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The ncq_sense_buf buffer field of struct ata_port is allocated and used only for devices that support the Command Duration Limits (CDL) feature. However, the cdl buffer of struct ata_device, which is used to cache the command duration limits log page for devices supporting CDL is always allocated as part of struct ata_device, which is wasteful of memory for devices that do not support this feature. Clean this up by defining both buffers as part of the new ata_cdl structure and allocating this structure only for devices that support the CDL feature. This new structure is attached to struct ata_device using the cdl pointer. The functions ata_dev_init_cdl_resources() and ata_dev_cleanup_cdl_resources() are defined to manage this new structure allocation, initialization and freeing when a port is removed or a device disabled. ata_dev_init_cdl_resources() is called from ata_dev_config_cdl() only for devices that support CDL. ata_dev_cleanup_cdl_resources() is called from ata_dev_free_resources() to free the ata_cdl structure when a device is being disabled by EH. Note that the name of the former cdl log buffer of struct ata_device is changed to desc_log_buf to make it clearer that it is a buffer for the limit descriptors log page. This change reduces the size of struct ata_device, thus reducing memory usage for ATA devices that do not support the CDL feature. Signed-off-by: Damien Le Moal <dlemoal@kernel.org> Reviewed-by: Niklas Cassel <cassel@kernel.org>
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.