Re: [PATCH] genhd must_check warning fix

From: Jeff Garzik
Date: Tue Mar 11 2008 - 23:53:34 EST


Nick Piggin wrote:
On Wednesday 12 March 2008 14:25, Jeff Garzik wrote:
Roland McGrath wrote:
Fixes:

block/genhd.c:361: warning: ignoring return value of âclass_registerâ,
declared with attribute warn_unused_result

Signed-off-by: Roland McGrath <roland@xxxxxxxxxx>
---
block/genhd.c | 4 +++-
1 files changed, 3 insertions(+), 1 deletions(-)

diff --git a/block/genhd.c b/block/genhd.c
index c44527d..00da521 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -360,7 +360,9 @@ static struct kobject *base_probe(dev_t devt, int
*part, void *data)

static int __init genhd_device_init(void)
{
- class_register(&block_class);
+ int error = class_register(&block_class);
+ if (unlikely(error))
+ return error;
bdev_map = kobj_map_init(base_probe, &block_class_lock);
blk_dev_init();
ACK

I was silly and simply tuned out this warning, assuming [wrongly] that
it was difficult to fix like the fs/partitions.c warning.

Shows how "helpful" those warnings are...

I don't see why? If the warning wasn't there, then Roland probably
wouldn't have noticed. So to me it shows that the warning actually
is helpful (without "") in this case.

The point was more that the warnings are so often silly that it teaches the human to tune out the warnings -- even when they turn out to reveal real problems, as in this case.

I've been working quietly, the past several kernels, trying to kill most compiler warnings, so I've been paying close attention to this sort of stuff in general.

Jeff




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