On Thu, May 23, 2019 at 12:25:37AM -0700, john.hubbard@xxxxxxxxx wrote: > From: John Hubbard <jhubbard@xxxxxxxxxx> > > For infiniband code that retains pages via get_user_pages*(), > release those pages via the new put_user_page(), or > put_user_pages*(), instead of put_page() > > This is a tiny part of the second step of fixing the problem described > in [1]. The steps are: > > 1) Provide put_user_page*() routines, intended to be used > for releasing pages that were pinned via get_user_pages*(). > > 2) Convert all of the call sites for get_user_pages*(), to > invoke put_user_page*(), instead of put_page(). This involves dozens of > call sites, and will take some time. > > 3) After (2) is complete, use get_user_pages*() and put_user_page*() to > implement tracking of these pages. This tracking will be separate from > the existing struct page refcounting. > > 4) Use the tracking and identification of these pages, to implement > special handling (especially in writeback paths) when the pages are > backed by a filesystem. Again, [1] provides details as to why that is > desirable. > > [1] https://lwn.net/Articles/753027/ : "The Trouble with get_user_pages()" > > Cc: Doug Ledford <dledford@xxxxxxxxxx> > Cc: Jason Gunthorpe <jgg@xxxxxxxx> > Cc: Mike Marciniszyn <mike.marciniszyn@xxxxxxxxx> > Cc: Dennis Dalessandro <dennis.dalessandro@xxxxxxxxx> > Cc: Christian Benvenuti <benve@xxxxxxxxx> > > Reviewed-by: Jan Kara <jack@xxxxxxx> > Reviewed-by: Dennis Dalessandro <dennis.dalessandro@xxxxxxxxx> > Acked-by: Jason Gunthorpe <jgg@xxxxxxxxxxxx> > Tested-by: Ira Weiny <ira.weiny@xxxxxxxxx> > Signed-off-by: John Hubbard <jhubbard@xxxxxxxxxx> > --- > drivers/infiniband/core/umem.c | 7 ++++--- > drivers/infiniband/core/umem_odp.c | 10 +++++----- > drivers/infiniband/hw/hfi1/user_pages.c | 11 ++++------- > drivers/infiniband/hw/mthca/mthca_memfree.c | 6 +++--- > drivers/infiniband/hw/qib/qib_user_pages.c | 11 ++++------- > drivers/infiniband/hw/qib/qib_user_sdma.c | 6 +++--- > drivers/infiniband/hw/usnic/usnic_uiom.c | 7 ++++--- > 7 files changed, 27 insertions(+), 31 deletions(-) > > diff --git a/drivers/infiniband/core/umem.c b/drivers/infiniband/core/umem.c > index e7ea819fcb11..673f0d240b3e 100644 > --- a/drivers/infiniband/core/umem.c > +++ b/drivers/infiniband/core/umem.c > @@ -54,9 +54,10 @@ static void __ib_umem_release(struct ib_device *dev, struct ib_umem *umem, int d > > for_each_sg_page(umem->sg_head.sgl, &sg_iter, umem->sg_nents, 0) { > page = sg_page_iter_page(&sg_iter); > - if (!PageDirty(page) && umem->writable && dirty) > - set_page_dirty_lock(page); > - put_page(page); > + if (umem->writable && dirty) > + put_user_pages_dirty_lock(&page, 1); > + else > + put_user_page(page); > } > > sg_free_table(&umem->sg_head); > diff --git a/drivers/infiniband/core/umem_odp.c b/drivers/infiniband/core/umem_odp.c > index f962b5bbfa40..17e46df3990a 100644 > --- a/drivers/infiniband/core/umem_odp.c > +++ b/drivers/infiniband/core/umem_odp.c > @@ -487,7 +487,7 @@ void ib_umem_odp_release(struct ib_umem_odp *umem_odp) > * The function returns -EFAULT if the DMA mapping operation fails. It returns > * -EAGAIN if a concurrent invalidation prevents us from updating the page. > * > - * The page is released via put_page even if the operation failed. For > + * The page is released via put_user_page even if the operation failed. For > * on-demand pinning, the page is released whenever it isn't stored in the > * umem. > */ > @@ -536,7 +536,7 @@ static int ib_umem_odp_map_dma_single_page( > } > > out: > - put_page(page); > + put_user_page(page); > > if (remove_existing_mapping) { > ib_umem_notifier_start_account(umem_odp); > @@ -659,7 +659,7 @@ int ib_umem_odp_map_dma_pages(struct ib_umem_odp *umem_odp, u64 user_virt, > ret = -EFAULT; > break; > } > - put_page(local_page_list[j]); > + put_user_page(local_page_list[j]); > continue; > } > > @@ -686,8 +686,8 @@ int ib_umem_odp_map_dma_pages(struct ib_umem_odp *umem_odp, u64 user_virt, > * ib_umem_odp_map_dma_single_page(). > */ > if (npages - (j + 1) > 0) > - release_pages(&local_page_list[j+1], > - npages - (j + 1)); > + put_user_pages(&local_page_list[j+1], > + npages - (j + 1)); I don't know if we discussed this before but it looks like the use of release_pages() was not entirely correct (or at least not necessary) here. So I think this is ok. As for testing, I have been running with this patch for a while but I don't have ODP hardware so that testing would not cover this code path. So you can add my: Reviewed-by: Ira Weiny <ira.weiny@xxxxxxxxx> > break; > } > } > diff --git a/drivers/infiniband/hw/hfi1/user_pages.c b/drivers/infiniband/hw/hfi1/user_pages.c > index 02eee8eff1db..b89a9b9aef7a 100644 > --- a/drivers/infiniband/hw/hfi1/user_pages.c > +++ b/drivers/infiniband/hw/hfi1/user_pages.c > @@ -118,13 +118,10 @@ int hfi1_acquire_user_pages(struct mm_struct *mm, unsigned long vaddr, size_t np > void hfi1_release_user_pages(struct mm_struct *mm, struct page **p, > size_t npages, bool dirty) > { > - size_t i; > - > - for (i = 0; i < npages; i++) { > - if (dirty) > - set_page_dirty_lock(p[i]); > - put_page(p[i]); > - } > + if (dirty) > + put_user_pages_dirty_lock(p, npages); > + else > + put_user_pages(p, npages); > > if (mm) { /* during close after signal, mm can be NULL */ > atomic64_sub(npages, &mm->pinned_vm); > diff --git a/drivers/infiniband/hw/mthca/mthca_memfree.c b/drivers/infiniband/hw/mthca/mthca_memfree.c > index 8ff0e90d7564..edccfd6e178f 100644 > --- a/drivers/infiniband/hw/mthca/mthca_memfree.c > +++ b/drivers/infiniband/hw/mthca/mthca_memfree.c > @@ -482,7 +482,7 @@ int mthca_map_user_db(struct mthca_dev *dev, struct mthca_uar *uar, > > ret = pci_map_sg(dev->pdev, &db_tab->page[i].mem, 1, PCI_DMA_TODEVICE); > if (ret < 0) { > - put_page(pages[0]); > + put_user_page(pages[0]); > goto out; > } > > @@ -490,7 +490,7 @@ int mthca_map_user_db(struct mthca_dev *dev, struct mthca_uar *uar, > mthca_uarc_virt(dev, uar, i)); > if (ret) { > pci_unmap_sg(dev->pdev, &db_tab->page[i].mem, 1, PCI_DMA_TODEVICE); > - put_page(sg_page(&db_tab->page[i].mem)); > + put_user_page(sg_page(&db_tab->page[i].mem)); > goto out; > } > > @@ -556,7 +556,7 @@ void mthca_cleanup_user_db_tab(struct mthca_dev *dev, struct mthca_uar *uar, > if (db_tab->page[i].uvirt) { > mthca_UNMAP_ICM(dev, mthca_uarc_virt(dev, uar, i), 1); > pci_unmap_sg(dev->pdev, &db_tab->page[i].mem, 1, PCI_DMA_TODEVICE); > - put_page(sg_page(&db_tab->page[i].mem)); > + put_user_page(sg_page(&db_tab->page[i].mem)); > } > } > > diff --git a/drivers/infiniband/hw/qib/qib_user_pages.c b/drivers/infiniband/hw/qib/qib_user_pages.c > index f712fb7fa82f..bfbfbb7e0ff4 100644 > --- a/drivers/infiniband/hw/qib/qib_user_pages.c > +++ b/drivers/infiniband/hw/qib/qib_user_pages.c > @@ -40,13 +40,10 @@ > static void __qib_release_user_pages(struct page **p, size_t num_pages, > int dirty) > { > - size_t i; > - > - for (i = 0; i < num_pages; i++) { > - if (dirty) > - set_page_dirty_lock(p[i]); > - put_page(p[i]); > - } > + if (dirty) > + put_user_pages_dirty_lock(p, num_pages); > + else > + put_user_pages(p, num_pages); > } > > /** > diff --git a/drivers/infiniband/hw/qib/qib_user_sdma.c b/drivers/infiniband/hw/qib/qib_user_sdma.c > index 0c204776263f..ac5bdb02144f 100644 > --- a/drivers/infiniband/hw/qib/qib_user_sdma.c > +++ b/drivers/infiniband/hw/qib/qib_user_sdma.c > @@ -317,7 +317,7 @@ static int qib_user_sdma_page_to_frags(const struct qib_devdata *dd, > * the caller can ignore this page. > */ > if (put) { > - put_page(page); > + put_user_page(page); > } else { > /* coalesce case */ > kunmap(page); > @@ -631,7 +631,7 @@ static void qib_user_sdma_free_pkt_frag(struct device *dev, > kunmap(pkt->addr[i].page); > > if (pkt->addr[i].put_page) > - put_page(pkt->addr[i].page); > + put_user_page(pkt->addr[i].page); > else > __free_page(pkt->addr[i].page); > } else if (pkt->addr[i].kvaddr) { > @@ -706,7 +706,7 @@ static int qib_user_sdma_pin_pages(const struct qib_devdata *dd, > /* if error, return all pages not managed by pkt */ > free_pages: > while (i < j) > - put_page(pages[i++]); > + put_user_page(pages[i++]); > > done: > return ret; > diff --git a/drivers/infiniband/hw/usnic/usnic_uiom.c b/drivers/infiniband/hw/usnic/usnic_uiom.c > index e312f522a66d..0b0237d41613 100644 > --- a/drivers/infiniband/hw/usnic/usnic_uiom.c > +++ b/drivers/infiniband/hw/usnic/usnic_uiom.c > @@ -75,9 +75,10 @@ static void usnic_uiom_put_pages(struct list_head *chunk_list, int dirty) > for_each_sg(chunk->page_list, sg, chunk->nents, i) { > page = sg_page(sg); > pa = sg_phys(sg); > - if (!PageDirty(page) && dirty) > - set_page_dirty_lock(page); > - put_page(page); > + if (dirty) > + put_user_pages_dirty_lock(&page, 1); > + else > + put_user_page(page); > usnic_dbg("pa: %pa\n", &pa); > } > kfree(chunk); > -- > 2.21.0 >
