Hi Sasha, Thank you for the patch.
> -----Original Message----- > From: Sasha Levin <sas...@kernel.org> > Sent: Thursday 18 June 2020 02:15 > To: linux-kernel@vger.kernel.org; sta...@vger.kernel.org > Cc: John Hubbard <jhubb...@nvidia.com>; Derek Kiernan <dkier...@xilinx.com>; > Dragan Cvetic <drag...@xilinx.com>; Arnd > Bergmann <a...@arndb.de>; Greg Kroah-Hartman <gre...@linuxfoundation.org>; > Michal Simek <mich...@xilinx.com>; linux-arm- > ker...@lists.infradead.org; Sasha Levin <sas...@kernel.org> > Subject: [PATCH AUTOSEL 5.4 199/266] misc: xilinx-sdfec: improve > get_user_pages_fast() error handling > > From: John Hubbard <jhubb...@nvidia.com> > > [ Upstream commit 57343d51613227373759f5b0f2eede257fd4b82e ] > > This fixes the case of get_user_pages_fast() returning a -errno. > The result needs to be stored in a signed integer. And for safe > signed/unsigned comparisons, it's best to keep everything signed. > And get_user_pages_fast() also expects a signed value for number > of pages to pin. > > Therefore, change most relevant variables, from u32 to int. Leave > "n" unsigned, for convenience in checking for overflow. And provide > a WARN_ON_ONCE() and early return, if overflow occurs. > > Also, as long as we're tidying up: rename the page array from page, > to pages, in order to match the conventions used in most other call > sites. > > Fixes: 20ec628e8007e ("misc: xilinx_sdfec: Add ability to configure LDPC") > Cc: Derek Kiernan <derek.kier...@xilinx.com> > Cc: Dragan Cvetic <dragan.cve...@xilinx.com> > Cc: Arnd Bergmann <a...@arndb.de> > Cc: Greg Kroah-Hartman <gre...@linuxfoundation.org> > Cc: Michal Simek <michal.si...@xilinx.com> > Cc: linux-arm-ker...@lists.infradead.org > Signed-off-by: John Hubbard <jhubb...@nvidia.com> > Link: https://lore.kernel.org/r/20200527012628.1100649-2-jhubb...@nvidia.com > Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org> > Signed-off-by: Sasha Levin <sas...@kernel.org> > --- > drivers/misc/xilinx_sdfec.c | 27 +++++++++++++++++---------- > 1 file changed, 17 insertions(+), 10 deletions(-) > > diff --git a/drivers/misc/xilinx_sdfec.c b/drivers/misc/xilinx_sdfec.c > index 48ba7e02bed7..d4c14b617201 100644 > --- a/drivers/misc/xilinx_sdfec.c > +++ b/drivers/misc/xilinx_sdfec.c > @@ -602,10 +602,10 @@ static int xsdfec_table_write(struct xsdfec_dev > *xsdfec, u32 offset, > const u32 depth) > { > u32 reg = 0; > - u32 res; > - u32 n, i; > + int res, i, nr_pages; > + u32 n; > u32 *addr = NULL; > - struct page *page[MAX_NUM_PAGES]; > + struct page *pages[MAX_NUM_PAGES]; > > /* > * Writes that go beyond the length of > @@ -622,15 +622,22 @@ static int xsdfec_table_write(struct xsdfec_dev > *xsdfec, u32 offset, > if ((len * XSDFEC_REG_WIDTH_JUMP) % PAGE_SIZE) > n += 1; > > - res = get_user_pages_fast((unsigned long)src_ptr, n, 0, page); > - if (res < n) { > - for (i = 0; i < res; i++) > - put_page(page[i]); > + if (WARN_ON_ONCE(n > INT_MAX)) > + return -EINVAL; > + > + nr_pages = n; > + > + res = get_user_pages_fast((unsigned long)src_ptr, nr_pages, 0, pages); > + if (res < nr_pages) { > + if (res > 0) { > + for (i = 0; i < res; i++) > + put_page(pages[i]); > + } > return -EINVAL; > } > > - for (i = 0; i < n; i++) { > - addr = kmap(page[i]); > + for (i = 0; i < nr_pages; i++) { > + addr = kmap(pages[i]); > do { > xsdfec_regwrite(xsdfec, > base_addr + ((offset + reg) * > @@ -639,7 +646,7 @@ static int xsdfec_table_write(struct xsdfec_dev *xsdfec, > u32 offset, > reg++; > } while ((reg < len) && > ((reg * XSDFEC_REG_WIDTH_JUMP) % PAGE_SIZE)); > - put_page(page[i]); > + put_page(pages[i]); > } > return reg; > } > -- > 2.25.1 Acked-by: Dragan Cvetic <dragan.cve...@xilinx.com> Regards Dragan