| Message ID | 1564058658-3551-1-git-send-email-linux.bhar@gmail.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [v4] staging: kpc2000: Convert put_page() to put_user_page*() | expand |
On 7/25/19 5:44 AM, Bharath Vedartham wrote: > For pages that were retained via get_user_pages*(), release those pages > via the new put_user_page*() routines, instead of via put_page(). > > This is part a tree-wide conversion, as described in commit fc1d8e7cca2d > ("mm: introduce put_user_page*(), placeholder versions"). > Hi Bharath, If you like, I could re-post your patch here, modified slightly, as part of the next version of the miscellaneous call site conversion series [1]. As part of that, we should change this to use put_user_pages_dirty_lock() (see below). > Cc: Ira Weiny <ira.weiny@intel.com> > Cc: John Hubbard <jhubbard@nvidia.com> > Cc: Jérôme Glisse <jglisse@redhat.com> > Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> > Cc: Matt Sickler <Matt.Sickler@daktronics.com> > Cc: devel@driverdev.osuosl.org > Cc: linux-kernel@vger.kernel.org > Cc: linux-mm@kvack.org > Reviewed-by: John Hubbard <jhubbard@nvidia.com> > Signed-off-by: Bharath Vedartham <linux.bhar@gmail.com> > --- > Changes since v1 > - Improved changelog by John's suggestion. > - Moved logic to dirty pages below sg_dma_unmap > and removed PageReserved check. > Changes since v2 > - Added back PageResevered check as > suggested by John Hubbard. > Changes since v3 > - Changed the changelog as suggested by John. > - Added John's Reviewed-By tag. > Changes since v4 > - Rebased the patch on the staging tree. > - Improved commit log by fixing a line wrap. > --- > drivers/staging/kpc2000/kpc_dma/fileops.c | 17 ++++++----------- > 1 file changed, 6 insertions(+), 11 deletions(-) > > diff --git a/drivers/staging/kpc2000/kpc_dma/fileops.c b/drivers/staging/kpc2000/kpc_dma/fileops.c > index 48ca88b..f15e292 100644 > --- a/drivers/staging/kpc2000/kpc_dma/fileops.c > +++ b/drivers/staging/kpc2000/kpc_dma/fileops.c > @@ -190,9 +190,7 @@ static int kpc_dma_transfer(struct dev_private_data *priv, > sg_free_table(&acd->sgt); > err_dma_map_sg: > err_alloc_sg_table: > - for (i = 0 ; i < acd->page_count ; i++) { > - put_page(acd->user_pages[i]); > - } > + put_user_pages(acd->user_pages, acd->page_count); > err_get_user_pages: > kfree(acd->user_pages); > err_alloc_userpages: > @@ -211,16 +209,13 @@ void transfer_complete_cb(struct aio_cb_data *acd, size_t xfr_count, u32 flags) > BUG_ON(acd->ldev == NULL); > BUG_ON(acd->ldev->pldev == NULL); > > - for (i = 0 ; i < acd->page_count ; i++) { > - if (!PageReserved(acd->user_pages[i])) { > - set_page_dirty(acd->user_pages[i]); > - } > - } > - > dma_unmap_sg(&acd->ldev->pldev->dev, acd->sgt.sgl, acd->sgt.nents, acd->ldev->dir); > > - for (i = 0 ; i < acd->page_count ; i++) { > - put_page(acd->user_pages[i]); > + for (i = 0; i < acd->page_count; i++) { > + if (!PageReserved(acd->user_pages[i])) > + put_user_pages_dirty(&acd->user_pages[i], 1); This would change to: put_user_pages_dirty_lock(&acd->user_pages[i], 1, true); ...and we'd add this blurb (this time with CH's name spelled properly) to the commit description: Note that this effectively changes the code's behavior in qp_release_pages(): it now ultimately calls set_page_dirty_lock(), instead of set_page_dirty(). This is probably more accurate. As Christoph Hellwig put it, "set_page_dirty() is only safe if we are dealing with a file backed page where we have reference on the inode it hangs off." [1] [1] https://lore.kernel.org/r/20190723153640.GB720@lst.de Also, future: I don't know the driver well enough to say, but maybe "true" could be replaced by "acd->ldev->dir == DMA_FROM_DEVICE", there, but that would be a separate patch. thanks,
diff --git a/drivers/staging/kpc2000/kpc_dma/fileops.c b/drivers/staging/kpc2000/kpc_dma/fileops.c index 48ca88b..f15e292 100644 --- a/drivers/staging/kpc2000/kpc_dma/fileops.c +++ b/drivers/staging/kpc2000/kpc_dma/fileops.c @@ -190,9 +190,7 @@ static int kpc_dma_transfer(struct dev_private_data *priv, sg_free_table(&acd->sgt); err_dma_map_sg: err_alloc_sg_table: - for (i = 0 ; i < acd->page_count ; i++) { - put_page(acd->user_pages[i]); - } + put_user_pages(acd->user_pages, acd->page_count); err_get_user_pages: kfree(acd->user_pages); err_alloc_userpages: @@ -211,16 +209,13 @@ void transfer_complete_cb(struct aio_cb_data *acd, size_t xfr_count, u32 flags) BUG_ON(acd->ldev == NULL); BUG_ON(acd->ldev->pldev == NULL); - for (i = 0 ; i < acd->page_count ; i++) { - if (!PageReserved(acd->user_pages[i])) { - set_page_dirty(acd->user_pages[i]); - } - } - dma_unmap_sg(&acd->ldev->pldev->dev, acd->sgt.sgl, acd->sgt.nents, acd->ldev->dir); - for (i = 0 ; i < acd->page_count ; i++) { - put_page(acd->user_pages[i]); + for (i = 0; i < acd->page_count; i++) { + if (!PageReserved(acd->user_pages[i])) + put_user_pages_dirty(&acd->user_pages[i], 1); + else + put_user_page(acd->user_pages[i]); } sg_free_table(&acd->sgt);
For pages that were retained via get_user_pages*(), release those pages via the new put_user_page*() routines, instead of via put_page(). This is part a tree-wide conversion, as described in commit fc1d8e7cca2d ("mm: introduce put_user_page*(), placeholder versions"). Cc: Ira Weiny <ira.weiny@intel.com> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Jérôme Glisse <jglisse@redhat.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Matt Sickler <Matt.Sickler@daktronics.com> Cc: devel@driverdev.osuosl.org Cc: linux-kernel@vger.kernel.org Cc: linux-mm@kvack.org Reviewed-by: John Hubbard <jhubbard@nvidia.com> Signed-off-by: Bharath Vedartham <linux.bhar@gmail.com> --- Changes since v1 - Improved changelog by John's suggestion. - Moved logic to dirty pages below sg_dma_unmap and removed PageReserved check. Changes since v2 - Added back PageResevered check as suggested by John Hubbard. Changes since v3 - Changed the changelog as suggested by John. - Added John's Reviewed-By tag. Changes since v4 - Rebased the patch on the staging tree. - Improved commit log by fixing a line wrap. --- drivers/staging/kpc2000/kpc_dma/fileops.c | 17 ++++++----------- 1 file changed, 6 insertions(+), 11 deletions(-)