- 10 Aug, 2010 40 commits
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Alek Du authored
This patch will enable Per-port event feature defined in EHCI 1.1 addendum. This feature addresses an issue where HCD is currently required to read and parse PORTSC for all enabled root hub ports. With this patch, the overhead will be reduced. Signed-off-by: Alek Du <alek.du@intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
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Alek Du authored
With this patch, the LPM capable EHCI host controller can put device into L1 sleep state which is a mode that can enter/exit quickly, and reduce power consumption. Signed-off-by: Jacob Pan <jacob.jun.pan@intel.com> Signed-off-by: Alek Du <alek.du@intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
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Alek Du authored
EHCI 1.1 addendum introduced several energy efficiency extensions for EHCI USB host controllers: 1. LPM (link power management) 2. Per-port change 3. Shorter periodic frame list 4. Hardware prefetching This patch is intended to define the HW bits and debug interface for EHCI 1.1 addendum. The LPM and Per-port change patches will be sent out after this patch. Signed-off-by: Jacob Pan <jacob.jun.pan@intel.com> Signed-off-by: Alek Du <alek.du@intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
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Andy Shevchenko authored
Recent kernel has common method to convert hex digit to its value. Signed-off-by: Andy Shevchenko <ext-andriy.shevchenko@nokia.com> Cc: David Brownell <dbrownell@users.sourceforge.net> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
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Joe Perches authored
Signed-off-by: Joe Perches <joe@perches.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
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Julia Lawall authored
The test above allows std to be NULL, so check that std is not NULL before doing the dereference. A simplified version of the semantic match that finds this problem is as follows: (http://coccinelle.lip6.fr/) // <smpl> @r exists@ expression E,E1; identifier f; statement S1,S2,S3; @@ if ((E == NULL && ...) || ...) { ... when != if (...) S1 else S2 when != E = E1 * E->f ... when any } else S3 // </smpl> Signed-off-by: Julia Lawall <julia@diku.dk> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
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Igor Grinberg authored
otg_io_write() function does not follow the declaration of struct otg_io_access_ops. Signed-off-by: Igor Grinberg <grinberg@compulab.co.il> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
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csanchez@neurowork.net authored
Fixed coding styles in the core usb endpoint. Signed-off-by: Carlos Sánchez Acosta <csanchez@neurowork.net> Signed-off-by: Alejandro Sánchez Acosta <asanchez@neurowork.net> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
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csanchez@neurowork.net authored
Fixed coding styles in the core usb driver. Signed-off-by: Carlos Sánchez Acosta <csanchez@neurowork.net> Signed-off-by: Alejandro Sánchez Acosta <asanchez@neurowork.net> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
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Andrea Gelmini authored
Documentation/usb/linux.inf:66: ERROR: trailing whitespace Documentation/usb/linux.inf:67: ERROR: trailing whitespace Documentation/usb/linux.inf:98: ERROR: trailing whitespace Documentation/usb/linux.inf:99: ERROR: trailing whitespace Documentation/usb/linux.inf:115: ERROR: trailing whitespace Documentation/usb/linux.inf:116: ERROR: trailing whitespace Documentation/usb/linux.inf:120: ERROR: trailing whitespace Documentation/usb/linux.inf:121: ERROR: trailing whitespace Documentation/usb/linux.inf:122: ERROR: trailing whitespace Documentation/usb/linux.inf:123: ERROR: trailing whitespace Documentation/usb/linux.inf:144: ERROR: trailing whitespace Documentation/usb/linux.inf:145: ERROR: trailing whitespace Documentation/usb/linux.inf:146: ERROR: trailing whitespace Documentation/usb/linux.inf:147: ERROR: trailing whitespace Documentation/usb/linux.inf:158: ERROR: trailing whitespace Signed-off-by: Andrea Gelmini <andrea.gelmini@gelma.net> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
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Andrea Gelmini authored
Documentation/usb/hotplug.txt:13: ERROR: trailing whitespace Documentation/usb/hotplug.txt:87: ERROR: trailing whitespace Signed-off-by: Andrea Gelmini <andrea.gelmini@gelma.net> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
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Andrea Gelmini authored
Documentation/usb/ehci.txt:12: ERROR: trailing whitespace Signed-off-by: Andrea Gelmini <andrea.gelmini@gelma.net> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
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Julia Lawall authored
Use memdup_user when user data is immediately copied into the allocated region. The semantic patch that makes this change is as follows: (http://coccinelle.lip6.fr/) // <smpl> @@ expression from,to,size,flag; position p; identifier l1,l2; @@ - to = \(kmalloc@p\|kzalloc@p\)(size,flag); + to = memdup_user(from,size); if ( - to==NULL + IS_ERR(to) || ...) { <+... when != goto l1; - -ENOMEM + PTR_ERR(to) ...+> } - if (copy_from_user(to, from, size) != 0) { - <+... when != goto l2; - -EFAULT - ...+> - } // </smpl> Signed-off-by: Julia Lawall <julia@diku.dk> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
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Alan Stern authored
This patch (as1382) changes the USB_EHCI_TT_NEWSCHED Kconfig option to be non-experimental and to default to Y. This option has existed for a long time, and I have not heard any complaints concerning it. By contrast, several people have reported that their devices could be made to work only by enabling the option. The point of changing the default is to cause the option to be enabled by distros that simply use the default settings for esoteric things like this. This change was motivated by Bugzilla #15649. Signed-off-by: Alan Stern <stern@rowland.harvard.edu> CC: David Brownell <david-b@pacbell.net> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
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James Courtier-Dutton authored
Signed-off-by: James Courtier-Dutton <James@superbug.co.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
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Sarah Sharp authored
When code to manipulate the command register was refactored from xhci_run() to xhci_start(), a debugging statement was left behind that no longer applies. Remove that statement. Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com> Reported-by: Sergei Shtylyov <sshtylyov@mvista.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
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Nicolas Kaiser authored
Fixed spacing coding style issues. Signed-off-by: Nicolas Kaiser <nikai@nikai.net> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
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Nicolas Kaiser authored
Fixed brace coding style issues. Signed-off-by: Nicolas Kaiser <nikai@nikai.net> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
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Alan Stern authored
This patch (as1392) fixes a bug in uhci-hcd: The start_rh() routine is supposed to be called with the private spinlock held. If an IRQ comes in at just the wrong time, the driver will think the controller has died when in fact it simply hasn't start yet. The patch also addresses some issues that may prevent an URB from being unlinked after the controller has stopped. This is an abnormal occurrence (ordinarily the controller stops only when the entire bus is suspended and hence there are no active URBs), so the pathways haven't gotten much testing. These two changes may be a little more than is strictly necessary, but clearly they won't hurt. Signed-off-by: Alan Stern <stern@rowland.harvard.edu> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
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Alan Stern authored
This patch (as1391) fixes a problem that can occur when USB host controller hardware is hot-unplugged. If no interrupts are generated by the unplug then the HCD may not realize that the controller is gone, and the subsequent unbind may hang waiting for interrupts that never arrive. The solution (for PCI-based controllers) is to call the HCD's interrupt handler at the start of usb_hcd_pci_remove(). If the hardware is gone, the handler will realize this when it tries to read the controller's status register. Signed-off-by: Alan Stern <stern@rowland.harvard.edu> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
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Alan Stern authored
This patch (as1390) fixes a problem that crops up when a UHCI host controller is unbound from uhci-hcd while there are still some active URBs. The URBs have to be unlinked when the root hub is unregistered, and uhci-hcd relies upon root-hub status polls as part of its unlinking procedure. But usb_hcd_poll_rh_status() won't make those status calls if hcd->rh_registered is clear, and the flag is cleared _before_ the unregistration takes place. Since hcd->rh_registered is used for other things and needs to be cleared early, the solution is to add a new flag (rh_pollable) and use it instead. It gets cleared _after_ the root hub is unregistered. Now that the status polls don't end too soon, we have to make sure they also don't occur too late -- after the root hub's usb_device structure or the HCD's private structures are deallocated. Therefore the patch adds usb_get_device() and usb_put_device() calls to protect the root hub structure, and it adds an extra del_timer_sync() to prevent the root-hub timer from causing an unexpected status poll. This additional complexity would not be needed if the HCD framework had provided separate stop() and release() callbacks instead of just stop(). This lack could be fixed at some future time (although it would require changes to every host controller driver); when that happens this patch won't be needed any more. Signed-off-by: Alan Stern <stern@rowland.harvard.edu> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
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Alan Stern authored
This patch (as1389) fixes some errors in the failure pathway of usb_add_hcd(). The actions it takes ought to be exactly the same as those taken by usb_remove_hcd(), but they aren't. In one case (removal of the usb_bus_attr_group), the two routines are brought into agreement by changing usb_remove_hcd(). All the other discrepancies are fixed by changing usb_add_hcd(). Signed-off-by: Alan Stern <stern@rowland.harvard.edu> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
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git://decibel.fi.muni.cz/~xslaby/linuxLinus Torvalds authored
* 'writable_limits' of git://decibel.fi.muni.cz/~xslaby/linux: unistd: add __NR_prlimit64 syscall numbers rlimits: implement prlimit64 syscall rlimits: switch more rlimit syscalls to do_prlimit rlimits: redo do_setrlimit to more generic do_prlimit rlimits: add rlimit64 structure rlimits: do security check under task_lock rlimits: allow setrlimit to non-current tasks rlimits: split sys_setrlimit rlimits: selinux, do rlimits changes under task_lock rlimits: make sure ->rlim_max never grows in sys_setrlimit rlimits: add task_struct to update_rlimit_cpu rlimits: security, add task_struct to setrlimit Fix up various system call number conflicts. We not only added fanotify system calls in the meantime, but asm-generic/unistd.h added a wait4 along with a range of reserved per-architecture system calls.
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git://git.infradead.org/mtd-2.6Linus Torvalds authored
* git://git.infradead.org/mtd-2.6: (79 commits) mtd: Remove obsolete <mtd/compatmac.h> include mtd: Update copyright notices jffs2: Update copyright notices mtd-physmap: add support users can assign the probe type in board files mtd: remove redwood map driver mxc_nand: Add v3 (i.MX51) Support mxc_nand: support 8bit ecc mxc_nand: fix correct_data function mxc_nand: add V1_V2 namespace to registers mxc_nand: factor out a check_int function mxc_nand: make some internally used functions overwriteable mxc_nand: rework get_dev_status mxc_nand: remove 0xe00 offset from registers mtd: denali: Add multi connected NAND support mtd: denali: Remove set_ecc_config function mtd: denali: Remove unuseful code in get_xx_nand_para functions mtd: denali: Remove device_info_tag structure mtd: m25p80: add support for the Winbond W25Q32 SPI flash chip mtd: m25p80: add support for the Intel/Numonyx {16,32,64}0S33B SPI flash chips mtd: m25p80: add support for the EON EN25P{32, 64} SPI flash chips ... Fix up trivial conflicts in drivers/mtd/maps/{Kconfig,redwood.c} due to redwood driver removal.
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git://git.kernel.org/pub/scm/linux/kernel/git/bcopeland/omfsLinus Torvalds authored
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/bcopeland/omfs: omfs: fix uninitialized variable warning omfs: sanity check cluster size omfs: refuse to mount if bitmap pointer is obviously wrong omfs: check bounds on block numbers before passing to sb_bread omfs: fix memory leak
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git://git.infradead.org/users/eparis/notifyLinus Torvalds authored
* 'for-linus' of git://git.infradead.org/users/eparis/notify: (132 commits) fanotify: use both marks when possible fsnotify: pass both the vfsmount mark and inode mark fsnotify: walk the inode and vfsmount lists simultaneously fsnotify: rework ignored mark flushing fsnotify: remove global fsnotify groups lists fsnotify: remove group->mask fsnotify: remove the global masks fsnotify: cleanup should_send_event fanotify: use the mark in handler functions audit: use the mark in handler functions dnotify: use the mark in handler functions inotify: use the mark in handler functions fsnotify: send fsnotify_mark to groups in event handling functions fsnotify: Exchange list heads instead of moving elements fsnotify: srcu to protect read side of inode and vfsmount locks fsnotify: use an explicit flag to indicate fsnotify_destroy_mark has been called fsnotify: use _rcu functions for mark list traversal fsnotify: place marks on object in order of group memory address vfs/fsnotify: fsnotify_close can delay the final work in fput fsnotify: store struct file not struct path ... Fix up trivial delete/modify conflict in fs/notify/inotify/inotify.c.
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git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6Linus Torvalds authored
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6: (96 commits) no need for list_for_each_entry_safe()/resetting with superblock list Fix sget() race with failing mount vfs: don't hold s_umount over close_bdev_exclusive() call sysv: do not mark superblock dirty on remount sysv: do not mark superblock dirty on mount btrfs: remove junk sb_dirt change BFS: clean up the superblock usage AFFS: wait for sb synchronization when needed AFFS: clean up dirty flag usage cifs: truncate fallout mbcache: fix shrinker function return value mbcache: Remove unused features add f_flags to struct statfs(64) pass a struct path to vfs_statfs update VFS documentation for method changes. All filesystems that need invalidate_inode_buffers() are doing that explicitly convert remaining ->clear_inode() to ->evict_inode() Make ->drop_inode() just return whether inode needs to be dropped fs/inode.c:clear_inode() is gone fs/inode.c:evict() doesn't care about delete vs. non-delete paths now ... Fix up trivial conflicts in fs/nilfs2/super.c
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git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-2.6Linus Torvalds authored
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-2.6: (59 commits) igbvf.txt: Add igbvf Documentation igb.txt: Add igb documentation e100/e1000*/igb*/ixgb*: Add missing read memory barrier ixgbe: fix build error with FCOE_CONFIG without DCB_CONFIG netxen: protect tx timeout recovery by rtnl lock isdn: gigaset: use after free isdn: gigaset: add missing unlock solos-pci: Fix race condition in tasklet RX handling pkt_sched: Fix sch_sfq vs tcf_bind_filter oops net: disable preemption before call smp_processor_id() tcp: no md5sig option size check bug iwlwifi: fix locking assertions iwlwifi: fix TX tracer isdn: fix information leak net: Fix napi_gro_frags vs netpoll path usbnet: remove noisy and hardly useful printk rtl8180: avoid potential NULL deref in rtl8180_beacon_work ath9k: Remove myself from the MAINTAINERS list libertas: scan before assocation if no BSSID was given libertas: fix association with some APs by using extended rates ...
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git://git.kernel.org/pub/scm/linux/kernel/git/davem/ide-2.6Linus Torvalds authored
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/ide-2.6: tx493xide: use min_t() macro instead of min() drivers/ide: Use memdup_user via82cxxx: fix typo for VT6415 PCIE PATA IDE Host Controller support. ide-cd: Do not access completed requests in the irq handler
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git://git.kernel.org/pub/scm/linux/kernel/git/davem/sparc-2.6Linus Torvalds authored
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/sparc-2.6: sparc64: Update defconfig. sparc: Kill user copy check code. sparc64: Fix perf_arch_get_caller_regs(). sparc64: Add missing ID to parport probing code.
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git://www.jni.nu/crisLinus Torvalds authored
* 'rs485fix' of git://www.jni.nu/cris: CRIS: ioctl for getting RS485 information
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git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpcLinus Torvalds authored
* 'merge' of git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpc: powerpc: fix build with make 3.82 Revert "Input: appletouch - fix integer overflow issue" memblock: Fix memblock_is_region_reserved() to return a boolean powerpc: Trim defconfigs powerpc: fix i8042 module build error sound/soc: mpc5200_psc_ac97: Use gpio pins for cold reset powerpc/5200: add mpc5200_psc_ac97_gpio_reset
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git://git.kernel.org/pub/scm/linux/kernel/git/vapier/blackfinLinus Torvalds authored
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/vapier/blackfin: (32 commits) Blackfin: gpio: add a debounce stub Blackfin: update defconfigs Blackfin: remove CONFIG_MEM_GENERIC_BOARD Blackfin: dpmc: punt unnecessary RTC_ISTAT clearing Blackfin: unify rotary encoder bitmasks Blackfin: unify SDH/RSI bitmasks Blackfin: BF54x: tweak DMAC MMR naming to match other ports Blackfin: TWI: clean up the MMR names Blackfin: add EVT_OVERRIDE/IPRIO core MMR helpers Blackfin: add support for dynamic ftrace Blackfin: add support for LZO compressed kernels Blackfin: portmux: fix peripheral map overflow when requesting pins Blackfin: document SPI CS limitations with CPHA=0 Blackfin: remove useless and outdated documentation Blackfin: BF51x/BF52x: support GPIO Hysteresis/Schmitt Trigger options Blackfin: gpio/portmux: clean up whitespace corruption Blackfin: make sure mmiowb inserts a write barrier with SSYNC Blackfin: fix DMA/cache bug when resuming from suspend to RAM Blackfin: BF51x: fix handling of PH8 (the "internal" SPI0SEL4 pin) Blackfin: add a GPIO_DEFAULT_BOOT_SPI_CS ...
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git://git.kernel.org/pub/scm/linux/kernel/git/djbw/async_txLinus Torvalds authored
* 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/djbw/async_tx: (30 commits) DMAENGINE: at_hdmac: locking fixlet DMAENGINE: pch_dma: kill another usage of __raw_{read|write}l dma: dmatest: fix potential sign bug ioat2: catch and recover from broken vtd configurations v6 DMAENGINE: add runtime slave control to COH 901 318 v3 DMAENGINE: add runtime slave config to DMA40 v3 DMAENGINE: generic slave channel control v3 dmaengine: Driver for Topcliff PCH DMA controller intel_mid: Add Mrst & Mfld DMA Drivers drivers/dma: Eliminate a NULL pointer dereference dma/timb_dma: compile warning on 32 bit DMAENGINE: ste_dma40: support older silicon DMAENGINE: ste_dma40: support disabling physical channels DMAENGINE: ste_dma40: no disabled phy channels on ux500 DMAENGINE: ste_dma40: fix suspend bug DMAENGINE: ste_dma40: add DB8500 memcpy channels DMAENGINE: ste_dma40: no flow control on memcpy DMAENGINE: ste_dma40: arch updates for LCLA and LCPA DMAENGINE: ste_dma40: allocate LCLA dynamically DMAENGINE: ste_dma40: no premature stop ... Fix up trivial conflicts in arch/arm/mach-ux500/devices-db8500.c
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qiaochong authored
According include/linux/console_struct.h,vc_scr_end is unsigned long. struct vc_data { unsigned short vc_num; /* Console number */ unsigned int vc_cols; /* [#] Console size */ unsigned int vc_rows; unsigned int vc_size_row; /* Bytes per row */ unsigned int vc_scan_lines; /* # of scan lines */ unsigned long vc_origin; /* [!] Start of real screen */ unsigned long vc_scr_end; /* [!] End of real screen */ unsigned long vc_visible_origin; /* [!] Top of visible window */ unsigned int vc_top, vc_bottom; /* Scrolling region */ const struct consw *vc_sw; unsigned short *vc_screenbuf; ... } Signed-off-by: qiaochong <qiaochong@loongson.cn> Cc: Greg KH <greg@kroah.com> Cc: Alan Cox <alan@lxorguk.ukuu.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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qiaochong authored
kernel will die on some platform when switch from vga mode to framebuffer mode. The reason of this bug is that bind_con_driver reset vc->vc_origin to (unsigned long)vc->vc_screenbuf. On vgacon vc->vc_origin is not releated to vc->vc_screenbuf,if set vc->vc_origin to vc->vc_screenbuf,kernel will die on vc_do_resize. static int vc_do_resize(struct tty_struct *tty, struct tty_struct *real_tty, struct vc_data *vc, unsigned int cols, unsigned int lines) { unsigned long old_origin, new_origin, new_scr_end, rlth, rrem, err = 0; unsigned int old_cols, old_rows, old_row_size, old_screen_size; unsigned int new_cols, new_rows, new_row_size, new_screen_size; unsigned int end, user; ... end = (old_rows > new_rows) ? old_origin + (old_row_size * new_rows) : vc->vc_scr_end; ... /* here for a test from vgacon to framebuffer: old_origin=0x810814a0,end=0xb00b8fa0,vc->vc_origin=0x810814a0 the code bellow will copy memory from 0x810814a0 to 0xb00b8fa0, this will cover kernel code,kernel died here. */ while (old_origin < end) { scr_memcpyw((unsigned short *) new_origin, (unsigned short *) old_origin, rlth); if (rrem) scr_memsetw((void *)(new_origin + rlth), vc->vc_video_erase_char, rrem); old_origin += old_row_size; new_origin += new_row_size; } ... } [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: qiaochong <qiaochong@loongson.cn> Cc: Greg KH <greg@kroah.com> Cc: Alan Cox <alan@lxorguk.ukuu.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Michel Lespinasse authored
More code can be pushed from rwsem_down_read_failed and rwsem_down_write_failed into rwsem_down_failed_common. Following change adding down_read_critical infrastructure support also enjoys having flags available in a register rather than having to fish it out in the struct rwsem_waiter... Signed-off-by: Michel Lespinasse <walken@google.com> Acked-by: David Howells <dhowells@redhat.com> Cc: Mike Waychison <mikew@google.com> Cc: Suleiman Souhlal <suleiman@google.com> Cc: Ying Han <yinghan@google.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Michel Lespinasse authored
This change addresses the following situation: - Thread A acquires the rwsem for read - Thread B tries to acquire the rwsem for write, notices there is already an active owner for the rwsem. - Thread C tries to acquire the rwsem for read, notices that thread B already tried to acquire it. - Thread C grabs the spinlock and queues itself on the wait queue. - Thread B grabs the spinlock and queues itself behind C. At this point A is the only remaining active owner on the rwsem. In this situation thread B could notice that it was the last active writer on the rwsem, and decide to wake C to let it proceed in parallel with A since they both only want the rwsem for read. Signed-off-by: Michel Lespinasse <walken@google.com> Acked-by: David Howells <dhowells@redhat.com> Cc: Mike Waychison <mikew@google.com> Cc: Suleiman Souhlal <suleiman@google.com> Cc: Ying Han <yinghan@google.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Michel Lespinasse authored
Previously each waiting thread added a bias of RWSEM_WAITING_BIAS. With this change, the bias is added only once to indicate that the wait list is non-empty. This has a few nice properties which will be used in following changes: - when the spinlock is held and the waiter list is known to be non-empty, count < RWSEM_WAITING_BIAS <=> there is an active writer on that sem - count == RWSEM_WAITING_BIAS <=> there are waiting threads and no active readers/writers on that sem Signed-off-by: Michel Lespinasse <walken@google.com> Acked-by: David Howells <dhowells@redhat.com> Cc: Mike Waychison <mikew@google.com> Cc: Suleiman Souhlal <suleiman@google.com> Cc: Ying Han <yinghan@google.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Michel Lespinasse authored
In __rwsem_do_wake(), we can skip the active count check unless we come there from up_xxxx(). Also when checking the active count, it is not actually necessary to increment it; this allows us to get rid of the read side undo code and simplify the calculation of the final rwsem count adjustment once we've counted the reader threads to wake. The basic observation is the following. When there are waiter threads on a rwsem and the spinlock is held, other threads can only increment the active count by trying to grab the rwsem in down_xxxx(). However down_xxxx() will notice there are waiter threads and take the down_failed path, blocking to acquire the spinlock on the way there. Therefore, a thread observing an active count of zero with waiters queued and the spinlock held, is protected against other threads acquiring the rwsem until it wakes the last waiter or releases the spinlock. Signed-off-by: Michel Lespinasse <walken@google.com> Acked-by: David Howells <dhowells@redhat.com> Cc: Mike Waychison <mikew@google.com> Cc: Suleiman Souhlal <suleiman@google.com> Cc: Ying Han <yinghan@google.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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