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* [PATCH 0/5] convert sg to use the block layer
@ 2008-08-26  2:10 FUJITA Tomonori
  2008-08-26  2:10 ` [PATCH 1/5] block: add gfp_mask argument to blk_rq_map_user and blk_rq_map_user_iov FUJITA Tomonori
                   ` (2 more replies)
  0 siblings, 3 replies; 23+ messages in thread
From: FUJITA Tomonori @ 2008-08-26  2:10 UTC (permalink / raw)
  To: linux-scsi; +Cc: jens.axboe, dougg, michaelc, James.Bottomley, fujita.tomonori

This patchset converts sg to use the block layer functions. That is,
sg doesn't use scsi_execute_async() any more. This is a part of the
overdue task to remove scsi_req_map_sg.

I tested this patchset with sg v3 and the old interface (struct
sg_header) via SG_IO (v3) and the vfs API.


Doug,

1. I don't demote the sg driver's GFP_ATOMIC to GFP_KERNEL. sg always
uses GFP_ATOMIC as before.

2. I don't remove GFP_DMA allocation. As before, sg allocates reserved
pages with GFP_DMA (sfp->low_dma case).

3. I keep the reserved buffer per struct sg_fd as before.

4. I use high-order page allocation for reserved buffer as before. sg
works well with HBAs that have the limitation of the number of sg
entries.

5. I think that you were concern about the overhead of the block layer
functions. But if you look at scsi_execute_async() that sg uses now,
you can find that scsi_execute_async() uses the block layer functions
internally. So the current sg incurs the overhead (if such overhead
exists).


Jens,

I keep the block API changes to a minimum (I might need more changes
for st/osst but I'd like to progress step by step). I did only two
things.

1. I add gfp_mask argument to blk_rq_map_user and blk_rq_map_user_iov.

2. I introduces struct rq_map_data holding pages. sg puts
pre-allocated pages to it and passes it to bio_copy_user_iov(). The
current users of bio_copy_user_iov simply passes NULL. blk_rq_map_user
and blk_rq_map_user_iov take a pointer to struct rq_map_data and in
the end bio_copy_user_iov gets it.


This patchset against the for-linus branch in Jens' tree + the two
patches for 2.6.27:

http://marc.info/?l=linux-kernel&m=121964251911717&w=2
http://marc.info/?l=linux-kernel&m=121964241911611&w=2

After Jens rebases the for-2.6.28 brach, I'll update this patchset
too.

This patchset also is available at:

git://git.kernel.org/pub/scm/linux/kernel/git/tomo/linux-2.6-misc.git sg-block




^ permalink raw reply	[flat|nested] 23+ messages in thread

end of thread, other threads:[~2008-08-28  7:34 UTC | newest]

Thread overview: 23+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2008-08-26  2:10 [PATCH 0/5] convert sg to use the block layer FUJITA Tomonori
2008-08-26  2:10 ` [PATCH 1/5] block: add gfp_mask argument to blk_rq_map_user and blk_rq_map_user_iov FUJITA Tomonori
2008-08-26  2:10   ` [PATCH 2/5] block: introduce struct rq_map_data to use reserved pages FUJITA Tomonori
2008-08-26  2:10     ` [PATCH 3/5] sg: convert the non-data path to use the block layer FUJITA Tomonori
2008-08-26  2:10       ` [PATCH 4/5] sg: convert the direct IO " FUJITA Tomonori
2008-08-26  2:10         ` [PATCH 5/5] sg: convert the indirect " FUJITA Tomonori
2008-08-26 16:35   ` [PATCH 1/5] block: add gfp_mask argument to blk_rq_map_user and blk_rq_map_user_iov Christoph Hellwig
2008-08-27  1:30     ` FUJITA Tomonori
2008-08-26  7:56 ` [PATCH 0/5] convert sg to use the block layer Jens Axboe
2008-08-27  2:14   ` FUJITA Tomonori
2008-08-27  7:10     ` Jens Axboe
2008-08-27 23:26       ` FUJITA Tomonori
2008-08-28  6:51         ` Jens Axboe
2008-08-28  7:07           ` Jens Axboe
2008-08-28  7:17             ` [PATCH 1/5] block: add gfp_mask argument to blk_rq_map_user and blk_rq_map_user_iov FUJITA Tomonori
2008-08-28  7:17               ` [PATCH 2/5] block: introduce struct rq_map_data to use reserved pages FUJITA Tomonori
2008-08-28  7:17                 ` [PATCH 3/5] sg: convert the non-data path to use the block layer FUJITA Tomonori
2008-08-28  7:17                   ` [PATCH 4/5] sg: convert the direct IO " FUJITA Tomonori
2008-08-28  7:17                     ` [PATCH 5/5] sg: convert the indirect " FUJITA Tomonori
2008-08-28  7:34               ` [PATCH 1/5] block: add gfp_mask argument to blk_rq_map_user and blk_rq_map_user_iov Jens Axboe
2008-08-28  7:32             ` [PATCH 0/5] convert sg to use the block layer FUJITA Tomonori
2008-08-27 20:14 ` Douglas Gilbert
2008-08-27 23:26   ` FUJITA Tomonori

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