[PATCH v4 3/8] mtd: spi-nor: Reorder the preparation vs locking steps

[Miquel Raynal]

The ->prepare()/->unprepare() hooks are now legacy, we no longer accept
new drivers supporting them. The only remaining controllers using them
acquires a per-chip mutex, which should not interfere with the rest of
the operation done in the core. As a result, we should be safe to
reorganize these helpers to first perform the preparation, before
acquiring the core locks. This is necessary in order to be able to
improve the locking mechanism in the core (coming next). No side effects
are expected.

Signed-off-by: Miquel Raynal <miquel.raynal at bootlin.com>
---
 drivers/mtd/spi-nor/core.c | 23 ++++++++++-------------
 1 file changed, 10 insertions(+), 13 deletions(-)

diff --git a/drivers/mtd/spi-nor/core.c b/drivers/mtd/spi-nor/core.c
index 3845de9c874c..01932dbaa5b9 100644
--- a/drivers/mtd/spi-nor/core.c
+++ b/drivers/mtd/spi-nor/core.c
@@ -1071,27 +1071,24 @@ static void spi_nor_set_4byte_opcodes(struct spi_nor *nor)
 	}
 }
 
-int spi_nor_lock_and_prep(struct spi_nor *nor)
+int spi_nor_prep_and_lock(struct spi_nor *nor)
 {
 	int ret = 0;
 
-	mutex_lock(&nor->lock);
-
-	if (nor->controller_ops &&  nor->controller_ops->prepare) {
+	if (nor->controller_ops && nor->controller_ops->prepare)
 		ret = nor->controller_ops->prepare(nor);
-		if (ret) {
-			mutex_unlock(&nor->lock);
-			return ret;
-		}
-	}
+
+	mutex_lock(&nor->lock);
+
 	return ret;
 }
 
 void spi_nor_unlock_and_unprep(struct spi_nor *nor)
 {
+	mutex_unlock(&nor->lock);
+
 	if (nor->controller_ops && nor->controller_ops->unprepare)
 		nor->controller_ops->unprepare(nor);
-	mutex_unlock(&nor->lock);
 }
 
 static u32 spi_nor_convert_addr(struct spi_nor *nor, loff_t addr)
@@ -1447,7 +1444,7 @@ static int spi_nor_erase(struct mtd_info *mtd, struct erase_info *instr)
 	addr = instr->addr;
 	len = instr->len;
 
-	ret = spi_nor_lock_and_prep(nor);
+	ret = spi_nor_prep_and_lock(nor);
 	if (ret)
 		return ret;
 
@@ -1707,7 +1704,7 @@ static int spi_nor_read(struct mtd_info *mtd, loff_t from, size_t len,
 
 	dev_dbg(nor->dev, "from 0x%08x, len %zd\n", (u32)from, len);
 
-	ret = spi_nor_lock_and_prep(nor);
+	ret = spi_nor_prep_and_lock(nor);
 	if (ret)
 		return ret;
 
@@ -1753,7 +1750,7 @@ static int spi_nor_write(struct mtd_info *mtd, loff_t to, size_t len,
 
 	dev_dbg(nor->dev, "to 0x%08x, len %zd\n", (u32)to, len);
 
-	ret = spi_nor_lock_and_prep(nor);
+	ret = spi_nor_prep_and_lock(nor);
 	if (ret)
 		return ret;
 
-- 
2.34.1