From: "wanghai (M)" <wanghai38@huawei.com>
To: Joe Perches <joe@perches.com>, <dchickles@marvell.com>,
<sburla@marvell.com>, <fmanlunas@marvell.com>,
<davem@davemloft.net>, <kuba@kernel.org>
Cc: <netdev@vger.kernel.org>, <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH net-next] liquidio: Remove unneeded cast from memory allocation
Date: Tue, 28 Jul 2020 21:38:14 +0800 [thread overview]
Message-ID: <2996569e-5e1a-db02-2c78-0ee0d572706d@huawei.com> (raw)
In-Reply-To: <bffcc7d513e186734d224bda6afdd55033b451de.camel@perches.com>
在 2020/7/28 17:11, Joe Perches 写道:
> On Tue, 2020-07-28 at 16:42 +0800, wanghai (M) wrote:
>> 在 2020/7/25 5:29, Joe Perches 写道:
>>> On Fri, 2020-07-24 at 21:00 +0800, Wang Hai wrote:
>>>> Remove casting the values returned by memory allocation function.
>>>>
>>>> Coccinelle emits WARNING:
>>>>
>>>> ./drivers/net/ethernet/cavium/liquidio/octeon_device.c:1155:14-36: WARNING:
>>>> casting value returned by memory allocation function to (struct octeon_dispatch *) is useless.
>>> []
>>>> diff --git a/drivers/net/ethernet/cavium/liquidio/octeon_device.c b/drivers/net/ethernet/cavium/liquidio/octeon_device.c
>>> []
>>>> @@ -1152,8 +1152,7 @@ octeon_register_dispatch_fn(struct octeon_device *oct,
>>>>
>>>> dev_dbg(&oct->pci_dev->dev,
>>>> "Adding opcode to dispatch list linked list\n");
>>>> - dispatch = (struct octeon_dispatch *)
>>>> - vmalloc(sizeof(struct octeon_dispatch));
>>>> + dispatch = vmalloc(sizeof(struct octeon_dispatch));
>>> More the question is why this is vmalloc at all
>>> as the structure size is very small.
>>>
>>> Likely this should just be kmalloc.
>>>
>>>
>> Thanks for your advice. It is indeed best to use kmalloc here.
>>>> if (!dispatch) {
>>>> dev_err(&oct->pci_dev->dev,
>>>> "No memory to add dispatch function\n");
>>> And this dev_err is unnecessary.
>>>
>>>
>> I don't understand why dev_err is not needed here. We can easily know
>> that an error has occurred here through dev_err
> Memory allocation failures without __GFP_NOWARN. already
> do a dump_stack to show the location of the code that
> could not successfully allocate memory.
>
>
Thanks for your explanation. I got it.
Can it be modified like this?
--- a/drivers/net/ethernet/cavium/liquidio/octeon_device.c
+++ b/drivers/net/ethernet/cavium/liquidio/octeon_device.c
@@ -1152,11 +1152,8 @@ octeon_register_dispatch_fn(struct octeon_device
*oct,
dev_dbg(&oct->pci_dev->dev,
"Adding opcode to dispatch list linked list\n");
- dispatch = (struct octeon_dispatch *)
- vmalloc(sizeof(struct octeon_dispatch));
+ dispatch = kmalloc(sizeof(struct octeon_dispatch),
GFP_KERNEL);
if (!dispatch) {
- dev_err(&oct->pci_dev->dev,
- "No memory to add dispatch function\n");
return 1;
}
dispatch->opcode = combined_opcode;
> .
>
next prev parent reply other threads:[~2020-07-28 13:38 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-24 13:00 [PATCH net-next] liquidio: Remove unneeded cast from memory allocation Wang Hai
2020-07-24 21:29 ` Joe Perches
2020-07-28 8:42 ` wanghai (M)
2020-07-28 9:11 ` Joe Perches
2020-07-28 13:38 ` wanghai (M) [this message]
2020-07-28 15:54 ` Joe Perches
2020-07-30 6:19 ` wanghai (M)
2020-07-28 15:39 Derek Chickles
2020-07-28 15:56 ` Joe Perches
2020-07-28 16:32 Derek Chickles
2020-09-01 14:11 YueHaibing
2020-09-01 18:49 ` David Miller
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