)]}'
{
  "log": [
    {
      "commit": "b835996f628eadb55c5fb222ba46fe9395bf73c7",
      "tree": "d63d80585d197e1ffc299af4a0034049790fb197",
      "parents": [
        "ab2af1f5005069321c5d130f09cce577b03f43ef"
      ],
      "author": {
        "name": "Dipankar Sarma",
        "email": "dipankar@in.ibm.com",
        "time": "Fri Sep 09 13:04:14 2005 -0700"
      },
      "committer": {
        "name": "Linus Torvalds",
        "email": "torvalds@g5.osdl.org",
        "time": "Fri Sep 09 13:57:55 2005 -0700"
      },
      "message": "[PATCH] files: lock-free fd look-up\n\nWith the use of RCU in files structure, the look-up of files using fds can now\nbe lock-free.  The lookup is protected by rcu_read_lock()/rcu_read_unlock().\nThis patch changes the readers to use lock-free lookup.\n\nSigned-off-by: Maneesh Soni \u003cmaneesh@in.ibm.com\u003e\nSigned-off-by: Ravikiran Thirumalai \u003ckiran_th@gmail.com\u003e\nSigned-off-by: Dipankar Sarma \u003cdipankar@in.ibm.com\u003e\nSigned-off-by: Andrew Morton \u003cakpm@osdl.org\u003e\nSigned-off-by: Linus Torvalds \u003ctorvalds@osdl.org\u003e\n"
    },
    {
      "commit": "ab2af1f5005069321c5d130f09cce577b03f43ef",
      "tree": "73a70ba486f522cd9eeeef376ede2b5a1c1b473b",
      "parents": [
        "6e72ad2c581de121cc7e772469e2a8f6b1fd4379"
      ],
      "author": {
        "name": "Dipankar Sarma",
        "email": "dipankar@in.ibm.com",
        "time": "Fri Sep 09 13:04:13 2005 -0700"
      },
      "committer": {
        "name": "Linus Torvalds",
        "email": "torvalds@g5.osdl.org",
        "time": "Fri Sep 09 13:57:55 2005 -0700"
      },
      "message": "[PATCH] files: files struct with RCU\n\nPatch to eliminate struct files_struct.file_lock spinlock on the reader side\nand use rcu refcounting rcuref_xxx api for the f_count refcounter.  The\nupdates to the fdtable are done by allocating a new fdtable structure and\nsetting files-\u003efdt to point to the new structure.  The fdtable structure is\nprotected by RCU thereby allowing lock-free lookup.  For fd arrays/sets that\nare vmalloced, we use keventd to free them since RCU callbacks can\u0027t sleep.  A\nglobal list of fdtable to be freed is not scalable, so we use a per-cpu list.\nIf keventd is already handling the current cpu\u0027s work, we use a timer to defer\nqueueing of that work.\n\nSince the last publication, this patch has been re-written to avoid using\nexplicit memory barriers and use rcu_assign_pointer(), rcu_dereference()\npremitives instead.  This required that the fd information is kept in a\nseparate structure (fdtable) and updated atomically.\n\nSigned-off-by: Dipankar Sarma \u003cdipankar@in.ibm.com\u003e\nSigned-off-by: Andrew Morton \u003cakpm@osdl.org\u003e\nSigned-off-by: Linus Torvalds \u003ctorvalds@osdl.org\u003e\n"
    },
    {
      "commit": "badf16621c1f9d1ac753be056fce11b43d6e0be5",
      "tree": "3fdf833fdf2e3d3a439090743539680449ec3428",
      "parents": [
        "c0dfb2905126e9e94edebbce8d3e05001301f52d"
      ],
      "author": {
        "name": "Dipankar Sarma",
        "email": "dipankar@in.ibm.com",
        "time": "Fri Sep 09 13:04:10 2005 -0700"
      },
      "committer": {
        "name": "Linus Torvalds",
        "email": "torvalds@g5.osdl.org",
        "time": "Fri Sep 09 13:57:55 2005 -0700"
      },
      "message": "[PATCH] files: break up files struct\n\nIn order for the RCU to work, the file table array, sets and their sizes must\nbe updated atomically.  Instead of ensuring this through too many memory\nbarriers, we put the arrays and their sizes in a separate structure.  This\npatch takes the first step of putting the file table elements in a separate\nstructure fdtable that is embedded withing files_struct.  It also changes all\nthe users to refer to the file table using files_fdtable() macro.  Subsequent\napplciation of RCU becomes easier after this.\n\nSigned-off-by: Dipankar Sarma \u003cdipankar@in.ibm.com\u003e\nSigned-Off-By: David Howells \u003cdhowells@redhat.com\u003e\nSigned-off-by: Andrew Morton \u003cakpm@osdl.org\u003e\nSigned-off-by: Linus Torvalds \u003ctorvalds@osdl.org\u003e\n"
    },
    {
      "commit": "c293621bbf678a3d85e3ed721c3921c8a670610d",
      "tree": "c72fc522cf3fd2d12f7fd716b7eb4db8d7fcaf52",
      "parents": [
        "3e5ea098446e19175fdee4c2c4ec9366b0217db4"
      ],
      "author": {
        "name": "Peter Staubach",
        "email": "staubach@redhat.com",
        "time": "Wed Jul 27 11:45:09 2005 -0700"
      },
      "committer": {
        "name": "Linus Torvalds",
        "email": "torvalds@g5.osdl.org",
        "time": "Wed Jul 27 16:26:06 2005 -0700"
      },
      "message": "[PATCH] stale POSIX lock handling\n\nI believe that there is a problem with the handling of POSIX locks, which\nthe attached patch should address.\n\nThe problem appears to be a race between fcntl(2) and close(2).  A\nmultithreaded application could close a file descriptor at the same time as\nit is trying to acquire a lock using the same file descriptor.  I would\nsuggest that that multithreaded application is not providing the proper\nsynchronization for itself, but the OS should still behave correctly.\n\nSUS3 (Single UNIX Specification Version 3, read: POSIX) indicates that when\na file descriptor is closed, that all POSIX locks on the file, owned by the\nprocess which closed the file descriptor, should be released.\n\nThe trick here is when those locks are released.  The current code releases\nall locks which exist when close is processing, but any locks in progress\nare handled when the last reference to the open file is released.\n\nThere are three cases to consider.\n\nOne is the simple case, a multithreaded (mt) process has a file open and\nraces to close it and acquire a lock on it.  In this case, the close will\nrelease one reference to the open file and when the fcntl is done, it will\nrelease the other reference.  For this situation, no locks should exist on\nthe file when both the close and fcntl operations are done.  The current\nsystem will handle this case because the last reference to the open file is\nbeing released.\n\nThe second case is when the mt process has dup(2)\u0027d the file descriptor.\nThe close will release one reference to the file and the fcntl, when done,\nwill release another, but there will still be at least one more reference\nto the open file.  One could argue that the existence of a lock on the file\nafter the close has completed is okay, because it was acquired after the\nclose operation and there is still a way for the application to release the\nlock on the file, using an existing file descriptor.\n\nThe third case is when the mt process has forked, after opening the file\nand either before or after becoming an mt process.  In this case, each\nprocess would hold a reference to the open file.  For each process, this\ndegenerates to first case above.  However, the lock continues to exist\nuntil both processes have released their references to the open file.  This\nlock could block other lock requests.\n\nThe changes to release the lock when the last reference to the open file\naren\u0027t quite right because they would allow the lock to exist as long as\nthere was a reference to the open file.  This is too long.\n\nThe new proposed solution is to add support in the fcntl code path to\ndetect a race with close and then to release the lock which was just\nacquired when such as race is detected.  This causes locks to be released\nin a timely fashion and for the system to conform to the POSIX semantic\nspecification.\n\nThis was tested by instrumenting a kernel to detect the handling locks and\nthen running a program which generates case #3 above.  A dangling lock\ncould be reliably generated.  When the changes to detect the close/fcntl\nrace were added, a dangling lock could no longer be generated.\n\nCc: Matthew Wilcox \u003cwilly@debian.org\u003e\nCc: Trond Myklebust \u003ctrond.myklebust@fys.uio.no\u003e\nSigned-off-by: Andrew Morton \u003cakpm@osdl.org\u003e\nSigned-off-by: Linus Torvalds \u003ctorvalds@osdl.org\u003e\n"
    },
    {
      "commit": "7ed20e1ad521b5f5df61bf6559ae60738e393741",
      "tree": "90931724e45eaedb3445314e8b94e78253642395",
      "parents": [
        "e5bdd883a189243541e7a132385580703b049102"
      ],
      "author": {
        "name": "Jesper Juhl",
        "email": "juhl-lkml@dif.dk",
        "time": "Sun May 01 08:59:14 2005 -0700"
      },
      "committer": {
        "name": "Linus Torvalds",
        "email": "torvalds@ppc970.osdl.org",
        "time": "Sun May 01 08:59:14 2005 -0700"
      },
      "message": "[PATCH] convert that currently tests _NSIG directly to use valid_signal()\n\nConvert most of the current code that uses _NSIG directly to instead use\nvalid_signal().  This avoids gcc -W warnings and off-by-one errors.\n\nSigned-off-by: Jesper Juhl \u003cjuhl-lkml@dif.dk\u003e\nSigned-off-by: Andrew Morton \u003cakpm@osdl.org\u003e\nSigned-off-by: Linus Torvalds \u003ctorvalds@osdl.org\u003e\n"
    },
    {
      "commit": "fc9c9ab22d5650977c417ef2032d02f455011b23",
      "tree": "27f9827f559cb732c78bb713e097c8a023e76768",
      "parents": [
        "4a534f93b371e8e6e87ae302757365f0f583e06b"
      ],
      "author": {
        "name": "Bharath Ramesh",
        "email": "bramesh@vt.edu",
        "time": "Sat Apr 16 15:25:41 2005 -0700"
      },
      "committer": {
        "name": "Linus Torvalds",
        "email": "torvalds@ppc970.osdl.org",
        "time": "Sat Apr 16 15:25:41 2005 -0700"
      },
      "message": "[PATCH] AYSNC IO using singals other than SIGIO\n\nA question on sigwaitinfo based IO mechanism in multithreaded applications.\n\nI am trying to use RT signals to notify me of IO events using RT signals\ninstead of SIGIO in a multithreaded applications.  I noticed that there was\nsome discussion on lkml during november 1999 with the subject of the\ndiscussion as \"Signal driven IO\".  In the thread I noticed that RT signals\nwere being delivered to the worker thread.  I am running 2.6.10 kernel and\nI am trying to use the very same mechanism and I find that only SIGIO being\npropogated to the worker threads and RT signals only being propogated to\nthe main thread and not the worker threads where I actually want them to be\npropogated too.  On further inspection I found that the following patch\nwhich I have attached solves the problem.\n\nI am not sure if this is a bug or feature in the kernel.\n\n\nRoland McGrath \u003croland@redhat.com\u003e said:\n\nThis relates only to fcntl F_SETSIG, which is a Linux extension.  So there is\nno POSIX issue.  When changing various things like the normal SIGIO signalling\nto do group signals, I was concerned strictly with the POSIX semantics and\ngenerally avoided touching things in the domain of Linux inventions.  That\u0027s\nwhy I didn\u0027t change this when I changed the call right next to it.  There is\nno reason I can see that F_SETSIG-requested signals shouldn\u0027t use a group\nsignal like normal SIGIO does.  I\u0027m happy to ACK this patch, there is nothing\nwrong with its change to the semantics in my book.  But neither POSIX nor I\ncare a whit what F_SETSIG does.\n\nSigned-off-by: Andrew Morton \u003cakpm@osdl.org\u003e\nSigned-off-by: Linus Torvalds \u003ctorvalds@osdl.org\u003e\n"
    },
    {
      "commit": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2",
      "tree": "0bba044c4ce775e45a88a51686b5d9f90697ea9d",
      "parents": [],
      "author": {
        "name": "Linus Torvalds",
        "email": "torvalds@ppc970.osdl.org",
        "time": "Sat Apr 16 15:20:36 2005 -0700"
      },
      "committer": {
        "name": "Linus Torvalds",
        "email": "torvalds@ppc970.osdl.org",
        "time": "Sat Apr 16 15:20:36 2005 -0700"
      },
      "message": "Linux-2.6.12-rc2\n\nInitial git repository build. I\u0027m not bothering with the full history,\neven though we have it. We can create a separate \"historical\" git\narchive of that later if we want to, and in the meantime it\u0027s about\n3.2GB when imported into git - space that would just make the early\ngit days unnecessarily complicated, when we don\u0027t have a lot of good\ninfrastructure for it.\n\nLet it rip!\n"
    }
  ]
}