Messages in this thread | | | Subject | Re: [PATCH v2] orangefs: convert get_user_pages() --> pin_user_pages() | From | John Hubbard <> | Date | Sat, 30 May 2020 00:39:22 -0700 |
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On 2020-05-22 20:59, John Hubbard wrote: > This code was using get_user_pages*(), in a "Case 1" scenario > (Direct IO), using the categorization from [1]. That means that it's > time to convert the get_user_pages*() + put_page() calls to > pin_user_pages*() + unpin_user_pages() calls. > > There is some helpful background in [2]: basically, this is a small > part of fixing a long-standing disconnect between pinning pages, and > file systems' use of those pages. > > [1] Documentation/core-api/pin_user_pages.rst > > [2] "Explicit pinning of user-space pages": > https://lwn.net/Articles/807108/ > > Cc: Mike Marshall <hubcap@omnibond.com> > Cc: Martin Brandenburg <martin@omnibond.com> > Cc: devel@lists.orangefs.org > Cc: linux-fsdevel@vger.kernel.org > Signed-off-by: John Hubbard <jhubbard@nvidia.com> > --- > > Hi, > > Note that I have only compile-tested this patch, although that does > also include cross-compiling for a few other arches.
An update on the run-time testing: Just now, I got basic orangefs tests running in xfstests, with this patch applied, and it all looks normal.
thanks, -- John Hubbard NVIDIA
> > Changes since v1 [3]: correct the commit description, so that > it refers to "Case 1" instead of "Case 2". > > > [3] https://lore.kernel.org/r/20200518060139.2828423-1-jhubbard@nvidia.com > > thanks, > John Hubbard > NVIDIA > > fs/orangefs/orangefs-bufmap.c | 9 +++------ > 1 file changed, 3 insertions(+), 6 deletions(-) > > diff --git a/fs/orangefs/orangefs-bufmap.c b/fs/orangefs/orangefs-bufmap.c > index 2bb916d68576..538e839590ef 100644 > --- a/fs/orangefs/orangefs-bufmap.c > +++ b/fs/orangefs/orangefs-bufmap.c > @@ -168,10 +168,7 @@ static DEFINE_SPINLOCK(orangefs_bufmap_lock); > static void > orangefs_bufmap_unmap(struct orangefs_bufmap *bufmap) > { > - int i; > - > - for (i = 0; i < bufmap->page_count; i++) > - put_page(bufmap->page_array[i]); > + unpin_user_pages(bufmap->page_array, bufmap->page_count); > } > > static void > @@ -268,7 +265,7 @@ orangefs_bufmap_map(struct orangefs_bufmap *bufmap, > int offset = 0, ret, i; > > /* map the pages */ > - ret = get_user_pages_fast((unsigned long)user_desc->ptr, > + ret = pin_user_pages_fast((unsigned long)user_desc->ptr, > bufmap->page_count, FOLL_WRITE, bufmap->page_array); > > if (ret < 0) > @@ -280,7 +277,7 @@ orangefs_bufmap_map(struct orangefs_bufmap *bufmap, > > for (i = 0; i < ret; i++) { > SetPageError(bufmap->page_array[i]); > - put_page(bufmap->page_array[i]); > + unpin_user_page(bufmap->page_array[i]); > } > return -ENOMEM; > } >
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