1. 25 12月, 2008 6 次提交
    • H
      crypto: hash - Export shash through hash · 5f7082ed
      Herbert Xu 提交于
      This patch allows shash algorithms to be used through the old hash
      interface.  This is a transitional measure so we can convert the
      underlying algorithms to shash before converting the users across.
      Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>
      5f7082ed
    • H
      crypto: hash - Add import/export interface · dec8b786
      Herbert Xu 提交于
      It is often useful to save the partial state of a hash function
      so that it can be used as a base for two or more computations.
      
      The most prominent example is HMAC where all hashes start from
      a base determined by the key.  Having an import/export interface
      means that we only have to compute that base once rather than
      for each message.
      Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>
      dec8b786
    • H
      crypto: hash - Export shash through ahash · 3b2f6df0
      Herbert Xu 提交于
      This patch allows shash algorithms to be used through the ahash
      interface.  This is required before we can convert digest algorithms
      over to shash.
      Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>
      3b2f6df0
    • H
      crypto: hash - Add shash interface · 7b5a080b
      Herbert Xu 提交于
      The shash interface replaces the current synchronous hash interface.
      It improves over hash in two ways.  Firstly shash is reentrant,
      meaning that the same tfm may be used by two threads simultaneously
      as all hashing state is stored in a local descriptor.
      
      The other enhancement is that shash no longer takes scatter list
      entries.  This is because shash is specifically designed for
      synchronous algorithms and as such scatter lists are unnecessary.
      
      All existing hash users will be converted to shash once the
      algorithms have been completely converted.
      
      There is also a new finup function that combines update with final.
      This will be extended to ahash once the algorithm conversion is
      done.
      
      This is also the first time that an algorithm type has their own
      registration function.  Existing algorithm types will be converted
      to this way in due course.
      Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>
      7b5a080b
    • H
      crypto: api - Rebirth of crypto_alloc_tfm · 7b0bac64
      Herbert Xu 提交于
      This patch reintroduces a completely revamped crypto_alloc_tfm.
      The biggest change is that we now take two crypto_type objects
      when allocating a tfm, a frontend and a backend.  In fact this
      simply formalises what we've been doing behind the API's back.
      
      For example, as it stands crypto_alloc_ahash may use an
      actual ahash algorithm or a crypto_hash algorithm.  Putting
      this in the API allows us to do this much more cleanly.
      
      The existing types will be converted across gradually.
      Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>
      7b0bac64
    • H
      crypto: api - Move type exit function into crypto_tfm · 4a779486
      Herbert Xu 提交于
      The type exit function needs to undo any allocations done by the type
      init function.  However, the type init function may differ depending
      on the upper-level type of the transform (e.g., a crypto_blkcipher
      instantiated as a crypto_ablkcipher).
      
      So we need to move the exit function out of the lower-level
      structure and into crypto_tfm itself.
      
      As it stands this is a no-op since nobody uses exit functions at
      all.  However, all cases where a lower-level type is instantiated
      as a different upper-level type (such as blkcipher as ablkcipher)
      will be converted such that they allocate the underlying transform
      and use that instead of casting (e.g., crypto_ablkcipher casted
      into crypto_blkcipher).  That will need to use a different exit
      function depending on the upper-level type.
      
      This patch also allows the type init/exit functions to call (or not)
      cra_init/cra_exit instead of always calling them from the top level.
      Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>
      4a779486
  2. 18 12月, 2008 1 次提交
  3. 16 12月, 2008 2 次提交
  4. 11 12月, 2008 3 次提交
    • H
      KSYM_SYMBOL_LEN fixes · 9c246247
      Hugh Dickins 提交于
      Miles Lane tailing /sys files hit a BUG which Pekka Enberg has tracked
      to my 966c8c12 sprint_symbol(): use
      less stack exposing a bug in slub's list_locations() -
      kallsyms_lookup() writes a 0 to namebuf[KSYM_NAME_LEN-1], but that was
      beyond the end of page provided.
      
      The 100 slop which list_locations() allows at end of page looks roughly
      enough for all the other stuff it might print after the symbol before
      it checks again: break out KSYM_SYMBOL_LEN earlier than before.
      
      Latencytop and ftrace and are using KSYM_NAME_LEN buffers where they
      need KSYM_SYMBOL_LEN buffers, and vmallocinfo a 2*KSYM_NAME_LEN buffer
      where it wants a KSYM_SYMBOL_LEN buffer: fix those before anyone copies
      them.
      
      [akpm@linux-foundation.org: ftrace.h needs module.h]
      Signed-off-by: NHugh Dickins <hugh@veritas.com>
      Cc: Christoph Lameter <cl@linux-foundation.org>
      Cc Miles Lane <miles.lane@gmail.com>
      Acked-by: NPekka Enberg <penberg@cs.helsinki.fi>
      Acked-by: NSteven Rostedt <srostedt@redhat.com>
      Acked-by: NFrederic Weisbecker <fweisbec@gmail.com>
      Cc: Rusty Russell <rusty@rustcorp.com.au>
      Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      9c246247
    • A
      revert "percpu_counter: new function percpu_counter_sum_and_set" · 02d21168
      Andrew Morton 提交于
      Revert
      
          commit e8ced39d
          Author: Mingming Cao <cmm@us.ibm.com>
          Date:   Fri Jul 11 19:27:31 2008 -0400
      
              percpu_counter: new function percpu_counter_sum_and_set
      
      As described in
      
      	revert "percpu counter: clean up percpu_counter_sum_and_set()"
      
      the new percpu_counter_sum_and_set() is racy against updates to the
      cpu-local accumulators on other CPUs.  Revert that change.
      
      This means that ext4 will be slow again.  But correct.
      Reported-by: NEric Dumazet <dada1@cosmosbay.com>
      Cc: "David S. Miller" <davem@davemloft.net>
      Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
      Cc: Mingming Cao <cmm@us.ibm.com>
      Cc: <linux-ext4@vger.kernel.org>
      Cc: <stable@kernel.org>		[2.6.27.x]
      Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      02d21168
    • A
      revert "percpu counter: clean up percpu_counter_sum_and_set()" · 71c5576f
      Andrew Morton 提交于
      Revert
      
          commit 1f7c14c6
          Author: Mingming Cao <cmm@us.ibm.com>
          Date:   Thu Oct 9 12:50:59 2008 -0400
      
              percpu counter: clean up percpu_counter_sum_and_set()
      
      Before this patch we had the following:
      
      percpu_counter_sum(): return the percpu_counter's value
      
      percpu_counter_sum_and_set(): return the percpu_counter's value, copying
      that value into the central value and zeroing the per-cpu counters before
      returning.
      
      After this patch, percpu_counter_sum_and_set() has gone, and
      percpu_counter_sum() gets the old percpu_counter_sum_and_set()
      functionality.
      
      Problem is, as Eric points out, the old percpu_counter_sum_and_set()
      functionality was racy and wrong.  It zeroes out counters on "other" cpus,
      without holding any locks which will prevent races agaist updates from
      those other CPUS.
      
      This patch reverts 1f7c14c6.  This means
      that percpu_counter_sum_and_set() still has the race, but
      percpu_counter_sum() does not.
      
      Note that this is not a simple revert - ext4 has since started using
      percpu_counter_sum() for its dirty_blocks counter as well.
      
      Note that this revert patch changes percpu_counter_sum() semantics.
      
      Before the patch, a call to percpu_counter_sum() will bring the counter's
      central counter mostly up-to-date, so a following percpu_counter_read()
      will return a close value.
      
      After this patch, a call to percpu_counter_sum() will leave the counter's
      central accumulator unaltered, so a subsequent call to
      percpu_counter_read() can now return a significantly inaccurate result.
      
      If there is any code in the tree which was introduced after
      e8ced39d was merged, and which depends
      upon the new percpu_counter_sum() semantics, that code will break.
      Reported-by: NEric Dumazet <dada1@cosmosbay.com>
      Cc: "David S. Miller" <davem@davemloft.net>
      Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
      Cc: Mingming Cao <cmm@us.ibm.com>
      Cc: <linux-ext4@vger.kernel.org>
      Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      71c5576f
  5. 10 12月, 2008 1 次提交
    • N
      netpoll: fix race on poll_list resulting in garbage entry · 7b363e44
      Neil Horman 提交于
      	A few months back a race was discused between the netpoll napi service
      path, and the fast path through net_rx_action:
      http://kerneltrap.org/mailarchive/linux-netdev/2007/10/16/345470
      
      A patch was submitted for that bug, but I think we missed a case.
      
      Consider the following scenario:
      
      INITIAL STATE
      CPU0 has one napi_struct A on its poll_list
      CPU1 is calling netpoll_send_skb and needs to call poll_napi on the same
      napi_struct A that CPU0 has on its list
      
      
      
      CPU0						CPU1
      net_rx_action					poll_napi
      !list_empty (returns true)			locks poll_lock for A
      						 poll_one_napi
      						  napi->poll
      						   netif_rx_complete
      						    __napi_complete
      						    (removes A from poll_list)
      list_entry(list->next)
      
      
      In the above scenario, net_rx_action assumes that the per-cpu poll_list is
      exclusive to that cpu.  netpoll of course violates that, and because the netpoll
      path can dequeue from the poll list, its possible for CPU0 to detect a non-empty
      list at the top of the while loop in net_rx_action, but have it become empty by
      the time it calls list_entry.  Since the poll_list isn't surrounded by any other
      structure, the returned data from that list_entry call in this situation is
      garbage, and any number of crashes can result based on what exactly that garbage
      is.
      
      Given that its not fasible for performance reasons to place exclusive locks
      arround each cpus poll list to provide that mutal exclusion, I think the best
      solution is modify the netpoll path in such a way that we continue to guarantee
      that the poll_list for a cpu is in fact exclusive to that cpu.  To do this I've
      implemented the patch below.  It adds an additional bit to the state field in
      the napi_struct.  When executing napi->poll from the netpoll_path, this bit will
      be set. When a driver calls netif_rx_complete, if that bit is set, it will not
      remove the napi_struct from the poll_list.  That work will be saved for the next
      iteration of net_rx_action.
      
      I've tested this and it seems to work well.  About the biggest drawback I can
      see to it is the fact that it might result in an extra loop through
      net_rx_action in the event that the device is actually contended for (i.e. the
      netpoll path actually preforms all the needed work no the device, and the call
      to net_rx_action winds up doing nothing, except removing the napi_struct from
      the poll_list.  However I think this is probably a small price to pay, given
      that the alternative is a crash.
      Signed-off-by: NNeil Horman <nhorman@tuxdriver.com>
      Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      7b363e44
  6. 09 12月, 2008 2 次提交
  7. 06 12月, 2008 1 次提交
  8. 04 12月, 2008 3 次提交
  9. 03 12月, 2008 4 次提交
    • M
      block: fix setting of max_segment_size and seg_boundary mask · 0e435ac2
      Milan Broz 提交于
      Fix setting of max_segment_size and seg_boundary mask for stacked md/dm
      devices.
      
      When stacking devices (LVM over MD over SCSI) some of the request queue
      parameters are not set up correctly in some cases by default, namely
      max_segment_size and and seg_boundary mask.
      
      If you create MD device over SCSI, these attributes are zeroed.
      
      Problem become when there is over this mapping next device-mapper mapping
      - queue attributes are set in DM this way:
      
      request_queue   max_segment_size  seg_boundary_mask
      SCSI                65536             0xffffffff
      MD RAID1                0                      0
      LVM                 65536                 -1 (64bit)
      
      Unfortunately bio_add_page (resp.  bio_phys_segments) calculates number of
      physical segments according to these parameters.
      
      During the generic_make_request() is segment cout recalculated and can
      increase bio->bi_phys_segments count over the allowed limit.  (After
      bio_clone() in stack operation.)
      
      Thi is specially problem in CCISS driver, where it produce OOPS here
      
          BUG_ON(creq->nr_phys_segments > MAXSGENTRIES);
      
      (MAXSEGENTRIES is 31 by default.)
      
      Sometimes even this command is enough to cause oops:
      
        dd iflag=direct if=/dev/<vg>/<lv> of=/dev/null bs=128000 count=10
      
      This command generates bios with 250 sectors, allocated in 32 4k-pages
      (last page uses only 1024 bytes).
      
      For LVM layer, it allocates bio with 31 segments (still OK for CCISS),
      unfortunatelly on lower layer it is recalculated to 32 segments and this
      violates CCISS restriction and triggers BUG_ON().
      
      The patch tries to fix it by:
      
       * initializing attributes above in queue request constructor
         blk_queue_make_request()
      
       * make sure that blk_queue_stack_limits() inherits setting
      
       (DM uses its own function to set the limits because it
       blk_queue_stack_limits() was introduced later.  It should probably switch
       to use generic stack limit function too.)
      
       * sets the default seg_boundary value in one place (blkdev.h)
      
       * use this mask as default in DM (instead of -1, which differs in 64bit)
      
      Bugs related to this:
      https://bugzilla.redhat.com/show_bug.cgi?id=471639
      http://bugzilla.kernel.org/show_bug.cgi?id=8672Signed-off-by: NMilan Broz <mbroz@redhat.com>
      Reviewed-by: NAlasdair G Kergon <agk@redhat.com>
      Cc: Neil Brown <neilb@suse.de>
      Cc: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
      Cc: Tejun Heo <htejun@gmail.com>
      Cc: Mike Miller <mike.miller@hp.com>
      Signed-off-by: NJens Axboe <jens.axboe@oracle.com>
      0e435ac2
    • T
      block: internal dequeue shouldn't start timer · 53a08807
      Tejun Heo 提交于
      blkdev_dequeue_request() and elv_dequeue_request() are equivalent and
      both start the timeout timer.  Barrier code dequeues the original
      barrier request but doesn't passes the request itself to lower level
      driver, only broken down proxy requests; however, as the original
      barrier code goes through the same dequeue path and timeout timer is
      started on it.  If barrier sequence takes long enough, this timer
      expires but the low level driver has no idea about this request and
      oops follows.
      
      Timeout timer shouldn't have been started on the original barrier
      request as it never goes through actual IO.  This patch unexports
      elv_dequeue_request(), which has no external user anyway, and makes it
      operate on elevator proper w/o adding the timer and make
      blkdev_dequeue_request() call elv_dequeue_request() and add timer.
      Internal users which don't pass the request to driver - barrier code
      and end_that_request_last() - are converted to use
      elv_dequeue_request().
      Signed-off-by: NTejun Heo <tj@kernel.org>
      Cc: Mike Anderson <andmike@linux.vnet.ibm.com>
      Signed-off-by: NJens Axboe <jens.axboe@oracle.com>
      53a08807
    • J
      nfsd: fix vm overcommit crash fix #2 · 1b79cd04
      Junjiro R. Okajima 提交于
      The previous patch from Alan Cox ("nfsd: fix vm overcommit crash",
      commit 731572d3) fixed the problem where
      knfsd crashes on exported shmemfs objects and strict overcommit is set.
      
      But the patch forgot supporting the case when CONFIG_SECURITY is
      disabled.
      
      This patch copies a part of his fix which is mainly for detecting a bug
      earlier.
      Acked-by: NJames Morris <jmorris@namei.org>
      Signed-off-by: NAlan Cox <alan@redhat.com>
      Signed-off-by: NJunjiro R. Okajima <hooanon05@yahoo.co.jp>
      Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      1b79cd04
    • B
      amd74xx: workaround unreliable AltStatus register for nVidia controllers · 6636487e
      Bartlomiej Zolnierkiewicz 提交于
      It seems that on some nVidia controllers using AltStatus register
      can be unreliable so default to Status register if the PCI device
      is in Compatibility Mode.  In order to achieve this:
      
      * Add ide_pci_is_in_compatibility_mode() inline helper to <linux/ide.h>.
      
      * Add IDE_HFLAG_BROKEN_ALTSTATUS host flag and set it in amd74xx host
        driver for nVidia controllers in Compatibility Mode.
      
      * Teach actual_try_to_identify() and drive_is_ready() about the new flag.
      
      This fixes the regression caused by removal of CONFIG_IDEPCI_SHARE_IRQ
      config option in 2.6.25 and using AltStatus register unconditionally when
      available (kernel.org bugs #11659 and #10216).
      
      [ Moreover for CONFIG_IDEPCI_SHARE_IRQ=y (which is what most people
        and distributions use) it never worked correctly. ]
      
      Thanks to Remy LABENE and Lars Winterfeld for help with debugging the problem.
      
      More info at:
      http://bugzilla.kernel.org/show_bug.cgi?id=11659
      http://bugzilla.kernel.org/show_bug.cgi?id=10216Reported-by: NRemy LABENE <remy.labene@free.fr>
      Tested-by: NRemy LABENE <remy.labene@free.fr>
      Tested-by: NLars Winterfeld <lars.winterfeld@tu-ilmenau.de>
      Acked-by: NBorislav Petkov <petkovbb@gmail.com>
      Signed-off-by: NBartlomiej Zolnierkiewicz <bzolnier@gmail.com>
      6636487e
  10. 02 12月, 2008 3 次提交
    • M
      lib/idr.c: fix rcu related race with idr_find · 6ff2d39b
      Manfred Spraul 提交于
      2nd part of the fixes needed for
      http://bugzilla.kernel.org/show_bug.cgi?id=11796.
      
      When the idr tree is either grown or shrunk, then the update to the number
      of layers and the top pointer were not atomic.  This race caused crashes.
      
      The attached patch fixes that by replicating the layers counter in each
      layer, thus idr_find doesn't need idp->layers anymore.
      Signed-off-by: NManfred Spraul <manfred@colorfullife.com>
      Cc: Clement Calmels <cboulte@gmail.com>
      Cc: Nadia Derbey <Nadia.Derbey@bull.net>
      Cc: Pierre Peiffer <peifferp@gmail.com>
      Cc: <stable@kernel.org>
      Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      6ff2d39b
    • D
      epoll: introduce resource usage limits · 7ef9964e
      Davide Libenzi 提交于
      It has been thought that the per-user file descriptors limit would also
      limit the resources that a normal user can request via the epoll
      interface.  Vegard Nossum reported a very simple program (a modified
      version attached) that can make a normal user to request a pretty large
      amount of kernel memory, well within the its maximum number of fds.  To
      solve such problem, default limits are now imposed, and /proc based
      configuration has been introduced.  A new directory has been created,
      named /proc/sys/fs/epoll/ and inside there, there are two configuration
      points:
      
        max_user_instances = Maximum number of devices - per user
      
        max_user_watches   = Maximum number of "watched" fds - per user
      
      The current default for "max_user_watches" limits the memory used by epoll
      to store "watches", to 1/32 of the amount of the low RAM.  As example, a
      256MB 32bit machine, will have "max_user_watches" set to roughly 90000.
      That should be enough to not break existing heavy epoll users.  The
      default value for "max_user_instances" is set to 128, that should be
      enough too.
      
      This also changes the userspace, because a new error code can now come out
      from EPOLL_CTL_ADD (-ENOSPC).  The EMFILE from epoll_create() was already
      listed, so that should be ok.
      
      [akpm@linux-foundation.org: use get_current_user()]
      Signed-off-by: NDavide Libenzi <davidel@xmailserver.org>
      Cc: Michael Kerrisk <mtk.manpages@gmail.com>
      Cc: <stable@kernel.org>
      Cc: Cyrill Gorcunov <gorcunov@gmail.com>
      Reported-by: NVegard Nossum <vegardno@ifi.uio.no>
      Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      7ef9964e
    • T
      libata: blacklist Seagate drives which time out FLUSH_CACHE when used with NCQ · ac70a964
      Tejun Heo 提交于
      Some recent Seagate harddrives have firmware bug which causes FLUSH
      CACHE to timeout under certain circumstances if NCQ is being used.
      This can be worked around by disabling NCQ and fixed by updating the
      firmware.  Implement ATA_HORKAGE_FIRMWARE_UPDATE and blacklist these
      devices.
      
      The wiki page has been updated to contain information on this issue.
      
        http://ata.wiki.kernel.org/index.php/Known_issuesSigned-off-by: NTejun Heo <tj@kernel.org>
      Signed-off-by: NJeff Garzik <jgarzik@redhat.com>
      ac70a964
  11. 01 12月, 2008 3 次提交
  12. 29 11月, 2008 1 次提交
  13. 28 11月, 2008 1 次提交
    • R
      Allow architectures to override copy_user_highpage() · 487ff320
      Russell King 提交于
      With aliasing VIPT cache support, the ARM implementation of
      clear_user_page() and copy_user_page() sets up a temporary kernel space
      mapping such that we have the same cache colour as the userspace page.
      This avoids having to consider any userspace aliases from this operation.
      
      However, when highmem is enabled, kmap_atomic() have to setup mappings.
      The copy_user_highpage() and clear_user_highpage() call these functions
      before delegating the copies to copy_user_page() and clear_user_page().
      
      The effect of this is that each of the *_user_highpage() functions setup
      their own kmap mapping, followed by the *_user_page() functions setting
      up another mapping.  This is rather wasteful.
      
      Thankfully, copy_user_highpage() can be overriden by architectures by
      defining __HAVE_ARCH_COPY_USER_HIGHPAGE.  However, replacement of
      clear_user_highpage() is more difficult because its inline definition
      is not conditional.  It seems that you're expected to define
      __HAVE_ARCH_ALLOC_ZEROED_USER_HIGHPAGE and provide a replacement
      __alloc_zeroed_user_highpage() implementation instead.
      
      The allocation itself is fine, so we don't want to override that.  What
      we really want to do is to override clear_user_highpage() with our own
      version which doesn't kmap_atomic() unnecessarily.
      
      Other VIPT architectures (PARISC and SH) would also like to override
      this function as well.
      Acked-by: NHugh Dickins <hugh@veritas.com>
      Acked-by: NJames Bottomley <James.Bottomley@HansenPartnership.com>
      Acked-by: NPaul Mundt <lethal@linux-sh.org>
      Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>
      487ff320
  14. 25 11月, 2008 1 次提交
  15. 23 11月, 2008 1 次提交
  16. 20 11月, 2008 2 次提交
    • M
      cpuset: update top cpuset's mems after adding a node · f481891f
      Miao Xie 提交于
      After adding a node into the machine, top cpuset's mems isn't updated.
      
      By reviewing the code, we found that the update function
      
        cpuset_track_online_nodes()
      
      was invoked after node_states[N_ONLINE] changes.  It is wrong because
      N_ONLINE just means node has pgdat, and if node has/added memory, we use
      N_HIGH_MEMORY.  So, We should invoke the update function after
      node_states[N_HIGH_MEMORY] changes, just like its commit says.
      
      This patch fixes it.  And we use notifier of memory hotplug instead of
      direct calling of cpuset_track_online_nodes().
      Signed-off-by: NMiao Xie <miaox@cn.fujitsu.com>
      Acked-by: NYasunori Goto <y-goto@jp.fujitsu.com>
      Cc: David Rientjes <rientjes@google.com>
      Cc: Paul Menage <menage@google.com
      Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      f481891f
    • U
      reintroduce accept4 · de11defe
      Ulrich Drepper 提交于
      Introduce a new accept4() system call.  The addition of this system call
      matches analogous changes in 2.6.27 (dup3(), evenfd2(), signalfd4(),
      inotify_init1(), epoll_create1(), pipe2()) which added new system calls
      that differed from analogous traditional system calls in adding a flags
      argument that can be used to access additional functionality.
      
      The accept4() system call is exactly the same as accept(), except that
      it adds a flags bit-mask argument.  Two flags are initially implemented.
      (Most of the new system calls in 2.6.27 also had both of these flags.)
      
      SOCK_CLOEXEC causes the close-on-exec (FD_CLOEXEC) flag to be enabled
      for the new file descriptor returned by accept4().  This is a useful
      security feature to avoid leaking information in a multithreaded
      program where one thread is doing an accept() at the same time as
      another thread is doing a fork() plus exec().  More details here:
      http://udrepper.livejournal.com/20407.html "Secure File Descriptor Handling",
      Ulrich Drepper).
      
      The other flag is SOCK_NONBLOCK, which causes the O_NONBLOCK flag
      to be enabled on the new open file description created by accept4().
      (This flag is merely a convenience, saving the use of additional calls
      fcntl(F_GETFL) and fcntl (F_SETFL) to achieve the same result.
      
      Here's a test program.  Works on x86-32.  Should work on x86-64, but
      I (mtk) don't have a system to hand to test with.
      
      It tests accept4() with each of the four possible combinations of
      SOCK_CLOEXEC and SOCK_NONBLOCK set/clear in 'flags', and verifies
      that the appropriate flags are set on the file descriptor/open file
      description returned by accept4().
      
      I tested Ulrich's patch in this thread by applying against 2.6.28-rc2,
      and it passes according to my test program.
      
      /* test_accept4.c
      
        Copyright (C) 2008, Linux Foundation, written by Michael Kerrisk
             <mtk.manpages@gmail.com>
      
        Licensed under the GNU GPLv2 or later.
      */
      #define _GNU_SOURCE
      #include <unistd.h>
      #include <sys/syscall.h>
      #include <sys/socket.h>
      #include <netinet/in.h>
      #include <stdlib.h>
      #include <fcntl.h>
      #include <stdio.h>
      #include <string.h>
      
      #define PORT_NUM 33333
      
      #define die(msg) do { perror(msg); exit(EXIT_FAILURE); } while (0)
      
      /**********************************************************************/
      
      /* The following is what we need until glibc gets a wrapper for
        accept4() */
      
      /* Flags for socket(), socketpair(), accept4() */
      #ifndef SOCK_CLOEXEC
      #define SOCK_CLOEXEC    O_CLOEXEC
      #endif
      #ifndef SOCK_NONBLOCK
      #define SOCK_NONBLOCK   O_NONBLOCK
      #endif
      
      #ifdef __x86_64__
      #define SYS_accept4 288
      #elif __i386__
      #define USE_SOCKETCALL 1
      #define SYS_ACCEPT4 18
      #else
      #error "Sorry -- don't know the syscall # on this architecture"
      #endif
      
      static int
      accept4(int fd, struct sockaddr *sockaddr, socklen_t *addrlen, int flags)
      {
         printf("Calling accept4(): flags = %x", flags);
         if (flags != 0) {
             printf(" (");
             if (flags & SOCK_CLOEXEC)
                 printf("SOCK_CLOEXEC");
             if ((flags & SOCK_CLOEXEC) && (flags & SOCK_NONBLOCK))
                 printf(" ");
             if (flags & SOCK_NONBLOCK)
                 printf("SOCK_NONBLOCK");
             printf(")");
         }
         printf("\n");
      
      #if USE_SOCKETCALL
         long args[6];
      
         args[0] = fd;
         args[1] = (long) sockaddr;
         args[2] = (long) addrlen;
         args[3] = flags;
      
         return syscall(SYS_socketcall, SYS_ACCEPT4, args);
      #else
         return syscall(SYS_accept4, fd, sockaddr, addrlen, flags);
      #endif
      }
      
      /**********************************************************************/
      
      static int
      do_test(int lfd, struct sockaddr_in *conn_addr,
             int closeonexec_flag, int nonblock_flag)
      {
         int connfd, acceptfd;
         int fdf, flf, fdf_pass, flf_pass;
         struct sockaddr_in claddr;
         socklen_t addrlen;
      
         printf("=======================================\n");
      
         connfd = socket(AF_INET, SOCK_STREAM, 0);
         if (connfd == -1)
             die("socket");
         if (connect(connfd, (struct sockaddr *) conn_addr,
                     sizeof(struct sockaddr_in)) == -1)
             die("connect");
      
         addrlen = sizeof(struct sockaddr_in);
         acceptfd = accept4(lfd, (struct sockaddr *) &claddr, &addrlen,
                            closeonexec_flag | nonblock_flag);
         if (acceptfd == -1) {
             perror("accept4()");
             close(connfd);
             return 0;
         }
      
         fdf = fcntl(acceptfd, F_GETFD);
         if (fdf == -1)
             die("fcntl:F_GETFD");
         fdf_pass = ((fdf & FD_CLOEXEC) != 0) ==
                    ((closeonexec_flag & SOCK_CLOEXEC) != 0);
         printf("Close-on-exec flag is %sset (%s); ",
                 (fdf & FD_CLOEXEC) ? "" : "not ",
                 fdf_pass ? "OK" : "failed");
      
         flf = fcntl(acceptfd, F_GETFL);
         if (flf == -1)
             die("fcntl:F_GETFD");
         flf_pass = ((flf & O_NONBLOCK) != 0) ==
                    ((nonblock_flag & SOCK_NONBLOCK) !=0);
         printf("nonblock flag is %sset (%s)\n",
                 (flf & O_NONBLOCK) ? "" : "not ",
                 flf_pass ? "OK" : "failed");
      
         close(acceptfd);
         close(connfd);
      
         printf("Test result: %s\n", (fdf_pass && flf_pass) ? "PASS" : "FAIL");
         return fdf_pass && flf_pass;
      }
      
      static int
      create_listening_socket(int port_num)
      {
         struct sockaddr_in svaddr;
         int lfd;
         int optval;
      
         memset(&svaddr, 0, sizeof(struct sockaddr_in));
         svaddr.sin_family = AF_INET;
         svaddr.sin_addr.s_addr = htonl(INADDR_ANY);
         svaddr.sin_port = htons(port_num);
      
         lfd = socket(AF_INET, SOCK_STREAM, 0);
         if (lfd == -1)
             die("socket");
      
         optval = 1;
         if (setsockopt(lfd, SOL_SOCKET, SO_REUSEADDR, &optval,
                        sizeof(optval)) == -1)
             die("setsockopt");
      
         if (bind(lfd, (struct sockaddr *) &svaddr,
                  sizeof(struct sockaddr_in)) == -1)
             die("bind");
      
         if (listen(lfd, 5) == -1)
             die("listen");
      
         return lfd;
      }
      
      int
      main(int argc, char *argv[])
      {
         struct sockaddr_in conn_addr;
         int lfd;
         int port_num;
         int passed;
      
         passed = 1;
      
         port_num = (argc > 1) ? atoi(argv[1]) : PORT_NUM;
      
         memset(&conn_addr, 0, sizeof(struct sockaddr_in));
         conn_addr.sin_family = AF_INET;
         conn_addr.sin_addr.s_addr = htonl(INADDR_LOOPBACK);
         conn_addr.sin_port = htons(port_num);
      
         lfd = create_listening_socket(port_num);
      
         if (!do_test(lfd, &conn_addr, 0, 0))
             passed = 0;
         if (!do_test(lfd, &conn_addr, SOCK_CLOEXEC, 0))
             passed = 0;
         if (!do_test(lfd, &conn_addr, 0, SOCK_NONBLOCK))
             passed = 0;
         if (!do_test(lfd, &conn_addr, SOCK_CLOEXEC, SOCK_NONBLOCK))
             passed = 0;
      
         close(lfd);
      
         exit(passed ? EXIT_SUCCESS : EXIT_FAILURE);
      }
      
      [mtk.manpages@gmail.com: rewrote changelog, updated test program]
      Signed-off-by: NUlrich Drepper <drepper@redhat.com>
      Tested-by: NMichael Kerrisk <mtk.manpages@gmail.com>
      Acked-by: NMichael Kerrisk <mtk.manpages@gmail.com>
      Cc: <linux-api@vger.kernel.org>
      Cc: <linux-arch@vger.kernel.org>
      Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      de11defe
  17. 18 11月, 2008 1 次提交
  18. 16 11月, 2008 2 次提交
    • A
      Fix inotify watch removal/umount races · 8f7b0ba1
      Al Viro 提交于
      Inotify watch removals suck violently.
      
      To kick the watch out we need (in this order) inode->inotify_mutex and
      ih->mutex.  That's fine if we have a hold on inode; however, for all
      other cases we need to make damn sure we don't race with umount.  We can
      *NOT* just grab a reference to a watch - inotify_unmount_inodes() will
      happily sail past it and we'll end with reference to inode potentially
      outliving its superblock.
      
      Ideally we just want to grab an active reference to superblock if we
      can; that will make sure we won't go into inotify_umount_inodes() until
      we are done.  Cleanup is just deactivate_super().
      
      However, that leaves a messy case - what if we *are* racing with
      umount() and active references to superblock can't be acquired anymore?
      We can bump ->s_count, grab ->s_umount, which will almost certainly wait
      until the superblock is shut down and the watch in question is pining
      for fjords.  That's fine, but there is a problem - we might have hit the
      window between ->s_active getting to 0 / ->s_count - below S_BIAS (i.e.
      the moment when superblock is past the point of no return and is heading
      for shutdown) and the moment when deactivate_super() acquires
      ->s_umount.
      
      We could just do drop_super() yield() and retry, but that's rather
      antisocial and this stuff is luser-triggerable.  OTOH, having grabbed
      ->s_umount and having found that we'd got there first (i.e.  that
      ->s_root is non-NULL) we know that we won't race with
      inotify_umount_inodes().
      
      So we could grab a reference to watch and do the rest as above, just
      with drop_super() instead of deactivate_super(), right? Wrong.  We had
      to drop ih->mutex before we could grab ->s_umount.  So the watch
      could've been gone already.
      
      That still can be dealt with - we need to save watch->wd, do idr_find()
      and compare its result with our pointer.  If they match, we either have
      the damn thing still alive or we'd lost not one but two races at once,
      the watch had been killed and a new one got created with the same ->wd
      at the same address.  That couldn't have happened in inotify_destroy(),
      but inotify_rm_wd() could run into that.  Still, "new one got created"
      is not a problem - we have every right to kill it or leave it alone,
      whatever's more convenient.
      
      So we can use idr_find(...) == watch && watch->inode->i_sb == sb as
      "grab it and kill it" check.  If it's been our original watch, we are
      fine, if it's a newcomer - nevermind, just pretend that we'd won the
      race and kill the fscker anyway; we are safe since we know that its
      superblock won't be going away.
      
      And yes, this is far beyond mere "not very pretty"; so's the entire
      concept of inotify to start with.
      Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
      Acked-by: NGreg KH <greg@kroah.com>
      Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      8f7b0ba1
    • M
      Add 'pr_fmt()' format modifier to pr_xyz macros. · d091c2f5
      Martin Schwidefsky 提交于
      A common reason for device drivers to implement their own printk macros
      is the lack of a printk prefix with the standard pr_xyz macros.
      Introduce a pr_fmt() macro that is applied for every pr_xyz macro to the
      format string.
      
      The most common use of the pr_fmt macro would be to add the name of the
      device driver to all pr_xyz messages in a source file.
      Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>
      Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      d091c2f5
  19. 14 11月, 2008 2 次提交
    • I
      lockdep: include/linux/lockdep.h - fix warning in net/bluetooth/af_bluetooth.c · e8f6fbf6
      Ingo Molnar 提交于
      fix this warning:
      
        net/bluetooth/af_bluetooth.c:60: warning: ‘bt_key_strings’ defined but not used
        net/bluetooth/af_bluetooth.c:71: warning: ‘bt_slock_key_strings’ defined but not used
      
      this is a lockdep macro problem in the !LOCKDEP case.
      
      We cannot convert it to an inline because the macro works on multiple types,
      but we can mark the parameter used.
      
      [ also clean up a misaligned tab in sock_lock_init_class_and_name() ]
      
      [ also remove #ifdefs from around af_family_clock_key strings - which
        were certainly added to get rid of the ugly build warnings. ]
      Signed-off-by: NIngo Molnar <mingo@elte.hu>
      Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      e8f6fbf6
    • A
      USB: don't register endpoints for interfaces that are going away · 352d0263
      Alan Stern 提交于
      This patch (as1155) fixes a bug in usbcore.  When interfaces are
      deleted, either because the device was disconnected or because of a
      configuration change, the extra attribute files and child endpoint
      devices may get left behind.  This is because the core removes them
      before calling device_del().  But during device_del(), after the
      driver is unbound the core will reinstall altsetting 0 and recreate
      those extra attributes and children.
      
      The patch prevents this by adding a flag to record when the interface
      is in the midst of being unregistered.  When the flag is set, the
      attribute files and child devices will not be created.
      Signed-off-by: NAlan Stern <stern@rowland.harvard.edu>
      Cc: stable <stable@kernel.org> [2.6.27, 2.6.26, 2.6.25]
      Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>
      
      352d0263