Overlayed separate dma mapping of adapters

A data storage system comprising:

• at least one data storage device configured to store data;
• a computer processing system comprising at least one computer processor with a common memory structure configured for DMA mapping space for control information and data, said DMA mapping of at least three types:
• type “H” mapping, type “D” mapping, and shared mapping for said control information;
• and
• at least two groups of adapters, said adapters configured to communicate with respect to said common memory structure and configured to have DMA mapping space for control information and data;
• said DMA mapping space of one of said groups of adapters configured for said type “H” mapping and said shared mapping for control information;
• another of said groups of adapters configured to communicate with said at least one data storage device, and said DMA mapping space for said another of said groups of adapters configured for said type “D” mapping and said shared mapping for control information;
• and said type “H” mapping of said one of said groups of adapters and said type “D” mapping of said another of said groups of adapters overlayed in said DMA mapping space for control information of said respective adapters;
• wherein said type “H” mapping of said one of said groups of adapters and said type “D” mapping of said another of said groups of adapters overlayed in said DMA mapping space of said common memory structure.

A computer program for providing DMA mapping configured for a plurality of adapters, said adapters configured to communicate with respect to a computer processor memory structure via DMA and configured to have DMA mapping space for control information and data, said computer program product comprising a computer usable medium embodying a computer readable program when executed on at least one computer processor causes the at least one computer processor to:

• separated said plurality of adapters into at least two groups;
• separate control information DMA mapping of said adapters into at least three types:
• type “H” mapping, type “D” mapping, and shared mapping;
• and
• apply said type “H” mapping and said shared mapping to one of said groups of adapters for said DMA mapping space for control information, and apply said type “D” mapping and said shared mapping to another of said groups of adapters for said DMA mapping space for control information, and overlay said type “H” mapping of said one of said groups of adapters and said type “D” mapping of said another of said groups of adapters in said DMA mapping space for control information of said respective adapters.

A computer program product for mapping DMA mapping space of a plurality of adapters of communication system, said adapters configured to communicate with respect to a computer processor memory structure of said communication system via DMA, said DMA mapping space for control information and data, said computer program product comprising a computer usable medium embodying a computer readable program when executed on at least one computer processor causes the at least one computer processor to:

• initiate an IML of said communication system;
• separate said plurality of adapters into at least two groups;
• separate control information DMA mapping of said computer processor memory structure for said adapters into at least three types:
• type “H” mapping, type “D” mapping, and shared mapping;
• allocate DMA memory space of said DMA mapping space to each of said plurality of adapters;
• and
• apply said type “H” mapping and said shared mapping to one of said groups of adapters for said DMA mapping space for control information, and apply said type “D” mapping and said shared mapping to another of said groups of adapters for said DMA mapping space for control information, and overlay said type “H” mapping of said one of said groups of adapters and said type “D” mapping of said another of said groups of adapters in said DMA mapping space for control information of said respective adapters.