each_bvec to support zero len bvec
include/linux/bvec.h
ALSA: firewire-digi00x: exclude Avid Adrenaline from detection
ALSA: pcm: oss: Remove superfluous WARN_ON() for mulaw sanity check
ALSA: ca0106: fix error code handling
usb: qmi_wwan: add D-Link DWM-222 A2 device ID
qmi_wwan: new Telewell and Sierra device IDs
drivers: net: usb: qmi_wwan: add QMI_QUIRK_SET_DTR for Telit PID 0x1201
net: usb: qmi_wwan: add Telit 0x1050 composition
btrfs: fix potential deadlock in the search ioctl
* uaccess: Add non-pagefault user-space write function
include/linux/uaccess.h
mm/maccess.c
* uaccess: Add non-pagefault user-space read functions
include/linux/uaccess.h
mm/maccess.c
btrfs: set the lockdep class for log tree extent buffers
btrfs: Remove extraneous extent_buffer_get from tree_mod_log_rewind
btrfs: Remove redundant extent_buffer_get in get_old_root
btrfs: drop path before adding new uuid tree entry
* include/linux/log2.h: add missing () around n in roundup_pow_of_two()
include/linux/log2.h
thermal: ti-soc-thermal: Fix bogus thermal shutdowns for omap4430
iommu/vt-d: Serialize IOMMU GCMD register modifications
tg3: Fix soft lockup when tg3_reset_task() fails.
* fix regression in "epoll: Keep a reference on files added to the check list"
fs/eventpoll.c
bnxt_en: Fix PCI AER error recovery flow
bnxt_en: Check for zero dir entries in NVRAM.
dmaengine: pl330: Fix burst length if burst size is smaller than bus width
net: arc_emac: Fix memleak in arc_mdio_probe
ravb: Fixed to be able to unload modules
net: hns: Fix memleak in hns_nic_dev_probe
netfilter: nf_tables: fix destination register zeroing
netfilter: nf_tables: incorrect enum nft_list_attributes definition
netfilter: nf_tables: add NFTA_SET_USERDATA if not null
MIPS: BMIPS: Also call bmips_cpu_setup() for secondary cores
MIPS: mm: BMIPS5000 has inclusive physical caches
dmaengine: at_hdmac: check return value of of_find_device_by_node() in at_dma_xlate()
batman-adv: bla: use netif_rx_ni when not in interrupt context
batman-adv: Avoid uninitialized chaddr when handling DHCP
* dmaengine: of-dma: Fix of_dma_router_xlate's of_dma_xlate handling
drivers/dma/of-dma.c
xen/xenbus: Fix granting of vmalloc'd memory
s390: don't trace preemption in percpu macros
ceph: don't allow setlease on cephfs
nvmet: Disable keep-alive timer when kato is cleared to 0h
hwmon: (applesmc) check status earlier.
perf record/stat: Explicitly call out event modifiers in the documentation
* HID: core: Sanitize event code and type when mapping input
drivers/hid/hid-input.c
drivers/hid/hid-multitouch.c
include/linux/hid.h
* HID: core: Correctly handle ReportSize being zero
drivers/hid/hid-core.c
* ANDROID: overflow.h: fix merge issue with 4.9.235
include/linux/overflow.h
Merge 4.9.235 into android-4.9-q
Linux 4.9.235
* ALSA: usb-audio: Update documentation comment for MS2109 quirk
sound/usb/quirks-table.h
* HID: hiddev: Fix slab-out-of-bounds write in hiddev_ioctl_usage()
drivers/hid/usbhid/hiddev.c
btrfs: check the right error variable in btrfs_del_dir_entries_in_log
usb: storage: Add unusual_uas entry for Sony PSZ drives
* USB: gadget: u_f: Unbreak offset calculation in VLAs
drivers/usb/gadget/u_f.h
USB: gadget: f_ncm: add bounds checks to ncm_unwrap_ntb()
* USB: gadget: u_f: add overflow checks to VLA macros
drivers/usb/gadget/u_f.h
* overflow.h: Add allocation size calculation helpers
drivers/md/dm-table.c
include/linux/overflow.h
usb: host: ohci-exynos: Fix error handling in exynos_ohci_probe()
* USB: Ignore UAS for JMicron JMS567 ATA/ATAPI Bridge
drivers/usb/storage/unusual_devs.h
* USB: quirks: Add no-lpm quirk for another Raydium touchscreen
drivers/usb/core/quirks.c
usb: uas: Add quirk for PNY Pro Elite
USB: yurex: Fix bad gfp argument
* device property: Fix the secondary firmware node handling in set_primary_fwnode()
drivers/base/core.c
* PM: sleep: core: Fix the handling of pending runtime resume requests
drivers/base/power/main.c
* xhci: Do warm-reset when both CAS and XDEV_RESUME are set
drivers/usb/host/xhci-hub.c
XEN uses irqdesc::irq_data_common::handler_data to store a per interrupt XEN data pointer which contains XEN specific information.
* writeback: Fix sync livelock due to b_dirty_time processing
fs/fs-writeback.c
include/trace/events/writeback.h
* writeback: Avoid skipping inode writeback
fs/fs-writeback.c
include/linux/fs.h
* writeback: Protect inode->i_io_list with inode->i_lock
fs/fs-writeback.c
serial: 8250: change lock order in serial8250_do_startup()
serial: pl011: Don't leak amba_ports entry on driver register error
serial: pl011: Fix oops on -EPROBE_DEFER
serial: samsung: Removes the IRQ not found warning
* vt_ioctl: change VT_RESIZEX ioctl to check for error return from vc_resize()
drivers/tty/vt/vt_ioctl.c
* vt: defer kfree() of vc_screenbuf in vc_do_resize()
drivers/tty/vt/vt.c
* USB: lvtest: return proper error code in probe
drivers/usb/misc/lvstest.c
fbcon: prevent user font height or width change from causing potential out-of-bounds access
btrfs: fix space cache memory leak after transaction abort
HID: i2c-hid: Always sleep 60ms after I2C_HID_PWR_ON commands
powerpc/perf: Fix soft lockups due to missed interrupt accounting
net: gianfar: Add of_node_put() before goto statement
* scsi: ufs: Improve interrupt handling for shared interrupts
drivers/scsi/ufs/ufshcd.c
* scsi: ufs: Fix possible infinite loop in ufshcd_hold
drivers/scsi/ufs/ufshcd.c
s390/cio: add cond_resched() in the slow_eval_known_fn() loop
* fs: prevent BUG_ON in submit_bh_wbc()
fs/buffer.c
fs/ext4/super.c
* jbd2: abort journal if free a async write error metadata buffer
fs/jbd2/transaction.c
* jbd2: make sure jh have b_transaction set in refile/unfile_buffer
fs/jbd2/transaction.c
usb: gadget: f_tcm: Fix some resource leaks in some error paths
i2c: rcar: in slave mode, clear NACK earlier
Revert "ath10k: fix DMA related firmware crashes on multiple devices"
* efi: provide empty efi_enter_virtual_mode implementation
include/linux/efi.h
USB: sisusbvga: Fix a potential UB casued by left shifting a negative value
powerpc/spufs: add CONFIG_COREDUMP dependency
KVM: arm64: Fix symbol dependency in __hyp_call_panic_nvhe
media: davinci: vpif_capture: fix potential double free
EDAC/ie31200: Fallback if host bridge device is already initialized
scsi: fcoe: Memory leak fix in fcoe_sysfs_fcf_del()
ceph: fix potential mdsc use-after-free crash
scsi: iscsi: Do not put host in iscsi_set_flashnode_param()
locking/lockdep: Fix overflow in presentation of average lock-time
drm/nouveau: Fix reference count leak in nouveau_connector_detect
drm/nouveau/drm/noveau: fix reference count leak in nouveau_fbcon_open
cec-api: prevent leaking memory through hole in structure
mips/vdso: Fix resource leaks in genvdso.c
rtlwifi: rtl8192cu: Prevent leaking urb
* PCI: Fix pci_create_slot() reference count leak
drivers/pci/slot.c
omapfb: fix multiple reference count leaks due to pm_runtime_get_sync
selftests/powerpc: Purge extra count_pmc() calls of ebb selftests
scsi: lpfc: Fix shost refcount mismatch when deleting vport
drm/amdgpu/display: fix ref count leak when pm_runtime_get_sync fails
drm/amdgpu: fix ref count leak in amdgpu_display_crtc_set_config
drm/amd/display: fix ref count leak in amdgpu_drm_ioctl
drm/amdgpu: fix ref count leak in amdgpu_driver_open_kms
drm/radeon: fix multiple reference count leak
drm/amdkfd: Fix reference count leaks.
* iommu/iova: Don't BUG on invalid PFNs
drivers/iommu/iova.c
scsi: target: tcmu: Fix crash on ARM during cmd completion
media: pci: ttpci: av7110: fix possible buffer overflow caused by bad DMA value in debiirq()
arm64: dts: qcom: msm8916: Pull down PDM GPIOs during sleep
ASoC: tegra: Fix reference count leaks.
ALSA: pci: delete repeated words in comments
* gre6: Fix reception with IP6_TNL_F_RCV_DSCP_COPY
net/ipv6/ip6_tunnel.c
ipvlan: fix device features
tipc: fix uninit skb->data in tipc_nl_compat_dumpit()
* net: Fix potential wrong skb->protocol in skb_vlan_untag()
net/core/skbuff.c
* bonding: show saner speed for broadcast mode
drivers/net/bonding/bond_main.c
* bonding: fix a potential double-unregister
drivers/net/bonding/bond_main.c
Change-Id: Ic5e975d213782585fedbf8a5869b9b0aaad0bf66
Signed-off-by: lucaswei <lucaswei@google.com>
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Jason Gunthorpe
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ad68326969 |
include/linux/log2.h: add missing () around n in roundup_pow_of_two()
[ Upstream commit 428fc0aff4e59399ec719ffcc1f7a5d29a4ee476 ]
Otherwise gcc generates warnings if the expression is complicated.
Fixes:
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Martin Wilck
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fc5777620b |
UPSTREAM: scsi: ilog2: create truly constant version for sparse
Sparse emits errors about ilog2() in array indices because of the use of __ilog2_32() and __ilog2_64(), rightly so (https://www.spinics.net/lists/linux-sparse/msg03471.html). Create a const_ilog2() variant that works with sparse for this scenario. (Note: checkpatch.pl complains about missing parentheses, but that appears to be a false positive. I can get rid of the warning simply by inserting whitespace, making checkpatch "see" the whole macro). Signed-off-by: Martin Wilck <mwilck@suse.com> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com> (cherry picked from commit dbef91ec5482239055dd2db8ec656fc13d382add) Change-Id: I58dd621bddce6b07e48d45f9828be023811d2e07 Bug: 140252993 Signed-off-by: Jeff Vander Stoep <jeffv@google.com> |
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Ard Biesheuvel
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8de6ea44af |
log2: make order_base_2() behave correctly on const input value zero
commit 29905b52fad0854351f57bab867647e4982285bf upstream.
The function order_base_2() is defined (according to the comment block)
as returning zero on input zero, but subsequently passes the input into
roundup_pow_of_two(), which is explicitly undefined for input zero.
This has gone unnoticed until now, but optimization passes in GCC 7 may
produce constant folded function instances where a constant value of
zero is passed into order_base_2(), resulting in link errors against the
deliberately undefined '____ilog2_NaN'.
So update order_base_2() to adhere to its own documented interface.
[ See
http://marc.info/?l=linux-kernel&m=147672952517795&w=2
and follow-up discussion for more background. The gcc "optimization
pass" is really just broken, but now the GCC trunk problem seems to
have escaped out of just specially built daily images, so we need to
work around it in mainline. - Linus ]
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Linus Torvalds
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85f687708c |
give up on gcc ilog2() constant optimizations
commit 474c90156c8dcc2fa815e6716cc9394d7930cb9c upstream. gcc-7 has an "optimization" pass that completely screws up, and generates the code expansion for the (impossible) case of calling ilog2() with a zero constant, even when the code gcc compiles does not actually have a zero constant. And we try to generate a compile-time error for anybody doing ilog2() on a constant where that doesn't make sense (be it zero or negative). So now gcc7 will fail the build due to our sanity checking, because it created that constant-zero case that didn't actually exist in the source code. There's a whole long discussion on the kernel mailing about how to work around this gcc bug. The gcc people themselevs have discussed their "feature" in https://gcc.gnu.org/bugzilla/show_bug.cgi?id=72785 but it's all water under the bridge, because while it looked at one point like it would be solved by the time gcc7 was released, that was not to be. So now we have to deal with this compiler braindamage. And the only simple approach seems to be to just delete the code that tries to warn about bad uses of ilog2(). So now "ilog2()" will just return 0 not just for the value 1, but for any non-positive value too. It's not like I can recall anybody having ever actually tried to use this function on any invalid value, but maybe the sanity check just meant that such code never made it out in public. Reported-by: Laura Abbott <labbott@redhat.com> Cc: John Stultz <john.stultz@linaro.org>, Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Jiri Slaby <jslaby@suse.cz> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
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Linus Torvalds
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13c07b0286 |
linux/log2.h: Fix rounddown_pow_of_two(1)
Exactly like roundup_pow_of_two(1), the rounddown version was buggy for
the case of a compile-time constant '1' argument. Probably because it
originated from the same code, sharing history with the roundup version
from before the bugfix (for that one, see commit
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Robert P. J. Day
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de9330d13e |
log2.h: Define order_base_2() macro for convenience.
Given a number of places in the tree that need to calculate this value explicitly, might as well just create a macro for it. (akpm: must be implemented as a macro for callee typeof() usage) Signed-off-by: Robert P. J. Day <rpjday@crashcourse.ca> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Robert P. J. Day
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b311e921b3 |
Add a "rounddown_pow_of_two" routine to log2.h
To go along with the existing "roundup_pow_of_two" routine, add one for rounding down since that operation appears to crop up on a regular basis in the source tree. [m.kozlowski@tuxland.pl: fix unbalanced parentheses] Signed-off-by: Robert P. J. Day <rpjday@mindspring.com> Signed-off-by: Mariusz Kozlowski <m.kozlowski@tuxland.pl> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Rolf Eike Beer
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1a06a52ee1 |
Fix roundup_pow_of_two(1)
1 is a power of two, therefore roundup_pow_of_two(1) should return 1. It does in case the argument is a variable but in case it's a constant it behaves wrong and returns 0. Probably nobody ever did it so this was never noticed. Signed-off-by: Rolf Eike Beer <eike-kernel@sf-tec.de> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Robert P. J. Day
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6fb189c2a4 |
Correct trivial typo in log2.h.
Single typo correction in include/linux/log2.h. Signed-off-by: Robert P. J. Day <rpjday@mindspring.com> Signed-Off-By: David Howells <dhowells@redhat.com> Signed-off-by: Adrian Bunk <bunk@stusta.de> |
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Robert P. J. Day
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63c2f782e8 |
[POWERPC] Add "is_power_of_2" checking to log2.h.
Add the inline function "is_power_of_2()" to log2.h, where the value zero is *not* considered to be a power of two. Signed-off-by: Robert P. J. Day <rpjday@mindspring.com> Acked-by: Kumar Gala <galak@kernel.crashing.org> Signed-off-by: Paul Mackerras <paulus@samba.org> |
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David Howells
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312a0c1709 |
[PATCH] LOG2: Alter roundup_pow_of_two() so that it can use a ilog2() on a constant
Alter roundup_pow_of_two() so that it can make use of ilog2() on a constant to produce a constant value, retaining the ability for an arch to override it in the non-const case. This permits the function to be used to initialise variables. Signed-off-by: David Howells <dhowells@redhat.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org> |
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David Howells
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f0d1b0b30d |
[PATCH] LOG2: Implement a general integer log2 facility in the kernel
This facility provides three entry points:
ilog2() Log base 2 of unsigned long
ilog2_u32() Log base 2 of u32
ilog2_u64() Log base 2 of u64
These facilities can either be used inside functions on dynamic data:
int do_something(long q)
{
...;
y = ilog2(x)
...;
}
Or can be used to statically initialise global variables with constant values:
unsigned n = ilog2(27);
When performing static initialisation, the compiler will report "error:
initializer element is not constant" if asked to take a log of zero or of
something not reducible to a constant. They treat negative numbers as
unsigned.
When not dealing with a constant, they fall back to using fls() which permits
them to use arch-specific log calculation instructions - such as BSR on
x86/x86_64 or SCAN on FRV - if available.
[akpm@osdl.org: MMC fix]
Signed-off-by: David Howells <dhowells@redhat.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: David Howells <dhowells@redhat.com>
Cc: Wojtek Kaniewski <wojtekka@toxygen.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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