1. 03 5月, 2012 5 次提交
  2. 26 4月, 2012 2 次提交
    • E
      userns: Rework the user_namespace adding uid/gid mapping support · 22d917d8
      Eric W. Biederman 提交于
      - Convert the old uid mapping functions into compatibility wrappers
      - Add a uid/gid mapping layer from user space uid and gids to kernel
        internal uids and gids that is extent based for simplicty and speed.
        * Working with number space after mapping uids/gids into their kernel
          internal version adds only mapping complexity over what we have today,
          leaving the kernel code easy to understand and test.
      - Add proc files /proc/self/uid_map /proc/self/gid_map
        These files display the mapping and allow a mapping to be added
        if a mapping does not exist.
      - Allow entering the user namespace without a uid or gid mapping.
        Since we are starting with an existing user our uids and gids
        still have global mappings so are still valid and useful they just don't
        have local mappings.  The requirement for things to work are global uid
        and gid so it is odd but perfectly fine not to have a local uid
        and gid mapping.
        Not requiring global uid and gid mappings greatly simplifies
        the logic of setting up the uid and gid mappings by allowing
        the mappings to be set after the namespace is created which makes the
        slight weirdness worth it.
      - Make the mappings in the initial user namespace to the global
        uid/gid space explicit.  Today it is an identity mapping
        but in the future we may want to twist this for debugging, similar
        to what we do with jiffies.
      - Document the memory ordering requirements of setting the uid and
        gid mappings.  We only allow the mappings to be set once
        and there are no pointers involved so the requirments are
        trivial but a little atypical.
      
      Performance:
      
      In this scheme for the permission checks the performance is expected to
      stay the same as the actuall machine instructions should remain the same.
      
      The worst case I could think of is ls -l on a large directory where
      all of the stat results need to be translated with from kuids and
      kgids to uids and gids.  So I benchmarked that case on my laptop
      with a dual core hyperthread Intel i5-2520M cpu with 3M of cpu cache.
      
      My benchmark consisted of going to single user mode where nothing else
      was running. On an ext4 filesystem opening 1,000,000 files and looping
      through all of the files 1000 times and calling fstat on the
      individuals files.  This was to ensure I was benchmarking stat times
      where the inodes were in the kernels cache, but the inode values were
      not in the processors cache.  My results:
      
      v3.4-rc1:         ~= 156ns (unmodified v3.4-rc1 with user namespace support disabled)
      v3.4-rc1-userns-: ~= 155ns (v3.4-rc1 with my user namespace patches and user namespace support disabled)
      v3.4-rc1-userns+: ~= 164ns (v3.4-rc1 with my user namespace patches and user namespace support enabled)
      
      All of the configurations ran in roughly 120ns when I performed tests
      that ran in the cpu cache.
      
      So in summary the performance impact is:
      1ns improvement in the worst case with user namespace support compiled out.
      8ns aka 5% slowdown in the worst case with user namespace support compiled in.
      Acked-by: NSerge Hallyn <serge.hallyn@canonical.com>
      Signed-off-by: NEric W. Biederman <ebiederm@xmission.com>
      22d917d8
    • E
      userns: Simplify the user_namespace by making userns->creator a kuid. · 783291e6
      Eric W. Biederman 提交于
      - Transform userns->creator from a user_struct reference to a simple
        kuid_t, kgid_t pair.
      
        In cap_capable this allows the check to see if we are the creator of
        a namespace to become the classic suser style euid permission check.
      
        This allows us to remove the need for a struct cred in the mapping
        functions and still be able to dispaly the user namespace creators
        uid and gid as 0.
      
      - Remove the now unnecessary delayed_work in free_user_ns.
      
        All that is left for free_user_ns to do is to call kmem_cache_free
        and put_user_ns.  Those functions can be called in any context
        so call them directly from free_user_ns removing the need for delayed work.
      Acked-by: NSerge Hallyn <serge.hallyn@canonical.com>
      Signed-off-by: NEric W. Biederman <ebiederm@xmission.com>
      783291e6
  3. 08 4月, 2012 8 次提交
  4. 03 4月, 2012 1 次提交
  5. 01 4月, 2012 4 次提交
  6. 31 3月, 2012 1 次提交
  7. 30 3月, 2012 8 次提交
  8. 29 3月, 2012 11 次提交
    • K
      radix-tree: introduce bit-optimized iterator · 78c1d784
      Konstantin Khlebnikov 提交于
      A series of radix tree cleanups, and usage of them in the core pagecache
      code.
      
      Micro-benchmark:
      
      lookup 14 slots (typical page-vector size)
      in radix-tree there earch <step> slot filled and tagged
      before/after - nsec per full scan through tree
      
      * Intel Sandy Bridge i7-2620M 4Mb L3
      New code always faster
      
      * AMD Athlon 6000+ 2x1Mb L2, without L3
      New code generally faster,
      Minor degradation (marked with "*") for huge sparse trees
      
      * i386 on Sandy Bridge
      New code faster for common cases: tagged and dense trees.
      Some degradations for non-tagged lookup on sparse trees.
      
      Ideally, there might help __ffs() analog for searching first non-zero
      long element in array, gcc sometimes cannot optimize this loop corretly.
      
      Numbers:
      
      CPU: Intel Sandy Bridge i7-2620M 4Mb L3
      
      radix-tree with 1024 slots:
      
      tagged lookup
      
      step  1      before  7156        after  3613
      step  2      before  5399        after  2696
      step  3      before  4779        after  1928
      step  4      before  4456        after  1429
      step  5      before  4292        after  1213
      step  6      before  4183        after  1052
      step  7      before  4157        after  951
      step  8      before  4016        after  812
      step  9      before  3952        after  851
      step  10     before  3937        after  732
      step  11     before  4023        after  709
      step  12     before  3872        after  657
      step  13     before  3892        after  633
      step  14     before  3720        after  591
      step  15     before  3879        after  578
      step  16     before  3561        after  513
      
      normal lookup
      
      step  1      before  4266       after  3301
      step  2      before  2695       after  2129
      step  3      before  2083       after  1712
      step  4      before  1801       after  1534
      step  5      before  1628       after  1313
      step  6      before  1551       after  1263
      step  7      before  1475       after  1185
      step  8      before  1432       after  1167
      step  9      before  1373       after  1092
      step  10     before  1339       after  1134
      step  11     before  1292       after  1056
      step  12     before  1319       after  1030
      step  13     before  1276       after  1004
      step  14     before  1256       after  987
      step  15     before  1228       after  992
      step  16     before  1247       after  999
      
      radix-tree with 1024*1024*128 slots:
      
      tagged lookup
      
      step  1      before  1086102841  after  674196409
      step  2      before  816839155   after  498138306
      step  7      before  599728907   after  240676762
      step  15     before  555729253   after  185219677
      step  63     before  606637748   after  128585664
      step  64     before  608384432   after  102945089
      step  65     before  596987114   after  123996019
      step  128    before  304459225   after  56783056
      step  256    before  158846855   after  31232481
      step  512    before  86085652    after  18950595
      step  12345  before  6517189     after  1674057
      
      normal lookup
      
      step  1      before  626064869  after  544418266
      step  2      before  418809975  after  336321473
      step  7      before  242303598  after  207755560
      step  15     before  208380563  after  176496355
      step  63     before  186854206  after  167283638
      step  64     before  176188060  after  170143976
      step  65     before  185139608  after  167487116
      step  128    before  88181865   after  86913490
      step  256    before  45733628   after  45143534
      step  512    before  24506038   after  23859036
      step  12345  before  2177425    after  2018662
      
      * AMD Athlon 6000+ 2x1Mb L2, without L3
      
      radix-tree with 1024 slots:
      
      tag-lookup
      
      step  1      before  8164        after  5379
      step  2      before  5818        after  5581
      step  3      before  4959        after  4213
      step  4      before  4371        after  3386
      step  5      before  4204        after  2997
      step  6      before  4950        after  2744
      step  7      before  4598        after  2480
      step  8      before  4251        after  2288
      step  9      before  4262        after  2243
      step  10     before  4175        after  2131
      step  11     before  3999        after  2024
      step  12     before  3979        after  1994
      step  13     before  3842        after  1929
      step  14     before  3750        after  1810
      step  15     before  3735        after  1810
      step  16     before  3532        after  1660
      
      normal-lookup
      
      step  1      before  7875        after  5847
      step  2      before  4808        after  4071
      step  3      before  4073        after  3462
      step  4      before  3677        after  3074
      step  5      before  4308        after  2978
      step  6      before  3911        after  3807
      step  7      before  3635        after  3522
      step  8      before  3313        after  3202
      step  9      before  3280        after  3257
      step  10     before  3166        after  3083
      step  11     before  3066        after  3026
      step  12     before  2985        after  2982
      step  13     before  2925        after  2924
      step  14     before  2834        after  2808
      step  15     before  2805        after  2803
      step  16     before  2647        after  2622
      
      radix-tree with 1024*1024*128 slots:
      
      tag-lookup
      
      step  1      before  1288059720  after  951736580
      step  2      before  961292300   after  884212140
      step  7      before  768905140   after  547267580
      step  15     before  771319480   after  456550640
      step  63     before  504847640   after  242704304
      step  64     before  392484800   after  177920786
      step  65     before  491162160   after  246895264
      step  128    before  208084064   after  97348392
      step  256    before  112401035   after  51408126
      step  512    before  75825834    after  29145070
      step  12345  before  5603166     after  2847330
      
      normal-lookup
      
      step  1      before  1025677120  after  861375100
      step  2      before  647220080   after  572258540
      step  7      before  505518960   after  484041813
      step  15     before  430483053   after  444815320	*
      step  63     before  388113453   after  404250546	*
      step  64     before  374154666   after  396027440	*
      step  65     before  381423973   after  396704853	*
      step  128    before  190078700   after  202619384	*
      step  256    before  100886756   after  102829108	*
      step  512    before  64074505    after  56158720
      step  12345  before  4237289     after  4422299		*
      
      * i686 on Sandy bridge
      
      radix-tree with 1024 slots:
      
      tagged lookup
      
      step  1      before  7990        after  4019
      step  2      before  5698        after  2897
      step  3      before  5013        after  2475
      step  4      before  4630        after  1721
      step  5      before  4346        after  1759
      step  6      before  4299        after  1556
      step  7      before  4098        after  1513
      step  8      before  4115        after  1222
      step  9      before  3983        after  1390
      step  10     before  4077        after  1207
      step  11     before  3921        after  1231
      step  12     before  3894        after  1116
      step  13     before  3840        after  1147
      step  14     before  3799        after  1090
      step  15     before  3797        after  1059
      step  16     before  3783        after  745
      
      normal lookup
      
      step  1      before  5103       after  3499
      step  2      before  3299       after  2550
      step  3      before  2489       after  2370
      step  4      before  2034       after  2302		*
      step  5      before  1846       after  2268		*
      step  6      before  1752       after  2249		*
      step  7      before  1679       after  2164		*
      step  8      before  1627       after  2153		*
      step  9      before  1542       after  2095		*
      step  10     before  1479       after  2109		*
      step  11     before  1469       after  2009		*
      step  12     before  1445       after  2039		*
      step  13     before  1411       after  2013		*
      step  14     before  1374       after  2046		*
      step  15     before  1340       after  1975		*
      step  16     before  1331       after  2000		*
      
      radix-tree with 1024*1024*128 slots:
      
      tagged lookup
      
      step  1      before  1225865377  after  667153553
      step  2      before  842427423   after  471533007
      step  7      before  609296153   after  276260116
      step  15     before  544232060   after  226859105
      step  63     before  519209199   after  141343043
      step  64     before  588980279   after  141951339
      step  65     before  521099710   after  138282060
      step  128    before  298476778   after  83390628
      step  256    before  149358342   after  43602609
      step  512    before  76994713    after  22911077
      step  12345  before  53286669     after  1472111
      
      normal lookup
      
      step  1      before  819284564  after  533635310
      step  2      before  512421605  after  364956155
      step  7      before  271443305  after  305721345	*
      step  15     before  223591630  after  273960216	*
      step  63     before  190320247  after  217770207	*
      step  64     before  178538168  after  267411372	*
      step  65     before  186400423  after  215347937	*
      step  128    before  88106045   after  140540612	*
      step  256    before  44812420   after  70660377		*
      step  512    before  24435438   after  36328275		*
      step  12345  before  2123924    after  2148062		*
      
      bloat-o-meter delta for this patchset + patchset with related shmem cleanups
      
      bloat-o-meter: x86_64
      
      add/remove: 4/3 grow/shrink: 5/6 up/down: 928/-939 (-11)
      function                                     old     new   delta
      radix_tree_next_chunk                          -     499    +499
      shmem_unuse                                  428     554    +126
      shmem_radix_tree_replace                     131     227     +96
      find_get_pages_tag                           354     419     +65
      find_get_pages_contig                        345     407     +62
      find_get_pages                               362     396     +34
      __kstrtab_radix_tree_next_chunk                -      22     +22
      __ksymtab_radix_tree_next_chunk                -      16     +16
      __kcrctab_radix_tree_next_chunk                -       8      +8
      radix_tree_gang_lookup_slot                  204     203      -1
      static.shmem_xattr_set                       384     381      -3
      radix_tree_gang_lookup_tag_slot              208     191     -17
      radix_tree_gang_lookup                       231     187     -44
      radix_tree_gang_lookup_tag                   247     199     -48
      shmem_unlock_mapping                         278     190     -88
      __lookup                                     217       -    -217
      __lookup_tag                                 242       -    -242
      radix_tree_locate_item                       279       -    -279
      
      bloat-o-meter: i386
      
      add/remove: 3/3 grow/shrink: 8/9 up/down: 1075/-1275 (-200)
      function                                     old     new   delta
      radix_tree_next_chunk                          -     757    +757
      shmem_unuse                                  352     449     +97
      find_get_pages_contig                        269     322     +53
      shmem_radix_tree_replace                     113     154     +41
      find_get_pages_tag                           277     318     +41
      dcache_dir_lseek                             426     458     +32
      __kstrtab_radix_tree_next_chunk                -      22     +22
      vc_do_resize                                 968     977      +9
      snd_pcm_lib_read1                            725     733      +8
      __ksymtab_radix_tree_next_chunk                -       8      +8
      netlbl_cipsov4_list                         1120    1127      +7
      find_get_pages                               293     291      -2
      new_slab                                     467     459      -8
      bitfill_unaligned_rev                        425     417      -8
      radix_tree_gang_lookup_tag_slot              177     146     -31
      blk_dump_cmd                                 267     229     -38
      radix_tree_gang_lookup_slot                  212     134     -78
      shmem_unlock_mapping                         221     128     -93
      radix_tree_gang_lookup_tag                   275     162    -113
      radix_tree_gang_lookup                       255     126    -129
      __lookup                                     227       -    -227
      __lookup_tag                                 271       -    -271
      radix_tree_locate_item                       277       -    -277
      
      This patch:
      
      Implement a clean, simple and effective radix-tree iteration routine.
      
      Iterating divided into two phases:
      * lookup next chunk in radix-tree leaf node
      * iterating through slots in this chunk
      
      Main iterator function radix_tree_next_chunk() returns pointer to first
      slot, and stores in the struct radix_tree_iter index of next-to-last slot.
       For tagged-iterating it also constuct bitmask of tags for retunted chunk.
       All additional logic implemented as static-inline functions and macroses.
      
      Also adds radix_tree_find_next_bit() static-inline variant of
      find_next_bit() optimized for small constant size arrays, because
      find_next_bit() too heavy for searching in an array with one/two long
      elements.
      
      [akpm@linux-foundation.org: rework comments a bit]
      Signed-off-by: NKonstantin Khlebnikov <khlebnikov@openvz.org>
      Tested-by: NHugh Dickins <hughd@google.com>
      Cc: Christoph Hellwig <hch@lst.de>
      Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      78c1d784
    • D
      pidns: add reboot_pid_ns() to handle the reboot syscall · cf3f8921
      Daniel Lezcano 提交于
      In the case of a child pid namespace, rebooting the system does not really
      makes sense.  When the pid namespace is used in conjunction with the other
      namespaces in order to create a linux container, the reboot syscall leads
      to some problems.
      
      A container can reboot the host.  That can be fixed by dropping the
      sys_reboot capability but we are unable to correctly to poweroff/
      halt/reboot a container and the container stays stuck at the shutdown time
      with the container's init process waiting indefinitively.
      
      After several attempts, no solution from userspace was found to reliabily
      handle the shutdown from a container.
      
      This patch propose to make the init process of the child pid namespace to
      exit with a signal status set to : SIGINT if the child pid namespace
      called "halt/poweroff" and SIGHUP if the child pid namespace called
      "reboot".  When the reboot syscall is called and we are not in the initial
      pid namespace, we kill the pid namespace for "HALT", "POWEROFF",
      "RESTART", and "RESTART2".  Otherwise we return EINVAL.
      
      Returning EINVAL is also an easy way to check if this feature is supported
      by the kernel when invoking another 'reboot' option like CAD.
      
      By this way the parent process of the child pid namespace knows if it
      rebooted or not and can take the right decision.
      
      Test case:
      ==========
      
      #include <alloca.h>
      #include <stdio.h>
      #include <sched.h>
      #include <unistd.h>
      #include <signal.h>
      #include <sys/reboot.h>
      #include <sys/types.h>
      #include <sys/wait.h>
      
      #include <linux/reboot.h>
      
      static int do_reboot(void *arg)
      {
              int *cmd = arg;
      
              if (reboot(*cmd))
                      printf("failed to reboot(%d): %m\n", *cmd);
      }
      
      int test_reboot(int cmd, int sig)
      {
              long stack_size = 4096;
              void *stack = alloca(stack_size) + stack_size;
              int status;
              pid_t ret;
      
              ret = clone(do_reboot, stack, CLONE_NEWPID | SIGCHLD, &cmd);
              if (ret < 0) {
                      printf("failed to clone: %m\n");
                      return -1;
              }
      
              if (wait(&status) < 0) {
                      printf("unexpected wait error: %m\n");
                      return -1;
              }
      
              if (!WIFSIGNALED(status)) {
                      printf("child process exited but was not signaled\n");
                      return -1;
              }
      
              if (WTERMSIG(status) != sig) {
                      printf("signal termination is not the one expected\n");
                      return -1;
              }
      
              return 0;
      }
      
      int main(int argc, char *argv[])
      {
              int status;
      
              status = test_reboot(LINUX_REBOOT_CMD_RESTART, SIGHUP);
              if (status < 0)
                      return 1;
              printf("reboot(LINUX_REBOOT_CMD_RESTART) succeed\n");
      
              status = test_reboot(LINUX_REBOOT_CMD_RESTART2, SIGHUP);
              if (status < 0)
                      return 1;
              printf("reboot(LINUX_REBOOT_CMD_RESTART2) succeed\n");
      
              status = test_reboot(LINUX_REBOOT_CMD_HALT, SIGINT);
              if (status < 0)
                      return 1;
              printf("reboot(LINUX_REBOOT_CMD_HALT) succeed\n");
      
              status = test_reboot(LINUX_REBOOT_CMD_POWER_OFF, SIGINT);
              if (status < 0)
                      return 1;
              printf("reboot(LINUX_REBOOT_CMD_POWERR_OFF) succeed\n");
      
              status = test_reboot(LINUX_REBOOT_CMD_CAD_ON, -1);
              if (status >= 0) {
                      printf("reboot(LINUX_REBOOT_CMD_CAD_ON) should have failed\n");
                      return 1;
              }
              printf("reboot(LINUX_REBOOT_CMD_CAD_ON) has failed as expected\n");
      
              return 0;
      }
      
      [akpm@linux-foundation.org: tweak and add comments]
      [akpm@linux-foundation.org: checkpatch fixes]
      Signed-off-by: NDaniel Lezcano <daniel.lezcano@free.fr>
      Acked-by: NSerge Hallyn <serge.hallyn@canonical.com>
      Tested-by: NSerge Hallyn <serge.hallyn@canonical.com>
      Reviewed-by: NOleg Nesterov <oleg@redhat.com>
      Cc: Michael Kerrisk <mtk.manpages@gmail.com>
      Cc: "Eric W. Biederman" <ebiederm@xmission.com>
      Cc: Tejun Heo <tj@kernel.org>
      Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      cf3f8921
    • S
      lib/cpumask.c: remove __any_online_cpu() · 38b93780
      Srivatsa S. Bhat 提交于
      __any_online_cpu() is not optimal and also unnecessary.  So, replace its
      use by faster cpumask_* operations.
      Signed-off-by: NSrivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
      Cc: Eric Dumazet <eric.dumazet@gmail.com>
      Cc: Venkatesh Pallipadi <venki@google.com>
      Cc: Rusty Russell <rusty@rustcorp.com.au>
      Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
      Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      38b93780
    • G
      smp: add func to IPI cpus based on parameter func · b3a7e98e
      Gilad Ben-Yossef 提交于
      Add the on_each_cpu_cond() function that wraps on_each_cpu_mask() and
      calculates the cpumask of cpus to IPI by calling a function supplied as a
      parameter in order to determine whether to IPI each specific cpu.
      
      The function works around allocation failure of cpumask variable in
      CONFIG_CPUMASK_OFFSTACK=y by itereating over cpus sending an IPI a time
      via smp_call_function_single().
      
      The function is useful since it allows to seperate the specific code that
      decided in each case whether to IPI a specific cpu for a specific request
      from the common boilerplate code of handling creating the mask, handling
      failures etc.
      
      [akpm@linux-foundation.org: s/gfpflags/gfp_flags/]
      [akpm@linux-foundation.org: avoid double-evaluation of `info' (per Michal), parenthesise evaluation of `cond_func']
      [akpm@linux-foundation.org: s/CPU/CPUs, use all 80 cols in comment]
      Signed-off-by: NGilad Ben-Yossef <gilad@benyossef.com>
      Cc: Chris Metcalf <cmetcalf@tilera.com>
      Cc: Christoph Lameter <cl@linux-foundation.org>
      Acked-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
      Cc: Frederic Weisbecker <fweisbec@gmail.com>
      Cc: Russell King <linux@arm.linux.org.uk>
      Cc: Pekka Enberg <penberg@kernel.org>
      Cc: Matt Mackall <mpm@selenic.com>
      Cc: Sasha Levin <levinsasha928@gmail.com>
      Cc: Rik van Riel <riel@redhat.com>
      Cc: Andi Kleen <andi@firstfloor.org>
      Cc: Alexander Viro <viro@zeniv.linux.org.uk>
      Cc: Avi Kivity <avi@redhat.com>
      Acked-by: NMichal Nazarewicz <mina86@mina86.org>
      Cc: Kosaki Motohiro <kosaki.motohiro@gmail.com>
      Cc: Milton Miller <miltonm@bga.com>
      Reviewed-by: N"Srivatsa S. Bhat" <srivatsa.bhat@linux.vnet.ibm.com>
      Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      b3a7e98e
    • G
      smp: introduce a generic on_each_cpu_mask() function · 3fc498f1
      Gilad Ben-Yossef 提交于
      We have lots of infrastructure in place to partition multi-core systems
      such that we have a group of CPUs that are dedicated to specific task:
      cgroups, scheduler and interrupt affinity, and cpuisol= boot parameter.
      Still, kernel code will at times interrupt all CPUs in the system via IPIs
      for various needs.  These IPIs are useful and cannot be avoided
      altogether, but in certain cases it is possible to interrupt only specific
      CPUs that have useful work to do and not the entire system.
      
      This patch set, inspired by discussions with Peter Zijlstra and Frederic
      Weisbecker when testing the nohz task patch set, is a first stab at trying
      to explore doing this by locating the places where such global IPI calls
      are being made and turning the global IPI into an IPI for a specific group
      of CPUs.  The purpose of the patch set is to get feedback if this is the
      right way to go for dealing with this issue and indeed, if the issue is
      even worth dealing with at all.  Based on the feedback from this patch set
      I plan to offer further patches that address similar issue in other code
      paths.
      
      This patch creates an on_each_cpu_mask() and on_each_cpu_cond()
      infrastructure API (the former derived from existing arch specific
      versions in Tile and Arm) and uses them to turn several global IPI
      invocation to per CPU group invocations.
      
      Core kernel:
      
      on_each_cpu_mask() calls a function on processors specified by cpumask,
      which may or may not include the local processor.
      
      You must not call this function with disabled interrupts or from a
      hardware interrupt handler or from a bottom half handler.
      
      arch/arm:
      
      Note that the generic version is a little different then the Arm one:
      
      1. It has the mask as first parameter
      2. It calls the function on the calling CPU with interrupts disabled,
         but this should be OK since the function is called on the other CPUs
         with interrupts disabled anyway.
      
      arch/tile:
      
      The API is the same as the tile private one, but the generic version
      also calls the function on the with interrupts disabled in UP case
      
      This is OK since the function is called on the other CPUs
      with interrupts disabled.
      Signed-off-by: NGilad Ben-Yossef <gilad@benyossef.com>
      Reviewed-by: NChristoph Lameter <cl@linux.com>
      Acked-by: NChris Metcalf <cmetcalf@tilera.com>
      Acked-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
      Cc: Frederic Weisbecker <fweisbec@gmail.com>
      Cc: Russell King <linux@arm.linux.org.uk>
      Cc: Pekka Enberg <penberg@kernel.org>
      Cc: Matt Mackall <mpm@selenic.com>
      Cc: Rik van Riel <riel@redhat.com>
      Cc: Andi Kleen <andi@firstfloor.org>
      Cc: Sasha Levin <levinsasha928@gmail.com>
      Cc: Mel Gorman <mel@csn.ul.ie>
      Cc: Alexander Viro <viro@zeniv.linux.org.uk>
      Cc: Avi Kivity <avi@redhat.com>
      Acked-by: NMichal Nazarewicz <mina86@mina86.org>
      Cc: Kosaki Motohiro <kosaki.motohiro@gmail.com>
      Cc: Milton Miller <miltonm@bga.com>
      Cc: Russell King <linux@arm.linux.org.uk>
      Acked-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
      Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      3fc498f1
    • H
      swapon: check validity of swap_flags · d15cab97
      Hugh Dickins 提交于
      Most system calls taking flags first check that the flags passed in are
      valid, and that helps userspace to detect when new flags are supported.
      
      But swapon never did so: start checking now, to help if we ever want to
      support more swap_flags in future.
      
      It's difficult to get stray bits set in an int, and swapon is not widely
      used, so this is most unlikely to break any userspace; but we can just
      revert if it turns out to do so.
      Signed-off-by: NHugh Dickins <hughd@google.com>
      Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      d15cab97
    • H
      mm for fs: add truncate_pagecache_range() · 623e3db9
      Hugh Dickins 提交于
      Holepunching filesystems ext4 and xfs are using truncate_inode_pages_range
      but forgetting to unmap pages first (ocfs2 remembers).  This is not really
      a bug, since races already require truncate_inode_page() to handle that
      case once the page is locked; but it can be very inefficient if the file
      being punched happens to be mapped into many vmas.
      
      Provide a drop-in replacement truncate_pagecache_range() which does the
      unmapping pass first, handling the awkward mismatch between arguments to
      truncate_inode_pages_range() and arguments to unmap_mapping_range().
      
      Note that holepunching does not unmap privately COWed pages in the range:
      POSIX requires that we do so when truncating, but it's hard to justify,
      difficult to implement without an i_size cutoff, and no filesystem is
      attempting to implement it.
      Signed-off-by: NHugh Dickins <hughd@google.com>
      Cc: "Theodore Ts'o" <tytso@mit.edu>
      Cc: Andreas Dilger <adilger.kernel@dilger.ca>
      Cc: Mark Fasheh <mfasheh@suse.com>
      Cc: Joel Becker <jlbec@evilplan.org>
      Cc: Ben Myers <bpm@sgi.com>
      Cc: Alex Elder <elder@kernel.org>
      Cc: Christoph Hellwig <hch@lst.de>
      Cc: Dave Chinner <david@fromorbit.com>
      Cc: Al Viro <viro@zeniv.linux.org.uk>
      Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      623e3db9
    • D
      Delete all instances of asm/system.h · 141124c0
      David Howells 提交于
      Delete all instances of asm/system.h as they should be redundant by this
      point.
      Signed-off-by: NDavid Howells <dhowells@redhat.com>
      141124c0
    • D
      Remove all #inclusions of asm/system.h · 9ffc93f2
      David Howells 提交于
      Remove all #inclusions of asm/system.h preparatory to splitting and killing
      it.  Performed with the following command:
      
      perl -p -i -e 's!^#\s*include\s*<asm/system[.]h>.*\n!!' `grep -Irl '^#\s*include\s*<asm/system[.]h>' *`
      Signed-off-by: NDavid Howells <dhowells@redhat.com>
      9ffc93f2
    • D
      Add #includes needed to permit the removal of asm/system.h · 96f951ed
      David Howells 提交于
      asm/system.h is a cause of circular dependency problems because it contains
      commonly used primitive stuff like barrier definitions and uncommonly used
      stuff like switch_to() that might require MMU definitions.
      
      asm/system.h has been disintegrated by this point on all arches into the
      following common segments:
      
       (1) asm/barrier.h
      
           Moved memory barrier definitions here.
      
       (2) asm/cmpxchg.h
      
           Moved xchg() and cmpxchg() here.  #included in asm/atomic.h.
      
       (3) asm/bug.h
      
           Moved die() and similar here.
      
       (4) asm/exec.h
      
           Moved arch_align_stack() here.
      
       (5) asm/elf.h
      
           Moved AT_VECTOR_SIZE_ARCH here.
      
       (6) asm/switch_to.h
      
           Moved switch_to() here.
      Signed-off-by: NDavid Howells <dhowells@redhat.com>
      96f951ed
    • D
      Move all declarations of free_initmem() to linux/mm.h · 49a7f04a
      David Howells 提交于
      Move all declarations of free_initmem() to linux/mm.h so that there's only one
      and it's used by everything.
      Signed-off-by: NDavid Howells <dhowells@redhat.com>
      cc: linux-c6x-dev@linux-c6x.org
      cc: microblaze-uclinux@itee.uq.edu.au
      cc: linux-sh@vger.kernel.org
      cc: sparclinux@vger.kernel.org
      cc: x86@kernel.org
      cc: linux-mm@kvack.org
      49a7f04a