4.18-stable review patch. If anyone has any objections, please let me know.
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From: Boris Brezillon boris.brezillon@bootlin.com
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 jarkko.nikula@linux.intel.com Cc: stable@vger.kernel.org Signed-off-by: Boris Brezillon boris.brezillon@bootlin.com Tested-by: Jarkko Nikula jarkko.nikula@linux.intel.com Reviewed-by: Jarkko Nikula jarkko.nikula@linux.intel.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- 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,