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author | Linus Torvalds <torvalds@woody.linux-foundation.org> | 2007-10-11 22:14:22 -0400 |
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committer | Linus Torvalds <torvalds@woody.linux-foundation.org> | 2007-10-11 22:14:22 -0400 |
commit | 1ce48904285fe4b0298864f9153a8502ebeac35c (patch) | |
tree | ffe1e0c31cdea427b48ae4d4d59a96ff9d208f32 /Documentation/block/biodoc.txt | |
parent | 55982fd184a065b1c69279d29cbc01dbf424d2f4 (diff) | |
parent | 780513ecb80ea0934fc6833efc4f5ed9ab4ff9bb (diff) |
Merge branch 'block-2.6.24' of git://git.kernel.dk/data/git/linux-2.6-block
* 'block-2.6.24' of git://git.kernel.dk/data/git/linux-2.6-block: (37 commits)
[BLOCK] Fix failing compile with BLK_DEV_IO_TRACE=n
compat_ioctl: move floppy handlers to block/compat_ioctl.c
compat_ioctl: move cdrom handlers to block/compat_ioctl.c
compat_ioctl: move BLKPG handling to block/compat_ioctl.c
compat_ioctl: move hdio calls to block/compat_ioctl.c
compat_ioctl: handle blk_trace ioctls
compat_ioctl: add compat_blkdev_driver_ioctl()
compat_ioctl: move common block ioctls to compat_blkdev_ioctl
Sysace: Don't enable IRQ until after interrupt handler is registered
Sysace: sparse fixes
Sysace: Minor coding convention fixup
drivers/block/umem: use DRIVER_NAME where appropriate
drivers/block/umem: trim trailing whitespace
drivers/block/umem: minor cleanups
drivers/block/umem: use dev_printk()
drivers/block/umem: move private include away from include/linux
Sysace: Labels in C code should not be indented.
Sysace: Add of_platform_bus binding
Sysace: Move IRQ handler registration to occur after FSM is initialized
Sysace: minor rework and cleanup changes
...
Diffstat (limited to 'Documentation/block/biodoc.txt')
-rw-r--r-- | Documentation/block/biodoc.txt | 20 |
1 files changed, 10 insertions, 10 deletions
diff --git a/Documentation/block/biodoc.txt b/Documentation/block/biodoc.txt index 8af392fc6ef0..dc3f49e3e539 100644 --- a/Documentation/block/biodoc.txt +++ b/Documentation/block/biodoc.txt | |||
@@ -477,9 +477,9 @@ With this multipage bio design: | |||
477 | the same bi_io_vec array, but with the index and size accordingly modified) | 477 | the same bi_io_vec array, but with the index and size accordingly modified) |
478 | - A linked list of bios is used as before for unrelated merges (*) - this | 478 | - A linked list of bios is used as before for unrelated merges (*) - this |
479 | avoids reallocs and makes independent completions easier to handle. | 479 | avoids reallocs and makes independent completions easier to handle. |
480 | - Code that traverses the req list needs to make a distinction between | 480 | - Code that traverses the req list can find all the segments of a bio |
481 | segments of a request (bio_for_each_segment) and the distinct completion | 481 | by using rq_for_each_segment. This handles the fact that a request |
482 | units/bios (rq_for_each_bio). | 482 | has multiple bios, each of which can have multiple segments. |
483 | - Drivers which can't process a large bio in one shot can use the bi_idx | 483 | - Drivers which can't process a large bio in one shot can use the bi_idx |
484 | field to keep track of the next bio_vec entry to process. | 484 | field to keep track of the next bio_vec entry to process. |
485 | (e.g a 1MB bio_vec needs to be handled in max 128kB chunks for IDE) | 485 | (e.g a 1MB bio_vec needs to be handled in max 128kB chunks for IDE) |
@@ -664,14 +664,14 @@ in lvm or md. | |||
664 | 664 | ||
665 | 3.2.1 Traversing segments and completion units in a request | 665 | 3.2.1 Traversing segments and completion units in a request |
666 | 666 | ||
667 | The macros bio_for_each_segment() and rq_for_each_bio() should be used for | 667 | The macro rq_for_each_segment() should be used for traversing the bios |
668 | traversing the bios in the request list (drivers should avoid directly | 668 | in the request list (drivers should avoid directly trying to do it |
669 | trying to do it themselves). Using these helpers should also make it easier | 669 | themselves). Using these helpers should also make it easier to cope |
670 | to cope with block changes in the future. | 670 | with block changes in the future. |
671 | 671 | ||
672 | rq_for_each_bio(bio, rq) | 672 | struct req_iterator iter; |
673 | bio_for_each_segment(bio_vec, bio, i) | 673 | rq_for_each_segment(bio_vec, rq, iter) |
674 | /* bio_vec is now current segment */ | 674 | /* bio_vec is now current segment */ |
675 | 675 | ||
676 | I/O completion callbacks are per-bio rather than per-segment, so drivers | 676 | I/O completion callbacks are per-bio rather than per-segment, so drivers |
677 | that traverse bio chains on completion need to keep that in mind. Drivers | 677 | that traverse bio chains on completion need to keep that in mind. Drivers |