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Damien Le Moal <dlemoal@kernel.org> says: blk_revalidate_disk_zones() implements checks of the zones of a zoned block device, verifying that the zone size is a power of 2 number of sectors, that all zones (except possibly the last one) have the same size and that zones cover the entire addressing space of the device. While these checks are appropriate to verify that well tested hardware devices have an adequate zone configurations, they lack in certain areas which may result in issues with potentially buggy emulated devices implemented with user drivers such as ublk or tcmu. Specifically, this function does not check if the device driver indicated support for the mandatory zone append writes, that is, if the device max_zone_append_sectors queue limit is set to a non-zero value. Additionally, invalid zones such as a zero length zone with a start sector equal to the device capacity will not be detected and result in out of bounds use of the zone bitmaps prepared with the callback function blk_revalidate_zone_cb(). This series address these issues by modifying the 4 block device drivers that currently support zoned block devices to ensure that they all set a zoned device zone size and max zone append sectors limit before executing blk_revalidate_disk_zones(). With these changes in place, patch 5 improves blk_revalidate_disk_zones() to address the missing checks, relying on the fact that the zone size and zone append limit are normally set when this function is called. Link: https://lore.kernel.org/r/20230703024812.76778-1-dlemoal@kernel.org Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
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.