diff mbox series

[2/2] vfs: separate __sb_start_write into blocking and non-blocking helpers

Message ID 160463583438.1669281.14783057013328963357.stgit@magnolia (mailing list archive)
State New, archived
Headers show
Series vfs: remove lockdep fs freeze weirdness | expand

Commit Message

Darrick J. Wong Nov. 6, 2020, 4:10 a.m. UTC 
From: Darrick J. Wong <darrick.wong@oracle.com>

Break this function into two helpers so that it's obvious that the
trylock versions return a value that must be checked, and the blocking
versions don't require that.  While we're at it, clean up the return
type mismatch.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
---
 fs/aio.c           |    2 +-
 fs/io_uring.c      |    3 +--
 fs/super.c         |   18 ++++++++++++------
 include/linux/fs.h |   21 +++++++++++----------
 4 files changed, 25 insertions(+), 19 deletions(-)

Comments

Christoph Hellwig Nov. 6, 2020, 7:48 a.m. UTC | #1 
On Thu, Nov 05, 2020 at 08:10:34PM -0800, Darrick J. Wong wrote:
> From: Darrick J. Wong <darrick.wong@oracle.com>
> 
> Break this function into two helpers so that it's obvious that the
> trylock versions return a value that must be checked, and the blocking
> versions don't require that.  While we're at it, clean up the return
> type mismatch.
> 
> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
> ---
>  fs/aio.c           |    2 +-
>  fs/io_uring.c      |    3 +--
>  fs/super.c         |   18 ++++++++++++------
>  include/linux/fs.h |   21 +++++++++++----------
>  4 files changed, 25 insertions(+), 19 deletions(-)
> 
> 
> diff --git a/fs/aio.c b/fs/aio.c
> index c45c20d87538..04bb4bac327f 100644
> --- a/fs/aio.c
> +++ b/fs/aio.c
> @@ -1572,7 +1572,7 @@ static int aio_write(struct kiocb *req, const struct iocb *iocb,
>  		 * we return to userspace.
>  		 */
>  		if (S_ISREG(file_inode(file)->i_mode)) {
> -			__sb_start_write(file_inode(file)->i_sb, SB_FREEZE_WRITE, true);
> +			__sb_start_write(file_inode(file)->i_sb, SB_FREEZE_WRITE);

This should use sb_start_write()

>  	if (req->flags & REQ_F_ISREG) {
> -		__sb_start_write(file_inode(req->file)->i_sb,
> -					SB_FREEZE_WRITE, true);
> +		__sb_start_write(file_inode(req->file)->i_sb, SB_FREEZE_WRITE);

Same.

> +void __sb_start_write(struct super_block *sb, int level)
>  {
> +	percpu_down_read(sb->s_writers.rw_sem + level - 1);
>  }
>  EXPORT_SYMBOL(__sb_start_write);
>  
> +/*
> + * This is an internal function, please use sb_start_{write,pagefault,intwrite}
> + * instead.
> + */
> +bool __sb_start_write_trylock(struct super_block *sb, int level)
> +{
> +	return percpu_down_read_trylock(sb->s_writers.rw_sem + level - 1);
> +}
> +EXPORT_SYMBOL_GPL(__sb_start_write_trylock);

I think these can be inline in the headers, or even be merged into
the few callers.

> @@ -2756,14 +2757,14 @@ static inline void file_start_write(struct file *file)
>  {
>  	if (!S_ISREG(file_inode(file)->i_mode))
>  		return;
> -	__sb_start_write(file_inode(file)->i_sb, SB_FREEZE_WRITE, true);
> +	__sb_start_write(file_inode(file)->i_sb, SB_FREEZE_WRITE);

This should use sb_start_write.

>  }
>  
>  static inline bool file_start_write_trylock(struct file *file)
>  {
>  	if (!S_ISREG(file_inode(file)->i_mode))
>  		return true;
> -	return __sb_start_write(file_inode(file)->i_sb, SB_FREEZE_WRITE, false);
> +	return __sb_start_write_trylock(file_inode(file)->i_sb, SB_FREEZE_WRITE);

And this one sb_start_write_trylock.
diff mbox series

Patch

diff --git a/fs/aio.c b/fs/aio.c
index c45c20d87538..04bb4bac327f 100644
--- a/fs/aio.c
+++ b/fs/aio.c
@@ -1572,7 +1572,7 @@  static int aio_write(struct kiocb *req, const struct iocb *iocb,
 		 * we return to userspace.
 		 */
 		if (S_ISREG(file_inode(file)->i_mode)) {
-			__sb_start_write(file_inode(file)->i_sb, SB_FREEZE_WRITE, true);
+			__sb_start_write(file_inode(file)->i_sb, SB_FREEZE_WRITE);
 			__sb_writers_release(file_inode(file)->i_sb, SB_FREEZE_WRITE);
 		}
 		req->ki_flags |= IOCB_WRITE;
diff --git a/fs/io_uring.c b/fs/io_uring.c
index b42dfa0243bf..b735fecb49da 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -3532,8 +3532,7 @@  static int io_write(struct io_kiocb *req, bool force_nonblock,
 	 * we return to userspace.
 	 */
 	if (req->flags & REQ_F_ISREG) {
-		__sb_start_write(file_inode(req->file)->i_sb,
-					SB_FREEZE_WRITE, true);
+		__sb_start_write(file_inode(req->file)->i_sb, SB_FREEZE_WRITE);
 		__sb_writers_release(file_inode(req->file)->i_sb,
 					SB_FREEZE_WRITE);
 	}
diff --git a/fs/super.c b/fs/super.c
index e1fd667454d4..59aa59279133 100644
--- a/fs/super.c
+++ b/fs/super.c
@@ -1645,16 +1645,22 @@  EXPORT_SYMBOL(__sb_end_write);
  * This is an internal function, please use sb_start_{write,pagefault,intwrite}
  * instead.
  */
-int __sb_start_write(struct super_block *sb, int level, bool wait)
+void __sb_start_write(struct super_block *sb, int level)
 {
-	if (!wait)
-		return percpu_down_read_trylock(sb->s_writers.rw_sem + level-1);
-
-	percpu_down_read(sb->s_writers.rw_sem + level-1);
-	return 1;
+	percpu_down_read(sb->s_writers.rw_sem + level - 1);
 }
 EXPORT_SYMBOL(__sb_start_write);
 
+/*
+ * This is an internal function, please use sb_start_{write,pagefault,intwrite}
+ * instead.
+ */
+bool __sb_start_write_trylock(struct super_block *sb, int level)
+{
+	return percpu_down_read_trylock(sb->s_writers.rw_sem + level - 1);
+}
+EXPORT_SYMBOL_GPL(__sb_start_write_trylock);
+
 /**
  * sb_wait_write - wait until all writers to given file system finish
  * @sb: the super for which we wait
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 0bd126418bb6..98548ec7de0b 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -1581,7 +1581,8 @@  extern struct timespec64 current_time(struct inode *inode);
  */
 
 void __sb_end_write(struct super_block *sb, int level);
-int __sb_start_write(struct super_block *sb, int level, bool wait);
+void __sb_start_write(struct super_block *sb, int level);
+bool __sb_start_write_trylock(struct super_block *sb, int level);
 
 #define __sb_writers_acquired(sb, lev)	\
 	percpu_rwsem_acquire(&(sb)->s_writers.rw_sem[(lev)-1], 1, _THIS_IP_)
@@ -1645,12 +1646,12 @@  static inline void sb_end_intwrite(struct super_block *sb)
  */
 static inline void sb_start_write(struct super_block *sb)
 {
-	__sb_start_write(sb, SB_FREEZE_WRITE, true);
+	__sb_start_write(sb, SB_FREEZE_WRITE);
 }
 
-static inline int sb_start_write_trylock(struct super_block *sb)
+static inline bool sb_start_write_trylock(struct super_block *sb)
 {
-	return __sb_start_write(sb, SB_FREEZE_WRITE, false);
+	return __sb_start_write_trylock(sb, SB_FREEZE_WRITE);
 }
 
 /**
@@ -1674,7 +1675,7 @@  static inline int sb_start_write_trylock(struct super_block *sb)
  */
 static inline void sb_start_pagefault(struct super_block *sb)
 {
-	__sb_start_write(sb, SB_FREEZE_PAGEFAULT, true);
+	__sb_start_write(sb, SB_FREEZE_PAGEFAULT);
 }
 
 /*
@@ -1692,12 +1693,12 @@  static inline void sb_start_pagefault(struct super_block *sb)
  */
 static inline void sb_start_intwrite(struct super_block *sb)
 {
-	__sb_start_write(sb, SB_FREEZE_FS, true);
+	__sb_start_write(sb, SB_FREEZE_FS);
 }
 
-static inline int sb_start_intwrite_trylock(struct super_block *sb)
+static inline bool sb_start_intwrite_trylock(struct super_block *sb)
 {
-	return __sb_start_write(sb, SB_FREEZE_FS, false);
+	return __sb_start_write_trylock(sb, SB_FREEZE_FS);
 }
 
 
@@ -2756,14 +2757,14 @@  static inline void file_start_write(struct file *file)
 {
 	if (!S_ISREG(file_inode(file)->i_mode))
 		return;
-	__sb_start_write(file_inode(file)->i_sb, SB_FREEZE_WRITE, true);
+	__sb_start_write(file_inode(file)->i_sb, SB_FREEZE_WRITE);
 }
 
 static inline bool file_start_write_trylock(struct file *file)
 {
 	if (!S_ISREG(file_inode(file)->i_mode))
 		return true;
-	return __sb_start_write(file_inode(file)->i_sb, SB_FREEZE_WRITE, false);
+	return __sb_start_write_trylock(file_inode(file)->i_sb, SB_FREEZE_WRITE);
 }
 
 static inline void file_end_write(struct file *file)