nvme: add support for the Write Zeroes command
Allow write zeroes operations (REQ_OP_WRITE_ZEROES) on the block device, if the device supports an optional command bit set for write zeroes. Add support to setup write zeroes command. Set maximum possible write zeroes sectors in one write zeroes command according to nvme write zeroes command definition. This patch was posted as a part of block-write-zeroes support implementation (https://patchwork.kernel.org/patch/9454859/), but did not make into mainline kernel as it got reverted due to failure on the Linus's machine. In this patch in order to be more cautious, we use NVMe controller's maximum hardware sector size which is calculated based on the controller's MDTS (Maximum Data Transfer Size) field to calculate the maximum sectors for the write zeroes request. Signed-off-by:Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com> Reviewed-by:
Martin K. Petersen <martin.petersen@oracle.com> [folded a fix from Keith Busch to properly respect NVME_QUIRK_DEALLOCATE_ZEROES] Signed-off-by:
Christoph Hellwig <hch@lst.de>
parent
bb94aea1