[PATCH] zram: move init_done check to the beginning of disksize_store

From: Geliang Tang
Date: Sat Oct 31 2015 - 10:52:24 EST


If we set disksize when disksize has been set, we will get the following
error report: "write error: Cannot allocate memory". This is because
disksize_store fails at zram_meta_alloc. This is not what we expect.
To solve this problem, this patch moves init_done check to the beginning
of disksize_store.

Signed-off-by: Geliang Tang <geliangtang@xxxxxxx>
---
drivers/block/zram/zram_drv.c | 17 ++++++++---------
1 file changed, 8 insertions(+), 9 deletions(-)

diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
index 81a557c..609fc2b 100644
--- a/drivers/block/zram/zram_drv.c
+++ b/drivers/block/zram/zram_drv.c
@@ -1028,6 +1028,14 @@ static ssize_t disksize_store(struct device *dev,
struct zram *zram = dev_to_zram(dev);
int err;

+ down_read(&zram->init_lock);
+ if (init_done(zram)) {
+ up_read(&zram->init_lock);
+ pr_info("Cannot change disksize for initialized device\n");
+ return -EBUSY;
+ }
+ up_read(&zram->init_lock);
+
disksize = memparse(buf, NULL);
if (!disksize)
return -EINVAL;
@@ -1046,12 +1054,6 @@ static ssize_t disksize_store(struct device *dev,
}

down_write(&zram->init_lock);
- if (init_done(zram)) {
- pr_info("Cannot change disksize for initialized device\n");
- err = -EBUSY;
- goto out_destroy_comp;
- }
-
init_waitqueue_head(&zram->io_done);
atomic_set(&zram->refcount, 1);
zram->meta = meta;
@@ -1069,9 +1071,6 @@ static ssize_t disksize_store(struct device *dev,

return len;

-out_destroy_comp:
- up_write(&zram->init_lock);
- zcomp_destroy(comp);
out_free_meta:
zram_meta_free(meta, disksize);
return err;
--
2.4.3


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