linux.git/block/bio.c, branch v5.4-rc2

block: move same page handling from __bio_add_pc_page to the callers

2019-08-22T13:14:39+00:00

Hiding page refcount manipulation inside a low-level bio helper is
somewhat awkward.  Instead return the same page information to the
callers, where it fits in much better.

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

block: create a bio_try_merge_pc_page helper

2019-08-22T13:14:38+00:00

Passsthrough bio handling should be the same as normal bio handling,
except that we need to take hardware limitations into account.  Thus
use the common try_merge implementation after checking the hardware
limits.  This changes behavior in that we now also check segment
and dma boundary settings for same page merges, which is a little
more work but has no effect as those need to be larger than the
page size.

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

block: improve the gap check in __bio_add_pc_page

2019-08-22T13:14:36+00:00

If we can add more data into an existing segment we do not create a gap
per definition, so move the check for a gap after the attempt to merge
into the segment.

Signed-off-by: Christoph Hellwig 
Reviewed-by: Johannes Thumshirn 
Signed-off-by: Jens Axboe

block: annotate refault stalls from IO submission

2019-08-14T14:50:01+00:00

psi tracks the time tasks wait for refaulting pages to become
uptodate, but it does not track the time spent submitting the IO. The
submission part can be significant if backing storage is contended or
when cgroup throttling (io.latency) is in effect - a lot of time is
spent in submit_bio(). In that case, we underreport memory pressure.

Annotate submit_bio() to account submission time as memory stall when
the bio is reading userspace workingset pages.

Tested-by: Suren Baghdasaryan 
Signed-off-by: Johannes Weiner 
Signed-off-by: Jens Axboe

block: stop exporting bio_map_kern

2019-08-06T14:20:10+00:00

Now that there no module users left of bio_map_kern, stop exporting the
symbol.

Reviewed-by: Javier González 
Reviewed-by: Christoph Hellwig 
Signed-off-by: Hans Holmberg 
Signed-off-by: Jens Axboe

block: Document the bio splitting functions

2019-08-05T03:41:29+00:00

Since what the bio splitting functions do is nontrivial, document these
functions.

Reviewed-by: Johannes Thumshirn 
Cc: Christoph Hellwig 
Cc: Ming Lei 
Cc: Hannes Reinecke 
Signed-off-by: Bart Van Assche 
Signed-off-by: Jens Axboe

block: Allow mapping of vmalloc-ed buffers

2019-07-12T02:04:36+00:00

To allow the SCSI subsystem scsi_execute_req() function to issue
requests using large buffers that are better allocated with vmalloc()
rather than kmalloc(), modify bio_map_kern() to allow passing a buffer
allocated with vmalloc().

To do so, detect vmalloc-ed buffers using is_vmalloc_addr(). For
vmalloc-ed buffers, flush the buffer using flush_kernel_vmap_range(),
use vmalloc_to_page() instead of virt_to_page() to obtain the pages of
the buffer, and invalidate the buffer addresses with
invalidate_kernel_vmap_range() on completion of read BIOs. This last
point is executed using the function bio_invalidate_vmalloc_pages()
which is defined only if the architecture defines
ARCH_HAS_FLUSH_KERNEL_DCACHE_PAGE, that is, if the architecture
actually needs the invalidation done.

Fixes: 515ce6061312 ("scsi: sd_zbc: Fix sd_zbc_report_zones() buffer allocation")
Fixes: e76239a3748c ("block: add a report_zones method")
Cc: stable@vger.kernel.org
Reviewed-by: Martin K. Petersen 
Signed-off-by: Damien Le Moal 
Reviewed-by: Christoph Hellwig 
Reviewed-by: Chaitanya Kulkarni 
Reviewed-by: Ming Lei 
Signed-off-by: Jens Axboe

block: fix .bi_size overflow

2019-07-01T14:18:54+00:00

'bio->bi_iter.bi_size' is 'unsigned int', which at most hold 4G - 1
bytes.

Before 07173c3ec276 ("block: enable multipage bvecs"), one bio can
include very limited pages, and usually at most 256, so the fs bio
size won't be bigger than 1M bytes most of times.

Since we support multi-page bvec, in theory one fs bio really can
be added > 1M pages, especially in case of hugepage, or big writeback
with too many dirty pages. Then there is chance in which .bi_size
is overflowed.

Fixes this issue by using bio_full() to check if the added segment may
overflow .bi_size.

Cc: Liu Yiding 
Cc: kernel test robot 
Cc: "Darrick J. Wong" 
Cc: linux-xfs@vger.kernel.org
Cc: linux-fsdevel@vger.kernel.org
Cc: stable@vger.kernel.org
Fixes: 07173c3ec276 ("block: enable multipage bvecs")
Reviewed-by: Christoph Hellwig 
Signed-off-by: Ming Lei 
Signed-off-by: Jens Axboe

Merge tag 'v5.2-rc6' into for-5.3/block

2019-07-01T14:16:08+00:00

Merge 5.2-rc6 into for-5.3/block, so we get the same page merge leak
fix. Otherwise we end up having conflicts with future patches between
for-5.3/block and master that touch this area. In particular, it makes
the bio_full() fix hard to backport to stable.

* tag 'v5.2-rc6': (482 commits)
  Linux 5.2-rc6
  Revert "iommu/vt-d: Fix lock inversion between iommu->lock and device_domain_lock"
  Bluetooth: Fix regression with minimum encryption key size alignment
  tcp: refine memory limit test in tcp_fragment()
  x86/vdso: Prevent segfaults due to hoisted vclock reads
  SUNRPC: Fix a credential refcount leak
  Revert "SUNRPC: Declare RPC timers as TIMER_DEFERRABLE"
  net :sunrpc :clnt :Fix xps refcount imbalance on the error path
  NFS4: Only set creation opendata if O_CREAT
  ARM: 8867/1: vdso: pass --be8 to linker if necessary
  KVM: nVMX: reorganize initial steps of vmx_set_nested_state
  KVM: PPC: Book3S HV: Invalidate ERAT when flushing guest TLB entries
  habanalabs: use u64_to_user_ptr() for reading user pointers
  nfsd: replace Jeff by Chuck as nfsd co-maintainer
  inet: clear num_timeout reqsk_alloc()
  PCI/P2PDMA: Ignore root complex whitelist when an IOMMU is present
  net: mvpp2: debugfs: Add pmap to fs dump
  ipv6: Default fib6_type to RTN_UNICAST when not set
  net: hns3: Fix inconsistent indenting
  net/af_iucv: always register net_device notifier
  ...

block: never take page references for ITER_BVEC

2019-06-29T15:47:32+00:00

If we pass pages through an iov_iter we always already have a reference
in the caller.  Thus remove the ITER_BVEC_FLAG_NO_REF and don't take
reference to pages by default for bvec backed iov_iters.

Reviewed-by: Minwoo Im 
Reviewed-by: Johannes Thumshirn 
Signed-off-by: Christoph Hellwig 
Signed-off-by: Jens Axboe