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
     

03 Jul, 2008

1 commit


12 Jan, 2008

1 commit


13 Oct, 2007

1 commit

  • tgt uses scsi_host as I_T nexus. This works for ibmvstgt because it
    creates one scsi_host for one initiator. However, other target drivers
    don't work like that.

    This adds I_T nexus support, which enable one scsi_host to handle
    multiple initiators. New scsi_tgt_it_nexus_create/destroy functions
    are expected be called transport classes. For example, ibmvstgt
    creates an initiator remote port, then the srp transport calls
    tgt_it_nexus_create. tgt doesn't manages I_T nexus, instead it tells
    tgtd, user-space daemon, to create a new I_T nexus.

    On the receiving the response from tgtd, tgt calls
    shost->transportt->it_nexus_response. transports should notify a
    lld. The srp transport uses it_nexus_response callback in
    srp_function_template to do that.

    Signed-off-by: FUJITA Tomonori
    Signed-off-by: Mike Christie
    Signed-off-by: James Bottomley

    FUJITA Tomonori
     

12 Mar, 2007

1 commit

  • This patch simplify the way to notify LLDs of the command completion
    and addresses the following sense buffer problems:

    - can't handle both data and sense.
    - forces user-space to use aligned sense buffer

    tgt copies sense_data from userspace to cmnd->sense_buffer (if
    necessary), maps user-space pages (if necessary) and then calls
    host->transfer_response (host->transfer_data is removed).

    Signed-off-by: FUJITA Tomonori
    Signed-off-by: Mike Christie
    Signed-off-by: James Bottomley

    FUJITA Tomonori
     

16 Feb, 2007

1 commit

  • This patches fixes two bugs in the scsi target infrastructure's
    user/kernel interface.

    - It wrongly assumes that the ring buffer size of the interface (64KB)
    is larger than or equal to the system page size. This patch sets the
    ring buffer size to PAGE_SIZE if the system page size is larger.

    - It uses PAGE_SIZE in the header file exported to userspace. This
    patch removes it.

    Signed-off-by: FUJITA Tomonori
    Signed-off-by: James Bottomley

    FUJITA Tomonori
     

13 Feb, 2007

1 commit

  • Many struct file_operations in the kernel can be "const". Marking them const
    moves these to the .rodata section, which avoids false sharing with potential
    dirty data. In addition it'll catch accidental writes at compile time to
    these shared resources.

    Signed-off-by: Arjan van de Ven
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Arjan van de Ven
     

05 Dec, 2006

1 commit


26 Nov, 2006

1 commit

  • The user-space daemon and tgt kernel module need bi-directional
    kernel/user high-performance interface, however, mainline provides no
    standard interface like that.

    This patch adds shared memory interface between kernel and user spaces
    like some other drivers do by using own character device. The
    user-space daemon and tgt kernel module creates shared memory via mmap
    and use it like ring buffer. poll (kernel to user) and write (user to
    kernel) system calls are used for notification.

    Signed-off-by: FUJITA Tomonori
    Signed-off-by: Mike Christie
    Signed-off-by: James Bottomley

    FUJITA Tomonori