linux-kernel - [PATCH v4] fs/buffer: remove the min and max limit checks in __getblk

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Message-ID: <20250626113223.181399-1-p.raghav@samsung.com>
Date: Thu, 26 Jun 2025 13:32:23 +0200
From: Pankaj Raghav <p.raghav@...sung.com>
To: Alexander Viro <viro@...iv.linux.org.uk>,
	Jan Kara <jack@...e.cz>,
	mcgrof@...nel.org,
	Christian Brauner <brauner@...nel.org>
Cc: linux-kernel@...r.kernel.org,
	linux-fsdevel@...r.kernel.org,
	kernel@...kajraghav.com,
	gost.dev@...sung.com,
	Pankaj Raghav <p.raghav@...sung.com>,
	Matthew Wilcox <willy@...radead.org>
Subject: [PATCH v4] fs/buffer: remove the min and max limit checks in __getblk_slow()

All filesystems will already check the max and min value of their block
size during their initialization. __getblk_slow() is a very low-level
function to have these checks. Remove them and only check for logical
block size alignment.

As this check with logical block size alignment might never trigger, add
WARN_ON_ONCE() to the check. As WARN_ON_ONCE() will already print the
stack, remove the call to dump_stack().

Suggested-by: Matthew Wilcox <willy@...radead.org>
Reviewed-by: Jan Kara <jack@...e.cz>
Signed-off-by: Pankaj Raghav <p.raghav@...sung.com>
---
Changes since v3:
- Use WARN_ON_ONCE on the logical block size check and remove the call
  to dump_stack.
- Use IS_ALIGNED() to check for aligned instead of open coding the
  check.

 fs/buffer.c | 11 +++--------
 1 file changed, 3 insertions(+), 8 deletions(-)

diff --git a/fs/buffer.c b/fs/buffer.c
index d61073143127..565fe88773c2 100644
--- a/fs/buffer.c
+++ b/fs/buffer.c
@@ -1122,14 +1122,9 @@ __getblk_slow(struct block_device *bdev, sector_t block,
 {
 	bool blocking = gfpflags_allow_blocking(gfp);
 
-	if (unlikely(size & (bdev_logical_block_size(bdev) - 1) ||
-		     (size < 512 || size > PAGE_SIZE))) {
-		printk(KERN_ERR "getblk(): invalid block size %d requested\n",
-					size);
-		printk(KERN_ERR "logical block size: %d\n",
-					bdev_logical_block_size(bdev));
-
-		dump_stack();
+	if (WARN_ON_ONCE(!IS_ALIGNED(size, bdev_logical_block_size(bdev)))) {
+		printk(KERN_ERR "getblk(): block size %d not aligned to logical block size %d\n",
+		       size, bdev_logical_block_size(bdev));
 		return NULL;
 	}
 

base-commit: b39f7d75dc41b5f5d028192cd5d66cff71179f35
-- 
2.49.0