From: Andrew Morton <akpm@linux-foundation.org>
To: Souptick Joarder <jrdr.linux@gmail.com>
Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] mm/gup.c: Handle error at earliest for incorrect nr_pages value
Date: Thu, 30 Apr 2020 14:23:11 -0700 [thread overview]
Message-ID: <20200430142311.091b82235141ca47b9c6475a@linux-foundation.org> (raw)
In-Reply-To: <1588277518-21425-1-git-send-email-jrdr.linux@gmail.com>
On Fri, 1 May 2020 01:41:58 +0530 Souptick Joarder <jrdr.linux@gmail.com> wrote:
> As per documentation, pin_user_pages_fast() & get_user_pages_fast()
> will return 0, if nr_pages <= 0. But this can be figure out only after
> going inside the internal_get_user_pages_fast().
>
> This can be handled early. Adding a check for the same.
Calling get_user_pages() for (nrpages <= 0) is a nonsensical thing to
do so it isn't a thing we should care to optimize. Adding new checks
will actually slow down the use cases which we *do* care about. And it
adds more code.
next prev parent reply other threads:[~2020-04-30 21:23 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-04-30 20:11 Souptick Joarder
2020-04-30 21:23 ` Andrew Morton [this message]
2020-04-30 21:24 ` Ira Weiny
2020-05-01 21:16 ` Souptick Joarder
2020-05-01 21:33 ` John Hubbard
2020-05-01 21:46 ` Souptick Joarder
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