On 10/4/22 21:54, Damien Le Moal wrote: > On 10/5/22 12:16, Chaitanya Kulkarni wrote: >> Add a helper function to enable the REQ_OP_WRITE_ZEROES operations >> when null_blk is configured with the non-membacked operations. >> >> Since write-zeroes is a non-trivial I/O operation we need this to >> add a blktest so we can test the non-trivial I/O path from the >> application to the block layer. >> >> Signed-off-by: Chaitanya Kulkarni <kch@xxxxxxxxxx> >> --- >> drivers/block/null_blk/main.c | 13 +++++++++++++ >> drivers/block/null_blk/null_blk.h | 1 + >> 2 files changed, 14 insertions(+) >> >> diff --git a/drivers/block/null_blk/main.c b/drivers/block/null_blk/main.c >> index 1f154f92f4c2..fc3e883f7b84 100644 >> --- a/drivers/block/null_blk/main.c >> +++ b/drivers/block/null_blk/main.c >> @@ -209,6 +209,10 @@ static bool g_discard; >> module_param_named(discard, g_discard, bool, 0444); >> MODULE_PARM_DESC(discard, "Support discard operations (requires memory-backed null_blk device). Default: false"); >> >> +static bool g_write_zeroes; >> +module_param_named(write_zeroes, g_write_zeroes, bool, 0444); >> +MODULE_PARM_DESC(write_zeroes, "Support write-zeores operations. Default: false"); > > Why not make this a number of sectors representing the maximum size of a > write zero command (blk_queue_max_write_zeroes_sectors()) ? That would > allow exercising split write zeros BIOs. > I kept the implementation identical to the g_discard. Perhaps it's time to change it so REQ_OP_DISCARD and REQ_OP_WRITE_ZEROES will have same implementation. I'll add a discard patch to match your suggested write-zeroes behavior. -ck
