linux-toradex.git/include/linux/bvec.h, branch v4.13-rc4

bio: add bvec_iter rewind API

2017-07-03T22:56:28+00:00

Some ->bi_end_io handlers (for example: pi_verify or decrypt handlers)
need to know original data vector, but after bio traverse io-stack it may
be advanced, splited and relocated many times so it is hard to guess
original iterator. Let's add 'bi_done' conter which accounts number
of bytes iterator was advanced during it's evolution. Later end_io handler
may easily restore original iterator by rewinding iterator to
iter->bi_done.

Note: this change makes sizeof (struct bvec_iter) multiple to 8

Reviewed-by: Hannes Reinecke 
Reviewed-by: Christoph Hellwig 
Signed-off-by: Dmitry Monakhov 
[hch: switched to true/false return]
Signed-off-by: Christoph Hellwig 
Signed-off-by: Jens Axboe

block: guard bvec iteration logic

2017-07-03T22:56:26+00:00

Currently if some one try to advance bvec beyond it's size we simply
dump WARN_ONCE and continue to iterate beyond bvec array boundaries.
This simply means that we endup dereferencing/corrupting random memory
region.

Sane reaction would be to propagate error back to calling context
But bvec_iter_advance's calling context is not always good for error
handling. For safity reason let truncate iterator size to zero which
will break external iteration loop which prevent us from unpredictable
memory range corruption. And even it caller ignores an error, it will
corrupt it's own bvecs, not others.

This patch does:
- Return error back to caller with hope that it will react on this
- Truncate iterator size

Code was added long time ago here 4550dd6c, luckily no one hit it
in real life :)

Signed-off-by: Dmitry Monakhov 
Reviewed-by: Ming Lei 
Reviewed-by: Martin K. Petersen 
[hch: switch to true/false returns instead of errno values]
Signed-off-by: Christoph Hellwig 
Signed-off-by: Jens Axboe

bvec: avoid variable shadowing warning

2016-08-11T15:41:35+00:00

Due to the (indirect) nesting of min(..., min(...)), sparse will
show a variable shadowing warning whenever bvec.h is included.

Avoid that by assigning the inner min() to a temporary variable first.

Signed-off-by: Johannes Berg 
Signed-off-by: Jens Axboe

block: mark 1st parameter of bvec_iter_advance as const

2016-06-09T16:02:47+00:00

bvec_iter_advance() only writes the parameter of iterator,
so the base address of bvec can be marked as const safely.

Without the change, we can see compiling warning in the
following patch for implementing iterate_bvec(): lib/iov_iter.c
with bvec iterator.

Reviewed-by: Christoph Hellwig 
Signed-off-by: Ming Lei 
Tested-by: Hannes Reinecke 
Signed-off-by: Jens Axboe

block: move two bvec structure into bvec.h

2016-06-09T16:02:47+00:00

This patch moves 'struct bio_vec' and 'struct bvec_iter'
into 'include/linux/bvec.h', then always include this header
into 'include/linux/blk_types.h'.

With this change, both 'struct bvec_iter' and bvec iterator
helpers don't depend on CONFIG_BLOCK any more, then we can
use bvec iterator to implement iterate_bvec(): lib/iov_iter.c.

Reviewed-by: Christoph Hellwig 
Suggested-by: Christoph Hellwig 
Signed-off-by: Ming Lei 
Tested-by: Hannes Reinecke 
Signed-off-by: Jens Axboe

block: move bvec iterator into include/linux/bvec.h

2016-06-09T16:00:58+00:00

bvec iterator helpers should be used to implement by
iterate_bvec():lib/iov_iter.c too, and move them into
one header, so that we can keep bvec iterator header
out of CONFIG_BLOCK. Then we can remove the reinventing
of wheel in iterate_bvec().

Reviewed-by: Christoph Hellwig 
Signed-off-by: Ming Lei 
Tested-by: Hannes Reinecke 
Signed-off-by: Jens Axboe