Allow block drivers to configure the following:
* Maximum number of hardware sectors values smaller than
PAGE_SIZE >> SECTOR_SHIFT. For PAGE_SIZE = 4096 this means that values
below 8 become supported.
* A maximum segment size below the page size. This is most useful
for page sizes above 4096 bytes.
The blk_sub_page_segments static branch will be used in later patches to
prevent that performance of block drivers that support segments >=
PAGE_SIZE and max_hw_sectors >= PAGE_SIZE >> SECTOR_SHIFT would be affected.
This patch may change the behavior of existing block drivers from not
working into working. If a block driver calls
blk_queue_max_hw_sectors() or blk_queue_max_segment_size(), this is
usually done to configure the maximum supported limits. An attempt to
configure a limit below what is supported by the block layer causes the
block layer to select a larger value. If that value is not supported by
the block driver, this may cause other data to be transferred than
requested, a kernel crash or other undesirable behavior.
Keeps the ABI stable by taking advantage of hole in struct queue_limits.
Bug: 308663717
Bug: 319125789
Bug: 324152549
Change-Id: I7358f3e16aa0c80a6d345cb7887fbe9276e52912
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
[jyescas@google.com: disable subpage limits in block/blk-sysfs.c
instead block/blk-core.c because the function
blk_free_queue() is not defined in 6.1 kernel]
Signed-off-by: Juan Yescas <jyescas@google.com>
4fd9a46455