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Date:   Thu, 31 Mar 2022 19:26:00 +0200
From:   David Sterba <dsterba@suse.cz>
To:     Sweet Tea Dorminy <sweettea-kernel@dorminy.me>
Cc:     Chris Mason <clm@fb.com>, Josef Bacik <josef@toxicpanda.com>,
        David Sterba <dsterba@suse.com>,
        Nick Terrell <terrelln@fb.com>, linux-kernel@vger.kernel.org,
        linux-btrfs@vger.kernel.org, kernel-team@fb.com,
        Nikolay Borisov <nborisov@suse.com>
Subject: Re: [PATCH v3 1/2] btrfs: factor out allocating an array of pages
Message-ID: <20220331172600.GE15609@twin.jikos.cz>
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        Sweet Tea Dorminy <sweettea-kernel@dorminy.me>,
        Chris Mason <clm@fb.com>, Josef Bacik <josef@toxicpanda.com>,
        David Sterba <dsterba@suse.com>, Nick Terrell <terrelln@fb.com>,
        linux-kernel@vger.kernel.org, linux-btrfs@vger.kernel.org,
        kernel-team@fb.com, Nikolay Borisov <nborisov@suse.com>
References: <cover.1648669832.git.sweettea-kernel@dorminy.me>
 <3feb62bb8e605e708a0f839136a7354ec66b7b6b.1648669832.git.sweettea-kernel@dorminy.me>
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On Wed, Mar 30, 2022 at 04:11:22PM -0400, Sweet Tea Dorminy wrote:
> +/**
> + * Populate every slot in a provided array with pages.
> + *
> + * @nr_pages:	the number of pages to request
> + * @page_array: the array to fill with pages; any existing non-null entries in
> + * 		the array will be skipped
> + *
> + * Return: 0 if all pages were able to be allocated; -ENOMEM otherwise, and the
> + * caller is responsible for freeing all non-null page pointers in the array.
> + */
> +int btrfs_alloc_page_array(unsigned long nr_pages, struct page **page_array)

I've switched nr_pages to 'unsigned int', that's what all callers use
and I don't see a reason for long.

> +{
> +	int i;
> +
> +	for (i = 0; i < nr_pages; i++) {
> +		struct page *page;
> +
> +		if (page_array[i])
> +			continue;
> +		page = alloc_page(GFP_NOFS);
> +		if (!page)
> +			return -ENOMEM;
> +		page_array[i] = page;
> +	}
> +	return 0;
> +}