linux-toradex.git/include/linux/bvec.h, branch v5.12-rc5

block: optimise for_each_bvec() advance

2020-12-02T16:46:55+00:00

Because of how for_each_bvec() works it never advances across multiple
entries at a time, so bvec_iter_advance() is an overkill. Add
specialised bvec_iter_advance_single() that is faster. It also handles
zero-len bvecs, so can kill bvec_iter_skip_zero_bvec().

   text    data     bss     dec     hex filename
before:
  23977     805       0   24782    60ce lib/iov_iter.o
before, bvec_iter_advance() w/o WARN_ONCE()
  22886     600       0   23486    5bbe ./lib/iov_iter.o
after:
  21862     600       0   22462    57be lib/iov_iter.o

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

kernel.h: split out min()/max() et al. helpers

2020-10-16T18:11:19+00:00

kernel.h is being used as a dump for all kinds of stuff for a long time.
Here is the attempt to start cleaning it up by splitting out min()/max()
et al.  helpers.

At the same time convert users in header and lib folder to use new header.
Though for time being include new header back to kernel.h to avoid
twisted indirected includes for other existing users.

Signed-off-by: Andy Shevchenko 
Signed-off-by: Andrew Morton 
Cc: "Rafael J. Wysocki" 
Cc: Steven Rostedt 
Cc: Rasmus Villemoes 
Cc: Joe Perches 
Cc: Linus Torvalds 
Link: https://lkml.kernel.org/r/20200910164152.GA1891694@smile.fi.intel.com
Signed-off-by: Linus Torvalds

block: allow for_each_bvec to support zero len bvec

2020-09-03T02:59:40+00:00

Block layer usually doesn't support or allow zero-length bvec. Since
commit 1bdc76aea115 ("iov_iter: use bvec iterator to implement
iterate_bvec()"), iterate_bvec() switches to bvec iterator. However,
Al mentioned that 'Zero-length segments are not disallowed' in iov_iter.

Fixes for_each_bvec() so that it can move on after seeing one zero
length bvec.

Fixes: 1bdc76aea115 ("iov_iter: use bvec iterator to implement iterate_bvec()")
Reported-by: syzbot 
Signed-off-by: Ming Lei 
Tested-by: Tetsuo Handa 
Cc: Al Viro 
Cc: Matthew Wilcox 
Cc: 
Link: https://www.mail-archive.com/linux-kernel@vger.kernel.org/msg2262077.html
Signed-off-by: Jens Axboe

block: Document the bio_vec properties

2020-05-19T15:40:29+00:00

Since it is nontrivial that nth_page() does not have to be used for a
bio_vec, document this.

Signed-off-by: Bart Van Assche 
Reviewed-by: Christoph Hellwig 
CC: Christoph Hellwig 
Cc: Ming Lei 
Signed-off-by: Jens Axboe

block: remove unused mp_bvec_last_segment

2020-01-05T03:23:39+00:00

After commit 85a8ce62c2ea ("block: add bio_truncate to fix guard_bio_eod")
this function is unused, remove it.

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

block: optimise bvec_iter_advance()

2019-12-03T14:36:38+00:00

bvec_iter_advance() is quite popular, but compilers fail to do proper
alias analysis and optimise it good enough. The assembly is checked
for gcc 9.2, x86-64.

- remove @iter->bi_size from min(...), as it's always less than @bytes.
Modify at the beginning and forget about it.

- the compiler isn't able to collapse memory dependencies and remove
writes in the loop. Help it by explicitely using local vars.

Signed-off-by: Arvind Sankar 
Signed-off-by: Pavel Begunkov 
Signed-off-by: Jens Axboe

block: fix mismerge in bvec_advance

2019-05-07T14:39:02+00:00

When Jens merged my commit to only allow contiguous page structs in a
bio_vec with Ming's 5.1 fix to ensue the bvec length didn't overflow
we failed to keep the removal of the expensive nth_page calls.  This
commits adds them back as intended.

Fixes: 5c61ee2cd586 ("Merge tag 'v5.1-rc6' into for-5.2/block")
Signed-off-by: Christoph Hellwig 
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

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

block: make sure that bvec length can't be overflow

2019-04-19T17:32:14+00:00

bvec->bv_offset may be bigger than PAGE_SIZE sometimes, such as,
when one bio is splitted in the middle of one bvec via bio_split(),
and bi_iter.bi_bvec_done is used to build offset of the 1st bvec of
remained bio. And the remained bio's bvec may be re-submitted to fs
layer via ITER_IBVEC, such as loop and nvme-loop.

So we have to make sure that every bvec's offset is less than
PAGE_SIZE from bio_for_each_segment_all() because some drivers(loop,
nvme-loop) passes the splitted bvec to fs layer via ITER_BVEC.

This patch fixes this issue reported by Zhang Yi When running nvme/011.

Cc: Christoph Hellwig 
Cc: Yi Zhang 
Reported-by: Yi Zhang 
Reviewed-by: Christoph Hellwig 
Fixes: 6dc4f100c175 ("block: allow bio_for_each_segment_all() to iterate over multi-page bvec")
Signed-off-by: Ming Lei 
Signed-off-by: Jens Axboe