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* [RFC PATCH] ecryptfs: Replace kmap() with kmap_local_page()
@ 2022-06-28 18:49 Fabio M. De Francesco
  2022-07-01 19:04   ` Ira Weiny
  0 siblings, 1 reply; 3+ messages in thread
From: Fabio M. De Francesco @ 2022-06-28 18:49 UTC (permalink / raw)
  To: Tyler Hicks, Christian Brauner, Seth Forshee, Amir Goldstein,
	Matthew Wilcox (Oracle),
	Damien Le Moal, Greg Kroah-Hartman, Andrew Morton, Jan Kara,
	Muchun Song, Roman Gushchin, Theodore Ts'o, ecryptfs,
	linux-kernel
  Cc: Fabio M. De Francesco, Ira Weiny

The use of kmap() is being deprecated in favor of kmap_local_page().

With kmap_local_page() the mappings are per thread, CPU local and not
globally visible.

Use kmap_local_page() on all calling sites where kmap() is currently used.

The mappings in fs/ecryptfs seem to conform to the prerequisites for
easy conversions to kmap_local_page(), however I am not familiar with this
code.

This is why this is an RFC PATCH. I'd appreciate if people familiar with
eCryptfs could test and confirm whether these conversions are safe or not.

Suggested-by: Ira Weiny <ira.weiny@intel.com>
Signed-off-by: Fabio M. De Francesco <fmdefrancesco@gmail.com>
---
 fs/ecryptfs/crypto.c     | 8 ++++----
 fs/ecryptfs/read_write.c | 8 ++++----
 2 files changed, 8 insertions(+), 8 deletions(-)

diff --git a/fs/ecryptfs/crypto.c b/fs/ecryptfs/crypto.c
index e3f5d7f3c8a0..03263ebcccc6 100644
--- a/fs/ecryptfs/crypto.c
+++ b/fs/ecryptfs/crypto.c
@@ -465,10 +465,10 @@ int ecryptfs_encrypt_page(struct page *page)
 	}
 
 	lower_offset = lower_offset_for_page(crypt_stat, page);
-	enc_extent_virt = kmap(enc_extent_page);
+	enc_extent_virt = kmap_local_page(enc_extent_page);
 	rc = ecryptfs_write_lower(ecryptfs_inode, enc_extent_virt, lower_offset,
 				  PAGE_SIZE);
-	kunmap(enc_extent_page);
+	kunmap_local(enc_extent_virt);
 	if (rc < 0) {
 		ecryptfs_printk(KERN_ERR,
 			"Error attempting to write lower page; rc = [%d]\n",
@@ -514,10 +514,10 @@ int ecryptfs_decrypt_page(struct page *page)
 	BUG_ON(!(crypt_stat->flags & ECRYPTFS_ENCRYPTED));
 
 	lower_offset = lower_offset_for_page(crypt_stat, page);
-	page_virt = kmap(page);
+	page_virt = kmap_local_page(page);
 	rc = ecryptfs_read_lower(page_virt, lower_offset, PAGE_SIZE,
 				 ecryptfs_inode);
-	kunmap(page);
+	kunmap_local(page_virt);
 	if (rc < 0) {
 		ecryptfs_printk(KERN_ERR,
 			"Error attempting to read lower page; rc = [%d]\n",
diff --git a/fs/ecryptfs/read_write.c b/fs/ecryptfs/read_write.c
index 60bdcaddcbe5..5edf027c8359 100644
--- a/fs/ecryptfs/read_write.c
+++ b/fs/ecryptfs/read_write.c
@@ -64,11 +64,11 @@ int ecryptfs_write_lower_page_segment(struct inode *ecryptfs_inode,
 
 	offset = ((((loff_t)page_for_lower->index) << PAGE_SHIFT)
 		  + offset_in_page);
-	virt = kmap(page_for_lower);
+	virt = kmap_local_page(page_for_lower);
 	rc = ecryptfs_write_lower(ecryptfs_inode, virt, offset, size);
 	if (rc > 0)
 		rc = 0;
-	kunmap(page_for_lower);
+	kunmap_local(virt);
 	return rc;
 }
 
@@ -253,11 +253,11 @@ int ecryptfs_read_lower_page_segment(struct page *page_for_ecryptfs,
 	int rc;
 
 	offset = ((((loff_t)page_index) << PAGE_SHIFT) + offset_in_page);
-	virt = kmap(page_for_ecryptfs);
+	virt = kmap_local_page(page_for_ecryptfs);
 	rc = ecryptfs_read_lower(virt, offset, size, ecryptfs_inode);
 	if (rc > 0)
 		rc = 0;
-	kunmap(page_for_ecryptfs);
+	kunmap_local(virt);
 	flush_dcache_page(page_for_ecryptfs);
 	return rc;
 }
-- 
2.36.1


^ permalink raw reply related	[flat|nested] 3+ messages in thread
* Re: [RFC PATCH] ecryptfs: Replace kmap() with kmap_local_page()
  2022-06-28 18:49 [RFC PATCH] ecryptfs: Replace kmap() with kmap_local_page() Fabio M. De Francesco
@ 2022-07-01 19:04   ` Ira Weiny
  0 siblings, 0 replies; 3+ messages in thread
From: Ira Weiny @ 2022-07-01 19:04 UTC (permalink / raw)
  To: Fabio M. De Francesco
  Cc: Tyler Hicks, Christian Brauner, Seth Forshee, Amir Goldstein,
	Matthew Wilcox (Oracle),
	Damien Le Moal, Greg Kroah-Hartman, Andrew Morton, Jan Kara,
	Muchun Song, Roman Gushchin, Theodore Ts'o, ecryptfs,
	linux-kernel

On Tue, Jun 28, 2022 at 08:49:50PM +0200, Fabio M. De Francesco wrote:
> The use of kmap() is being deprecated in favor of kmap_local_page().
> 
> With kmap_local_page() the mappings are per thread, CPU local and not
> globally visible.
> 
> Use kmap_local_page() on all calling sites where kmap() is currently used.
> 
> The mappings in fs/ecryptfs seem to conform to the prerequisites for
> easy conversions to kmap_local_page(), however I am not familiar with this
> code.
> 
> This is why this is an RFC PATCH. I'd appreciate if people familiar with
> eCryptfs could test and confirm whether these conversions are safe or not.
> 
> 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/crypto.c     | 8 ++++----
>  fs/ecryptfs/read_write.c | 8 ++++----
>  2 files changed, 8 insertions(+), 8 deletions(-)
> 
> diff --git a/fs/ecryptfs/crypto.c b/fs/ecryptfs/crypto.c
> index e3f5d7f3c8a0..03263ebcccc6 100644
> --- a/fs/ecryptfs/crypto.c
> +++ b/fs/ecryptfs/crypto.c
> @@ -465,10 +465,10 @@ int ecryptfs_encrypt_page(struct page *page)
>  	}
>  
>  	lower_offset = lower_offset_for_page(crypt_stat, page);
> -	enc_extent_virt = kmap(enc_extent_page);
> +	enc_extent_virt = kmap_local_page(enc_extent_page);
>  	rc = ecryptfs_write_lower(ecryptfs_inode, enc_extent_virt, lower_offset,
>  				  PAGE_SIZE);
> -	kunmap(enc_extent_page);
> +	kunmap_local(enc_extent_virt);
>  	if (rc < 0) {
>  		ecryptfs_printk(KERN_ERR,
>  			"Error attempting to write lower page; rc = [%d]\n",
> @@ -514,10 +514,10 @@ int ecryptfs_decrypt_page(struct page *page)
>  	BUG_ON(!(crypt_stat->flags & ECRYPTFS_ENCRYPTED));
>  
>  	lower_offset = lower_offset_for_page(crypt_stat, page);
> -	page_virt = kmap(page);
> +	page_virt = kmap_local_page(page);
>  	rc = ecryptfs_read_lower(page_virt, lower_offset, PAGE_SIZE,
>  				 ecryptfs_inode);
> -	kunmap(page);
> +	kunmap_local(page_virt);
>  	if (rc < 0) {
>  		ecryptfs_printk(KERN_ERR,
>  			"Error attempting to read lower page; rc = [%d]\n",
> diff --git a/fs/ecryptfs/read_write.c b/fs/ecryptfs/read_write.c
> index 60bdcaddcbe5..5edf027c8359 100644
> --- a/fs/ecryptfs/read_write.c
> +++ b/fs/ecryptfs/read_write.c
> @@ -64,11 +64,11 @@ int ecryptfs_write_lower_page_segment(struct inode *ecryptfs_inode,
>  
>  	offset = ((((loff_t)page_for_lower->index) << PAGE_SHIFT)
>  		  + offset_in_page);
> -	virt = kmap(page_for_lower);
> +	virt = kmap_local_page(page_for_lower);
>  	rc = ecryptfs_write_lower(ecryptfs_inode, virt, offset, size);
>  	if (rc > 0)
>  		rc = 0;
> -	kunmap(page_for_lower);
> +	kunmap_local(virt);
>  	return rc;
>  }
>  
> @@ -253,11 +253,11 @@ int ecryptfs_read_lower_page_segment(struct page *page_for_ecryptfs,
>  	int rc;
>  
>  	offset = ((((loff_t)page_index) << PAGE_SHIFT) + offset_in_page);
> -	virt = kmap(page_for_ecryptfs);
> +	virt = kmap_local_page(page_for_ecryptfs);
>  	rc = ecryptfs_read_lower(virt, offset, size, ecryptfs_inode);
>  	if (rc > 0)
>  		rc = 0;
> -	kunmap(page_for_ecryptfs);
> +	kunmap_local(virt);
>  	flush_dcache_page(page_for_ecryptfs);
>  	return rc;
>  }
> -- 
> 2.36.1
> 

^ permalink raw reply	[flat|nested] 3+ messages in thread
* Re: [RFC PATCH] ecryptfs: Replace kmap() with kmap_local_page()
@ 2022-07-01 19:04   ` Ira Weiny
  0 siblings, 0 replies; 3+ messages in thread
From: Ira Weiny @ 2022-07-01 19:04 UTC (permalink / raw)
  To: Fabio M. De Francesco
  Cc: Tyler Hicks, Christian Brauner, Seth Forshee, Amir Goldstein,
	Matthew Wilcox (Oracle),
	Damien Le Moal, Greg Kroah-Hartman, Andrew Morton, Jan Kara,
	Muchun Song, Roman Gushchin, Theodore Ts'o, ecryptfs,
	linux-kernel

On Tue, Jun 28, 2022 at 08:49:50PM +0200, Fabio M. De Francesco wrote:
> The use of kmap() is being deprecated in favor of kmap_local_page().
> 
> With kmap_local_page() the mappings are per thread, CPU local and not
> globally visible.
> 
> Use kmap_local_page() on all calling sites where kmap() is currently used.
> 
> The mappings in fs/ecryptfs seem to conform to the prerequisites for
> easy conversions to kmap_local_page(), however I am not familiar with this
> code.
> 
> This is why this is an RFC PATCH. I'd appreciate if people familiar with
> eCryptfs could test and confirm whether these conversions are safe or not.
> 
> 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/crypto.c     | 8 ++++----
>  fs/ecryptfs/read_write.c | 8 ++++----
>  2 files changed, 8 insertions(+), 8 deletions(-)
> 
> diff --git a/fs/ecryptfs/crypto.c b/fs/ecryptfs/crypto.c
> index e3f5d7f3c8a0..03263ebcccc6 100644
> --- a/fs/ecryptfs/crypto.c
> +++ b/fs/ecryptfs/crypto.c
> @@ -465,10 +465,10 @@ int ecryptfs_encrypt_page(struct page *page)
>  	}
>  
>  	lower_offset = lower_offset_for_page(crypt_stat, page);
> -	enc_extent_virt = kmap(enc_extent_page);
> +	enc_extent_virt = kmap_local_page(enc_extent_page);
>  	rc = ecryptfs_write_lower(ecryptfs_inode, enc_extent_virt, lower_offset,
>  				  PAGE_SIZE);
> -	kunmap(enc_extent_page);
> +	kunmap_local(enc_extent_virt);
>  	if (rc < 0) {
>  		ecryptfs_printk(KERN_ERR,
>  			"Error attempting to write lower page; rc = [%d]\n",
> @@ -514,10 +514,10 @@ int ecryptfs_decrypt_page(struct page *page)
>  	BUG_ON(!(crypt_stat->flags & ECRYPTFS_ENCRYPTED));
>  
>  	lower_offset = lower_offset_for_page(crypt_stat, page);
> -	page_virt = kmap(page);
> +	page_virt = kmap_local_page(page);
>  	rc = ecryptfs_read_lower(page_virt, lower_offset, PAGE_SIZE,
>  				 ecryptfs_inode);
> -	kunmap(page);
> +	kunmap_local(page_virt);
>  	if (rc < 0) {
>  		ecryptfs_printk(KERN_ERR,
>  			"Error attempting to read lower page; rc = [%d]\n",
> diff --git a/fs/ecryptfs/read_write.c b/fs/ecryptfs/read_write.c
> index 60bdcaddcbe5..5edf027c8359 100644
> --- a/fs/ecryptfs/read_write.c
> +++ b/fs/ecryptfs/read_write.c
> @@ -64,11 +64,11 @@ int ecryptfs_write_lower_page_segment(struct inode *ecryptfs_inode,
>  
>  	offset = ((((loff_t)page_for_lower->index) << PAGE_SHIFT)
>  		  + offset_in_page);
> -	virt = kmap(page_for_lower);
> +	virt = kmap_local_page(page_for_lower);
>  	rc = ecryptfs_write_lower(ecryptfs_inode, virt, offset, size);
>  	if (rc > 0)
>  		rc = 0;
> -	kunmap(page_for_lower);
> +	kunmap_local(virt);
>  	return rc;
>  }
>  
> @@ -253,11 +253,11 @@ int ecryptfs_read_lower_page_segment(struct page *page_for_ecryptfs,
>  	int rc;
>  
>  	offset = ((((loff_t)page_index) << PAGE_SHIFT) + offset_in_page);
> -	virt = kmap(page_for_ecryptfs);
> +	virt = kmap_local_page(page_for_ecryptfs);
>  	rc = ecryptfs_read_lower(virt, offset, size, ecryptfs_inode);
>  	if (rc > 0)
>  		rc = 0;
> -	kunmap(page_for_ecryptfs);
> +	kunmap_local(virt);
>  	flush_dcache_page(page_for_ecryptfs);
>  	return rc;
>  }
> -- 
> 2.36.1
> 

^ permalink raw reply	[flat|nested] 3+ messages in thread
end of thread, other threads:[~2022-07-01 19:04 UTC | newest]

Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed)
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2022-06-28 18:49 [RFC PATCH] ecryptfs: Replace kmap() with kmap_local_page() Fabio M. De Francesco
2022-07-01 19:04 ` Ira Weiny
2022-07-01 19:04   ` Ira Weiny

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