From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Jarkko Nikula , Boris Brezillon Subject: [PATCH 4.18 40/88] mtd: devices: m25p80: Make sure the buffer passed in op is DMA-able Date: Thu, 27 Sep 2018 11:03:21 +0200 Message-Id: <20180927090305.611960984@linuxfoundation.org> In-Reply-To: <20180927090300.631426620@linuxfoundation.org> References: <20180927090300.631426620@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: 4.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Boris Brezillon commit 4a3e85f2674cbfb81052059107d0165269778e2f upstream. As documented in spi-mem.h, spi_mem_op->data.buf.{in,out} must be DMA-able, and commit 4120f8d158ef ("mtd: spi-nor: Use the spi_mem_xx() API") failed to follow this rule as buffers passed to ->{read,write}_reg() are usually placed on the stack. Fix that by allocating a scratch buffer and copying the data around. Fixes: 4120f8d158ef ("mtd: spi-nor: Use the spi_mem_xx() API") Reported-by: Jarkko Nikula Cc: Signed-off-by: Boris Brezillon Tested-by: Jarkko Nikula Reviewed-by: Jarkko Nikula Signed-off-by: Greg Kroah-Hartman --- drivers/mtd/devices/m25p80.c | 26 +++++++++++++++++++++++--- 1 file changed, 23 insertions(+), 3 deletions(-) --- a/drivers/mtd/devices/m25p80.c +++ b/drivers/mtd/devices/m25p80.c @@ -41,13 +41,23 @@ static int m25p80_read_reg(struct spi_no struct spi_mem_op op = SPI_MEM_OP(SPI_MEM_OP_CMD(code, 1), SPI_MEM_OP_NO_ADDR, SPI_MEM_OP_NO_DUMMY, - SPI_MEM_OP_DATA_IN(len, val, 1)); + SPI_MEM_OP_DATA_IN(len, NULL, 1)); + void *scratchbuf; int ret; + scratchbuf = kmalloc(len, GFP_KERNEL); + if (!scratchbuf) + return -ENOMEM; + + op.data.buf.in = scratchbuf; ret = spi_mem_exec_op(flash->spimem, &op); if (ret < 0) dev_err(&flash->spimem->spi->dev, "error %d reading %x\n", ret, code); + else + memcpy(val, scratchbuf, len); + + kfree(scratchbuf); return ret; } @@ -58,9 +68,19 @@ static int m25p80_write_reg(struct spi_n struct spi_mem_op op = SPI_MEM_OP(SPI_MEM_OP_CMD(opcode, 1), SPI_MEM_OP_NO_ADDR, SPI_MEM_OP_NO_DUMMY, - SPI_MEM_OP_DATA_OUT(len, buf, 1)); + SPI_MEM_OP_DATA_OUT(len, NULL, 1)); + void *scratchbuf; + int ret; + + scratchbuf = kmemdup(buf, len, GFP_KERNEL); + if (!scratchbuf) + return -ENOMEM; - return spi_mem_exec_op(flash->spimem, &op); + op.data.buf.out = scratchbuf; + ret = spi_mem_exec_op(flash->spimem, &op); + kfree(scratchbuf); + + return ret; } static ssize_t m25p80_write(struct spi_nor *nor, loff_t to, size_t len,