linux-kernel - Re: [PATCH 4/5] block: turn bio_kmalloc into a simple kmalloc wrapper

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Date:   Fri, 1 Apr 2022 06:57:13 +0200
From:   Christoph Hellwig <hch@....de>
To:     Marek Szyprowski <m.szyprowski@...sung.com>
Cc:     Christoph Hellwig <hch@....de>, Jens Axboe <axboe@...nel.dk>,
        Coly Li <colyli@...e.de>, Mike Snitzer <snitzer@...hat.com>,
        Song Liu <song@...nel.org>,
        "Martin K. Petersen" <martin.petersen@...cle.com>,
        Josef Bacik <josef@...icpanda.com>,
        David Sterba <dsterba@...e.com>,
        Phillip Lougher <phillip@...ashfs.org.uk>,
        linux-block@...r.kernel.org, dm-devel@...hat.com,
        linux-kernel@...r.kernel.org, linux-bcache@...r.kernel.org,
        linux-raid@...r.kernel.org, target-devel@...r.kernel.org,
        linux-btrfs@...r.kernel.org
Subject: Re: [PATCH 4/5] block: turn bio_kmalloc into a simple kmalloc
 wrapper

On Thu, Mar 31, 2022 at 11:18:03PM +0200, Marek Szyprowski wrote:
> Hi Christoph,
> 
> On 08.03.2022 07:15, Christoph Hellwig wrote:
> > Remove the magic autofree semantics and require the callers to explicitly
> > call bio_init to initialize the bio.
> >
> > This allows bio_free to catch accidental bio_put calls on bio_init()ed
> > bios as well.
> >
> > Signed-off-by: Christoph Hellwig <hch@....de>
> 
> This patch, which landed in today's next-20220331 as commit 57c47b42f454 
> ("block: turn bio_kmalloc into a simple kmalloc wrapper"), breaks badly 
> all my test systems, which use squashfs initrd:

In addition to the revert, this is the patch I had already queued up:

diff --git a/fs/squashfs/block.c b/fs/squashfs/block.c
index 930eb530fa622..fed99bb3df3be 100644
--- a/fs/squashfs/block.c
+++ b/fs/squashfs/block.c
@@ -72,6 +72,13 @@ static int copy_bio_to_actor(struct bio *bio,
 	return copied_bytes;
 }
 
+static void squashfs_bio_free(struct bio *bio)
+{
+	bio_free_pages(bio);
+	bio_uninit(bio);
+	kfree(bio);
+}
+
 static int squashfs_bio_read(struct super_block *sb, u64 index, int length,
 			     struct bio **biop, int *block_offset)
 {
@@ -118,9 +125,7 @@ static int squashfs_bio_read(struct super_block *sb, u64 index, int length,
 	return 0;
 
 out_free_bio:
-	bio_free_pages(bio);
-	bio_uninit(bio);
-	kfree(bio);
+	squashfs_bio_free(bio);
 	return error;
 }
 
@@ -183,8 +188,7 @@ int squashfs_read_data(struct super_block *sb, u64 index, int length,
 			data = bvec_virt(bvec);
 			length |= data[0] << 8;
 		}
-		bio_free_pages(bio);
-		bio_put(bio);
+		squashfs_bio_free(bio);
 
 		compressed = SQUASHFS_COMPRESSED(length);
 		length = SQUASHFS_COMPRESSED_SIZE(length);
@@ -217,8 +221,7 @@ int squashfs_read_data(struct super_block *sb, u64 index, int length,
 	}
 
 out_free_bio:
-	bio_free_pages(bio);
-	bio_put(bio);
+	squashfs_bio_free(bio);
 out:
 	if (res < 0) {
 		ERROR("Failed to read block 0x%llx: %d\n", index, res);