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a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1674226696; bh=x+sLxMcKIASeuBMNVbqNYZxs6SZIaU9oe3IMGp+db8A=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=SFLwGwG4qE2oyi+7mIUsp+hu4HQDXOzLTgx8k4loxFVxZt0wcUR4LxhDJGlRvf1SR WLm8YZS36R32OLKxI8xKObTaSAZw1xTCuCGJ1rwj2ozSHFBsLVIKx1ptLWXO9SCc1j V2aTTTKkB0sFv/EK1TgopzF8lHs3TuM5QPJDzZ12440SLrKTjjBkvzreUuWOdyTxVo krqHLDjticHk5ckzM3fKRNwoibKFjirLUpUp90fZcDqc+c5XFMAMuuuVjZMQNOaid8 IUVTJivQnfBkHQGi5Y3fkz2T4U2khqMTCYqAwtNi4hNWeo9jlt6/omA9b0R461zNhH UomQgUFUTLBrA== Date: Fri, 20 Jan 2023 16:58:05 +0200 From: Mike Rapoport To: Jason Gunthorpe Cc: Alistair Popple , John Hubbard , linux-mm@kvack.org Subject: Re: [PATCH 5/8] mm/gup: add FOLL_UNLOCK Message-ID: References: <0-v1-dd94f8f0d5ad+716-gup_tidy_jgg@nvidia.com> <5-v1-dd94f8f0d5ad+716-gup_tidy_jgg@nvidia.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Rspam-User: X-Rspamd-Queue-Id: 5656780015 X-Rspamd-Server: rspam01 X-Stat-Signature: 97jtmtpfzbdkce3dk4q8pznecx7mhe99 X-HE-Tag: 1674226699-331997 X-HE-Meta: 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 kWM3aWIQ 8n3zkHwWNW61l/bpxEveeKga9cbzHrhh+GtTit3Nj74RuOo9j3U5ADPy5GE8luLBUj/Y/y2tyG6kMVJjz6SGMopxeSoVf7BOw8/9tM8qW2XcJtnKOcfNOLvFo04H1ZAvQQG3uoL3WJ3JTqpL3Abb9xqegc5lrQEzSPAMccwXjgjqH6bjbrHKjEbE7Bqz7tZHdP6q22Nncb0zn2vHTDFkmPuNe162FxGgq1suiZ4nATLrvVl1E2RPOTvMsy5HY8enCT+J0kAh87e5soU2Wto7eMhHqYneJ81vkZb1dUDne92tt18OHqEKM+XPohual/8hpFjWh6V/Wb8dsVKRrZhltBHGVxTKE1m4ElZG8nCI8Nyh8qdHZSlzbc+y3cQ== X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Fri, Jan 20, 2023 at 09:45:02AM -0400, Jason Gunthorpe wrote: > On Thu, Jan 19, 2023 at 01:18:08PM +0200, Mike Rapoport wrote: > > On Tue, Jan 17, 2023 at 11:58:36AM -0400, Jason Gunthorpe wrote: > > > Setting FOLL_UNLOCK allows GUP to lock/unlock the mmap lock on its own. It > > > is a more explicit replacement for locked != NULL. This clears the way for > > > passing in locked = 1, without intending that the lock can be unlocked. > > > > > > Set the flag in all cases where it is used, eg locked is present in the > > > external interface or locked is used internally with locked = 0. > > > > > > Signed-off-by: Jason Gunthorpe > > > --- > > > include/linux/mm.h | 1 + > > > mm/gup.c | 31 +++++++++++++++++++------------ > > > 2 files changed, 20 insertions(+), 12 deletions(-) > > > > > > diff --git a/include/linux/mm.h b/include/linux/mm.h > > > index f3f196e4d66d6f..7496a5c8acede1 100644 > > > --- a/include/linux/mm.h > > > +++ b/include/linux/mm.h > > > @@ -3089,6 +3089,7 @@ struct page *follow_page(struct vm_area_struct *vma, unsigned long address, > > > #define FOLL_FAST_ONLY 0x80000 /* gup_fast: prevent fall-back to slow gup */ > > > #define FOLL_PCI_P2PDMA 0x100000 /* allow returning PCI P2PDMA pages */ > > > #define FOLL_INTERRUPTIBLE 0x200000 /* allow interrupts from generic signals */ > > > +#define FOLL_UNLOCK 0x400000 /* allow unlocking the mmap lock */ > > > > Please add a comment that this is an internal flag. > > #define FOLL_UNLOCK 0x400000 /* allow unlocking the mmap lock (internal only) */ > > OK? Yep. > Jason -- Sincerely yours, Mike.