From: John Hubbard jhubbard@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.kiernan@xilinx.com Cc: Dragan Cvetic dragan.cvetic@xilinx.com Cc: Arnd Bergmann arnd@arndb.de Cc: Greg Kroah-Hartman gregkh@linuxfoundation.org Cc: Michal Simek michal.simek@xilinx.com Cc: linux-arm-kernel@lists.infradead.org Signed-off-by: John Hubbard jhubbard@nvidia.com Link: https://lore.kernel.org/r/20200527012628.1100649-2-jhubbard@nvidia.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Sasha Levin sashal@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 71bbaa56bdb5..e2766aad9e14 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; }