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Handling checks of ZBC device capacity using the max_lba field of the REPORT ZONES command reply for disks with rc_basis == 0 can be done using the same report zones command reply used to check the "same" field. Avoid executing a report zones command solely to check the disk capacity by merging sd_zbc_check_capacity() into sd_zbc_check_zone_size() and renaming that function to sd_zbc_check_zones(). This removes a costly execution of a full report zones command and so reduces device scan duration at boot time as well as the duration of disk revalidate calls. Furthermore, setting the partial report bit in the REPORT ZONES command cdb can significantly reduce this command execution time as the device does not have to count and report the total number of zones that could be reported assuming a large enough reply buffer. A non-partial zone report is necessary only for the first execution of report zones used to check the same field value (to ensure that this value applies to all zones of the disk). All other calls to sd_zbc_report_zones() can use a partial report to reduce execution time. Using a 14 TB ZBC disk, these simple changes reduce device scan time at boot from about 3.5s down to about 900ms. Disk revalidate times are also reduced from about 450ms down to 230ms. Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Hannes Reinecke <hare@suse.com> Acked-by: Martin K. Petersen <martin.petersen@oracle.com> Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
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.