mtd: spi-nor: Check the return value from read_sr()

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Gitweb:     http://git.infradead.org/?p=mtd-2.6.git;a=commit;h=f49289ce64b7f7da4d7129666854b499b9d415eb
Commit:     f49289ce64b7f7da4d7129666854b499b9d415eb
Parent:     adc83bf8896353603213754353dd66dae69e3d7f
Author:     Fabio Estevam <fabio.estevam at freescale.com>
AuthorDate: Fri Nov 20 16:26:11 2015 -0200
Committer:  Brian Norris <computersforpeace at gmail.com>
CommitDate: Wed Dec 9 18:15:01 2015 -0800

    mtd: spi-nor: Check the return value from read_sr()
    
    We should better check the return value from read_sr() and
    propagate it in the case of error.
    
    Signed-off-by: Fabio Estevam <fabio.estevam at freescale.com>
    Signed-off-by: Brian Norris <computersforpeace at gmail.com>
---
 drivers/mtd/spi-nor/spi-nor.c | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/drivers/mtd/spi-nor/spi-nor.c b/drivers/mtd/spi-nor/spi-nor.c
index 3b2460e..7e5051e 100644
--- a/drivers/mtd/spi-nor/spi-nor.c
+++ b/drivers/mtd/spi-nor/spi-nor.c
@@ -478,11 +478,13 @@ static int stm_is_locked_sr(struct spi_nor *nor, loff_t ofs, uint64_t len,
 static int stm_lock(struct spi_nor *nor, loff_t ofs, uint64_t len)
 {
 	struct mtd_info *mtd = &nor->mtd;
-	u8 status_old, status_new;
+	int status_old, status_new;
 	u8 mask = SR_BP2 | SR_BP1 | SR_BP0;
 	u8 shift = ffs(mask) - 1, pow, val;
 
 	status_old = read_sr(nor);
+	if (status_old < 0)
+		return status_old;
 
 	/* SPI NOR always locks to the end */
 	if (ofs + len != mtd->size) {
@@ -528,11 +530,13 @@ static int stm_lock(struct spi_nor *nor, loff_t ofs, uint64_t len)
 static int stm_unlock(struct spi_nor *nor, loff_t ofs, uint64_t len)
 {
 	struct mtd_info *mtd = &nor->mtd;
-	uint8_t status_old, status_new;
+	int status_old, status_new;
 	u8 mask = SR_BP2 | SR_BP1 | SR_BP0;
 	u8 shift = ffs(mask) - 1, pow, val;
 
 	status_old = read_sr(nor);
+	if (status_old < 0)
+		return status_old;
 
 	/* Cannot unlock; would unlock larger region than requested */
 	if (stm_is_locked_sr(nor, status_old, ofs - mtd->erasesize,
@@ -1032,6 +1036,8 @@ static int macronix_quad_enable(struct spi_nor *nor)
 	int ret, val;
 
 	val = read_sr(nor);
+	if (val < 0)
+		return val;
 	write_enable(nor);
 
 	write_sr(nor, val | SR_QUAD_EN_MX);