[PATCH v2 02/10] mtd: powernv_flash: Lock around concurrent access to OPAL

Cyril Bur
2017-07-10T01:31:55Z

OPAL can only manage one flash access at a time and will return an
OPAL_BUSY error for each concurrent access to the flash. The simplest
way to prevent this from happening is with a mutex.

Signed-off-by: Cyril Bur <cyrilbur@gmail.com>
---
drivers/mtd/devices/powernv_flash.c | 18 +++++++++++++++---
1 file changed, 15 insertions(+), 3 deletions(-)

diff --git a/drivers/mtd/devices/powernv_flash.c b/drivers/mtd/devices/powernv_flash.c
index a9a20c00687c..7b41af06f4fe 100644
--- a/drivers/mtd/devices/powernv_flash.c
+++ b/drivers/mtd/devices/powernv_flash.c
@@ -38,6 +38,7 @@

struct powernv_flash {
struct mtd_info mtd;
+ struct mutex lock;
u32 id;
};

@@ -59,12 +60,15 @@ static int powernv_flash_async_op(struct mtd_info *mtd, enum flash_op op,
dev_dbg(dev, "%s(op=%d, offset=0x%llx, len=%zu)\n",
__func__, op, offset, len);

+ mutex_lock(&info->lock);
+
token = opal_async_get_token_interruptible();
if (token < 0) {
if (token != -ERESTARTSYS)
dev_err(dev, "Failed to get an async token\n");

- return token;
+ rc = token;
+ goto out;
}

switch (op) {
@@ -79,18 +83,21 @@ static int powernv_flash_async_op(struct mtd_info *mtd, enum flash_op op,
break;
default:
WARN_ON_ONCE(1);
- return -EIO;
+ rc = -EIO;
+ goto out;
}

if (rc != OPAL_ASYNC_COMPLETION) {
dev_err(dev, "opal_flash_async_op(op=%d) failed (rc %d)\n",
op, rc);
opal_async_release_token(token);
- return -EIO;
+ rc = -EIO;
+ goto out;
}

rc = opal_async_wait_response(token, &msg);
opal_async_release_token(token);
+ mutex_unlock(&info->lock);
if (rc) {
dev_err(dev, "opal async wait failed (rc %d)\n", rc);
return -EIO;
@@ -106,6 +113,9 @@ static int powernv_flash_async_op(struct mtd_info *mtd, enum flash_op op,
}

return rc;
+out:
+ mutex_unlock(&info->lock);
+ return rc;
}

/**
@@ -237,6 +247,8 @@ static int powernv_flash_probe(struct platform_device *pdev)
if (ret)
goto out;

+ mutex_init(&data->lock);
+
dev_set_drvdata(dev, data);

/*
--
2.13.2