linux-kernel - Re: [RFC PATCH v11 12/29] KVM: Add KVM_CREATE_GUEST_MEMFD ioctl() for guest-specific backing memory

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Message-ID: <20230803191554.205599-1-afranji@google.com>
Date:   Thu,  3 Aug 2023 19:15:54 +0000
From:   Ryan Afranji <afranji@...gle.com>
To:     seanjc@...gle.com
Cc:     ackerleytng@...gle.com, akpm@...ux-foundation.org,
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Subject: Re: [RFC PATCH v11 12/29] KVM: Add KVM_CREATE_GUEST_MEMFD ioctl() for
 guest-specific backing memory

> +static struct folio *kvm_gmem_get_folio(struct file *file, pgoff_t index)
> +{
> +	struct folio *folio;
> +
> +	/* TODO: Support huge pages. */
> +	folio = filemap_grab_folio(file->f_mapping, index);
> +	if (!folio)
> +		return NULL;

In Linux 6.4, filemap_grab_folio() may also return an error value.
Instead of just checking for NULL, "IS_ERR_OR_NULL(folio)" will be needed.