target/iblock: Add WRITE_SAME w/ UNMAP=0 emulation support
This patch adds support for emulation of WRITE_SAME w/ UNMAP=0 within
iblock_execute_write_same() backend code.
The emulation uses a bio_add_page() call for each sector, and by default
enforces a limit of max_write_same_len=0xFFFF (65536) sectors following
what scsi_debug reports per default for MAXIMUM WRITE SAME LENGTH.
It also sets max_write_same_len to the operational default at setup ->
iblock_configure_device() time.
(hch: Move unmap logic into iblock_execute_write_same_unmap + add
check for single sector SGLs in iblock_execute_write_same)
(mkp: Update comment for 0xFFFF magic constant)
(nab: drop left-over max_write_same_len check in iblock_execute_write_same)
Cc: Christoph Hellwig <hch@lst.de>
Cc: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
1 file changed