There is only a single caller left, so fold the loop into that.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Acked-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Link: https://lore.kernel.org/r/20230601094459.1350643-9-hch@lst.de


Signed-off-by: Jens Axboe <axboe@kernel.dk>

Delay dropping the block_devices for partitions in del_gendisk until
after the call to blk_mark_disk_dead, so that we can implementat
notification of removed devices in blk_mark_disk_dead.

This requires splitting a lower-level drop_partition helper out of
delete_partition and using that from del_gendisk, while having a
common loop for the whole device and partitions that calls
remove_inode_hash, fsync_bdev and __invalidate_device before the
call to blk_mark_disk_dead.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Acked-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Link: https://lore.kernel.org/r/20230601094459.1350643-8-hch@lst.de


Signed-off-by: Jens Axboe <axboe@kernel.dk>

Move the call to remove_inode_hash to the beginning of delete_partition,
as we want to prevent opening a block_device that is about to be removed
ASAP.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Acked-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Link: https://lore.kernel.org/r/20230601094459.1350643-7-hch@lst.de


Signed-off-by: Jens Axboe <axboe@kernel.dk>

Check if GD_DEAD is already set in blk_mark_disk_dead, and don't
duplicate the work already done.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Acked-by: Christian Brauner <brauner@kernel.org>
Acked-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Link: https://lore.kernel.org/r/20230601094459.1350643-6-hch@lst.de


Signed-off-by: Jens Axboe <axboe@kernel.dk>

blk_mark_disk_dead does very similar work a a section of del_gendisk:

 - set the GD_DEAD flag
 - set the capacity to zero
 - start a queue drain

but del_gendisk also sets QUEUE_FLAG_DYING on the queue if it is owned by
the disk, sets the capacity to zero before starting the drain, and both
with sending a uevent and kernel message for this fake capacity change.

Move the exact logic from the more heavily used del_gendisk into
blk_mark_disk_dead and then call blk_mark_disk_dead from del_gendisk.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Acked-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Link: https://lore.kernel.org/r/20230601094459.1350643-5-hch@lst.de


Signed-off-by: Jens Axboe <axboe@kernel.dk>

There is no reason for this lock to spin, and being able to sleep under
it will come in handy soon.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Acked-by: Christian Brauner <brauner@kernel.org>
Acked-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Link: https://lore.kernel.org/r/20230601094459.1350643-4-hch@lst.de


Signed-off-by: Jens Axboe <axboe@kernel.dk>

The long if/else chain obsfucates the actual logic.  Tidy it up to be
more structured.  Also drop the whole argument, as it can be trivially
derived from bdev using bdev_whole, and having the bdev_whole in the
function makes it easier to follow.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Acked-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Link: https://lore.kernel.org/r/20230601094459.1350643-3-hch@lst.de


Signed-off-by: Jens Axboe <axboe@kernel.dk>

Move all the logic to release an exclusive claim into a helper.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Acked-by: Christian Brauner <brauner@kernel.org>
Acked-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Link: https://lore.kernel.org/r/20230601094459.1350643-2-hch@lst.de


Signed-off-by: Jens Axboe <axboe@kernel.dk>

__KERNEL_SYSCALLS__ hasn't been needed since Linux 2.6.19 so stop
defining it.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Christoph Böhmwalder <christoph.boehmwalder@linbit.com>
Link: https://lore.kernel.org/r/20230601151646.1386867-1-hch@lst.de


Signed-off-by: Jens Axboe <axboe@kernel.dk>

Add control command of UBLK_U_CMD_GET_FEATURES for returning driver's
feature set or capability.

This way can simplify userspace for maintaining compatibility because
userspace doesn't need to send command to one device for querying driver
feature set any more. Such as, with the queried feature set, userspace
can choose to use:

- UBLK_CMD_GET_DEV_INFO2 or UBLK_CMD_GET_DEV_INFO,
- UBLK_U_CMD_* or UBLK_CMD_*

Userspace code:
	https://github.com/ming1/ubdsrv/commits/features-cmd



Signed-off-by: Ming Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/20230603040601.775227-1-ming.lei@redhat.com


Signed-off-by: Jens Axboe <axboe@kernel.dk>

strlcpy() reads the entire source buffer first.
This read may exceed the destination size limit.
This is both inefficient and can lead to linear read
overflows if a source string is not NUL-terminated [1].
In an effort to remove strlcpy() completely [2], replace
strlcpy() here with strscpy().
No return values were used, so direct replacement is safe.

[1] https://www.kernel.org/doc/html/latest/process/deprecated.html#strlcpy
[2] https://github.com/KSPP/linux/issues/89



Signed-off-by: Azeem Shaikh <azeemshaikh38@gmail.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20230530155608.272266-1-azeemshaikh38@gmail.com


Signed-off-by: Jens Axboe <axboe@kernel.dk>

Currently, icq is tracked by both request_queue(icq->q_node) and
task(icq->ioc_node), and ioc_clear_queue() from elevator exit is not
safe because it can access the list without protection:

ioc_clear_queue			ioc_release_fn
 lock queue_lock
 list_splice
 /* move queue list to a local list */
 unlock queue_lock
 /*
  * lock is released, the local list
  * can be accessed through task exit.
  */

				lock ioc->lock
				while (!hlist_empty)
				 icq = hlist_entry
				 lock queue_lock
				  ioc_destroy_icq
				   delete icq->ioc_node
 while (!list_empty)
  icq = list_entry()		   list_del icq->q_node
  /*
   * This is not protected by any lock,
   * list_entry concurrent with list_del
   * is not safe.
   */

				 unlock queue_lock
				unlock ioc->lock

Fix this problem by protecting list 'icq->q_node' by queue_lock from
ioc_clear_queue().

Reported-and-tested-by: Pradeep Pragallapati <quic_pragalla@quicinc.com>
Link: https://lore.kernel.org/lkml/20230517084434.18932-1-quic_pragalla@quicinc.com/


Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20230531073435.2923422-1-yukuai1@huaweicloud.com


Signed-off-by: Jens Axboe <axboe@kernel.dk>

Now that all callers of bio_add_folio() check the return value, mark it as
__must_check.

Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/381360a45ac3684120cfbe1e07685e9c36256e47.1685532726.git.johannes.thumshirn@wdc.com


Signed-off-by: Jens Axboe <axboe@kernel.dk>

When the iomap buffered-io code can't add a folio to a bio, it allocates a
new bio and adds the folio to that one. This is done using bio_add_folio(),
but doesn't check for errors.

As adding a folio to a newly created bio can't fail, use the newly
introduced bio_add_folio_nofail() function.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/58fa893c24c67340a63323f09a179fefdca07f2a.1685532726.git.johannes.thumshirn@wdc.com


Signed-off-by: Jens Axboe <axboe@kernel.dk>

Just like for bio_add_pages() add a no-fail variant for bio_add_folio().

Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/924dff4077812804398ef84128fb920507fa4be1.1685532726.git.johannes.thumshirn@wdc.com


Signed-off-by: Jens Axboe <axboe@kernel.dk>

Now that all users of bio_add_page check for the return value, mark
bio_add_page as __must_check.

Reviewed-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/7ae4a902e08fe2e90c012ee07aeb35d4aae28373.1685532726.git.johannes.thumshirn@wdc.com


Signed-off-by: Jens Axboe <axboe@kernel.dk>

crypt_alloc_buffer() already allocates enough entries in the clone bio's
vector, so adding a page to the bio can't fail. Use __bio_add_page() to
reflect this.

Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/f9a4dee5e81389fd70ffc442da01006538e55aca.1685532726.git.johannes.thumshirn@wdc.com


Signed-off-by: Jens Axboe <axboe@kernel.dk>

Check if adding pages to resync bio fails and if bail out.

As the comment above suggests this cannot happen, WARN if it actually
happens. Technically __bio_add_pages() would be sufficient here, but
asserting the pages actually get added to the bio is preferred.

This way we can mark bio_add_pages as __must_check.

Reviewed-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Acked-by: Song Liu <song@kernel.org>
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/33aea4c271220dc9bcab58c4b7bec478c1511142.1685532726.git.johannes.thumshirn@wdc.com


Signed-off-by: Jens Axboe <axboe@kernel.dk>

The sync request code uses bio_add_page() to add a page to a newly created bio.
bio_add_page() can fail, but the return value is never checked.

Use __bio_add_page() as adding a single page to a newly created bio is
guaranteed to succeed.

This brings us a step closer to marking bio_add_page() as __must_check.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Acked-by: Song Liu <song@kernel.org>
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/6cf7f66c6e646231200d025dfd5f2d3ae75c8fe5.1685532726.git.johannes.thumshirn@wdc.com


Signed-off-by: Jens Axboe <axboe@kernel.dk>

alloc_behind_master_bio() can possibly add multiple pages to a bio, but it
is not checking for the return value of bio_add_page() if adding really
succeeded.

Check if the page adding succeeded and if not bail out.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Acked-by: Song Liu <song@kernel.org>
Reviewed-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/827aa12d44ebf3f50b41b47f5cedc0f80179f2c1.1685532726.git.johannes.thumshirn@wdc.com


[axboe: fold in s/free_page/put_page fix]
Signed-off-by: Jens Axboe <axboe@kernel.dk>

The floppy code uses bio_add_page() to add a page to a newly created bio.
bio_add_page() can fail, but the return value is never checked.

Use __bio_add_page() as adding a single page to a newly created bio is
guaranteed to succeed.

This brings us a step closer to marking bio_add_page() as __must_check.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/33c445a3b431270c72d9be03d5da1b08ae983920.1685532726.git.johannes.thumshirn@wdc.com


Signed-off-by: Jens Axboe <axboe@kernel.dk>

The zram writeback code uses bio_add_page() to add a page to a newly
created bio. bio_add_page() can fail, but the return value is never
checked.

Use __bio_add_page() as adding a single page to a newly created bio is
guaranteed to succeed.

This brings us a step closer to marking bio_add_page() as __must_check.

Reviewed-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Reviewed-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/cfd141dd7773315879a126f2aa81b7f698bc0e10.1685532726.git.johannes.thumshirn@wdc.com


Signed-off-by: Jens Axboe <axboe@kernel.dk>

The zonefs superblock reading code uses bio_add_page() to add a page to a
newly created bio. bio_add_page() can fail, but the return value is
never checked.

Use __bio_add_page() as adding a single page to a newly created bio is
guaranteed to succeed.

This brings us a step closer to marking bio_add_page() as __must_check.

Acked-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/04c9978ccaa0fc9871cd4248356638d98daccf0c.1685532726.git.johannes.thumshirn@wdc.com


Signed-off-by: Jens Axboe <axboe@kernel.dk>

The GFS2 superblock reading code uses bio_add_page() to add a page to a
newly created bio. bio_add_page() can fail, but the return value is never
checked.

Use __bio_add_page() as adding a single page to a newly created bio is
guaranteed to succeed.

This brings us a step closer to marking bio_add_page() as __must_check.

Reviewed-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Reviewed-by: Andreas Gruenbacher <agruenba@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/087c67d4e4973f949d3519c1e4822784ce583c5a.1685532726.git.johannes.thumshirn@wdc.com


Signed-off-by: Jens Axboe <axboe@kernel.dk>

The JFS IO code uses bio_add_page() to add a page to a newly created bio.
bio_add_page() can fail, but the return value is never checked.

Use __bio_add_page() as adding a single page to a newly created bio is
guaranteed to succeed.

This brings us a step closer to marking bio_add_page() as __must_check.

Reviewed-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Acked-by: Dave Kleikamp <dave.kleikamp@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/9fb5ed86d19f6e0b6f64dfc4109a48ff8ff24497.1685532726.git.johannes.thumshirn@wdc.com


Signed-off-by: Jens Axboe <axboe@kernel.dk>

The raid5-ppl submission code uses bio_add_page() to add a page to a
newly created bio. bio_add_page() can fail, but the return value is never
checked. For adding consecutive pages, the return is actually checked and
a new bio is allocated if adding the page fails.

Use __bio_add_page() as adding a single page to a newly created bio is
guaranteed to succeed.

This brings us a step closer to marking bio_add_page() as __must_check.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Acked-by: Song Liu <song@kernel.org>
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/27e6bcd762354bff74602e89159cdd12ae3d1fa9.1685532726.git.johannes.thumshirn@wdc.com


Signed-off-by: Jens Axboe <axboe@kernel.dk>

The raid5 log metadata submission code uses bio_add_page() to add a page
to a newly created bio. bio_add_page() can fail, but the return value is
never checked.

Use __bio_add_page() as adding a single page to a newly created bio is
guaranteed to succeed.

This brings us a step closer to marking bio_add_page() as __must_check.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Acked-by: Song Liu <song@kernel.org>
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/832a810d6c9e71f88b0a39cb076a8c70e8bcb821.1685532726.git.johannes.thumshirn@wdc.com


Signed-off-by: Jens Axboe <axboe@kernel.dk>

The md-raid superblock writing code uses bio_add_page() to add a page to a
newly created bio. bio_add_page() can fail, but the return value is never
checked.

Use __bio_add_page() as adding a single page to a newly created bio is
guaranteed to succeed.

This brings us a step closer to marking bio_add_page() as __must_check.

Signed-of_-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Acked-by: Song Liu <song@kernel.org>
Link: https://lore.kernel.org/r/ca196f5e650e318106dbb4496eb6cbac4bc800bd.1685532726.git.johannes.thumshirn@wdc.com



Signed-off-by: Jens Axboe <axboe@kernel.dk>

The buffer_head submission code uses bio_add_page() to add a page to a
newly created bio. bio_add_page() can fail, but the return value is never
checked.

Use __bio_add_page() as adding a single page to a newly created bio is
guaranteed to succeed.

This brings us a step closer to marking bio_add_page() as __must_check.

Reviewed-by: Gou Hao <gouhao@uniontech.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/84ff2dcbe81b258a73ad900adb5266e208b61a4d.1685532726.git.johannes.thumshirn@wdc.com


Signed-off-by: Jens Axboe <axboe@kernel.dk>

dm-zoned uses bio_add_page() for adding a single page to a freshly created
metadata bio.

Use __bio_add_page() instead as adding a single page to a new bio is
always guaranteed to succeed.

This brings us a step closer to marking bio_add_page() __must_check

Reviewed-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/55a0c8dad7550379647873b579dc7cfbe0191f96.1685532726.git.johannes.thumshirn@wdc.com


Signed-off-by: Jens Axboe <axboe@kernel.dk>

The drbd code only adds a single page to a newly created bio. So use
__bio_add_page() to add the page which is guaranteed to succeed in this
case.

This brings us closer to marking bio_add_page() as __must_check.

Reviewed-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/435007afac14f3766455559059d21843771fae53.1685532726.git.johannes.thumshirn@wdc.com


Signed-off-by: Jens Axboe <axboe@kernel.dk>

The swap code only adds a single page to a newly created bio. So use
__bio_add_page() to add the page which is guaranteed to succeed in this
case.

This brings us closer to marking bio_add_page() as __must_check.

Reviewed-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/5bdafd9de806b2dab92302b30eb7a3a5f10c37d9.1685532726.git.johannes.thumshirn@wdc.com


Signed-off-by: Jens Axboe <axboe@kernel.dk>

Change the old block-based direct-I/O code to use iov_iter_extract_pages()
to pin user pages or leave kernel pages unpinned rather than taking refs
when submitting bios.

This makes use of the preceding patches to not take pins on the zero page
(thereby allowing insertion of zero pages in with pinned pages) and to get
additional pins on pages, allowing an extracted page to be used in multiple
bios without having to re-extract it.

Signed-off-by: David Howells <dhowells@redhat.com>
cc: Christoph Hellwig <hch@infradead.org>
cc: David Hildenbrand <david@redhat.com>
cc: Lorenzo Stoakes <lstoakes@gmail.com>
cc: Andrew Morton <akpm@linux-foundation.org>
cc: Jens Axboe <axboe@kernel.dk>
cc: Al Viro <viro@zeniv.linux.org.uk>
cc: Matthew Wilcox <willy@infradead.org>
cc: Jan Kara <jack@suse.cz>
cc: Jeff Layton <jlayton@kernel.org>
cc: Jason Gunthorpe <jgg@nvidia.com>
cc: Logan Gunthorpe <logang@deltatee.com>
cc: Hillf Danton <hdanton@sina.com>
cc: Christian Brauner <brauner@kernel.org>
cc: Linus Torvalds <torvalds@linux-foundation.org>
cc: linux-fsdevel@vger.kernel.org
cc: linux-block@vger.kernel.org
cc: linux-kernel@vger.kernel.org
cc: linux-mm@kvack.org
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20230526214142.958751-4-dhowells@redhat.com


Signed-off-by: Jens Axboe <axboe@kernel.dk>

Provide a function to get an additional pin on a page that we already have
a pin on.  This will be used in fs/direct-io.c when dispatching multiple
bios to a page we've extracted from a user-backed iter rather than redoing
the extraction.

Signed-off-by: David Howells <dhowells@redhat.com>
cc: Christoph Hellwig <hch@infradead.org>
cc: David Hildenbrand <david@redhat.com>
cc: Lorenzo Stoakes <lstoakes@gmail.com>
cc: Andrew Morton <akpm@linux-foundation.org>
cc: Jens Axboe <axboe@kernel.dk>
cc: Al Viro <viro@zeniv.linux.org.uk>
cc: Matthew Wilcox <willy@infradead.org>
cc: Jan Kara <jack@suse.cz>
cc: Jeff Layton <jlayton@kernel.org>
cc: Jason Gunthorpe <jgg@nvidia.com>
cc: Logan Gunthorpe <logang@deltatee.com>
cc: Hillf Danton <hdanton@sina.com>
cc: Christian Brauner <brauner@kernel.org>
cc: Linus Torvalds <torvalds@linux-foundation.org>
cc: linux-fsdevel@vger.kernel.org
cc: linux-block@vger.kernel.org
cc: linux-kernel@vger.kernel.org
cc: linux-mm@kvack.org
Reviewed-by: Christoph Hellwig <hch@lst.de>
Acked-by: David Hildenbrand <david@redhat.com>
Link: https://lore.kernel.org/r/20230526214142.958751-3-dhowells@redhat.com


Signed-off-by: Jens Axboe <axboe@kernel.dk>

Make pin_user_pages*() leave a ZERO_PAGE unpinned if it extracts a pointer
to it from the page tables and make unpin_user_page*() correspondingly
ignore a ZERO_PAGE when unpinning.  We don't want to risk overrunning a
zero page's refcount as we're only allowed ~2 million pins on it -
something that userspace can conceivably trigger.

Add a pair of functions to test whether a page or a folio is a ZERO_PAGE.

Signed-off-by: David Howells <dhowells@redhat.com>
cc: Christoph Hellwig <hch@infradead.org>
cc: David Hildenbrand <david@redhat.com>
cc: Lorenzo Stoakes <lstoakes@gmail.com>
cc: Andrew Morton <akpm@linux-foundation.org>
cc: Jens Axboe <axboe@kernel.dk>
cc: Al Viro <viro@zeniv.linux.org.uk>
cc: Matthew Wilcox <willy@infradead.org>
cc: Jan Kara <jack@suse.cz>
cc: Jeff Layton <jlayton@kernel.org>
cc: Jason Gunthorpe <jgg@nvidia.com>
cc: Logan Gunthorpe <logang@deltatee.com>
cc: Hillf Danton <hdanton@sina.com>
cc: Christian Brauner <brauner@kernel.org>
cc: Linus Torvalds <torvalds@linux-foundation.org>
cc: linux-fsdevel@vger.kernel.org
cc: linux-block@vger.kernel.org
cc: linux-kernel@vger.kernel.org
cc: linux-mm@kvack.org
Reviewed-by: Lorenzo Stoakes <lstoakes@gmail.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Acked-by: David Hildenbrand <david@redhat.com>
Link: https://lore.kernel.org/r/20230526214142.958751-2-dhowells@redhat.com


Signed-off-by: Jens Axboe <axboe@kernel.dk>

The struct is never modified so it can be const.

Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Link: https://lore.kernel.org/r/20230419-const-partition-v3-4-4e14e48be367@weissschuh.net


Signed-off-by: Jens Axboe <axboe@kernel.dk>

The struct is never modified so it can be const.

Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Link: https://lore.kernel.org/r/20230419-const-partition-v3-3-4e14e48be367@weissschuh.net


Signed-off-by: Jens Axboe <axboe@kernel.dk>

The struct is never modified so it can be const.

Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Link: https://lore.kernel.org/r/20230419-const-partition-v3-2-4e14e48be367@weissschuh.net


Signed-off-by: Jens Axboe <axboe@kernel.dk>

The array is never modified so it can be const.

Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202304191640.SkNk7kVN-lkp@intel.com/


Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Link: https://lore.kernel.org/r/20230419-const-partition-v3-1-4e14e48be367@weissschuh.net


Signed-off-by: Jens Axboe <axboe@kernel.dk>

This will pin pages or leave them unaltered rather than getting a ref on
them as appropriate to the iterator.

The pages need to be pinned for DIO rather than having refs taken on them
to prevent VM copy-on-write from malfunctioning during a concurrent fork()
(the result of the I/O could otherwise end up being visible to/affected by
the child process).

Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: John Hubbard <jhubbard@nvidia.com>
cc: Al Viro <viro@zeniv.linux.org.uk>
cc: Jens Axboe <axboe@kernel.dk>
cc: Jan Kara <jack@suse.cz>
cc: Matthew Wilcox <willy@infradead.org>
cc: Logan Gunthorpe <logang@deltatee.com>
cc: linux-block@vger.kernel.org
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20230522205744.2825689-7-dhowells@redhat.com


Signed-off-by: Jens Axboe <axboe@kernel.dk>