linux-stable.git/block/bio.c, branch v5.2

block: fix page leak when merging to same page

2019-06-17T15:33:04+00:00

When multiple iovecs reference the same page, each get_user_page call
will add a reference to the page.  But once we've created the bio that
information gets lost and only a single reference will be dropped after
I/O completion.  Use the same_page information returned from
__bio_try_merge_page to drop additional references to pages that were
already present in the bio.

Based on a patch from Ming Lei.

Link: https://lkml.org/lkml/2019/4/23/64
Fixes: 576ed913 ("block: use bio_add_page in bio_iov_iter_get_pages")
Reported-by: David Gibson 
Signed-off-by: Christoph Hellwig 
Reviewed-by: Ming Lei 
Signed-off-by: Jens Axboe

block: return from __bio_try_merge_page if merging occured in the same page

2019-06-17T15:33:02+00:00

We currently have an input same_page parameter to __bio_try_merge_page
to prohibit merging in the same page.  The rationale for that is that
some callers need to account for every page added to a bio.  Instead of
letting these callers call twice into the merge code to account for the
new vs existing page cases, just turn the paramter into an output one that
returns if a merge in the same page occured and let them act accordingly.

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

block: switch all files cleared marked as GPLv2 to SPDX tags

2019-04-30T22:11:57+00:00

All these files have some form of the usual GPLv2 boilerplate.  Switch
them to use SPDX tags instead.

Reviewed-by: Chaitanya Kulkarni 
Signed-off-by: Christoph Hellwig 
Signed-off-by: Jens Axboe

block: clean up __bio_add_pc_page a bit

2019-04-30T15:26:44+00:00

Share the bi_size update by moving the done label up, and duplicate
the bv_len update in the two callers to get rid of the bvec_merge
label.

Signed-off-by: Christoph Hellwig 
Signed-off-by: Jens Axboe

block: remove bogus comments in __bio_add_pc_page

2019-04-30T15:26:42+00:00

We are never called with file system pages by defintions for the
passthrough interface, and we also never undo any addition later
these days.

Signed-off-by: Christoph Hellwig 
Signed-off-by: Jens Axboe

block: remove the __bio_add_pc_page export

2019-04-30T15:26:41+00:00

The same page optimization is a rather odd corner case, which is not
used outside bio.c and which really should not be used outside of bio.c
either - we have better highlevel helpers like the rq/bio mapping
helpers.

Signed-off-by: Christoph Hellwig 
Signed-off-by: Jens Axboe

block: remove the i argument to bio_for_each_segment_all

2019-04-30T15:26:13+00:00

We only have two callers that need the integer loop iterator, and they
can easily maintain it themselves.

Suggested-by: Matthew Wilcox 
Reviewed-by: Johannes Thumshirn 
Acked-by: David Sterba 
Reviewed-by: Hannes Reinecke 
Acked-by: Coly Li 
Reviewed-by: Matthew Wilcox 
Signed-off-by: Christoph Hellwig 
Signed-off-by: Jens Axboe

block: don't run get_page() on pages from non-bvec iov iter

2019-04-24T14:06:04+00:00

The refcount has been increased for pages retrieved from non-bvec iov iter
via __bio_iov_iter_get_pages(), so don't need to do that again.

Otherwise, IO pages are leaked easily.

Cc: Christoph Hellwig 
Reviewed-by: Chaitanya Kulkarni 
Fixes: 7321ecbfc7cf ("block: change how we get page references in bio_iov_iter_get_pages")
Signed-off-by: Ming Lei 
Signed-off-by: Jens Axboe

block: clarify that bio_add_page() and related helpers can add multi pages

2019-04-23T13:57:07+00:00

bio_add_page() and __bio_add_page() are capable of adding pages into
bio, and now we have at least two such usages alreay:

	- __bio_iov_bvec_add_pages()
	- nvmet_bdev_execute_rw().

So update comments on these two helpers.

The thing is a bit special for __bio_try_merge_page(), given the caller
needs to know if the new added page is same with the last added page,
then it isn't safe to pass multi-page in case that 'same_page' is true,
so adds warning on potential misuse, and updates comment on
__bio_try_merge_page().

Cc: linux-xfs@vger.kernel.org
Cc: linux-fsdevel@vger.kernel.org
Reviewed-by: Hannes Reinecke 
Reviewed-by: Christoph Hellwig 
Signed-off-by: Ming Lei 
Signed-off-by: Jens Axboe

Merge tag 'v5.1-rc6' into for-5.2/block

2019-04-22T15:47:36+00:00

Pull in v5.1-rc6 to resolve two conflicts. One is in BFQ, in just a
comment, and is trivial. The other one is a conflict due to a later fix
in the bio multi-page work, and needs a bit more care.

* tag 'v5.1-rc6': (770 commits)
  Linux 5.1-rc6
  block: make sure that bvec length can't be overflow
  block: kill all_q_node in request_queue
  x86/cpu/intel: Lower the "ENERGY_PERF_BIAS: Set to normal" message's log priority
  coredump: fix race condition between mmget_not_zero()/get_task_mm() and core dumping
  mm/kmemleak.c: fix unused-function warning
  init: initialize jump labels before command line option parsing
  kernel/watchdog_hld.c: hard lockup message should end with a newline
  kcov: improve CONFIG_ARCH_HAS_KCOV help text
  mm: fix inactive list balancing between NUMA nodes and cgroups
  mm/hotplug: treat CMA pages as unmovable
  proc: fixup proc-pid-vm test
  proc: fix map_files test on F29
  mm/vmstat.c: fix /proc/vmstat format for CONFIG_DEBUG_TLBFLUSH=y CONFIG_SMP=n
  mm/memory_hotplug: do not unlock after failing to take the device_hotplug_lock
  mm: swapoff: shmem_unuse() stop eviction without igrab()
  mm: swapoff: take notice of completion sooner
  mm: swapoff: remove too limiting SWAP_UNUSE_MAX_TRIES
  mm: swapoff: shmem_find_swap_entries() filter out other types
  slab: store tagged freelist for off-slab slabmgmt
  ...

Signed-off-by: Jens Axboe