linux-toradex.git/lib/scatterlist.c, branch v3.10.2

lib/scatterlist: sg_page_iter: support sg lists w/o backing pages

2013-03-27T16:13:44+00:00

The i915 driver uses sg lists for memory without backing 'struct page'
pages, similarly to other IO memory regions, setting only the DMA
address for these. It does this, so that it can program the HW MMU
tables in a uniform way both for sg lists with and without backing pages.

Without a valid page pointer we can't call nth_page to get the current
page in __sg_page_iter_next, so add a helper that relevant users can
call separately. Also add a helper to get the DMA address of the current
page (idea from Daniel).

Convert all places in i915, to use the new API.

Signed-off-by: Imre Deak 
Reviewed-by: Damien Lespiau 
Signed-off-by: Daniel Vetter

lib/scatterlist: use page iterator in the mapping iterator

2013-02-28T03:10:10+00:00

For better code reuse use the newly added page iterator to iterate
through the pages.  The offset, length within the page is still
calculated by the mapping iterator as well as the actual mapping.  Idea
from Tejun Heo.

Signed-off-by: Imre Deak 
Cc: Maxim Levitsky 
Cc: Tejun Heo 
Cc: Daniel Vetter 
Cc: James Hogan 
Cc: Stephen Warren 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

lib/scatterlist: add simple page iterator

2013-02-28T03:10:10+00:00

Add an iterator to walk through a scatter list a page at a time starting
at a specific page offset.  As opposed to the mapping iterator this is
meant to be small, performing well even in simple loops like collecting
all pages on the scatterlist into an array or setting up an iommu table
based on the pages' DMA address.

Signed-off-by: Imre Deak 
Cc: Maxim Levitsky 
Cc: Tejun Heo 
Cc: Daniel Vetter 
Tested-by: Stephen Warren 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

scatterlist: don't BUG when we can trivially return a proper error.

2012-12-18T01:15:28+00:00

There is absolutely no reason to crash the kernel when we have a
perfectly good return value already available to use for conveying
failure status.

Let's return an error code instead of crashing the kernel: that sounds
like a much better plan.

[akpm@linux-foundation.org: s/E2BIG/EINVAL/]
Signed-off-by: Nick Bowler 
Cc: Maxim Levitsky 
Cc: Tejun Heo 
Cc: Jens Axboe 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

Merge branch 'for-3.7/core' of git://git.kernel.dk/linux-block

2012-10-11T00:04:23+00:00

Pull block IO update from Jens Axboe:
 "Core block IO bits for 3.7.  Not a huge round this time, it contains:

   - First series from Kent cleaning up and generalizing bio allocation
     and freeing.

   - WRITE_SAME support from Martin.

   - Mikulas patches to prevent O_DIRECT crashes when someone changes
     the block size of a device.

   - Make bio_split() work on data-less bio's (like trim/discards).

   - A few other minor fixups."

Fixed up silent semantic mis-merge as per Mikulas Patocka and Andrew
Morton.  It is due to the VM no longer using a prio-tree (see commit
6b2dbba8b6ac: "mm: replace vma prio_tree with an interval tree").

So make set_blocksize() use mapping_mapped() instead of open-coding the
internal VM knowledge that has changed.

* 'for-3.7/core' of git://git.kernel.dk/linux-block: (26 commits)
  block: makes bio_split support bio without data
  scatterlist: refactor the sg_nents
  scatterlist: add sg_nents
  fs: fix include/percpu-rwsem.h export error
  percpu-rw-semaphore: fix documentation typos
  fs/block_dev.c:1644:5: sparse: symbol 'blkdev_mmap' was not declared
  blockdev: turn a rw semaphore into a percpu rw semaphore
  Fix a crash when block device is read and block size is changed at the same time
  block: fix request_queue->flags initialization
  block: lift the initial queue bypass mode on blk_register_queue() instead of blk_init_allocated_queue()
  block: ioctl to zero block ranges
  block: Make blkdev_issue_zeroout use WRITE SAME
  block: Implement support for WRITE SAME
  block: Consolidate command flag and queue limit checks for merges
  block: Clean up special command handling logic
  block/blk-tag.c: Remove useless kfree
  block: remove the duplicated setting for congestion_threshold
  block: reject invalid queue attribute values
  block: Add bio_clone_bioset(), bio_clone_kmalloc()
  block: Consolidate bio_alloc_bioset(), bio_kmalloc()
  ...

scatterlist: atomic sg_mapping_iter() no longer needs disabled IRQs

2012-10-05T18:04:58+00:00

SG mapping iterator w/ SG_MITER_ATOMIC set required IRQ disabled because
it originally used KM_BIO_SRC_IRQ to allow use from IRQ handlers.
kmap_atomic() has long been updated to handle stacking atomic mapping
requests on per-cpu basis and only requires not sleeping while mapped.

Update sg_mapping_iter such that atomic iterators only require disabling
preemption instead of disabling IRQ.

While at it, convert wte weird @ARG@ notations to @ARG in the comment of
sg_miter_start().

Signed-off-by: Tejun Heo 
Cc: Maxim Levitsky 
Cc: Alex Dubov 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

scatterlist: refactor the sg_nents

2012-09-28T08:38:15+00:00

Replace 'while' with 'for' as suggested by Tejun Heo

Signed-off-by: Maxim Levitsky 
Signed-off-by: Jens Axboe

scatterlist: add sg_nents

2012-09-27T10:45:28+00:00

Useful helper to know the number of entries in scatterlist.

Signed-off-by: Maxim Levitsky 
Cc: Alex Dubov 
Acked-by: Tejun Heo 
Cc: Jens Axboe 
Signed-off-by: Jens Axboe

Merge branch 'akpm' (Andrew's patch-bomb)

2012-07-31T00:25:34+00:00

Merge Andrew's first set of patches:
 "Non-MM patches:

   - lots of misc bits

   - tree-wide have_clk() cleanups

   - quite a lot of printk tweaks.  I draw your attention to "printk:
     convert the format for KERN_ to a 2 byte pattern" which
     looks a bit scary.  But afaict it's solid.

   - backlight updates

   - lib/ feature work (notably the addition and use of memweight())

   - checkpatch updates

   - rtc updates

   - nilfs updates

   - fatfs updates (partial, still waiting for acks)

   - kdump, proc, fork, IPC, sysctl, taskstats, pps, etc

   - new fault-injection feature work"

* Merge emailed patches from Andrew Morton : (128 commits)
  drivers/misc/lkdtm.c: fix missing allocation failure check
  lib/scatterlist: do not re-write gfp_flags in __sg_alloc_table()
  fault-injection: add tool to run command with failslab or fail_page_alloc
  fault-injection: add selftests for cpu and memory hotplug
  powerpc: pSeries reconfig notifier error injection module
  memory: memory notifier error injection module
  PM: PM notifier error injection module
  cpu: rewrite cpu-notifier-error-inject module
  fault-injection: notifier error injection
  c/r: fcntl: add F_GETOWNER_UIDS option
  resource: make sure requested range is included in the root range
  include/linux/aio.h: cpp->C conversions
  fs: cachefiles: add support for large files in filesystem caching
  pps: return PTR_ERR on error in device_create
  taskstats: check nla_reserve() return
  sysctl: suppress kmemleak messages
  ipc: use Kconfig options for __ARCH_WANT_[COMPAT_]IPC_PARSE_VERSION
  ipc: compat: use signed size_t types for msgsnd and msgrcv
  ipc: allow compat IPC version field parsing if !ARCH_WANT_OLD_COMPAT_IPC
  ipc: add COMPAT_SHMLBA support
  ...

lib/scatterlist: do not re-write gfp_flags in __sg_alloc_table()

2012-07-31T00:25:22+00:00

We are seeing a lot of sg_alloc_table allocation failures using the new
drm prime infrastructure.  We isolated the cause to code in
__sg_alloc_table that was re-writing the gfp_flags.

There is a comment in the code that suggest that there is an assumption
about the allocation coming from a memory pool.  This was likely true
when sg lists were primarily used for disk I/O.

Signed-off-by: Mandeep Singh Baines 
Cc: Jens Axboe 
Cc: Paul Gortmaker 
Cc: Cong Wang 
Cc: Daniel Vetter 
Cc: Rob Clark 
Cc: Sumit Semwal 
Cc: Inki Dae 
Cc: Dave Airlie 
Cc: Sonny Rao 
Cc: Olof Johansson 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds