From: Christoph Hellwig Date: Tue, 15 Apr 2014 12:38:31 +0000 (+0200) Subject: scatterlist: allow chaining to preallocated chunks X-Git-Tag: cleanup-for-v3.18~102^2~82 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=c53c6d6a68b13b1dff2892551b56cfdc07887d9e;p=pandora-kernel.git scatterlist: allow chaining to preallocated chunks Blk-mq drivers usually preallocate their S/G list as part of the request, but if we want to support the very large S/G lists currently supported by the SCSI code that would tie up a lot of memory in the preallocated request pool. Add support to the scatterlist code so that it can initialize a S/G list that uses a preallocated first chunks and dynamically allocated additional chunks. That way the scsi-mq code can preallocate a first page worth of S/G entries as part of the request, and dynamically extend the S/G list when needed. Signed-off-by: Christoph Hellwig Reviewed-by: Martin K. Petersen Reviewed-by: Hannes Reinecke Reviewed-by: Webb Scales Acked-by: Jens Axboe Tested-by: Bart Van Assche Tested-by: Robert Elliott --- Reading git-diff-tree failed