Re: [PATCH #upstream-fixes 2/4] libata: beef up iterators

[Jeff Garzik <jeff@garzik.org>]

Tejun Heo wrote:
> There currently are the following loop 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 loop 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 <tj@kernel.org>
> ---
>  drivers/ata/ahci.c           |    8 -
>  drivers/ata/ata_generic.c    |    5 -
>  drivers/ata/libata-acpi.c    |   19 +---
>  drivers/ata/libata-core.c    |  183 ++++++++++++++++++++++++++++---------------
>  drivers/ata/libata-eh.c      |   84 ++++++++-----------
>  drivers/ata/libata-pmp.c     |   22 ++---
>  drivers/ata/libata-scsi.c    |   22 ++---
>  drivers/ata/pata_it821x.c    |   34 +++----
>  drivers/ata/pata_ixp4xx_cf.c |   14 +--
>  drivers/ata/pata_legacy.c    |   17 +--
>  drivers/ata/pata_pdc2027x.c  |   27 ++----
>  drivers/ata/pata_platform.c  |   14 +--
>  drivers/ata/pata_rz1000.c    |   16 +--
>  drivers/ata/sata_sil.c       |    2 
>  include/linux/libata.h       |   50 +++++++----
>  15 files changed, 279 insertions(+), 238 deletions(-)

ACK... for 2.6.29.  I think this is too much change for -rc2.  It's a 
good idea though.

Also, it could use more documentation than just the commit message... 
something that programmers can easily refer to (header file comment?)

	Jeff