Messages in this thread |  | | | From | Tejun Heo <> | | Subject | [PATCH Linux 2.6.12-rc2 00/04] blk: generic tag support fixes | | Date | Wed, 20 Apr 2005 20:41:31 +0900 (KST) |
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Hello, Jens.
These are fixes to generic tag support in the blk layer. They all compile okay and I've proof read it, but as I don't have any HBA which uses generic tag support, I wasn't able to test directly. However, all changes are fairly straight-forward.
[ Start of patch descriptions ]
01_blk_tag_map_use_find_first_zero_bit.patch : use find_first_zero_bit() in blk_queue_start_tag()
blk_queue_start_tag() hand-coded searching for the first zero bit in the tag map. Replace it with find_first_zero_bit(). With this patch, blk_queue_star_tag() doesn't need to fill remains of tag map with 1, thus allowing it to work properly with the next remove_real_max_depth patch.
02_blk_tag_map_remove_real_max_depth.patch : remove blk_queue_tag->real_max_depth optimization
blk_queue_tag->real_max_depth was used to optimize out unnecessary allocations/frees on tag resize. However, the whole thing was very broken - tag_map was never allocated to real_max_depth resulting in access beyond the end of the map, bits in [max_depth..real_max_depth] were set when initializing a map and copied when resizing resulting in pre-occupied tags.
As the gain of the optimization is very small, well, almost nill, remove the whole thing.
03_blk_tag_map_remove_BLK_TAGS_PER_LONG.patch : remove BLK_TAGS_{PER_LONG|MASK} Replace BLK_TAGS_PER_LONG with BITS_PER_LONG and remove unused BLK_TAGS_MASK.
04_blk_tag_map_error_handling_cleanup.patch : cleanup generic tag support error messages
Add KERN_ERR and __FUNCTION__ to generic tag error messages, and add a comment in blk_queue_end_tag() which explains the silent failure path.
[ End of patch descriptions ]
Thanks a lot. :-)
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