On 13.02.2020 21:11, Darrick J. Wong wrote: > On Thu, Feb 13, 2020 at 10:39:35AM +0300, Kirill Tkhai wrote: >> Support for new modifier of REQ_OP_WRITE_ZEROES command. >> This results in allocation extents in backing file instead >> of actual blocks zeroing. >> >> Signed-off-by: Kirill Tkhai <ktkhai@xxxxxxxxxxxxx> >> Reviewed-by: Bob Liu <bob.liu@xxxxxxxxxx> >> Reviewed-by: Darrick J. Wong <darrick.wong@xxxxxxxxxx> >> --- >> drivers/block/loop.c | 20 +++++++++++++------- >> 1 file changed, 13 insertions(+), 7 deletions(-) >> >> diff --git a/drivers/block/loop.c b/drivers/block/loop.c >> index 739b372a5112..0704167a5aaa 100644 >> --- a/drivers/block/loop.c >> +++ b/drivers/block/loop.c >> @@ -581,6 +581,16 @@ static int lo_rw_aio(struct loop_device *lo, struct loop_cmd *cmd, >> return 0; >> } >> > > Urgh, I meant "copy the comment directly to here", e.g. > > /* > * Convert REQ_OP_WRITE_ZEROES modifiers into fallocate mode > * > * If the caller requires allocation, select that mode. If the caller > * doesn't want deallocation, call zeroout to write zeroes the range. > * Otherwise, punch out the blocks. > */ > > The goal here is to reinforce the notion that FL_ZERO_RANGE is how we > achieve nounmap zeroing... The function is pretty small, and its meaning is easily seen from the name and description. I don't think we have to retell every function code line in a separate sentence, since this distract the attention from really difficult places, which are really need it. Kirill
