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1) Introduce DM_TARGET_ZONED_HM feature flag: The target drivers currently available will not operate correctly if a table target maps onto a host-managed zoned block device. To avoid problems, introduce the new feature flag DM_TARGET_ZONED_HM to allow a target to explicitly state that it supports host-managed zoned block devices. This feature is checked for all targets in a table if any of the table's block devices are host-managed. Note that as host-aware zoned block devices are backward compatible with regular block devices, they can be used by any of the current target types. This new feature is thus restricted to host-managed zoned block devices. 2) Check device area zone alignment: If a target maps to a zoned block device, check that the device area is aligned on zone boundaries to avoid problems with REQ_OP_ZONE_RESET operations (resetting a partially mapped sequential zone would not be possible). This also facilitates the processing of zone report with REQ_OP_ZONE_REPORT bios. 3) Check block devices zone model compatibility When setting the DM device's queue limits, several possibilities exists for zoned block devices: 1) The DM target driver may want to expose a different zone model (e.g. host-managed device emulation or regular block device on top of host-managed zoned block devices) 2) Expose the underlying zone model of the devices as-is To allow both cases, the underlying block device zone model must be set in the target limits in dm_set_device_limits() and the compatibility of all devices checked similarly to the logical block size alignment. For this last check, introduce validate_hardware_zoned_model() to check that all targets of a table have the same zone model and that the zone size of the target devices are equal. Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com> Reviewed-by: Hannes Reinecke <hare@suse.com> Reviewed-by: Bart Van Assche <bart.vanassche@sandisk.com> [Mike Snitzer refactored Damien's original work to simplify the code] Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Linux kernel ============ This file was moved to Documentation/admin-guide/README.rst Please notice that there are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. See Documentation/00-INDEX for a list of what is contained in each file. Please read the Documentation/process/changes.rst file, as it contains the requirements for building and running the kernel, and information about the problems which may result by upgrading your kernel.