linux-toradex.git/include/linux/bio.h, branch v3.14-rc2

block: Kill bio_pair_split()

2013-11-24T06:33:57+00:00

Signed-off-by: Kent Overstreet 
Cc: Jens Axboe

block: Introduce new bio_split()

2013-11-24T06:33:57+00:00

The new bio_split() can split arbitrary bios - it's not restricted to
single page bios, like the old bio_split() (previously renamed to
bio_pair_split()). It also has different semantics - it doesn't allocate
a struct bio_pair, leaving it up to the caller to handle completions.

Then convert the existing bio_pair_split() users to the new bio_split()
- and also nvme, which was open coding bio splitting.

(We have to take that BUG_ON() out of bio_integrity_trim() because this
bio_split() needs to use it, and there's no reason it has to be used on
bios marked as cloned; BIO_CLONED doesn't seem to have clearly
documented semantics anyways.)

Signed-off-by: Kent Overstreet 
Cc: Jens Axboe 
Cc: Martin K. Petersen 
Cc: Matthew Wilcox 
Cc: Keith Busch 
Cc: Vishal Verma 
Cc: Jiri Kosina 
Cc: Neil Brown

block: Rename bio_split() -> bio_pair_split()

2013-11-24T06:33:56+00:00

This is prep work for introducing a more general bio_split().

Signed-off-by: Kent Overstreet 
Cc: Jens Axboe 
Cc: NeilBrown 
Cc: Alasdair Kergon 
Cc: Lars Ellenberg 
Cc: Peter Osterlund 
Cc: Sage Weil

block: Generic bio chaining

2013-11-24T06:33:56+00:00

This adds a generic mechanism for chaining bio completions. This is
going to be used for a bio_split() replacement, and it turns out to be
very useful in a fair amount of driver code - a fair number of drivers
were implementing this in their own roundabout ways, often painfully.

Note that this means it's no longer to call bio_endio() more than once
on the same bio! This can cause problems for drivers that save/restore
bi_end_io. Arguably they shouldn't be saving/restoring bi_end_io at all
- in all but the simplest cases they'd be better off just cloning the
bio, and immutable biovecs is making bio cloning cheaper. But for now,
we add a bio_endio_nodec() for these cases.

Signed-off-by: Kent Overstreet 
Cc: Jens Axboe

dm: Refactor for new bio cloning/splitting

2013-11-24T06:33:55+00:00

We need to convert the dm code to the new bvec_iter primitives which
respect bi_bvec_done; they also allow us to drastically simplify dm's
bio splitting code.

Also, it's no longer necessary to save/restore the bvec array anymore -
driver conversions for immutable bvecs are done, so drivers should never
be modifying it.

Also kill bio_sector_offset(), dm was the only user and it doesn't make
much sense anymore.

Signed-off-by: Kent Overstreet 
Cc: Jens Axboe 
Cc: Alasdair Kergon 
Cc: dm-devel@redhat.com
Reviewed-by: Mike Snitzer

block: Add bio_clone_fast()

2013-11-24T06:33:54+00:00

bio_clone() just got more expensive - however, most users of bio_clone()
don't actually need to modify the biovec. If they aren't modifying the
biovec, and they can guarantee that the original bio isn't freed before
the clone (also true in most cases), we can just point the clone at the
original bio's biovec.

Signed-off-by: Kent Overstreet

block: Kill bio_iovec_idx(), __bio_iovec()

2013-11-24T06:33:53+00:00

bio_iovec_idx() and __bio_iovec() don't have any valid uses anymore -
previous users have been converted to bio_iovec_iter() or other methods.

__BVEC_END() has to go too - the bvec array can't be used directly for
the last biovec because we might only be using the first portion of it,
we have to iterate over the bvec array with bio_for_each_segment() which
checks against the current value of bi_iter.bi_size.

Signed-off-by: Kent Overstreet 
Cc: Jens Axboe

block: Kill bio_segments()/bi_vcnt usage

2013-11-24T06:33:51+00:00

When we start sharing biovecs, keeping bi_vcnt accurate for splits is
going to be error prone - and unnecessary, if we refactor some code.

So bio_segments() has to go - but most of the existing users just needed
to know if the bio had multiple segments, which is easier - add a
bio_multiple_segments() for them.

(Two of the current uses of bio_segments() are going to go away in a
couple patches, but the current implementation of bio_segments() is
unsafe as soon as we start doing driver conversions for immutable
biovecs - so implement a dumb version for bisectability, it'll go away
in a couple patches)

Signed-off-by: Kent Overstreet 
Cc: Jens Axboe 
Cc: Neil Brown 
Cc: Nagalakshmi Nandigama 
Cc: Sreekanth Reddy 
Cc: "James E.J. Bottomley"

bio-integrity: Convert to bvec_iter

2013-11-24T06:33:50+00:00

The bio integrity is also stored in a bvec array, so if we use the bvec
iter code we just added, the integrity code won't need to implement its
own iteration stuff (bio_integrity_mark_head(), bio_integrity_mark_tail())

Signed-off-by: Kent Overstreet 
Cc: Jens Axboe 
Cc: "Martin K. Petersen" 
Cc: "James E.J. Bottomley"

block: Immutable bio vecs

2013-11-24T06:33:49+00:00

This adds a mechanism by which we can advance a bio by an arbitrary
number of bytes without modifying the biovec: bio->bi_iter.bi_bvec_done
indicates the number of bytes completed in the current bvec.

Various driver code still needs to be updated to not refer to the bvec
directly before we can use this for interesting things, like efficient
bio splitting.

Signed-off-by: Kent Overstreet 
Cc: Jens Axboe 
Cc: Lars Ellenberg 
Cc: Paul Clements 
Cc: drbd-user@lists.linbit.com
Cc: nbd-general@lists.sourceforge.net