[PATCH v4 3/3] nbd: correct the maximum value for discard sectors

[Wouter Verhelst]

The version of the NBD protocol implemented by the kernel driver
currently has a 32 bit field for length values. As the NBD protocol uses
bytes as a unit of length, length values larger than 2^32 bytes cannot
be expressed.

Update the max_hw_discard_sectors field to match that.

Signed-off-by: Wouter Verhelst <w@xxxxxxx>
Fixes: 268283244c0f ("nbd: use the atomic queue limits API in nbd_set_size")
Reviewed-by: Damien Le Moal <dlemoal@xxxxxxxxxx>
Cc: Eric Blake <eblake@xxxxxxxxxx>
---
 drivers/block/nbd.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c
index fdcf0bbedf3b..235ab5f59608 100644
--- a/drivers/block/nbd.c
+++ b/drivers/block/nbd.c
@@ -339,7 +339,7 @@ static int __nbd_set_size(struct nbd_device *nbd, loff_t bytesize,
 
 	lim = queue_limits_start_update(nbd->disk->queue);
 	if (nbd->config->flags & NBD_FLAG_SEND_TRIM)
-		lim.max_hw_discard_sectors = UINT_MAX;
+		lim.max_hw_discard_sectors = UINT_MAX >> SECTOR_SHIFT;
 	else
 		lim.max_hw_discard_sectors = 0;
 	if (!(nbd->config->flags & NBD_FLAG_SEND_FLUSH)) {
-- 
2.43.0