linux-kernel - [PATCH v2 3/3] nbd: correct the maximum value for discard sectors

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Message-ID: <20240806133058.268058-3-w@uter.be>
Date: Tue,  6 Aug 2024 15:30:56 +0200
From: Wouter Verhelst <w@...r.be>
To: Josef Bacik <josef@...icpanda.com>,
	Jens Axboe <axboe@...nel.dk>
Cc: Wouter Verhelst <w@...r.be>,
	linux-block@...r.kernel.org,
	nbd@...er.debian.org,
	linux-kernel@...r.kernel.org
Subject: [PATCH v2 3/3] nbd: correct the maximum value for discard sectors

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@...r.be>
Fixes: 268283244c0f018dec8bf4a9c69ce50684561f46
---
 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 20e9f9fdeaae..1457f0c8a4a4 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 / blksize;
 	else
 		lim.max_hw_discard_sectors = 0;
 	if (!(nbd->config->flags & NBD_FLAG_SEND_FLUSH)) {
-- 
2.43.0