Skip to content
Snippets Groups Projects
  1. May 16, 2014
  2. May 15, 2014
  3. May 14, 2014
    • Hannes Frederic Sowa's avatar
      net: avoid dependency of net_get_random_once on nop patching · 3d440522
      Hannes Frederic Sowa authored
      
      net_get_random_once depends on the static keys infrastructure to patch up
      the branch to the slow path during boot. This was realized by abusing the
      static keys api and defining a new initializer to not enable the call
      site while still indicating that the branch point should get patched
      up. This was needed to have the fast path considered likely by gcc.
      
      The static key initialization during boot up normally walks through all
      the registered keys and either patches in ideal nops or enables the jump
      site but omitted that step on x86 if ideal nops where already placed at
      static_key branch points. Thus net_get_random_once branches not always
      became active.
      
      This patch switches net_get_random_once to the ordinary static_key
      api and thus places the kernel fast path in the - by gcc considered -
      unlikely path.  Microbenchmarks on Intel and AMD x86-64 showed that
      the unlikely path actually beats the likely path in terms of cycle cost
      and that different nop patterns did not make much difference, thus this
      switch should not be noticeable.
      
      Fixes: a48e4292 ("net: introduce new macro net_get_random_once")
      Reported-by: default avatarTuomas Räsänen <tuomasjjrasanen@tjjr.fi>
      Cc: Linus Torvalds <torvalds@linux-foundation.org>
      Signed-off-by: default avatarHannes Frederic Sowa <hannes@stressinduktion.org>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      3d440522
  4. May 09, 2014
  5. May 07, 2014
  6. May 05, 2014
  7. May 04, 2014
  8. May 03, 2014
    • Marc Zyngier's avatar
      arm64: fixmap: fix missing sub-page offset for earlyprintk · f774b7d1
      Marc Zyngier authored
      
      Commit d57c33c5 (add generic fixmap.h) added (among other
      similar things) set_fixmap_io to deal with early ioremap of devices.
      
      More recently, commit bf4b558e (arm64: add early_ioremap support)
      converted the arm64 earlyprintk to use set_fixmap_io. A side effect of
      this conversion is that my virtual machines have stopped booting when
      I pass "earlyprintk=uart8250-8bit,0x3f8" to the guest kernel.
      
      Turns out that the new earlyprintk code doesn't care at all about
      sub-page offsets, and just assumes that the earlyprintk device will
      be page-aligned. Obviously, that doesn't play well with the above example.
      
      Further investigation shows that set_fixmap_io uses __set_fixmap instead
      of __set_fixmap_offset. A fix is to introduce a set_fixmap_offset_io that
      uses the latter, and to remove the superflous call to fix_to_virt
      (which only returns the value that set_fixmap_io has already given us).
      
      With this applied, my VMs are back in business. Tested on a Cortex-A57
      platform with kvmtool as platform emulation.
      
      Cc: Will Deacon <will.deacon@arm.com>
      Acked-by: default avatarMark Salter <msalter@redhat.com>
      Acked-by: default avatarArnd Bergmann <arnd@arndb.de>
      Signed-off-by: default avatarMarc Zyngier <marc.zyngier@arm.com>
      Signed-off-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
      f774b7d1
  9. May 01, 2014
  10. Apr 28, 2014
    • Steven Rostedt (Red Hat)'s avatar
      ftrace/module: Hardcode ftrace_module_init() call into load_module() · a949ae56
      Steven Rostedt (Red Hat) authored
      A race exists between module loading and enabling of function tracer.
      
      	CPU 1				CPU 2
      	-----				-----
        load_module()
         module->state = MODULE_STATE_COMING
      
      				register_ftrace_function()
      				 mutex_lock(&ftrace_lock);
      				 ftrace_startup()
      				  update_ftrace_function();
      				   ftrace_arch_code_modify_prepare()
      				    set_all_module_text_rw();
      				   <enables-ftrace>
      				    ftrace_arch_code_modify_post_process()
      				     set_all_module_text_ro();
      
      				[ here all module text is set to RO,
      				  including the module that is
      				  loading!! ]
      
         blocking_notifier_call_chain(MODULE_STATE_COMING);
          ftrace_init_module()
      
           [ tries to modify code, but it's RO, and fails!
             ftrace_bug() is called]
      
      When this race happens, ftrace_bug() will produces a nasty warning and
      all of the function tracing features will be disabled until reboot.
      
      The simple solution is to treate module load the same way the core
      kernel is treated at boot. To hardcode the ftrace function modification
      of converting calls to mcount into nops. This is done in init/main.c
      there's no reason it could not be done in load_module(). This gives
      a better control of the changes and doesn't tie the state of the
      module to its notifiers as much. Ftrace is special, it needs to be
      treated as such.
      
      The reason this would work, is that the ftrace_module_init() would be
      called while the module is in MODULE_STATE_UNFORMED, which is ignored
      by the set_all_module_text_ro() call.
      
      Link: http://lkml.kernel.org/r/1395637826-3312-1-git-send-email-indou.takao@jp.fujitsu.com
      
      
      
      Reported-by: default avatarTakao Indoh <indou.takao@jp.fujitsu.com>
      Acked-by: default avatarRusty Russell <rusty@rustcorp.com.au>
      Cc: stable@vger.kernel.org # 2.6.38+
      Signed-off-by: default avatarSteven Rostedt <rostedt@goodmis.org>
      a949ae56
    • Thomas Gleixner's avatar
      genirq: x86: Ensure that dynamic irq allocation does not conflict · 62a08ae2
      Thomas Gleixner authored
      
      On x86 the allocation of irq descriptors may allocate interrupts which
      are in the range of the GSI interrupts. That's wrong as those
      interrupts are hardwired and we don't have the irq domain translation
      like PPC. So one of these interrupts can be hooked up later to one of
      the devices which are hard wired to it and the io_apic init code for
      that particular interrupt line happily reuses that descriptor with a
      completely different configuration so hell breaks lose.
      
      Inside x86 we allocate dynamic interrupts from above nr_gsi_irqs,
      except for a few usage sites which have not yet blown up in our face
      for whatever reason. But for drivers which need an irq range, like the
      GPIO drivers, we have no limit in place and we don't want to expose
      such a detail to a driver.
      
      To cure this introduce a function which an architecture can implement
      to impose a lower bound on the dynamic interrupt allocations.
      
      Implement it for x86 and set the lower bound to nr_gsi_irqs, which is
      the end of the hardwired interrupt space, so all dynamic allocations
      happen above.
      
      That not only allows the GPIO driver to work sanely, it also protects
      the bogus callsites of create_irq_nr() in hpet, uv, irq_remapping and
      htirq code. They need to be cleaned up as well, but that's a separate
      issue.
      
      Reported-by: default avatarJin Yao <yao.jin@linux.intel.com>
      Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
      Tested-by: default avatarMika Westerberg <mika.westerberg@linux.intel.com>
      Cc: Mathias Nyman <mathias.nyman@linux.intel.com>
      Cc: Linus Torvalds <torvalds@linux-foundation.org>
      Cc: Grant Likely <grant.likely@linaro.org>
      Cc: H. Peter Anvin <hpa@linux.intel.com>
      Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
      Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
      Cc: Krogerus Heikki <heikki.krogerus@intel.com>
      Cc: Linus Walleij <linus.walleij@linaro.org>
      Link: http://lkml.kernel.org/r/alpine.DEB.2.02.1404241617360.28206@ionos.tec.linutronix.de
      
      
      Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
      62a08ae2
    • Randy Dunlap's avatar
      linux/interrupt.h: fix new kernel-doc warnings · def5f127
      Randy Dunlap authored
      
      Fix new kernel-doc warnings in <linux/interrupt.h>:
      
      Warning(include/linux/interrupt.h:219): No description found for parameter 'cpumask'
      Warning(include/linux/interrupt.h:219): Excess function parameter 'mask' description in 'irq_set_affinity'
      Warning(include/linux/interrupt.h:236): No description found for parameter 'cpumask'
      Warning(include/linux/interrupt.h:236): Excess function parameter 'mask' description in 'irq_force_affinity'
      
      Signed-off-by: default avatarRandy Dunlap <rdunlap@infradead.org>
      Link: http://lkml.kernel.org/r/535DD2FD.7030804@infradead.org
      
      
      Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
      def5f127
    • Will Deacon's avatar
      word-at-a-time: avoid undefined behaviour in zero_bytemask macro · ec6931b2
      Will Deacon authored
      
      The asm-generic, big-endian version of zero_bytemask creates a mask of
      bytes preceding the first zero-byte by left shifting ~0ul based on the
      position of the first zero byte.
      
      Unfortunately, if the first (top) byte is zero, the output of
      prep_zero_mask has only the top bit set, resulting in undefined C
      behaviour as we shift left by an amount equal to the width of the type.
      As it happens, GCC doesn't manage to spot this through the call to fls(),
      but the issue remains if architectures choose to implement their shift
      instructions differently.
      
      An example would be arch/arm/ (AArch32), where LSL Rd, Rn, #32 results
      in Rd == 0x0, whilst on arch/arm64 (AArch64) LSL Xd, Xn, #64 results in
      Xd == Xn.
      
      Rather than check explicitly for the problematic shift, this patch adds
      an extra shift by 1, replacing fls with __fls. Since zero_bytemask is
      never called with a zero argument (has_zero() is used to check the data
      first), we don't need to worry about calling __fls(0), which is
      undefined.
      
      Cc: <stable@vger.kernel.org>
      Cc: Victor Kamensky <victor.kamensky@linaro.org>
      Signed-off-by: default avatarWill Deacon <will.deacon@arm.com>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      ec6931b2
  11. Apr 25, 2014
    • Manfred Schlaegl's avatar
      tty: Fix race condition between __tty_buffer_request_room and flush_to_ldisc · 6a20dbd6
      Manfred Schlaegl authored
      
      The race was introduced while development of linux-3.11 by
      e8437d7e and
      e9975fde.
      Originally it was found and reproduced on linux-3.12.15 and
      linux-3.12.15-rt25, by sending 500 byte blocks with 115kbaud to the
      target uart in a loop with 100 milliseconds delay.
      
      In short:
       1. The consumer flush_to_ldisc is on to remove the head tty_buffer.
       2. The producer adds a number of bytes, so that a new tty_buffer must
      	be allocated and added by __tty_buffer_request_room.
       3. The consumer removes the head tty_buffer element, without handling
      	newly committed data.
      
      Detailed example:
       * Initial buffer:
         * Head, Tail -> 0: used=250; commit=250; read=240; next=NULL
       * Consumer: ''flush_to_ldisc''
         * consumed 10 Byte
         * buffer:
           * Head, Tail -> 0: used=250; commit=250; read=250; next=NULL
      {{{
      		count = head->commit - head->read;	// count = 0
      		if (!count) {				// enter
      			// INTERRUPTED BY PRODUCER ->
      			if (head->next == NULL)
      				break;
      			buf->head = head->next;
      			tty_buffer_free(port, head);
      			continue;
      		}
      }}}
       * Producer: tty_insert_flip_... 10 bytes + tty_flip_buffer_push
         * buffer:
           * Head, Tail -> 0: used=250; commit=250; read=250; next=NULL
         * added 6 bytes: head-element filled to maximum.
           * buffer:
             * Head, Tail -> 0: used=256; commit=250; read=250; next=NULL
         * added 4 bytes: __tty_buffer_request_room is called
           * buffer:
             * Head -> 0: used=256; commit=256; read=250; next=1
             * Tail -> 1: used=4; commit=0; read=250 next=NULL
         * push (tty_flip_buffer_push)
           * buffer:
             * Head -> 0: used=256; commit=256; read=250; next=1
             * Tail -> 1: used=4; commit=4; read=250 next=NULL
       * Consumer
      {{{
      		count = head->commit - head->read;
      		if (!count) {
      			// INTERRUPTED BY PRODUCER <-
      			if (head->next == NULL)		// -> no break
      				break;
      			buf->head = head->next;
      			tty_buffer_free(port, head);
      			// ERROR: tty_buffer head freed -> 6 bytes lost
      			continue;
      		}
      }}}
      
      This patch reintroduces a spin_lock to protect this case. Perhaps later
      a lock-less solution could be found.
      
      Signed-off-by: default avatarManfred Schlaegl <manfred.schlaegl@gmx.at>
      Cc: stable <stable@vger.kernel.org> # 3.11
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      6a20dbd6
  12. Apr 24, 2014
  13. Apr 23, 2014
  14. Apr 22, 2014
    • Andrew Lutomirski's avatar
      net: Fix ns_capable check in sock_diag_put_filterinfo · 78541c1d
      Andrew Lutomirski authored
      
      The caller needs capabilities on the namespace being queried, not on
      their own namespace.  This is a security bug, although it likely has
      only a minor impact.
      
      Cc: stable@vger.kernel.org
      Signed-off-by: default avatarAndy Lutomirski <luto@amacapital.net>
      Acked-by: default avatarNicolas Dichtel <nicolas.dichtel@6wind.com>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      78541c1d
    • Jeff Layton's avatar
      locks: rename file-private locks to "open file description locks" · 0d3f7a2d
      Jeff Layton authored
      
      File-private locks have been merged into Linux for v3.15, and *now*
      people are commenting that the name and macro definitions for the new
      file-private locks suck.
      
      ...and I can't even disagree. The names and command macros do suck.
      
      We're going to have to live with these for a long time, so it's
      important that we be happy with the names before we're stuck with them.
      The consensus on the lists so far is that they should be rechristened as
      "open file description locks".
      
      The name isn't a big deal for the kernel, but the command macros are not
      visually distinct enough from the traditional POSIX lock macros. The
      glibc and documentation folks are recommending that we change them to
      look like F_OFD_{GETLK|SETLK|SETLKW}. That lessens the chance that a
      programmer will typo one of the commands wrong, and also makes it easier
      to spot this difference when reading code.
      
      This patch makes the following changes that I think are necessary before
      v3.15 ships:
      
      1) rename the command macros to their new names. These end up in the uapi
         headers and so are part of the external-facing API. It turns out that
         glibc doesn't actually use the fcntl.h uapi header, but it's hard to
         be sure that something else won't. Changing it now is safest.
      
      2) make the the /proc/locks output display these as type "OFDLCK"
      
      Cc: Michael Kerrisk <mtk.manpages@gmail.com>
      Cc: Christoph Hellwig <hch@infradead.org>
      Cc: Carlos O'Donell <carlos@redhat.com>
      Cc: Stefan Metzmacher <metze@samba.org>
      Cc: Andy Lutomirski <luto@amacapital.net>
      Cc: Frank Filz <ffilzlnx@mindspring.com>
      Cc: Theodore Ts'o <tytso@mit.edu>
      Signed-off-by: default avatarJeff Layton <jlayton@redhat.com>
      0d3f7a2d
  15. Apr 20, 2014
    • Hans de Goede's avatar
      Input: Add INPUT_PROP_TOPBUTTONPAD device property · f37c0134
      Hans de Goede authored
      
      On some newer laptops with a trackpoint the physical buttons for the
      trackpoint have been removed to allow for a larger touchpad. On these
      laptops the buttonpad has clearly marked areas on the top which are to be
      used as trackpad buttons.
      
      Users of the event device-node need to know about this, so that they can
      properly interpret BTN_LEFT events as being a left / right / middle click
      depending on where on the button pad the clicking finger is.
      
      This commits adds a INPUT_PROP_TOPBUTTONPAD device property which drivers
      for such buttonpads will use to signal to the user that this buttonpad not
      only has the normal bottom button area, but also a top button area.
      
      Signed-off-by: default avatarHans de Goede <hdegoede@redhat.com>
      Signed-off-by: default avatarDmitry Torokhov <dmitry.torokhov@gmail.com>
      f37c0134
    • Hans de Goede's avatar
      Input: serio - add firmware_id sysfs attribute · 0456c66f
      Hans de Goede authored
      
      serio devices exposed via platform firmware interfaces such as ACPI may
      provide additional identifying information of use to userspace.
      
      We don't associate the serio devices with the firmware device (we don't
      set it as parent), so there's no way for userspace to make use of this
      information.
      
      We cannot change the parent for serio devices instantiated though a
      firmware interface as that would break suspend / resume ordering.
      
      Therefore this patch adds a new firmware_id sysfs attribute so that
      userspace can get a string from there with any additional identifying
      information the firmware interface may provide.
      
      Signed-off-by: default avatarHans de Goede <hdegoede@redhat.com>
      Acked-by: default avatarPeter Hutterer <peter.hutterer@who-t.net>
      Signed-off-by: default avatarDmitry Torokhov <dmitry.torokhov@gmail.com>
      0456c66f
  16. Apr 19, 2014
    • Mel Gorman's avatar
      mm: use paravirt friendly ops for NUMA hinting ptes · 29c77870
      Mel Gorman authored
      
      David Vrabel identified a regression when using automatic NUMA balancing
      under Xen whereby page table entries were getting corrupted due to the
      use of native PTE operations.  Quoting him
      
      	Xen PV guest page tables require that their entries use machine
      	addresses if the preset bit (_PAGE_PRESENT) is set, and (for
      	successful migration) non-present PTEs must use pseudo-physical
      	addresses.  This is because on migration MFNs in present PTEs are
      	translated to PFNs (canonicalised) so they may be translated back
      	to the new MFN in the destination domain (uncanonicalised).
      
      	pte_mknonnuma(), pmd_mknonnuma(), pte_mknuma() and pmd_mknuma()
      	set and clear the _PAGE_PRESENT bit using pte_set_flags(),
      	pte_clear_flags(), etc.
      
      	In a Xen PV guest, these functions must translate MFNs to PFNs
      	when clearing _PAGE_PRESENT and translate PFNs to MFNs when setting
      	_PAGE_PRESENT.
      
      His suggested fix converted p[te|md]_[set|clear]_flags to using
      paravirt-friendly ops but this is overkill.  He suggested an alternative
      of using p[te|md]_modify in the NUMA page table operations but this is
      does more work than necessary and would require looking up a VMA for
      protections.
      
      This patch modifies the NUMA page table operations to use paravirt
      friendly operations to set/clear the flags of interest.  Unfortunately
      this will take a performance hit when updating the PTEs on
      CONFIG_PARAVIRT but I do not see a way around it that does not break
      Xen.
      
      Signed-off-by: default avatarMel Gorman <mgorman@suse.de>
      Acked-by: default avatarDavid Vrabel <david.vrabel@citrix.com>
      Tested-by: default avatarDavid Vrabel <david.vrabel@citrix.com>
      Cc: Ingo Molnar <mingo@kernel.org>
      Cc: Peter Anvin <hpa@zytor.com>
      Cc: Fengguang Wu <fengguang.wu@intel.com>
      Cc: Linus Torvalds <torvalds@linux-foundation.org>
      Cc: Steven Noonan <steven@uplinklabs.net>
      Cc: Rik van Riel <riel@redhat.com>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: Andrea Arcangeli <aarcange@redhat.com>
      Cc: Dave Hansen <dave.hansen@intel.com>
      Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
      Cc: Cyrill Gorcunov <gorcunov@gmail.com>
      Cc: <stable@vger.kernel.org>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      29c77870
    • Peter Zijlstra's avatar
      wait: explain the shadowing and type inconsistencies · 8b32201d
      Peter Zijlstra authored
      
      Stick in a comment before someone else tries to fix the sparse warning
      this generates.
      
      Suggested-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarPeter Zijlstra <peterz@infradead.org>
      Link: http://lkml.kernel.org/n/tip-o2ro6f3vkxklni0bc8f7m68s@git.kernel.org
      
      
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      8b32201d
    • Viresh Kumar's avatar
      Shiraz has moved · 9cc23682
      Viresh Kumar authored
      
      shiraz.hashim@st.com email-id doesn't exist anymore as he has left the
      company.  Replace ST's id with shiraz.linux.kernel@gmail.com.
      
      It also updates .mailmap file to fix address for 'git shortlog'.
      
      Signed-off-by: default avatarViresh Kumar <viresh.kumar@linaro.org>
      Cc: Shiraz Hashim <shiraz.linux.kernel@gmail.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      9cc23682
    • Vlad Yasevich's avatar
      net: sctp: cache auth_enable per endpoint · b14878cc
      Vlad Yasevich authored
      
      Currently, it is possible to create an SCTP socket, then switch
      auth_enable via sysctl setting to 1 and crash the system on connect:
      
      Oops[#1]:
      CPU: 0 PID: 0 Comm: swapper Not tainted 3.14.1-mipsgit-20140415 #1
      task: ffffffff8056ce80 ti: ffffffff8055c000 task.ti: ffffffff8055c000
      [...]
      Call Trace:
      [<ffffffff8043c4e8>] sctp_auth_asoc_set_default_hmac+0x68/0x80
      [<ffffffff8042b300>] sctp_process_init+0x5e0/0x8a4
      [<ffffffff8042188c>] sctp_sf_do_5_1B_init+0x234/0x34c
      [<ffffffff804228c8>] sctp_do_sm+0xb4/0x1e8
      [<ffffffff80425a08>] sctp_endpoint_bh_rcv+0x1c4/0x214
      [<ffffffff8043af68>] sctp_rcv+0x588/0x630
      [<ffffffff8043e8e8>] sctp6_rcv+0x10/0x24
      [<ffffffff803acb50>] ip6_input+0x2c0/0x440
      [<ffffffff8030fc00>] __netif_receive_skb_core+0x4a8/0x564
      [<ffffffff80310650>] process_backlog+0xb4/0x18c
      [<ffffffff80313cbc>] net_rx_action+0x12c/0x210
      [<ffffffff80034254>] __do_softirq+0x17c/0x2ac
      [<ffffffff800345e0>] irq_exit+0x54/0xb0
      [<ffffffff800075a4>] ret_from_irq+0x0/0x4
      [<ffffffff800090ec>] rm7k_wait_irqoff+0x24/0x48
      [<ffffffff8005e388>] cpu_startup_entry+0xc0/0x148
      [<ffffffff805a88b0>] start_kernel+0x37c/0x398
      Code: dd0900b8  000330f8  0126302d <dcc60000> 50c0fff1  0047182a  a48306a0
      03e00008  00000000
      ---[ end trace b530b0551467f2fd ]---
      Kernel panic - not syncing: Fatal exception in interrupt
      
      What happens while auth_enable=0 in that case is, that
      ep->auth_hmacs is initialized to NULL in sctp_auth_init_hmacs()
      when endpoint is being created.
      
      After that point, if an admin switches over to auth_enable=1,
      the machine can crash due to NULL pointer dereference during
      reception of an INIT chunk. When we enter sctp_process_init()
      via sctp_sf_do_5_1B_init() in order to respond to an INIT chunk,
      the INIT verification succeeds and while we walk and process
      all INIT params via sctp_process_param() we find that
      net->sctp.auth_enable is set, therefore do not fall through,
      but invoke sctp_auth_asoc_set_default_hmac() instead, and thus,
      dereference what we have set to NULL during endpoint
      initialization phase.
      
      The fix is to make auth_enable immutable by caching its value
      during endpoint initialization, so that its original value is
      being carried along until destruction. The bug seems to originate
      from the very first days.
      
      Fix in joint work with Daniel Borkmann.
      
      Reported-by: default avatarJoshua Kinard <kumba@gentoo.org>
      Signed-off-by: default avatarVlad Yasevich <vyasevic@redhat.com>
      Signed-off-by: default avatarDaniel Borkmann <dborkman@redhat.com>
      Acked-by: default avatarNeil Horman <nhorman@tuxdriver.com>
      Tested-by: default avatarJoshua Kinard <kumba@gentoo.org>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      b14878cc
  17. Apr 18, 2014
    • Dan Williams's avatar
      libata/ahci: accommodate tag ordered controllers · 8a4aeec8
      Dan Williams authored
      
      The AHCI spec allows implementations to issue commands in tag order
      rather than FIFO order:
      
      	5.3.2.12 P:SelectCmd
      	HBA sets pSlotLoc = (pSlotLoc + 1) mod (CAP.NCS + 1)
      	or HBA selects the command to issue that has had the
      	PxCI bit set to '1' longer than any other command
      	pending to be issued.
      
      The result is that commands posted sequentially (time-wise) may play out
      of sequence when issued by hardware.
      
      This behavior has likely been hidden by drives that arrange for commands
      to complete in issue order.  However, it appears recent drives (two from
      different vendors that we have found so far) inflict out-of-order
      completions as a matter of course.  So, we need to take care to maintain
      ordered submission, otherwise we risk triggering a drive to fall out of
      sequential-io automation and back to random-io processing, which incurs
      large latency and degrades throughput.
      
      This issue was found in simple benchmarks where QD=2 seq-write
      performance was 30-50% *greater* than QD=32 seq-write performance.
      
      Tagging for -stable and making the change globally since it has a low
      risk-to-reward ratio.  Also, word is that recent versions of an unnamed
      OS also does it this way now.  So, drives in the field are already
      experienced with this tag ordering scheme.
      
      Cc: <stable@vger.kernel.org>
      Cc: Dave Jiang <dave.jiang@intel.com>
      Cc: Ed Ciechanowski <ed.ciechanowski@intel.com>
      Reviewed-by: default avatarMatthew Wilcox <matthew.r.wilcox@intel.com>
      Signed-off-by: default avatarDan Williams <dan.j.williams@intel.com>
      Signed-off-by: default avatarTejun Heo <tj@kernel.org>
      8a4aeec8
    • Tim Kryger's avatar
      regulator: core: Return error in get optional stub · df7926ff
      Tim Kryger authored
      
      Drivers that call regulator_get_optional are tolerant to the absence of
      that regulator.  By modifying the value returned from the stub function
      to match that seen when a regulator isn't present, callers can wrap the
      regulator logic with an IS_ERR based conditional even if they happen to
      call regulator_is_supported_voltage.  This improves efficiency as well
      as eliminates the possibility for a very subtle bug.
      
      Signed-off-by: default avatarTim Kryger <tim.kryger@linaro.org>
      Reviewed-by: default avatarAlex Elder <elder@linaro.org>
      Signed-off-by: default avatarMark Brown <broonie@linaro.org>
      df7926ff
    • Alexander Shiyan's avatar
      of: add empty of_find_node_by_path() for !OF · 20cd477c
      Alexander Shiyan authored
      
      Add an empty version of of_find_node_by_path().
      This fixes following build error for asoc tree:
      sound/soc/fsl/fsl_ssi.c: In function 'fsl_ssi_probe':
      sound/soc/fsl/fsl_ssi.c:1471:2: error: implicit declaration of function 'of_find_node_by_path' [-Werror=implicit-function-declaration]
        sprop = of_get_property(of_find_node_by_path("/"), "compatible", NULL);
      
      Reported-by: default avatarStephen Rothwell <sfr@canb.auug.org.au>
      Signed-off-by: default avatarAlexander Shiyan <shc_work@mail.ru>
      Signed-off-by: default avatarRob Herring <robh@kernel.org>
      20cd477c
    • Daniel Vetter's avatar
      drm: Split out drm_probe_helper.c from drm_crtc_helper.c · 8d754544
      Daniel Vetter authored
      
      This is leftover stuff from my previous doc round which I kinda wanted
      to do but didn't yet due to rebase hell.
      
      The modeset helpers and the probing helpers a independent and e.g.
      i915 uses the probing stuff but has its own modeset infrastructure. It
      hence makes to split this up. While at it add a DOC: comment for the
      probing libraray.
      
      It would be rather neat to pull some of the DocBook documenting these
      two helpers into in-line DOC: comments. But unfortunately kerneldoc
      doesn't support markdown or something similar to make nice-looking
      documentation, so the current state is better.
      
      Signed-off-by: default avatarDaniel Vetter <daniel.vetter@ffwll.ch>
      Signed-off-by: default avatarDave Airlie <airlied@redhat.com>
      8d754544
  18. Apr 17, 2014
    • Thomas Gleixner's avatar
      genirq: Allow forcing cpu affinity of interrupts · 01f8fa4f
      Thomas Gleixner authored
      
      The current implementation of irq_set_affinity() refuses rightfully to
      route an interrupt to an offline cpu.
      
      But there is a special case, where this is actually desired. Some of
      the ARM SoCs have per cpu timers which require setting the affinity
      during cpu startup where the cpu is not yet in the online mask.
      
      If we can't do that, then the local timer interrupt for the about to
      become online cpu is routed to some random online cpu.
      
      The developers of the affected machines tried to work around that
      issue, but that results in a massive mess in that timer code.
      
      We have a yet unused argument in the set_affinity callbacks of the irq
      chips, which I added back then for a similar reason. It was never
      required so it got not used. But I'm happy that I never removed it.
      
      That allows us to implement a sane handling of the above scenario. So
      the affected SoC drivers can add the required force handling to their
      interrupt chip, switch the timer code to irq_force_affinity() and
      things just work.
      
      This does not affect any existing user of irq_set_affinity().
      
      Tagged for stable to allow a simple fix of the affected SoC clock
      event drivers.
      
      Reported-and-tested-by: default avatarKrzysztof Kozlowski <k.kozlowski@samsung.com>
      Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
      Cc: Kyungmin Park <kyungmin.park@samsung.com>
      Cc: Marek Szyprowski <m.szyprowski@samsung.com>
      Cc: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
      Cc: Tomasz Figa <t.figa@samsung.com>,
      Cc: Daniel Lezcano <daniel.lezcano@linaro.org>,
      Cc: Kukjin Kim <kgene.kim@samsung.com>
      Cc: linux-arm-kernel@lists.infradead.org,
      Cc: stable@vger.kernel.org
      Link: http://lkml.kernel.org/r/20140416143315.717251504@linutronix.de
      
      
      Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
      01f8fa4f
    • Corey Minyard's avatar
      ipmi: boolify some things · 7aefac26
      Corey Minyard authored
      
      Convert some ints to bools.
      
      Signed-off-by: default avatarCorey Minyard <cminyard@mvista.com>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      7aefac26
Loading