12 Sep, 2017

1 commit

  • If the IOCB_DSYNC flag is set a sync is not being performed by
    fuse_file_write_iter.

    Honor IOCB_DSYNC/IOCB_SYNC by setting O_DYSNC/O_SYNC respectively in the
    flags filed of the write request.

    We don't need to sync data or metadata, since fuse_perform_write() does
    write-through and the filesystem is responsible for updating file times.

    Original patch by Vitaly Zolotusky.

    Reported-by: Nate Clark
    Cc: Vitaly Zolotusky .
    Signed-off-by: Miklos Szeredi

    Miklos Szeredi
     

14 Mar, 2016

1 commit

  • The 'reqs' member of fuse_io_priv serves two purposes. First is to track
    the number of oustanding async requests to the server and to signal that
    the io request is completed. The second is to be a reference count on the
    structure to know when it can be freed.

    For sync io requests these purposes can be at odds. fuse_direct_IO() wants
    to block until the request is done, and since the signal is sent when
    'reqs' reaches 0 it cannot keep a reference to the object. Yet it needs to
    use the object after the userspace server has completed processing
    requests. This leads to some handshaking and special casing that it
    needlessly complicated and responsible for at least one race condition.

    It's much cleaner and safer to maintain a separate reference count for the
    object lifecycle and to let 'reqs' just be a count of outstanding requests
    to the userspace server. Then we can know for sure when it is safe to free
    the object without any handshaking or special cases.

    The catch here is that most of the time these objects are stack allocated
    and should not be freed. Initializing these objects with a single reference
    that is never released prevents accidental attempts to free the objects.

    Fixes: 9d5722b7777e ("fuse: handle synchronous iocbs internally")
    Cc: stable@vger.kernel.org # v4.1+
    Signed-off-by: Seth Forshee
    Signed-off-by: Miklos Szeredi

    Seth Forshee
     

10 Nov, 2015

1 commit

  • The problem is that fuse_dev_alloc() acquires an extra reference to cc.fc,
    and the original ref count is never dropped.

    Reported-by: Colin Ian King
    Signed-off-by: Miklos Szeredi
    Fixes: cc080e9e9be1 ("fuse: introduce per-instance fuse_dev structure")
    Cc: # v4.2+

    Miklos Szeredi
     

01 Jul, 2015

2 commits


12 Apr, 2015

2 commits


26 Mar, 2015

1 commit


12 Dec, 2014

1 commit

  • Use fuse_abort_conn() instead of fuse_conn_kill() in fuse_put_super().
    This flushes and aborts requests still on any queues. But since we've
    already reset fc->connected, those requests would not be useful anyway and
    would be flushed when the fuse device is closed.

    Next patches will rely on requests being flushed before the superblock is
    destroyed.

    Use fuse_abort_conn() in cuse_process_init_reply() too, since it makes no
    difference there, and we can get rid of fuse_conn_kill().

    Signed-off-by: Miklos Szeredi

    Miklos Szeredi
     

07 May, 2014

1 commit


07 Apr, 2014

1 commit

  • Pull module updates from Rusty Russell:
    "Nothing major: the stricter permissions checking for sysfs broke a
    staging driver; fix included. Greg KH said he'd take the patch but
    hadn't as the merge window opened, so it's included here to avoid
    breaking build"

    * tag 'modules-next-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux:
    staging: fix up speakup kobject mode
    Use 'E' instead of 'X' for unsigned module taint flag.
    VERIFY_OCTAL_PERMISSIONS: stricter checking for sysfs perms.
    kallsyms: fix percpu vars on x86-64 with relocation.
    kallsyms: generalize address range checking
    module: LLVMLinux: Remove unused function warning from __param_check macro
    Fix: module signature vs tracepoints: add new TAINT_UNSIGNED_MODULE
    module: remove MODULE_GENERIC_TABLE
    module: allow multiple calls to MODULE_DEVICE_TABLE() per module
    module: use pr_cont

    Linus Torvalds
     

02 Apr, 2014

1 commit

  • The problem is:

    1. write cached data to a file
    2. read directly from the same file (via another fd)

    The 2nd operation may read stale data, i.e. the one that was in a file
    before the 1st op. Problem is in how fuse manages writeback.

    When direct op occurs the core kernel code calls filemap_write_and_wait
    to flush all the cached ops in flight. But fuse acks the writeback right
    after the ->writepages callback exits w/o waiting for the real write to
    happen. Thus the subsequent direct op proceeds while the real writeback
    is still in flight. This is a problem for backends that reorder operation.

    Fix this by making the fuse direct IO callback explicitly wait on the
    in-flight writeback to finish.

    Signed-off-by: Maxim Patlasov
    Signed-off-by: Miklos Szeredi

    Pavel Emelyanov
     

24 Mar, 2014

1 commit

  • Summary of http://lkml.org/lkml/2014/3/14/363 :

    Ted: module_param(queue_depth, int, 444)
    Joe: 0444!
    Rusty: User perms >= group perms >= other perms?
    Joe: CLASS_ATTR, DEVICE_ATTR, SENSOR_ATTR and SENSOR_ATTR_2?

    Side effect of stricter permissions means removing the unnecessary
    S_IFREG from several callers.

    Note that the BUILD_BUG_ON_ZERO((perm) & 2) test was removed: a fair
    number of drivers fail this test, so that will be the debate for a
    future patch.

    Suggested-by: Joe Perches
    Acked-by: Bjorn Helgaas for drivers/pci/slot.c
    Acked-by: Greg Kroah-Hartman
    Cc: Miklos Szeredi
    Cc: Mark Fasheh
    Cc: Joel Becker
    Signed-off-by: Rusty Russell

    Rusty Russell
     

13 Nov, 2013

1 commit

  • Pull vfs updates from Al Viro:
    "All kinds of stuff this time around; some more notable parts:

    - RCU'd vfsmounts handling
    - new primitives for coredump handling
    - files_lock is gone
    - Bruce's delegations handling series
    - exportfs fixes

    plus misc stuff all over the place"

    * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (101 commits)
    ecryptfs: ->f_op is never NULL
    locks: break delegations on any attribute modification
    locks: break delegations on link
    locks: break delegations on rename
    locks: helper functions for delegation breaking
    locks: break delegations on unlink
    namei: minor vfs_unlink cleanup
    locks: implement delegations
    locks: introduce new FL_DELEG lock flag
    vfs: take i_mutex on renamed file
    vfs: rename I_MUTEX_QUOTA now that it's not used for quotas
    vfs: don't use PARENT/CHILD lock classes for non-directories
    vfs: pull ext4's double-i_mutex-locking into common code
    exportfs: fix quadratic behavior in filehandle lookup
    exportfs: better variable name
    exportfs: move most of reconnect_path to helper function
    exportfs: eliminate unused "noprogress" counter
    exportfs: stop retrying once we race with rename/remove
    exportfs: clear DISCONNECTED on all parents sooner
    exportfs: more detailed comment for path_reconnect
    ...

    Linus Torvalds
     

25 Oct, 2013

1 commit


01 Oct, 2013

1 commit

  • This allows udev (or more recently systemd-tmpfiles) to create /dev/cuse on
    boot, in the same way as /dev/fuse is currently created, and the corresponding
    module to be loaded on first access.

    The corresponding functionalty was introduced for fuse in commit 578454f.

    Signed-off-by: Tom Gundersen
    Cc: Kay Sievers
    Signed-off-by: Miklos Szeredi

    Tom Gundersen
     

27 Jul, 2013

1 commit


08 May, 2013

2 commits

  • Merge more incoming from Andrew Morton:

    - Various fixes which were stalled or which I picked up recently

    - A large rotorooting of the AIO code. Allegedly to improve
    performance but I don't really have good performance numbers (I might
    have lost the email) and I can't raise Kent today. I held this out
    of 3.9 and we could give it another cycle if it's all too late/scary.

    I ended up taking only the first two thirds of the AIO rotorooting. I
    left the percpu parts and the batch completion for later. - Linus

    * emailed patches from Andrew Morton : (33 commits)
    aio: don't include aio.h in sched.h
    aio: kill ki_retry
    aio: kill ki_key
    aio: give shared kioctx fields their own cachelines
    aio: kill struct aio_ring_info
    aio: kill batch allocation
    aio: change reqs_active to include unreaped completions
    aio: use cancellation list lazily
    aio: use flush_dcache_page()
    aio: make aio_read_evt() more efficient, convert to hrtimers
    wait: add wait_event_hrtimeout()
    aio: refcounting cleanup
    aio: make aio_put_req() lockless
    aio: do fget() after aio_get_req()
    aio: dprintk() -> pr_debug()
    aio: move private stuff out of aio.h
    aio: add kiocb_cancel()
    aio: kill return value of aio_complete()
    char: add aio_{read,write} to /dev/{null,zero}
    aio: remove retry-based AIO
    ...

    Linus Torvalds
     
  • Faster kernel compiles by way of fewer unnecessary includes.

    [akpm@linux-foundation.org: fix fallout]
    [akpm@linux-foundation.org: fix build]
    Signed-off-by: Kent Overstreet
    Cc: Zach Brown
    Cc: Felipe Balbi
    Cc: Greg Kroah-Hartman
    Cc: Mark Fasheh
    Cc: Joel Becker
    Cc: Rusty Russell
    Cc: Jens Axboe
    Cc: Asai Thambi S P
    Cc: Selvan Mani
    Cc: Sam Bradshaw
    Cc: Jeff Moyer
    Cc: Al Viro
    Cc: Benjamin LaHaise
    Reviewed-by: "Theodore Ts'o"
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Kent Overstreet
     

18 Apr, 2013

1 commit

  • The patch implements passing "struct fuse_io_priv *io" down the stack up to
    fuse_send_read/write where it is used to submit request asynchronously.
    io->async==0 designates synchronous processing.

    Non-trivial part of the patch is changes in fuse_direct_io(): resources
    like fuse requests and user pages cannot be released immediately in async
    case.

    Signed-off-by: Maxim Patlasov
    Signed-off-by: Miklos Szeredi

    Maxim Patlasov
     

17 Apr, 2013

3 commits

  • A task may have at most one synchronous request allocated. So these
    requests need not be otherwise limited.

    The patch re-works fuse_get_req() to follow this idea.

    Signed-off-by: Maxim Patlasov
    Signed-off-by: Miklos Szeredi

    Maxim Patlasov
     
  • Existing flag fc->blocked is used to suspend request allocation both in case
    of many background request submitted and period of time before init_reply
    arrives from userspace. Next patch will skip blocking allocations of
    synchronous request (disregarding fc->blocked). This is mostly OK, but
    we still need to suspend allocations if init_reply is not arrived yet. The
    patch introduces flag fc->initialized which will serve this purpose.

    Signed-off-by: Maxim Patlasov
    Signed-off-by: Miklos Szeredi

    Maxim Patlasov
     
  • There are two types of processing requests in FUSE: synchronous (via
    fuse_request_send()) and asynchronous (via adding to fc->bg_queue).

    Fortunately, the type of processing is always known in advance, at the time
    of request allocation. This preparatory patch utilizes this fact making
    fuse_get_req() aware about the type. Next patches will use it.

    Signed-off-by: Maxim Patlasov
    Signed-off-by: Miklos Szeredi

    Maxim Patlasov
     

24 Jan, 2013

3 commits

  • Fix the following sparse warnings:

    fs/fuse/file.c:1216:43: warning: cast removes address space of expression
    fs/fuse/file.c:1216:43: warning: incorrect type in initializer (different address spaces)
    fs/fuse/file.c:1216:43: expected void [noderef] *iov_base
    fs/fuse/file.c:1216:43: got void *
    fs/fuse/file.c:1241:43: warning: cast removes address space of expression
    fs/fuse/file.c:1241:43: warning: incorrect type in initializer (different address spaces)
    fs/fuse/file.c:1241:43: expected void [noderef] *iov_base
    fs/fuse/file.c:1241:43: got void *
    fs/fuse/file.c:1267:43: warning: cast removes address space of expression
    fs/fuse/file.c:1267:43: warning: incorrect type in initializer (different address spaces)
    fs/fuse/file.c:1267:43: expected void [noderef] *iov_base
    fs/fuse/file.c:1267:43: got void *

    Signed-off-by: Miklos Szeredi

    Miklos Szeredi
     
  • Previously, anyone who set flag 'argpages' only filled req->pages[] and set
    per-request page_offset. This patch re-works all cases where argpages=1 to
    fill req->page_descs[] properly.

    Having req->page_descs[] filled properly allows to re-work fuse_copy_pages()
    to copy page fragments described by req->page_descs[]. This will be useful
    for next patches optimizing direct_IO.

    Signed-off-by: Maxim Patlasov
    Signed-off-by: Miklos Szeredi

    Maxim Patlasov
     
  • The patch categorizes all fuse_get_req() invocations into two categories:
    - fuse_get_req_nopages(fc) - when caller doesn't care about req->pages
    - fuse_get_req(fc, n) - when caller need n page pointers (n > 0)

    Adding fuse_get_req_nopages() helps to avoid numerous fuse_get_req(fc, 0)
    scattered over code. Now it's clear from the first glance when a caller need
    fuse_req with page pointers.

    The patch doesn't make any logic changes. In multi-page case, it silly
    allocates array of FUSE_MAX_PAGES_PER_REQ page pointers. This will be amended
    by future patches.

    Signed-off-by: Maxim Patlasov
    Signed-off-by: Miklos Szeredi

    Maxim Patlasov
     

17 Jan, 2013

3 commits

  • Fix the following compiler warnings:

    fs/fuse/cuse.c: In function 'cuse_process_init_reply':
    fs/fuse/cuse.c:288:24: warning: 'val' may be used uninitialized in this function [-Wmaybe-uninitialized]
    fs/fuse/cuse.c:272:14: note: 'val' was declared here
    fs/fuse/cuse.c:284:10: warning: 'key' may be used uninitialized in this function [-Wmaybe-uninitialized]
    fs/fuse/cuse.c:272:8: note: 'key' was declared here

    Signed-off-by: Miklos Szeredi

    Miklos Szeredi
     
  • Sysfs doesn't allow two devices with the same name, but we register a
    sysfs entry for each cuse device without checking for name collisions.
    This extends the registration to first check whether the name was already
    registered.

    To avoid race-conditions between the name-check and linking the device, we
    need to protect the whole registration with a mutex.

    Signed-off-by: David Herrmann
    Acked-by: Tejun Heo
    Signed-off-by: Miklos Szeredi

    David Herrmann
     
  • We need to check for name-collisions during cuse-device registration. To
    avoid race-conditions, this needs to be protected during the whole device
    registration. Therefore, replace the spinlocks by mutexes first so we can
    safely extend the locked regions to include more expensive or sleeping
    code paths.

    Signed-off-by: David Herrmann
    Acked-by: Tejun Heo
    Signed-off-by: Miklos Szeredi

    David Herrmann
     

31 Aug, 2012

1 commit

  • Luca Risolia reported that a CUSE daemon will continue to run even if
    initialization of the emulated device failes for some reason (e.g. the device
    number is already registered by another driver).

    This patch disconnects the fuse device on error, which will make the userspace
    CUSE daemon exit, albeit without indication about what the problem was.

    Reported-by: Luca Risolia
    Signed-off-by: Miklos Szeredi

    Miklos Szeredi
     

01 Nov, 2011

1 commit

  • Some files were using the complete module.h infrastructure without
    actually including the header at all. Fix them up in advance so
    once the implicit presence is removed, we won't get failures like this:

    CC [M] fs/nfsd/nfssvc.o
    fs/nfsd/nfssvc.c: In function 'nfsd_create_serv':
    fs/nfsd/nfssvc.c:335: error: 'THIS_MODULE' undeclared (first use in this function)
    fs/nfsd/nfssvc.c:335: error: (Each undeclared identifier is reported only once
    fs/nfsd/nfssvc.c:335: error: for each function it appears in.)
    fs/nfsd/nfssvc.c: In function 'nfsd':
    fs/nfsd/nfssvc.c:555: error: implicit declaration of function 'module_put_and_exit'
    make[3]: *** [fs/nfsd/nfssvc.o] Error 1

    Signed-off-by: Paul Gortmaker

    Paul Gortmaker
     

23 Mar, 2011

1 commit


21 Mar, 2011

1 commit


15 Feb, 2011

1 commit


15 Oct, 2010

1 commit

  • All file_operations should get a .llseek operation so we can make
    nonseekable_open the default for future file operations without a
    .llseek pointer.

    The three cases that we can automatically detect are no_llseek, seq_lseek
    and default_llseek. For cases where we can we can automatically prove that
    the file offset is always ignored, we use noop_llseek, which maintains
    the current behavior of not returning an error from a seek.

    New drivers should normally not use noop_llseek but instead use no_llseek
    and call nonseekable_open at open time. Existing drivers can be converted
    to do the same when the maintainer knows for certain that no user code
    relies on calling seek on the device file.

    The generated code is often incorrectly indented and right now contains
    comments that clarify for each added line why a specific variant was
    chosen. In the version that gets submitted upstream, the comments will
    be gone and I will manually fix the indentation, because there does not
    seem to be a way to do that using coccinelle.

    Some amount of new code is currently sitting in linux-next that should get
    the same modifications, which I will do at the end of the merge window.

    Many thanks to Julia Lawall for helping me learn to write a semantic
    patch that does all this.

    ===== begin semantic patch =====
    // This adds an llseek= method to all file operations,
    // as a preparation for making no_llseek the default.
    //
    // The rules are
    // - use no_llseek explicitly if we do nonseekable_open
    // - use seq_lseek for sequential files
    // - use default_llseek if we know we access f_pos
    // - use noop_llseek if we know we don't access f_pos,
    // but we still want to allow users to call lseek
    //
    @ open1 exists @
    identifier nested_open;
    @@
    nested_open(...)
    {

    }

    @ open exists@
    identifier open_f;
    identifier i, f;
    identifier open1.nested_open;
    @@
    int open_f(struct inode *i, struct file *f)
    {

    }

    @ read disable optional_qualifier exists @
    identifier read_f;
    identifier f, p, s, off;
    type ssize_t, size_t, loff_t;
    expression E;
    identifier func;
    @@
    ssize_t read_f(struct file *f, char *p, size_t s, loff_t *off)
    {

    }

    @ read_no_fpos disable optional_qualifier exists @
    identifier read_f;
    identifier f, p, s, off;
    type ssize_t, size_t, loff_t;
    @@
    ssize_t read_f(struct file *f, char *p, size_t s, loff_t *off)
    {
    ... when != off
    }

    @ write @
    identifier write_f;
    identifier f, p, s, off;
    type ssize_t, size_t, loff_t;
    expression E;
    identifier func;
    @@
    ssize_t write_f(struct file *f, const char *p, size_t s, loff_t *off)
    {

    }

    @ write_no_fpos @
    identifier write_f;
    identifier f, p, s, off;
    type ssize_t, size_t, loff_t;
    @@
    ssize_t write_f(struct file *f, const char *p, size_t s, loff_t *off)
    {
    ... when != off
    }

    @ fops0 @
    identifier fops;
    @@
    struct file_operations fops = {
    ...
    };

    @ has_llseek depends on fops0 @
    identifier fops0.fops;
    identifier llseek_f;
    @@
    struct file_operations fops = {
    ...
    .llseek = llseek_f,
    ...
    };

    @ has_read depends on fops0 @
    identifier fops0.fops;
    identifier read_f;
    @@
    struct file_operations fops = {
    ...
    .read = read_f,
    ...
    };

    @ has_write depends on fops0 @
    identifier fops0.fops;
    identifier write_f;
    @@
    struct file_operations fops = {
    ...
    .write = write_f,
    ...
    };

    @ has_open depends on fops0 @
    identifier fops0.fops;
    identifier open_f;
    @@
    struct file_operations fops = {
    ...
    .open = open_f,
    ...
    };

    // use no_llseek if we call nonseekable_open
    ////////////////////////////////////////////
    @ nonseekable1 depends on !has_llseek && has_open @
    identifier fops0.fops;
    identifier nso ~= "nonseekable_open";
    @@
    struct file_operations fops = {
    ... .open = nso, ...
    +.llseek = no_llseek, /* nonseekable */
    };

    @ nonseekable2 depends on !has_llseek @
    identifier fops0.fops;
    identifier open.open_f;
    @@
    struct file_operations fops = {
    ... .open = open_f, ...
    +.llseek = no_llseek, /* open uses nonseekable */
    };

    // use seq_lseek for sequential files
    /////////////////////////////////////
    @ seq depends on !has_llseek @
    identifier fops0.fops;
    identifier sr ~= "seq_read";
    @@
    struct file_operations fops = {
    ... .read = sr, ...
    +.llseek = seq_lseek, /* we have seq_read */
    };

    // use default_llseek if there is a readdir
    ///////////////////////////////////////////
    @ fops1 depends on !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
    identifier fops0.fops;
    identifier readdir_e;
    @@
    // any other fop is used that changes pos
    struct file_operations fops = {
    ... .readdir = readdir_e, ...
    +.llseek = default_llseek, /* readdir is present */
    };

    // use default_llseek if at least one of read/write touches f_pos
    /////////////////////////////////////////////////////////////////
    @ fops2 depends on !fops1 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
    identifier fops0.fops;
    identifier read.read_f;
    @@
    // read fops use offset
    struct file_operations fops = {
    ... .read = read_f, ...
    +.llseek = default_llseek, /* read accesses f_pos */
    };

    @ fops3 depends on !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
    identifier fops0.fops;
    identifier write.write_f;
    @@
    // write fops use offset
    struct file_operations fops = {
    ... .write = write_f, ...
    + .llseek = default_llseek, /* write accesses f_pos */
    };

    // Use noop_llseek if neither read nor write accesses f_pos
    ///////////////////////////////////////////////////////////

    @ fops4 depends on !fops1 && !fops2 && !fops3 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
    identifier fops0.fops;
    identifier read_no_fpos.read_f;
    identifier write_no_fpos.write_f;
    @@
    // write fops use offset
    struct file_operations fops = {
    ...
    .write = write_f,
    .read = read_f,
    ...
    +.llseek = noop_llseek, /* read and write both use no f_pos */
    };

    @ depends on has_write && !has_read && !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
    identifier fops0.fops;
    identifier write_no_fpos.write_f;
    @@
    struct file_operations fops = {
    ... .write = write_f, ...
    +.llseek = noop_llseek, /* write uses no f_pos */
    };

    @ depends on has_read && !has_write && !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
    identifier fops0.fops;
    identifier read_no_fpos.read_f;
    @@
    struct file_operations fops = {
    ... .read = read_f, ...
    +.llseek = noop_llseek, /* read uses no f_pos */
    };

    @ depends on !has_read && !has_write && !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
    identifier fops0.fops;
    @@
    struct file_operations fops = {
    ...
    +.llseek = noop_llseek, /* no read or write fn */
    };
    ===== End semantic patch =====

    Signed-off-by: Arnd Bergmann
    Cc: Julia Lawall
    Cc: Christoph Hellwig

    Arnd Bergmann
     

30 Mar, 2010

1 commit

  • …it slab.h inclusion from percpu.h

    percpu.h is included by sched.h and module.h and thus ends up being
    included when building most .c files. percpu.h includes slab.h which
    in turn includes gfp.h making everything defined by the two files
    universally available and complicating inclusion dependencies.

    percpu.h -> slab.h dependency is about to be removed. Prepare for
    this change by updating users of gfp and slab facilities include those
    headers directly instead of assuming availability. As this conversion
    needs to touch large number of source files, the following script is
    used as the basis of conversion.

    http://userweb.kernel.org/~tj/misc/slabh-sweep.py

    The script does the followings.

    * Scan files for gfp and slab usages and update includes such that
    only the necessary includes are there. ie. if only gfp is used,
    gfp.h, if slab is used, slab.h.

    * When the script inserts a new include, it looks at the include
    blocks and try to put the new include such that its order conforms
    to its surrounding. It's put in the include block which contains
    core kernel includes, in the same order that the rest are ordered -
    alphabetical, Christmas tree, rev-Xmas-tree or at the end if there
    doesn't seem to be any matching order.

    * If the script can't find a place to put a new include (mostly
    because the file doesn't have fitting include block), it prints out
    an error message indicating which .h file needs to be added to the
    file.

    The conversion was done in the following steps.

    1. The initial automatic conversion of all .c files updated slightly
    over 4000 files, deleting around 700 includes and adding ~480 gfp.h
    and ~3000 slab.h inclusions. The script emitted errors for ~400
    files.

    2. Each error was manually checked. Some didn't need the inclusion,
    some needed manual addition while adding it to implementation .h or
    embedding .c file was more appropriate for others. This step added
    inclusions to around 150 files.

    3. The script was run again and the output was compared to the edits
    from #2 to make sure no file was left behind.

    4. Several build tests were done and a couple of problems were fixed.
    e.g. lib/decompress_*.c used malloc/free() wrappers around slab
    APIs requiring slab.h to be added manually.

    5. The script was run on all .h files but without automatically
    editing them as sprinkling gfp.h and slab.h inclusions around .h
    files could easily lead to inclusion dependency hell. Most gfp.h
    inclusion directives were ignored as stuff from gfp.h was usually
    wildly available and often used in preprocessor macros. Each
    slab.h inclusion directive was examined and added manually as
    necessary.

    6. percpu.h was updated not to include slab.h.

    7. Build test were done on the following configurations and failures
    were fixed. CONFIG_GCOV_KERNEL was turned off for all tests (as my
    distributed build env didn't work with gcov compiles) and a few
    more options had to be turned off depending on archs to make things
    build (like ipr on powerpc/64 which failed due to missing writeq).

    * x86 and x86_64 UP and SMP allmodconfig and a custom test config.
    * powerpc and powerpc64 SMP allmodconfig
    * sparc and sparc64 SMP allmodconfig
    * ia64 SMP allmodconfig
    * s390 SMP allmodconfig
    * alpha SMP allmodconfig
    * um on x86_64 SMP allmodconfig

    8. percpu.h modifications were reverted so that it could be applied as
    a separate patch and serve as bisection point.

    Given the fact that I had only a couple of failures from tests on step
    6, I'm fairly confident about the coverage of this conversion patch.
    If there is a breakage, it's likely to be something in one of the arch
    headers which should be easily discoverable easily on most builds of
    the specific arch.

    Signed-off-by: Tejun Heo <tj@kernel.org>
    Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org>
    Cc: Ingo Molnar <mingo@redhat.com>
    Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>

    Tejun Heo
     

09 Jun, 2009

1 commit

  • CUSE enables implementing character devices in userspace. With recent
    additions of ioctl and poll support, FUSE already has most of what's
    necessary to implement character devices. All CUSE has to do is
    bonding all those components - FUSE, chardev and the driver model -
    nicely.

    When client opens /dev/cuse, kernel starts conversation with
    CUSE_INIT. The client tells CUSE which device it wants to create. As
    the previous patch made fuse_file usable without associated
    fuse_inode, CUSE doesn't create super block or inodes. It attaches
    fuse_file to cdev file->private_data during open and set ff->fi to
    NULL. The rest of the operation is almost identical to FUSE direct IO
    case.

    Each CUSE device has a corresponding directory /sys/class/cuse/DEVNAME
    (which is symlink to /sys/devices/virtual/class/DEVNAME if
    SYSFS_DEPRECATED is turned off) which hosts "waiting" and "abort"
    among other things. Those two files have the same meaning as the FUSE
    control files.

    The only notable lacking feature compared to in-kernel implementation
    is mmap support.

    Signed-off-by: Tejun Heo
    Signed-off-by: Miklos Szeredi

    Tejun Heo