From 1eca4365be25c540650693e941bc06a66cf38f94 Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Mon, 3 Nov 2008 20:03:17 +0900 Subject: 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 Signed-off-by: Jeff Garzik --- include/linux/libata.h | 76 +++++++++++++++++++++++++++++++++++++------------- 1 file changed, 56 insertions(+), 20 deletions(-) (limited to 'include') diff --git a/include/linux/libata.h b/include/linux/libata.h index ed3f26eb5df..3b2a0c6444e 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 -- cgit v1.2.3