On 14-07-13 10:35 AM, Martin K. Petersen wrote:
"Christoph" == Christoph Hellwig <hch@xxxxxx> writes:
Christoph> Simplify handling of discard requests by setting up the
Christoph> command directly instead of initializing request fields and
Christoph> then calling scsi_setup_blk_pc_cmnd to propagate the
Christoph> information into the command.
Would be nice to add a comment similar to the WRITE SAME one. Something
like:
/*
* Initially __data_len is set to the amount of data that needs to be
* transferred to the target. This amount depends on whether WRITE SAME
* or UNMAP is being used. After the scatterlist has been mapped by
* scsi_init_io() we set __data_len to the size of the area to be
* discarded on disk. This allows us to report completion on the full
* amount of blocks described by the request.
*/
Reviewed-by: Martin K. Petersen <martin.petersen@xxxxxxxxxx>
To make things clearer when referring to the WRITE SAME command
I would suggest "WRITE SAME(unmap)" for the case when its UNMAP
field is 1 (as I assume it is in this case).
Doug Gilbert
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