linux-kernel - Re: [PATCH 2/3] VMCI: No need to clear memory after a dma_alloc

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Message-ID: <00F97241-10DF-4D3D-9544-105C4E9DC5BB@vmware.com>
Date:   Thu, 17 Feb 2022 07:10:48 +0000
From:   Vishnu Dasa <vdasa@...are.com>
To:     Christophe JAILLET <christophe.jaillet@...adoo.fr>
CC:     Jorgen Hansen <jhansen@...are.com>,
        "arnd@...db.de" <arnd@...db.de>,
        "gregkh@...uxfoundation.org" <gregkh@...uxfoundation.org>,
        "acking@...are.com" <acking@...are.com>,
        "dtor@...are.com" <dtor@...are.com>,
        Pv-drivers <Pv-drivers@...are.com>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "kernel-janitors@...r.kernel.org" <kernel-janitors@...r.kernel.org>
Subject: Re: [PATCH 2/3] VMCI: No need to clear memory after a
 dma_alloc_coherent() call


> On Feb 10, 2022, at 2:27 PM, Christophe JAILLET <christophe.jaillet@...adoo.fr> wrote:
> 
> dma_alloc_coherent() already clear the allocated memory, there is no need
> to explicitly call memset().
> This saves a few cycles and a few lines of code.
> 
> Signed-off-by: Christophe JAILLET <christophe.jaillet@...adoo.fr>
> ---
> drivers/misc/vmw_vmci/vmci_guest.c | 6 ++----
> 1 file changed, 2 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/misc/vmw_vmci/vmci_guest.c b/drivers/misc/vmw_vmci/vmci_guest.c
> index 1a1858742f75..02d4722d8474 100644
> --- a/drivers/misc/vmw_vmci/vmci_guest.c
> +++ b/drivers/misc/vmw_vmci/vmci_guest.c
> @@ -706,13 +706,11 @@ static int vmci_guest_probe_device(struct pci_dev *pdev,
> 		vmci_dev->notification_bitmap = dma_alloc_coherent(
> 			&pdev->dev, PAGE_SIZE, &vmci_dev->notification_base,
> 			GFP_KERNEL);
> -		if (!vmci_dev->notification_bitmap) {
> +		if (!vmci_dev->notification_bitmap)
> 			dev_warn(&pdev->dev,
> 				 "Unable to allocate notification bitmap\n");
> -		} else {
> -			memset(vmci_dev->notification_bitmap, 0, PAGE_SIZE);
> +		else
> 			caps_in_use |= VMCI_CAPS_NOTIFICATIONS;
> -		}
> 	}
> 
> 	if (mmio_base != NULL) {
> -- 
> 2.32.0
> 

Thanks!

Acked-by: Vishnu Dasa <vdasa@...are.com>