linux-stable.git/block/bio.c, branch linux-5.2.y

block: Allow mapping of vmalloc-ed buffers

2019-07-26T07:11:03+00:00

commit b4c5875d36178e8df409bdce232f270cac89fafe upstream.

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 
Signed-off-by: Greg Kroah-Hartman

block: fix .bi_size overflow

2019-07-14T06:01:08+00:00

commit 79d08f89bb1b5c2c1ff90d9bb95497ab9e8aa7e0 upstream.

'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 
Signed-off-by: Greg Kroah-Hartman

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