[PATCH] fs/ecryptfs: Replace kmap_atomic() with kmap_local_page()

[PATCH] fs/ecryptfs: Replace kmap_atomic() with kmap_local_page()

[Fabio M. De Francesco]

kmap_atomic() is deprecated in favor of kmap_local_page(). Therefore,
replace kmap_atomic() with kmap_local_page() in ecryptfs_write().

kmap_atomic() is implemented like a kmap_local_page() which also disables
page-faults and preemption (the latter only for !PREEMPT_RT kernels).

The code within the mapping/un-mapping in ecryptfs_write() does not
depend on the above-mentioned side effects.

Therefore, a mere replacement of the old API with the new one is all that
is required (i.e., there is no need to explicitly add any calls to
pagefault_disable() and/or preempt_disable()).

Suggested-by: Ira Weiny <ira.weiny@intel.com>
Signed-off-by: Fabio M. De Francesco <fmdefrancesco@gmail.com>
---
 fs/ecryptfs/read_write.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/fs/ecryptfs/read_write.c b/fs/ecryptfs/read_write.c
index 5edf027c8359..3458f153a588 100644
--- a/fs/ecryptfs/read_write.c
+++ b/fs/ecryptfs/read_write.c
@@ -140,7 +140,7 @@ int ecryptfs_write(struct inode *ecryptfs_inode, char *data, loff_t offset,
 			       ecryptfs_page_idx, rc);
 			goto out;
 		}
-		ecryptfs_page_virt = kmap_atomic(ecryptfs_page);
+		ecryptfs_page_virt = kmap_local_page(ecryptfs_page);
 
 		/*
 		 * pos: where we're now writing, offset: where the request was
@@ -163,7 +163,7 @@ int ecryptfs_write(struct inode *ecryptfs_inode, char *data, loff_t offset,
 			       (data + data_offset), num_bytes);
 			data_offset += num_bytes;
 		}
-		kunmap_atomic(ecryptfs_page_virt);
+		kunmap_local(ecryptfs_page_virt);
 		flush_dcache_page(ecryptfs_page);
 		SetPageUptodate(ecryptfs_page);
 		unlock_page(ecryptfs_page);
-- 
2.39.0

Re: [PATCH] fs/ecryptfs: Replace kmap_atomic() with kmap_local_page()

[Ira Weiny]

Fabio M. De Francesco wrote:
> kmap_atomic() is deprecated in favor of kmap_local_page(). Therefore,
> replace kmap_atomic() with kmap_local_page() in ecryptfs_write().
> 
> kmap_atomic() is implemented like a kmap_local_page() which also disables
> page-faults and preemption (the latter only for !PREEMPT_RT kernels).
> 
> The code within the mapping/un-mapping in ecryptfs_write() does not
> depend on the above-mentioned side effects.
> 
> Therefore, a mere replacement of the old API with the new one is all that
> is required (i.e., there is no need to explicitly add any calls to
> pagefault_disable() and/or preempt_disable()).
> 
> Suggested-by: Ira Weiny <ira.weiny@intel.com>

Reviewed-by: Ira Weiny <ira.weiny@intel.com>

> Signed-off-by: Fabio M. De Francesco <fmdefrancesco@gmail.com>
> ---
>  fs/ecryptfs/read_write.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/fs/ecryptfs/read_write.c b/fs/ecryptfs/read_write.c
> index 5edf027c8359..3458f153a588 100644
> --- a/fs/ecryptfs/read_write.c
> +++ b/fs/ecryptfs/read_write.c
> @@ -140,7 +140,7 @@ int ecryptfs_write(struct inode *ecryptfs_inode, char *data, loff_t offset,
>  			       ecryptfs_page_idx, rc);
>  			goto out;
>  		}
> -		ecryptfs_page_virt = kmap_atomic(ecryptfs_page);
> +		ecryptfs_page_virt = kmap_local_page(ecryptfs_page);
>  
>  		/*
>  		 * pos: where we're now writing, offset: where the request was
> @@ -163,7 +163,7 @@ int ecryptfs_write(struct inode *ecryptfs_inode, char *data, loff_t offset,
>  			       (data + data_offset), num_bytes);
>  			data_offset += num_bytes;
>  		}
> -		kunmap_atomic(ecryptfs_page_virt);
> +		kunmap_local(ecryptfs_page_virt);
>  		flush_dcache_page(ecryptfs_page);
>  		SetPageUptodate(ecryptfs_page);
>  		unlock_page(ecryptfs_page);
> -- 
> 2.39.0
>