Re: [PATCH v2 1/2] block: make __register_blkdev() return an error

On Tue, Sep 28, 2021 at 10:57:18AM +1000, Finn Thain wrote:

On Mon, 27 Sep 2021, Luis Chamberlain wrote:

quoted

diff --git a/drivers/block/ataflop.c b/drivers/block/ataflop.c
index 5dc9b3d32415..be0627345b21 100644
--- a/drivers/block/ataflop.c
+++ b/drivers/block/ataflop.c

@@ -1989,24 +1989,34 @@ static int ataflop_alloc_disk(unsigned int drive, unsigned int type)
 
 static DEFINE_MUTEX(ataflop_probe_lock);
 
-static void ataflop_probe(dev_t dev)
+static int ataflop_probe(dev_t dev)
 {
 	int drive = MINOR(dev) & 3;
 	int type  = MINOR(dev) >> 2;
+	int err = 0;
 
 	if (type)
 		type--;
 
-	if (drive >= FD_MAX_UNITS || type >= NUM_DISK_MINORS)
-		return;
+	if (drive >= FD_MAX_UNITS || type >= NUM_DISK_MINORS) {
+		err = -EINVAL;
+		goto out;
+	}
+
 	mutex_lock(&ataflop_probe_lock);
 	if (!unit[drive].disk[type]) {
-		if (ataflop_alloc_disk(drive, type) == 0) {
-			add_disk(unit[drive].disk[type]);
+		err = ataflop_alloc_disk(drive, type);
+		if (err == 0) {
+			err = add_disk(unit[drive].disk[type]);
+			if (err)
+				blk_cleanup_disk(unit[drive].disk[type]);
 			unit[drive].registered[type] = true;
 		}
 	}
 	mutex_unlock(&ataflop_probe_lock);
+
+out:
+	return err;
 }
 
 static void atari_cleanup_floppy_disk(struct atari_floppy_struct *fs)

I think the change to ataflop_probe() would be more clear without adding 
an 'out' label, like your change to floppy.c:

Good point! Fixed.

quoted

diff --git a/drivers/block/floppy.c b/drivers/block/floppy.c
index 0434f28742e7..95a1c8ef62f7 100644
--- a/drivers/block/floppy.c
+++ b/drivers/block/floppy.c

@@ -4517,21 +4517,27 @@ static int floppy_alloc_disk(unsigned int drive, unsigned int type)
 
 static DEFINE_MUTEX(floppy_probe_lock);
 
-static void floppy_probe(dev_t dev)
+static int floppy_probe(dev_t dev)
 {
 	unsigned int drive = (MINOR(dev) & 3) | ((MINOR(dev) & 0x80) >> 5);
 	unsigned int type = (MINOR(dev) >> 2) & 0x1f;
+	int err = 0;
 
 	if (drive >= N_DRIVE || !floppy_available(drive) ||
 	    type >= ARRAY_SIZE(floppy_type))
-		return;
+		return -EINVAL;
 
 	mutex_lock(&floppy_probe_lock);
 	if (!disks[drive][type]) {
-		if (floppy_alloc_disk(drive, type) == 0)
-			add_disk(disks[drive][type]);
+		if (floppy_alloc_disk(drive, type) == 0) {
+			err = add_disk(disks[drive][type]);
+			if (err)
+				blk_cleanup_disk(disks[drive][type]);
+		}
 	}
 	mutex_unlock(&floppy_probe_lock);
+
+	return err;
 }
 
 static int __init do_floppy_init(void)

In floppy_probe(), I think you should return the potential error result 
from floppy_alloc_disk(), like you did in ataflop.c.

Indeed, thanks, fixed.

  Luis