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author | Tejun Heo <tj@kernel.org> | 2008-11-03 20:03:17 +0900 |
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committer | Jeff Garzik <jgarzik@redhat.com> | 2008-12-28 22:43:20 -0500 |
commit | 1eca4365be25c540650693e941bc06a66cf38f94 (patch) | |
tree | e3ed82850da00308180bf166118f9f9e69d92898 /include/linux/libata.h | |
parent | 3c92ec8ae91ecf59d88c798301833d7cf83f2179 (diff) | |
download | kernel_samsung_smdk4412-1eca4365be25c540650693e941bc06a66cf38f94.zip kernel_samsung_smdk4412-1eca4365be25c540650693e941bc06a66cf38f94.tar.gz kernel_samsung_smdk4412-1eca4365be25c540650693e941bc06a66cf38f94.tar.bz2 |
libata: beef up iterators
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 <tj@kernel.org>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
Diffstat (limited to 'include/linux/libata.h')
-rw-r--r-- | include/linux/libata.h | 76 |
1 files changed, 56 insertions, 20 deletions
diff --git a/include/linux/libata.h b/include/linux/libata.h index ed3f26e..3b2a0c6 100644 --- a/include/linux/libata.h +++ b/include/linux/libata.h @@ -1285,26 +1285,62 @@ static inline int ata_link_active(struct ata_link *link) return ata_tag_valid(link->active_tag) || link->sactive; } -extern struct ata_link *__ata_port_next_link(struct ata_port *ap, - struct ata_link *link, - bool dev_only); - -#define __ata_port_for_each_link(link, ap) \ - for ((link) = __ata_port_next_link((ap), NULL, false); (link); \ - (link) = __ata_port_next_link((ap), (link), false)) - -#define ata_port_for_each_link(link, ap) \ - for ((link) = __ata_port_next_link((ap), NULL, true); (link); \ - (link) = __ata_port_next_link((ap), (link), true)) - -#define ata_link_for_each_dev(dev, link) \ - for ((dev) = (link)->device; \ - (dev) < (link)->device + ata_link_max_devices(link) || ((dev) = NULL); \ - (dev)++) - -#define ata_link_for_each_dev_reverse(dev, link) \ - for ((dev) = (link)->device + ata_link_max_devices(link) - 1; \ - (dev) >= (link)->device || ((dev) = NULL); (dev)--) +/* + * Iterators + * + * ATA_LITER_* constants are used to select link iteration mode and + * ATA_DITER_* device iteration mode. + * + * For a custom iteration directly using ata_{link|dev}_next(), if + * @link or @dev, respectively, is NULL, the first element is + * returned. @dev and @link can be any valid device or link and the + * next element according to the iteration mode will be returned. + * After the last element, NULL is returned. + */ +enum ata_link_iter_mode { + ATA_LITER_EDGE, /* if present, PMP links only; otherwise, + * host link. no slave link */ + ATA_LITER_HOST_FIRST, /* host link followed by PMP or slave links */ + ATA_LITER_PMP_FIRST, /* PMP links followed by host link, + * slave link still comes after host link */ +}; + +enum ata_dev_iter_mode { + ATA_DITER_ENABLED, + ATA_DITER_ENABLED_REVERSE, + ATA_DITER_ALL, + ATA_DITER_ALL_REVERSE, +}; + +extern struct ata_link *ata_link_next(struct ata_link *link, + struct ata_port *ap, + enum ata_link_iter_mode mode); + +extern struct ata_device *ata_dev_next(struct ata_device *dev, + struct ata_link *link, + enum ata_dev_iter_mode mode); + +/* + * Shortcut notation for iterations + * + * ata_for_each_link() iterates over each link of @ap according to + * @mode. @link points to the current link in the loop. @link is + * NULL after loop termination. ata_for_each_dev() works the same way + * except that it iterates over each device of @link. + * + * Note that the mode prefixes ATA_{L|D}ITER_ shouldn't need to be + * specified when using the following shorthand notations. Only the + * mode itself (EDGE, HOST_FIRST, ENABLED, etc...) should be + * specified. This not only increases brevity but also makes it + * impossible to use ATA_LITER_* for device iteration or vice-versa. + */ +#define ata_for_each_link(link, ap, mode) \ + for ((link) = ata_link_next(NULL, (ap), ATA_LITER_##mode); (link); \ + (link) = ata_link_next((link), (ap), ATA_LITER_##mode)) + +#define ata_for_each_dev(dev, link, mode) \ + for ((dev) = ata_dev_next(NULL, (link), ATA_DITER_##mode); (dev); \ + (dev) = ata_dev_next((dev), (link), ATA_DITER_##mode)) /** * ata_ncq_enabled - Test whether NCQ is enabled |