[PATCH] mtd: m25p80: consider max message size in m25p80_read when use the spi_mem_xx() API

[Chuanhua Han]

Consider a message size limit when calculating the maximum amount
of data that can be read.

Signed-off-by: Chuanhua Han <chuanhua.han@xxxxxxx>
---
 drivers/mtd/devices/m25p80.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/drivers/mtd/devices/m25p80.c b/drivers/mtd/devices/m25p80.c
index e84563d..87efa56 100644
--- a/drivers/mtd/devices/m25p80.c
+++ b/drivers/mtd/devices/m25p80.c
@@ -128,7 +128,12 @@ static ssize_t m25p80_read(struct spi_nor *nor, loff_t from, size_t len,
 	op.dummy.nbytes = (nor->read_dummy * op.dummy.buswidth) / 8;
 
 	while (remaining) {
-		op.data.nbytes = remaining < UINT_MAX ? remaining : UINT_MAX;
+		op.data.nbytes = min3(remaining,
+				spi_max_transfer_size(flash->spimem->spi),
+				spi_max_message_size(flash->spimem->spi) -
+				sizeof(op.cmd.opcode) -
+				op.addr.nbytes -
+				op.dummy.nbytes);
 		ret = spi_mem_adjust_op_size(flash->spimem, &op);
 		if (ret)
 			return ret;
-- 
2.7.4