linux-kernel - [PATCH v3 1/2] block: decouple secure erase size limit from discard size limit

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Message-Id: <20260203102903.2953660-2-ziniu.wang_1@nxp.com>
Date: Tue,  3 Feb 2026 18:29:02 +0800
From: ziniu.wang_1@....com
To: axboe@...nel.dk,
	ulf.hansson@...aro.org,
	hch@...radead.org
Cc: linux-block@...r.kernel.org,
	linux-mmc@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	imx@...ts.linux.dev
Subject: [PATCH v3 1/2] block: decouple secure erase size limit from discard size limit

From: Luke Wang <ziniu.wang_1@....com>

Secure erase should use max_secure_erase_sectors instead of being limited
by max_discard_sectors. Separate the handling of REQ_OP_SECURE_ERASE from
REQ_OP_DISCARD to allow each operation to use its own size limit.

Signed-off-by: Luke Wang <ziniu.wang_1@....com>
---
 block/blk-merge.c | 21 +++++++++++++++++----
 1 file changed, 17 insertions(+), 4 deletions(-)

diff --git a/block/blk-merge.c b/block/blk-merge.c
index 0eb0aef97197..fcf09325b22e 100644
--- a/block/blk-merge.c
+++ b/block/blk-merge.c
@@ -158,8 +158,9 @@ static struct bio *bio_submit_split(struct bio *bio, int split_sectors)
 	return bio;
 }
 
-struct bio *bio_split_discard(struct bio *bio, const struct queue_limits *lim,
-		unsigned *nsegs)
+static struct bio *__bio_split_discard(struct bio *bio,
+		const struct queue_limits *lim, unsigned *nsegs,
+		unsigned int max_sectors)
 {
 	unsigned int max_discard_sectors, granularity;
 	sector_t tmp;
@@ -169,8 +170,7 @@ struct bio *bio_split_discard(struct bio *bio, const struct queue_limits *lim,
 
 	granularity = max(lim->discard_granularity >> 9, 1U);
 
-	max_discard_sectors =
-		min(lim->max_discard_sectors, bio_allowed_max_sectors(lim));
+	max_discard_sectors = min(max_sectors, bio_allowed_max_sectors(lim));
 	max_discard_sectors -= max_discard_sectors % granularity;
 	if (unlikely(!max_discard_sectors))
 		return bio;
@@ -194,6 +194,19 @@ struct bio *bio_split_discard(struct bio *bio, const struct queue_limits *lim,
 	return bio_submit_split(bio, split_sectors);
 }
 
+struct bio *bio_split_discard(struct bio *bio, const struct queue_limits *lim,
+		unsigned *nsegs)
+{
+	unsigned int max_sectors;
+
+	if (bio_op(bio) == REQ_OP_SECURE_ERASE)
+		max_sectors = lim->max_secure_erase_sectors;
+	else
+		max_sectors = lim->max_discard_sectors;
+
+	return __bio_split_discard(bio, lim, nsegs, max_sectors);
+}
+
 static inline unsigned int blk_boundary_sectors(const struct queue_limits *lim,
 						bool is_atomic)
 {
-- 
2.34.1