From: Biju Das biju.das.jz@bp.renesas.com
[ Upstream commit ebc4cb43ea5ada3db46c80156fca58a54b9bbca8 ]
While computing sgs in spi_map_buf(), the data type used in min_t() for max_seg_size is 'unsigned int' where as that of ctlr->max_dma_len is 'size_t'.
min_t(unsigned int,x,y) gives wrong results if one of x/y is 'size_t'
Consider the below examples on a 64-bit machine (ie size_t is 64-bits, and unsigned int is 32-bit). case 1) min_t(unsigned int, 5, 0x100000001); case 2) min_t(size_t, 5, 0x100000001);
Case 1 returns '1', where as case 2 returns '5'. As you can see the result from case 1 is wrong.
This patch fixes the above issue by using the data type of the parameters that are used in min_t with maximum data length.
Fixes: commit 1a4e53d2fc4f68aa ("spi: Fix invalid sgs value") Reported-by: Linus Torvalds torvalds@linux-foundation.org Suggested-by: Geert Uytterhoeven geert+renesas@glider.be Signed-off-by: Biju Das biju.das.jz@bp.renesas.com Reviewed-by: Lad Prabhakar prabhakar.mahadev-lad.rj@bp.renesas.com Link: https://lore.kernel.org/r/20220316175317.465-1-biju.das.jz@bp.renesas.com Signed-off-by: Mark Brown broonie@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/spi/spi.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c index 837fa947dec7..b18ae50db1f5 100644 --- a/drivers/spi/spi.c +++ b/drivers/spi/spi.c @@ -844,10 +844,10 @@ int spi_map_buf(struct spi_controller *ctlr, struct device *dev, int i, ret;
if (vmalloced_buf || kmap_buf) { - desc_len = min_t(unsigned int, max_seg_size, PAGE_SIZE); + desc_len = min_t(unsigned long, max_seg_size, PAGE_SIZE); sgs = DIV_ROUND_UP(len + offset_in_page(buf), desc_len); } else if (virt_addr_valid(buf)) { - desc_len = min_t(unsigned int, max_seg_size, ctlr->max_dma_len); + desc_len = min_t(size_t, max_seg_size, ctlr->max_dma_len); sgs = DIV_ROUND_UP(len, desc_len); } else { return -EINVAL;