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path: root/drivers/s390/block/dasd_alias.c
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2008-08-01[S390] dasd: Add support for enhanced VM UIDStefan Weinhuber
When z/VM provides two virtual devices (minidisks) that reside on the same real device, both will receive the configuration data from the real device and thus get the same uid. To fix this problem, z/VM provides an additional configuration data record that allows to distinguish between minidisks. z/VM APAR VM64273 needs be installed so this fix has an effect. Signed-off-by: Stefan Weinhuber <wein@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2008-04-17[S390] Fix a lot of sparse warnings.Heiko Carstens
Most noteable part of this commit is the new local header file entry.h which contains all the function declarations of functions that get only called from asm code or are arch internal. That way we can avoid extern declarations in C files. This is more or less the same that was done for sparc64. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
2008-01-26[S390] dasd: add hyper PAV support to DASD device driver, part 1Stefan Weinhuber
Parallel access volumes (PAV) is a storage server feature, that allows to start multiple channel programs on the same DASD in parallel. It defines alias devices which can be used as alternative paths to the same disk. With the old base PAV support we only needed rudimentary functionality in the DASD device driver. As the mapping between base and alias devices was static, we just had to export an identifier (uid) and could leave the combining of devices to external layers like a device mapper multipath. Now hyper PAV removes the requirement to dedicate alias devices to specific base devices. Instead each alias devices can be combined with multiple base device on a per request basis. This requires full support by the DASD device driver as now each channel program itself has to identify the target base device. The changes to the dasd device driver and the ECKD discipline are: - Separate subchannel device representation (dasd_device) from block device representation (dasd_block). Only base devices are block devices. - Gather information about base and alias devices and possible combinations. - For each request decide which dasd_device should be used (base or alias) and build specific channel program. - Support summary unit checks, which allow the storage server to upgrade / downgrade between base and hyper PAV at runtime (support is mandatory). Signed-off-by: Stefan Weinhuber <wein@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>