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fs/partition/check.c: fix return value warning

RFC In review Oliver Pinter 4 participants 5 messages Aug 2, 2008 – Aug 3, 2008

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Oliver Pinter

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#0 lore raw

RFC 1/1 fs/partition/check.c: fix return value warning

Quoted 1 line

From d805dda412346225a50af2d399d958a4bc676c38 Mon Sep 17 00:00:00 2001

From: Abdel Benamrouche <[email protected]>
Date: Fri, 25 Jul 2008 01:48:25 -0700
Subject: [PATCH] fs/partition/check.c: fix return value warning

[ Upstream commit d805dda412346225a50af2d399d958a4bc676c38 ]

fs/partitions/check.c:381: warning: ignoring return value of ___device_add___,
declared with attribute warn_unused_result

[[email protected]: multiple-return-statements-per-function are evil]
Signed-off-by Abdel Benamrouche <[email protected]>
Cc Jens Axboe <[email protected]>
Signed-off-by Andrew Morton <[email protected]>
Signed-off-by Linus Torvalds <[email protected]>
CC Oliver Pinter <[email protected]>
fs/partitions/check.c +22 -6
index efef715..2e6413f 100644
@@ -344,18 +344,18 @@ static ssize_t whole_disk_show(struct device *dev,
 static DEVICE_ATTR(whole_disk, S_IRUSR | S_IRGRP | S_IROTH,
 		   whole_disk_show, NULL);
 
-void add_partition(struct gendisk *disk, int part, sector_t start, sector_t len, int flags)
+int add_partition(struct gendisk *disk, int part, sector_t start, sector_t len, int flags)
 {
 	struct hd_struct *p;
 	int err;
 
 	p = kzalloc(sizeof(*p), GFP_KERNEL);
 	if (!p)
-		return;
+		return -ENOMEM;
 
 	if (!init_part_stats(p)) {
-		kfree(p);
-		return;
+		err = -ENOMEM;
+		goto out0;
 	}
 	p->start_sect = start;
 	p->nr_sects = len;

@@ -378,15 +378,31 @@ void add_partition(struct gendisk *disk, int part, sector_t start, sector_t len,
 
 	/* delay uevent until 'holders' subdir is created */
 	p->dev.uevent_suppress = 1;
-	device_add(&p->dev);
+	err = device_add(&p->dev);
+	if (err)
+		goto out1;
 	partition_sysfs_add_subdir(p);
 	p->dev.uevent_suppress = 0;
-	if (flags & ADDPART_FLAG_WHOLEDISK)
+	if (flags & ADDPART_FLAG_WHOLEDISK) {
 		err = device_create_file(&p->dev, &dev_attr_whole_disk);
+		if (err)
+			goto out2;
+	}
 
 	/* suppress uevent if the disk supresses it */
 	if (!disk->dev.uevent_suppress)
 		kobject_uevent(&p->dev.kobj, KOBJ_ADD);
+
+	return 0;
+
+out2:
+	device_del(&p->dev);
+out1:
+	put_device(&p->dev);
+	free_part_stats(p);
+out0:
+	kfree(p);
+	return err;
 }
 
 /* Not exported, helper to add_disk(). */
include/linux/genhd.h +1 -1
index e878741..118216f 100644
@@ -541,7 +541,7 @@ extern dev_t blk_lookup_devt(const char *name, int part);
 extern char *disk_name (struct gendisk *hd, int part, char *buf);
 
 extern int rescan_partitions(struct gendisk *disk, struct block_device *bdev);
-extern void add_partition(struct gendisk *, int, sector_t, sector_t, int);
+extern int __must_check add_partition(struct gendisk *, int, sector_t, sector_t, int);
 extern void delete_partition(struct gendisk *, int);
 extern void printk_all_partitions(void);
#1 lore raw
Quoted 4 lines · Oliver Pinter

Subject: [PATCH] fs/partition/check.c: fix return value warning

[ Upstream commit d805dda412346225a50af2d399d958a4bc676c38 ]

Why are these being submitted for stable kernels?

Oliver - stable kernels should _not_ get trivial fixes that don't actually have any problems associated with them.

Every patch in a stable kernel has a downside. It had better have a big upside too. These don't.

Please don't just send patches to the stable team because they "look fine". They should be real bugs, with real consequences. And no, a compiler warning is not a real consequence.

Linus

#2 lore raw
Quoted 3 lines · Linus Torvalds

Please don't just send patches to the stable team because they "look fine". They should be real bugs, with real consequences. And no, a compiler warning is not a real consequence.

BTW, before Oliver does the mistake, I'd suggest never forwarding network patches to stable either as Davem already maintains his own -stable queue ;-)

Willy

author
#3 lore raw

Willy, this good to know ...

and I think, this patch fixed a small leak:

+
+out2:
+ device_del(&p->dev);
+out1:
+ put_device(&p->dev);
+ free_part_stats(p);
+out0:
+ kfree(p);
+ return err;

Quoted 12 lines · Willy Tarreau
Quoted 3 lines · Linus Torvalds

Please don't just send patches to the stable team because they "look fine". They should be real bugs, with real consequences. And no, a compiler warning is not a real consequence.

BTW, before Oliver does the mistake, I'd suggest never forwarding network patches to stable either as Davem already maintains his own -stable queue ;-)

Willy

Signature · 2 lines
Thanks,
Oliver
#4 lore raw
Quoted 15 lines · Oliver Pinter

Willy, this good to know ...

and I think, this patch fixed a small leak:

fs/partitions/check.c +9 -0
+
+out2:
+       device_del(&p->dev);
+out1:
+       put_device(&p->dev);
+       free_part_stats(p);
+out0:
+       kfree(p);
+       return err;
Quoted 5 lines
Quoted 4 lines · Willy Tarreau
Quoted 3 lines · Linus Torvalds

Please don't just send patches to the stable team because they "look fine". They should be real bugs, with real consequences. And no, a compiler warning is not a real consequence.

Oliver, check under which circumstances the leak happens, and which problems the leak causes for the system.

Newly added failure handling paths, which by nature are insufficiently runtime-tested, need to be well considered before they are taken over into -stable even if the code looks OK. I.e. they need to address bugs which are known to cause problems of certain severity in practice.

Signature · 3 lines
Stefan Richter
-=====-==--- =--- ---==
http://arcgraph.de/sr/