Reducing data copy operations for writing data from a network to storage of a cached data storage system by organizing cache blocks as linked lists of data fragments

A storage system comprising a storage controller, a cache memory, and data storage, wherein the storage controller is programmed to respond to a request to access a specified logical block of data in the data storage by accessing a logical block index to determine whether or not the specified logical block of data is in the cache memory, and when the logical block index indicates that the specified logical block of data is in the cache memory, to access the specified logical block of data in the cache memory, and when the logical block index indicates that the specified logical block of data is not in the cache memory, to access the specified logical block of data in the data storage;

• wherein the cache memory contains a list element pool of list elements, and at least some of the list elements in the list element pool are linked in respective lists for a multiplicity of logical blocks of data;
• wherein each list element in the list element pool includes a data slot, a field for a pointer to a next list element in the list element pool, and a field for an indication of how many bytes of data are contained in the data slot;
• and
• wherein the storage controller has a network port for attachment to a data network for communicating data packets with clients in the data network, and the storage controller is programmed to use the list elements as transmit and receive buffers for communicating the data packets with the clients in the data network.

A method of operating a storage system having a storage controller, a cache memory, and data storage for storing logical blocks of data, the storage controller having a network port for attaching the storage controller to a data network for communicating data packets with clients in the data network, the storage controller being programmed to respond to a request to access a specified logical block of data in the data storage by accessing a logical block index to determine whether or not the specified logical block of data is in the cache memory, and when the logical block index indicates that the specified logical block of data is in the cache memory, to access the specified logical block of data in the cache memory, and when the logical block index indicates that the specified logical block of data is not in the cache memory, to access the specified logical block of data in the data storage;

• wherein said method comprises:
• said storage controller maintaining a pool of list elements in the cache memory, linking at least some of the list elements into respective linked lists for a multiplicity of the logical blocks of data stored in the data storage, and storing, in the list elements for each respective linked list for each of the multiplicity of the logical blocks of data stored in the data storage, the data of said each of the multiplicity of the logical blocks of data stored in the data storage;
• and
• said storage controller using the list elements as transmit and receive buffers for communicating the data packets with the clients in the data network.