15 Oct, 2015

1 commit


10 May, 2014

1 commit

  • This patch fixes host drivers to use CONFIG_PM_SLEEP instead of CONFIG_PM
    where applicable. Benefits of this change:

    * unused code is not being compiled in for CONFIG_PM=y, CONFIG_PM_SLEEP=n
    and CONFIG_PM_RUNTIME=y configurations

    * easier transition to use struct dev_pm_ops and SIMPLE_DEV_PM_OPS() in
    the future

    * more consistent code (there are host drivers which are using the correct
    CONFIG_PM_SLEEP checks already)

    The patch leaves the core libata code and ->port_[suspend,resume] support
    in sata_[inic162x,nv,sil24].c alone for now.

    Signed-off-by: Bartlomiej Zolnierkiewicz
    Signed-off-by: Tejun Heo

    Bartlomiej Zolnierkiewicz
     

14 Feb, 2014

1 commit


03 Jun, 2013

1 commit

  • Use the wrapper function for getting the driver data using pci_dev
    instead of using dev_get_drvdata() with &pdev->dev, so we can directly
    pass a struct pci_dev. This is a purely cosmetic change.

    Signed-off-by: Jingoo Han
    Signed-off-by: Tejun Heo

    Jingoo Han
     

26 Jul, 2012

1 commit

  • This patch converts the drivers in drivers/ata/* to use module_pci_driver()
    macro which makes the code smaller and a bit simpler.

    Signed-off-by: Axel Lin
    Cc: Alan Cox
    Cc: Jeff Garzik
    Cc: Mikael Pettersson
    Cc: Mark Lord
    Cc: Jeremy Higdon
    Cc: Benjamin Herrenschmidt
    Signed-off-by: Jeff Garzik

    Axel Lin
     

24 Jul, 2011

2 commits

  • The missing comma causes the wrong RAID type to be displayed.
    Introduced by commit 963e4975c6f93c148ca809d986d412201df9af89 three
    years ago, odd that nobody noticed before.

    Signed-off-by: Jean Delvare
    Cc: Jeff Garzik
    Cc: Alan Cox
    Signed-off-by: Jeff Garzik

    Jean Delvare
     
  • Saves text by removing nearly duplicated text format strings by
    creating ata__printk functions and printf extension %pV.

    ata defconfig size shrinks ~5% (~8KB), allyesconfig ~2.5% (~13KB)

    Format string duplication comes from:

    #define ata_link_printk(link, lv, fmt, args...) do { \
    if (sata_pmp_attached((link)->ap) || (link)->ap->slave_link) \
    printk("%sata%u.%02u: "fmt, lv, (link)->ap->print_id, \
    (link)->pmp , ##args); \
    else \
    printk("%sata%u: "fmt, lv, (link)->ap->print_id , ##args); \
    } while(0)

    Coalesce long formats.

    $ size drivers/ata/built-in.*
    text data bss dec hex filename
    544969 73893 116584 735446 b38d6 drivers/ata/built-in.allyesconfig.ata.o
    558429 73893 117864 750186 b726a drivers/ata/built-in.allyesconfig.dev_level.o
    141328 14689 4220 160237 271ed drivers/ata/built-in.defconfig.ata.o
    149567 14689 4220 168476 2921c drivers/ata/built-in.defconfig.dev_level.o

    Signed-off-by: Joe Perches
    Signed-off-by: Jeff Garzik

    Joe Perches
     

02 Mar, 2011

1 commit


18 Oct, 2010

1 commit

  • The patch below updates broken web addresses in the kernel

    Signed-off-by: Justin P. Mattock
    Cc: Maciej W. Rozycki
    Cc: Geert Uytterhoeven
    Cc: Finn Thain
    Cc: Randy Dunlap
    Cc: Matt Turner
    Cc: Dimitry Torokhov
    Cc: Mike Frysinger
    Acked-by: Ben Pfaff
    Acked-by: Hans J. Koch
    Reviewed-by: Finn Thain
    Signed-off-by: Jiri Kosina

    Justin P. Mattock
     

26 May, 2010

1 commit

  • Separate out ata_pci_bmdma_prepare_host() and ata_pci_bmdma_init_one()
    from their SFF counterparts. SFF ones no longer try to initialize
    BMDMA or set PCI master.

    Signed-off-by: Tejun Heo
    Signed-off-by: Jeff Garzik

    Tejun Heo
     

20 May, 2010

2 commits

  • Separate out ata_bmdma_qc_issue() from ata_sff_qc_issue() such that
    ata_sff_qc_issue() only deals with non-BMDMA SFF protocols (PIO and
    nodata) while ata_bmdma_qc_issue() deals with the BMDMA protocols and
    uses ata_sff_qc_issue() for non-DMA commands. All the users are
    updated accordingly.

    Signed-off-by: Tejun Heo
    Signed-off-by: Jeff Garzik

    Tejun Heo
     
  • When BMDMA initialization failed or BMDMA was not available for
    whatever reason, bmdma_addr was left at zero and used as an indication
    that BMDMA shouldn't be used. This leads to the following problems.

    p1. For BMDMA drivers which don't use traditional BMDMA register,
    ata_bmdma_mode_filter() incorrectly inhibits DMA modes. Those
    drivers either have to inherit from ata_sff_port_ops or clear
    ->mode_filter explicitly.

    p2. non-BMDMA drivers call into BMDMA PRD table allocation. It
    doesn't actually allocate PRD table if bmdma_addr is not
    initialized but is still confusing.

    p3. For BMDMA drivers which don't use traditional BMDMA register, some
    methods might not be invoked as expected (e.g. bmdma_stop from
    ata_sff_post_internal_cmd()).

    p4. SFF drivers w/ custom DMA interface implement noop BMDMA ops
    worrying libata core might call into one of them.

    These problems are caused by the muddy line between SFF and BMDMA and
    the assumption that all BMDMA controllers initialize bmdma_addr.

    This patch fixes p1 and p2 by removing the bmdma_addr assumption and
    moving prd allocation to BMDMA port start. Later patches will fix the
    remaining issues.

    This patch improves BMDMA initialization such that

    * When BMDMA register initialization fails, falls back to PIO instead
    of failing. ata_pci_bmdma_init() never fails now.

    * When ata_pci_bmdma_init() falls back to PIO, it clears
    ap->mwdma_mask and udma_mask instead of depending on
    ata_bmdma_mode_filter(). This makes ata_bmdma_mode_filter()
    unnecessary thus resolving p1.

    * ata_port_start() which actually is BMDMA specific is moved to
    ata_bmdma_port_start(). ata_port_start() and ata_sff_port_start()
    are killed.

    * ata_sff_port_start32() is moved and renamed to
    ata_bmdma_port_start32().

    Drivers which no longer call into PRD table allocation are...

    pdc_adma, sata_inic162x, sata_qstor, sata_sx4, pata_cmd640 and all
    drivers which inherit from ata_sff_port_ops.

    pata_icside sets ->port_start to ATA_OP_NULL as it doesn't need PRD
    but is a BMDMA controller and doesn't have custom port_start like
    other such controllers.

    Note that with the previous patch which makes all and only BMDMA
    drivers inherit from ata_bmdma_port_ops, this change doesn't break
    drivers which need PRD table.

    Signed-off-by: Tejun Heo
    Signed-off-by: Jeff Garzik

    Tejun Heo
     

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
     

02 Mar, 2010

1 commit

  • This allows parallel scan and the like to be set without having to stop
    using the existing full helper functions. This patch merely adds the argument
    and fixes up the callers. It doesn't undo the special cases already in the
    tree or add any new parallel callers.

    Signed-off-by: Alan Cox
    Signed-off-by: Jeff Garzik

    Alan Cox
     

03 Dec, 2009

1 commit


25 Mar, 2009

1 commit


26 Feb, 2009

1 commit

  • Hibernation didn't work for me since I started to use IT8212 controller.
    I did some debugging (booting with no_console_suspend init=/bin/sh).

    Found that resume fails (2.6.28) with "serial number mismatch 'some
    garbage' != 'some other garbage'" and "revalidation failed" messages.
    That's because the controller firmware fills different serial number in
    the IDENTIFY every boot.

    The patch below fixes the resume simply clearing the serial number. The
    proper fix would be probably to fill in the serial number of the RAID
    volume instead. I assume that there must be something like that stored on
    the drives but I don't know where.

    Fix resume on pata_it821x RAID volume by clearing the serial number in
    IDENTIFY data, which is otherwise different on each boot.

    Signed-off-by: Ondrej Zary
    Acked-by: Alan Cox
    Signed-off-by: Andrew Morton
    Signed-off-by: Jeff Garzik

    Ondrej Zary
     

13 Jan, 2009

1 commit


29 Dec, 2008

1 commit

  • There currently are the following looping constructs.

    * __ata_port_for_each_link() for all available links
    * ata_port_for_each_link() for edge links
    * ata_link_for_each_dev() for all devices
    * ata_link_for_each_dev_reverse() for all devices in reverse order

    Now there's a need for looping construct which is similar to
    __ata_port_for_each_link() but iterates over PMP links before the host
    link. Instead of adding another one with long name, do the following
    cleanup.

    * Implement and export ata_link_next() and ata_dev_next() which take
    @mode parameter and can be used to build custom loop.
    * Implement ata_for_each_link() and ata_for_each_dev() which take
    looping mode explicitly.

    The following iteration modes are implemented.

    * ATA_LITER_EDGE : loop over edge links
    * ATA_LITER_HOST_FIRST : loop over all links, host link first
    * ATA_LITER_PMP_FIRST : loop over all links, PMP links first

    * ATA_DITER_ENABLED : loop over enabled devices
    * ATA_DITER_ENABLED_REVERSE : loop over enabled devices in reverse order
    * ATA_DITER_ALL : loop over all devices
    * ATA_DITER_ALL_REVERSE : loop over all devices in reverse order

    This change removes exlicit device enabledness checks from many loops
    and makes it clear which ones are iterated over in which direction.

    Signed-off-by: Tejun Heo
    Signed-off-by: Jeff Garzik

    Tejun Heo
     

28 Oct, 2008

2 commits


22 Aug, 2008

1 commit

  • Reported by Andrew Morton:
    drivers/ata/pata_it821x.c: In function 'it821x_port_start':
    drivers/ata/pata_it821x.c:609: warning: 'mtype' may be used uninitialized in
    this function

    Pretty horrid fix, but so's a warning..

    Signed-off-by: Jeff Garzik

    Jeff Garzik
     

31 Jul, 2008

1 commit

  • - Add support for the RDC 1010 variant
    - Rework the core library to have a read_id method. This allows the hacky
    bits of it821x to go and prepares us for pata_hd
    - Switch from WARN to BUG in ata_id_string as it will reboot if you get
    it wrong so WARN won't be seen
    - Allow the issue of command 0xFC on the 821x. This is needed to query
    rebuild status.
    - Tidy up printk formatting
    - Do more ident rewriting on RAID volumes to handle firmware provided
    ident data which is rather wonky
    - Report the firmware revision and device layout in RAID mode
    - Don't try and disable raid on the 8211 or RDC - they don't have the
    relevant bits

    Signed-off-by: Alan Cox
    Signed-off-by: Jeff Garzik

    Alan Cox
     

18 Apr, 2008

7 commits

  • Add sff_ prefix to SFF specific port ops.

    This rename is in preparation of separating SFF support out of libata
    core layer. This patch strictly renames ops and doesn't introduce any
    behavior difference.

    Signed-off-by: Tejun Heo

    Tejun Heo
     
  • SFF functions have confusing names. Some have sff prefix, some have
    bmdma, some std, some pci and some none. Unify the naming by...

    * SFF functions which are common to both BMDMA and non-BMDMA are
    prefixed with ata_sff_.

    * SFF functions which are specific to BMDMA are prefixed with
    ata_bmdma_.

    * SFF functions which are specific to PCI but apply to both BMDMA and
    non-BMDMA are prefixed with ata_pci_sff_.

    * SFF functions which are specific to PCI and BMDMA are prefixed with
    ata_pci_bmdma_.

    * Drop generic prefixes from LLD specific routines. For example,
    bfin_std_dev_select -> bfin_dev_select.

    The following renames are noteworthy.

    ata_qc_issue_prot() -> ata_sff_qc_issue()
    ata_pci_default_filter() -> ata_bmdma_mode_filter()
    ata_dev_try_classify() -> ata_sff_dev_classify()

    This rename is in preparation of separating SFF support out of libata
    core layer. This patch strictly renames functions and doesn't
    introduce any behavior difference.

    Signed-off-by: Tejun Heo

    Tejun Heo
     
  • port_info->private_data is currently used for two purposes - to record
    private data about the port_info or to specify host->private_data to
    use when allocating ata_host.

    This overloading is confusing and counter-intuitive in that
    port_info->private_data becomes host->private_data instead of
    port->private_data. In addition, port_info and host don't correspond
    to each other 1-to-1. Currently, the first non-NULL
    port_info->private_data is used.

    This patch makes port_info->private_data just be what it is -
    private_data for the port_info where LLD can jot down extra info.
    libata no longer sets host->private_data to the first non-NULL
    port_info->private_data, @host_priv argument is added to
    ata_pci_init_one() instead. LLDs which use ata_pci_init_one() can use
    this argument to pass in pointer to host private data. LLDs which
    don't should use init-register model anyway and can initialize
    host->private_data directly.

    Adding @host_priv instead of using init-register model for LLDs which
    use ata_pci_init_one() is suggested by Alan Cox.

    Signed-off-by: Tejun Heo
    Cc: Alan Cox

    Tejun Heo
     
  • ata_pci_init_one() is the only function which uses ops->irq_handler
    and pi->sht. Other initialization functions take the same information
    as arguments. This causes confusion and duplicate unused entries in
    structures.

    Make ata_pci_init_one() take sht as an argument and use ata_interrupt
    implicitly. All current users use ata_interrupt and if different irq
    handler is necessary open coding ata_pci_init_one() using
    ata_prepare_sff_host() and ata_activate_sff_host can be done under ten
    lines including error handling and driver which requires custom
    interrupt handler is likely to require custom initialization anyway.

    As ata_pci_init_one() was the last user of ops->irq_handler, this
    patch also kills the field.

    Signed-off-by: Tejun Heo

    Tejun Heo
     
  • libata lets low level drivers build ata_port_operations table and
    register it with libata core layer. This allows low level drivers
    high level of flexibility but also burdens them with lots of
    boilerplate entries.

    This becomes worse for drivers which support related similar
    controllers which differ slightly. They share most of the operations
    except for a few. However, the driver still needs to list all
    operations for each variant. This results in large number of
    duplicate entries, which is not only inefficient but also error-prone
    as it becomes very difficult to tell what the actual differences are.

    This duplicate boilerplates all over the low level drivers also make
    updating the core layer exteremely difficult and error-prone. When
    compounded with multi-branched development model, it ends up
    accumulating inconsistencies over time. Some of those inconsistencies
    cause immediate problems and fixed. Others just remain there dormant
    making maintenance increasingly difficult.

    To rectify the problem, this patch implements ata_port_operations
    inheritance. To allow LLDs to easily re-use their own ops tables
    overriding only specific methods, this patch implements poor man's
    class inheritance. An ops table has ->inherits field which can be set
    to any ops table as long as it doesn't create a loop. When the host
    is started, the inheritance chain is followed and any operation which
    isn't specified is taken from the nearest ancestor which has it
    specified. This operation is called finalization and done only once
    per an ops table and the LLD doesn't have to do anything special about
    it other than making the ops table non-const such that libata can
    update it.

    libata provides four base ops tables lower drivers can inherit from -
    base, sata, pmp, sff and bmdma. To avoid overriding these ops
    accidentaly, these ops are declared const and LLDs should always
    inherit these instead of using them directly.

    After finalization, all the ops table are identical before and after
    the patch except for setting .irq_handler to ata_interrupt in drivers
    which didn't use to. The .irq_handler doesn't have any actual effect
    and the field will soon be removed by later patch.

    * sata_sx4 is still using old style EH and currently doesn't take
    advantage of ops inheritance.

    Signed-off-by: Tejun Heo

    Tejun Heo
     
  • libata lets low level drivers build scsi_host_template and register it
    to the SCSI layer. This allows low level drivers high level of
    flexibility but also burdens them with lots of boilerplate entries.

    This patch implements SHT initializers which can be used to initialize
    all the boilerplate entries in a sht. Three variants of them are
    implemented - BASE, BMDMA and NCQ - for different types of drivers.
    Note that entries can be overriden by putting individual initializers
    after the helper macro.

    All sht tables are identical before and after this patch.

    Signed-off-by: Tejun Heo

    Tejun Heo
     
  • PCI device should be powered up or powered up before its PCI regsiters
    are accessed. Although PCI configuration register access is allowed
    in D3hot, PCI device is free to reset its status when transiting from
    D3hot to D0 causing configuration data to change.

    Many libata SFF drivers which use ata_pci_init_one() read and update
    configuration registers before calling ata_pci_init_one() which
    enables the PCI device. Also, in resume paths, some drivers access
    registers without resuming the PCI device.

    This patch adds a call to pcim_enable_device() in init path if
    register is accessed before calling ata_pci_init_one() and make resume
    paths first resume PCI devices, access PCI configuration regiters then
    resume ATA host.

    While at it...

    * cmd640 was strange in that it set ->resume even when CONFIG_PM is
    not. This is by-product of minimal build fix. Updated.

    * In cs5530, Don't BUG() on reinit failure. Just whine and fail
    resume.

    Signed-off-by: Tejun Heo

    Tejun Heo
     

25 Mar, 2008

1 commit


23 Jan, 2008

1 commit

  • Some it821x RAID firmwares return 0 for the err return off both devices.
    A similar issue occurs with the slave returning 0 not 1 if you plug a
    gigabyte sata ramdisk into a controller that fakes two SATA ports as
    master/slave on an SFF channel.

    The patch does the following

    - Allow the 'failed diagnostics' case on both master and slave
    - Move the HORKAGE_DIAGNOSTIC check after ->dev_config

    This second change also allows IT821x to fix up a problem where we report
    drive diagnostic failures when in fact the drive is fine but the
    microcontroller firmware doesn't appear to get it right. IT821x clears
    the flag again to avoid giving the user bogus warnings about their disk.

    The other IT821x change is a bit ugly, we slightly abuse the cable type
    hook to fiddle with the identify data for the devices. We could add a new
    hook for this but as we have only one offender and no more seeming likely
    it seems better to keep libata-core clean.

    Please let this sit in -mm briefly, just in case the relaxed checking
    breaks some other emulated interface.

    Signed-off-by: Alan Cox
    Signed-off-by: Jeff Garzik

    Alan Cox
     

20 Oct, 2007

1 commit


13 Oct, 2007

6 commits

  • This avoids allocating DMA buffers if not needed but at the moment is
    mostly just a neatness item.

    Signed-off-by: Alan Cox
    Signed-off-by: Jeff Garzik

    Alan Cox
     
  • It was always set to ata_port_disable(). Removed the hook, and replaced
    the very few ap->ops->port_disable() callsites with direct calls to
    ata_port_disable().

    Signed-off-by: Jeff Garzik

    Jeff Garzik
     
  • * ->irq_ack() is redundant to what the irq handler already
    performs... chk-status + irq-clear. Furthermore, it is only
    called in one place, when screaming-irq-debugging is enabled,
    so we don't want to bother with a hook just for that.

    * ata_dummy_irq_on() is only ever used in drivers that have
    no callpath reaching ->irq_on(). Remove .irq_on hook from
    those drivers, and the now-unused ata_dummy_irq_on()

    Signed-off-by: Jeff Garzik

    Jeff Garzik
     
  • Make the following functions deal with ata_link instead of ata_port.

    * ata_set_mode()
    * ata_eh_autopsy() and related functions
    * ata_eh_report() and related functions
    * suspend/resume related functions
    * ata_eh_recover() and related functions

    Signed-off-by: Tejun Heo
    Signed-off-by: Jeff Garzik

    Tejun Heo
     
  • Multiple links and different number of devices per link should be
    considered to iterate over links and devices. This patch implements
    and uses link and device iterators - ata_port_for_each_link() and
    ata_link_for_each_dev() - and ata_link_max_devices().

    This change makes a lot of functions iterate over only possible
    devices instead of from dev 0 to dev ATA_MAX_DEVICES. All such
    changes have been examined and nothing should be broken.

    While at it, add a separating comment before device helpers to
    distinguish them better from link helpers and others.

    Signed-off-by: Tejun Heo
    Signed-off-by: Jeff Garzik

    Tejun Heo
     
  • Introduce ata_link. It abstracts PHY and sits between ata_port and
    ata_device. This new level of abstraction is necessary to support
    SATA Port Multiplier, which basically adds a bunch of links (PHYs) to
    a ATA host port. Fields related to command execution, spd_limit and
    EH are per-link and thus moved to ata_link.

    This patch only defines the host link. Multiple link handling will be
    added later. Also, a lot of ap->link derefences are added but many of
    them will be removed as each part is converted to deal directly with
    ata_link instead of ata_port.

    This patch introduces no behavior change.

    Signed-off-by: Tejun Heo
    Cc: James Bottomley
    Signed-off-by: Jeff Garzik

    Tejun Heo
     

11 Sep, 2007

1 commit

  • Fix "lost" interrupt problem when using dma with CD/DVD drives in some
    configurations. This problem can make installing linux from media
    impossible for distro's that have switched to libata-only configurations.

    The simple fix is to eliminate the use of dma for reading drive status, etc,
    by checking the number of bytes to transferred.

    This change will only affect the behavior of atapi devices, not disks.
    There is more info at http://bugzilla.redhat.com/show_bug.cgi?id=242229
    This patch is for 2.6.22.1

    Signed-off-by: Jeff Norden
    Reviewed-by: Alan Cox
    Signed-off-by: Jeff Garzik

    Jeff Norden