Re: [PATCH 05/10] writeback: Generalize and standardize I_SYNC waiting function

[Tejun Heo]

On Thu, Feb 09, 2017 at 01:44:28PM +0100, Jan Kara wrote:
> __inode_wait_for_writeback() waits for I_SYNC on inode to get cleared.
> There's nothing specific regarting I_SYNC for that function. Generalize
> it so that we can use it also for I_WB_SWITCH bit. Also the function
> uses __wait_on_bit() unnecessarily. Switch it to wait_on_bit() to remove
> some code.
> 
> Signed-off-by: Jan Kara 

Acked-by: Tejun Heo 

Thanks.

-- 
tejun

[PATCH 05/10] writeback: Generalize and standardize I_SYNC waiting function

[Jan Kara]

__inode_wait_for_writeback() waits for I_SYNC on inode to get cleared.
There's nothing specific regarting I_SYNC for that function. Generalize
it so that we can use it also for I_WB_SWITCH bit. Also the function
uses __wait_on_bit() unnecessarily. Switch it to wait_on_bit() to remove
some code.

Signed-off-by: Jan Kara 
---
 fs/fs-writeback.c | 17 ++---
 1 file changed, 6 insertions(+), 11 deletions(-)

diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c
index ef600591d96f..c9770de11650 100644
--- a/fs/fs-writeback.c
+++ b/fs/fs-writeback.c
@@ -1170,21 +1170,16 @@ static int write_inode(struct inode *inode, struct 
writeback_control *wbc)
 }
 
 /*
- * Wait for writeback on an inode to complete. Called with i_lock held.
+ * Wait for bit in inode->i_state to clear. Called with i_lock held.
  * Caller must make sure inode cannot go away when we drop i_lock.
  */
-static void __inode_wait_for_writeback(struct inode *inode)
+static void __inode_wait_for_state_bit(struct inode *inode, int bit_nr)
__releases(inode->i_lock)
__acquires(inode->i_lock)
 {
-   DEFINE_WAIT_BIT(wq, >i_state, __I_SYNC);
-   wait_queue_head_t *wqh;
-
-   wqh = bit_waitqueue(>i_state, __I_SYNC);
-   while (inode->i_state & I_SYNC) {
+   while (inode->i_state & (1 << bit_nr)) {
spin_unlock(>i_lock);
-   __wait_on_bit(wqh, , bit_wait,
- TASK_UNINTERRUPTIBLE);
+   wait_on_bit(>i_state, bit_nr, TASK_UNINTERRUPTIBLE);
spin_lock(>i_lock);
}
 }
@@ -1195,7 +1190,7 @@ static void __inode_wait_for_writeback(struct inode 
*inode)
 void inode_wait_for_writeback(struct inode *inode)
 {
spin_lock(>i_lock);
-   __inode_wait_for_writeback(inode);
+   __inode_wait_for_state_bit(inode, __I_SYNC);
spin_unlock(>i_lock);
 }
 
@@ -1397,7 +1392,7 @@ static int writeback_single_inode(struct inode *inode,
 * inode reference or inode has I_WILL_FREE set, it cannot go
 * away under us.
 */
-   __inode_wait_for_writeback(inode);
+   __inode_wait_for_state_bit(inode, __I_SYNC);
}
WARN_ON(inode->i_state & I_SYNC);
/*
-- 
2.10.2