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
     

05 Dec, 2009

4 commits

  • There are cases outside of our control that may result in a transmit
    skb being linearized in dev_queue_xmit. There are a couple of bugs
    in libfc/fcoe that can result in a panic at that point. This patch
    contains two fixes to prevent those panics.

    1) use fast cloning instead of shared skbs with dev_queue_xmit

    dev_queue_xmit doen't want shared skbuffs being passed in, and
    __skb_linearize will BUG if the skb is shared. FCoE is holding an extra
    reference around the call to dev_queue_xmit, so that when it returns an
    error code indicating the frame has been dropped it can maintain it's
    own backlog and retransmit. Switch to using fast skb cloning for this
    instead.

    2) don't append compound pages as > PAGE_SIZE skb fragments

    fc_fcp_send_data will append pages from a scatterlist to the nr_frags[]
    if the netdev supports it. But, it's using > PAGE_SIZE compound pages
    as a single skb_frag. In the highmem linearize case that page will be
    passed to kmap_atomic to get a mapping to copy out of, but
    kmap_atomic will only allow access to the first PAGE_SIZE part.
    The memcpy will keep going and cause a page fault once is crosses the
    first boundary.

    If fc_fcp_send_data uses linear buffers from the start, it calls
    kmap_atomic one PAGE_SIZE at a time. That same logic needs to be
    applied when setting up skb_frags.

    Signed-off-by: Chris Leech
    Signed-off-by: Robert Love
    Signed-off-by: James Bottomley

    Chris Leech
     
  • Cleans up frame allocation APIs to have just single fc_frame_alloc API.

    Removes _fc_frame_alloc, renames __fc_frame_alloc to _fc_frame_alloc.

    Modifies fc_fcp_send_data for removed _fc_frame_alloc, fc_fcp_send_data
    was the only user of removed _fc_frame_alloc.

    Also Adds check in fc_frame_alloc to do mod by 4 for only non-zero
    len value.

    This patch is prep work to fix can_queue reducing in next patch.
    Single fc_frame_alloc API helps in fixing can_queue reducing in
    next patch.

    Signed-off-by: Vasu Dev
    Signed-off-by: Robert Love
    Signed-off-by: James Bottomley

    Vasu Dev
     
  • Allow a vport specific string to be appended to the port symbolic
    name. The new symbolic name is sent to the name server after it
    is set.

    This currently messes with libhbalinux, which is looking for
    the fcoe "fcoe over " string and expects whatever
    comes after the "over" to be a network interface name only.

    Adds an EXPORT_SYMBOL to libfc for fc_frame_alloc_fill, which is
    needed to allow fcoe to allocate a frame of variable length for
    the RSPN request.

    Signed-off-by: Chris Leech
    Signed-off-by: Robert Love
    Signed-off-by: James Bottomley

    Chris Leech
     
  • These are a few functions that were not used by other
    modules. They did not need to be exported so this patch
    removes the EXPORT_SYMBOLS call for each.

    Signed-off-by: Robert Love
    Signed-off-by: James Bottomley

    Robert Love
     

30 Dec, 2008

1 commit

  • libFC is composed of 4 blocks supported by an exchange manager
    and a framing library. The upper 4 layers are fc_lport, fc_disc,
    fc_rport and fc_fcp. A LLD that uses libfc could choose to
    either use libfc's block, or using the transport template
    defined in libfc.h, override one or more blocks with its own
    implementation.

    The EM (Exchange Manager) manages exhcanges/sequences for all
    commands- ELS, CT and FCP.

    The framing library frames ELS and CT commands.

    The fc_lport block manages the library's representation of the
    host's FC enabled ports.

    The fc_disc block manages discovery of targets as well as
    handling changes that occur in the FC fabric (via. RSCN events).

    The fc_rport block manages the library's representation of other
    entities in the FC fabric. Currently the library uses this block
    for targets, its peer when in point-to-point mode and the
    directory server, but can be extended for other entities if
    needed.

    The fc_fcp block interacts with the scsi-ml and handles all
    I/O.

    Signed-off-by: Robert Love
    [jejb: added include of delay.h to fix ppc64 compile prob spotted by sfr]
    Signed-off-by: James Bottomley

    Robert Love