Message ID | 20190722043012.22945-2-jhubbard@nvidia.com |
---|---|
State | Not Applicable |
Delegated to: | David Miller |
Headers | show |
Series | put_user_page: new put_user_page_dirty*() helpers | expand |
On Sun, Jul 21, 2019 at 09:30:10PM -0700, john.hubbard@gmail.com wrote: > for (i = 0; i < vsg->num_pages; ++i) { > if (NULL != (page = vsg->pages[i])) { > if (!PageReserved(page) && (DMA_FROM_DEVICE == vsg->direction)) > - SetPageDirty(page); > - put_page(page); > + put_user_pages_dirty(&page, 1); > + else > + put_user_page(page); > } Can't just pass a dirty argument to put_user_pages? Also do we really need a separate put_user_page for the single page case? put_user_pages_dirty? Also the PageReserved check looks bogus, as I can't see how a reserved page can end up here. So IMHO the above snippled should really look something like this: put_user_pages(vsg->pages[i], vsg->num_pages, vsg->direction == DMA_FROM_DEVICE); in the end.
On 7/22/19 2:33 AM, Christoph Hellwig wrote: > On Sun, Jul 21, 2019 at 09:30:10PM -0700, john.hubbard@gmail.com wrote: >> for (i = 0; i < vsg->num_pages; ++i) { >> if (NULL != (page = vsg->pages[i])) { >> if (!PageReserved(page) && (DMA_FROM_DEVICE == vsg->direction)) >> - SetPageDirty(page); >> - put_page(page); >> + put_user_pages_dirty(&page, 1); >> + else >> + put_user_page(page); >> } > > Can't just pass a dirty argument to put_user_pages? Also do we really Yes, and in fact that would help a lot more than the single page case, which is really just cosmetic after all. > need a separate put_user_page for the single page case? > put_user_pages_dirty? Not really. I'm still zeroing in on the ideal API for all these call sites, and I agree that the approach below is cleaner. > > Also the PageReserved check looks bogus, as I can't see how a reserved > page can end up here. So IMHO the above snippled should really look > something like this: > > put_user_pages(vsg->pages[i], vsg->num_pages, > vsg->direction == DMA_FROM_DEVICE); > > in the end. > Agreed. thanks,
On Mon, Jul 22, 2019 at 11:53:54AM -0700, John Hubbard wrote: > On 7/22/19 2:33 AM, Christoph Hellwig wrote: > > On Sun, Jul 21, 2019 at 09:30:10PM -0700, john.hubbard@gmail.com wrote: > >> for (i = 0; i < vsg->num_pages; ++i) { > >> if (NULL != (page = vsg->pages[i])) { > >> if (!PageReserved(page) && (DMA_FROM_DEVICE == vsg->direction)) > >> - SetPageDirty(page); > >> - put_page(page); > >> + put_user_pages_dirty(&page, 1); > >> + else > >> + put_user_page(page); > >> } > > > > Can't just pass a dirty argument to put_user_pages? Also do we really > > Yes, and in fact that would help a lot more than the single page case, > which is really just cosmetic after all. > > > need a separate put_user_page for the single page case? > > put_user_pages_dirty? > > Not really. I'm still zeroing in on the ideal API for all these call sites, > and I agree that the approach below is cleaner. so enum { CLEAN = 0, DIRTY = 1, LOCK = 2, DIRTY_LOCK = 3 }; ?
On 7/22/19 12:07 PM, Matthew Wilcox wrote: > On Mon, Jul 22, 2019 at 11:53:54AM -0700, John Hubbard wrote: >> On 7/22/19 2:33 AM, Christoph Hellwig wrote: >>> On Sun, Jul 21, 2019 at 09:30:10PM -0700, john.hubbard@gmail.com wrote: >>>> for (i = 0; i < vsg->num_pages; ++i) { >>>> if (NULL != (page = vsg->pages[i])) { >>>> if (!PageReserved(page) && (DMA_FROM_DEVICE == vsg->direction)) >>>> - SetPageDirty(page); >>>> - put_page(page); >>>> + put_user_pages_dirty(&page, 1); >>>> + else >>>> + put_user_page(page); >>>> } >>> >>> Can't just pass a dirty argument to put_user_pages? Also do we really >> >> Yes, and in fact that would help a lot more than the single page case, >> which is really just cosmetic after all. >> >>> need a separate put_user_page for the single page case? >>> put_user_pages_dirty? >> >> Not really. I'm still zeroing in on the ideal API for all these call sites, >> and I agree that the approach below is cleaner. > > so enum { CLEAN = 0, DIRTY = 1, LOCK = 2, DIRTY_LOCK = 3 }; > ? > Sure. In fact, I just applied something similar to bio_release_pages() locally, in order to reconcile Christoph's and Jerome's approaches (they each needed to add a bool arg), so I'm all about the enums in the arg lists. :) I'm going to post that one shortly, let's see how it goes over. heh. thanks,
diff --git a/drivers/gpu/drm/via/via_dmablit.c b/drivers/gpu/drm/via/via_dmablit.c index 062067438f1d..219827ae114f 100644 --- a/drivers/gpu/drm/via/via_dmablit.c +++ b/drivers/gpu/drm/via/via_dmablit.c @@ -189,8 +189,9 @@ via_free_sg_info(struct pci_dev *pdev, drm_via_sg_info_t *vsg) for (i = 0; i < vsg->num_pages; ++i) { if (NULL != (page = vsg->pages[i])) { if (!PageReserved(page) && (DMA_FROM_DEVICE == vsg->direction)) - SetPageDirty(page); - put_page(page); + put_user_pages_dirty(&page, 1); + else + put_user_page(page); } } /* fall through */