For zoned block devices using zone write plugging, an rcu_barrier() call is needed in disk_free_zone_resources() to synchronize freeing of zone write plugs and the destrution of the mempool used to allocate the plugs. The barrier call does slow down a little teardown of zoned block devices but should not affect teardown of regular block devices or zoned block devices that do not use zone write plugging (e.g. zoned DM devices that do not require zone append emulation). Modify disk_free_zone_resources() to return early if we do not have a mempool to start with, that is, if the device does not use zone write plugging. This avoids the costly rcu_barrier() and speeds up disk teardown. Reported-by: Mikulas Patocka <mpatocka@redhat.com> Fixes: dd291d77cc90 ("block: Introduce zone write plugging") Signed-off-by: Damien Le Moal <dlemoal@kernel.org> Reviewed-by: Christoph Hellwig <hch@lst.de> Tested-by: Mikulas Patocka <mpatocka@redhat.com> Reviewed-by: Niklas Cassel <cassel@kernel.org> Link: https://lore.kernel.org/r/20240607002126.104227-1-dlemoal@kernel.org 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 reStructuredText 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.
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