[PATCH] fs: fix misleading comments in read_write.c

[Yingchao Deng]

generic_write_checks() returns the number of bytes that may be written
(possibly truncated by generic_write_check_limits()), not zero.  The
comment was likely copied from generic_copy_file_checks(), which is the
analogous function for copy_file_range() and does return 0 on success.

Also, no_seek_end_llseek() and no_seek_end_llseek_size() are helpers for
files that do not support SEEK_END (they only handle SEEK_SET and
SEEK_CUR), not for "fixed-sized devices"; that description was copied
from fixed_size_llseek().

Signed-off-by: Yingchao Deng <dengyingchao@xxxxxxxxxxxxxxx>
---
 fs/read_write.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/fs/read_write.c b/fs/read_write.c
index e8c14e2760b2..4da846a2bf17 100644
--- a/fs/read_write.c
+++ b/fs/read_write.c
@@ -274,7 +274,7 @@ loff_t fixed_size_llseek(struct file *file, loff_t offset, int whence, loff_t si
 EXPORT_SYMBOL(fixed_size_llseek);
 
 /**
- * no_seek_end_llseek - llseek implementation for fixed-sized devices
+ * no_seek_end_llseek - llseek implementation for files without SEEK_END
  * @file:	file structure to seek on
  * @offset:	file offset to seek to
  * @whence:	type of seek
@@ -293,7 +293,7 @@ loff_t no_seek_end_llseek(struct file *file, loff_t offset, int whence)
 EXPORT_SYMBOL(no_seek_end_llseek);
 
 /**
- * no_seek_end_llseek_size - llseek implementation for fixed-sized devices
+ * no_seek_end_llseek_size - llseek implementation for files without SEEK_END
  * @file:	file structure to seek on
  * @offset:	file offset to seek to
  * @whence:	type of seek
@@ -1761,8 +1761,8 @@ EXPORT_SYMBOL(generic_write_checks_count);
  * Performs necessary checks before doing a write
  *
  * Can adjust writing position or amount of bytes to write.
- * Returns appropriate error code that caller should return or
- * zero in case that write should be allowed.
+ * Returns the number of bytes that may be written on success (which
+ * may be less than requested if truncated), or a negative error code.
  */
 ssize_t generic_write_checks(struct kiocb *iocb, struct iov_iter *from)
 {
-- 
2.33.0