diff mbox series

[v11,3/9] iov_iter: introduce iov_iter_get_pages_[alloc_]flags()

Message ID 20221021174116.7200-4-logang@deltatee.com
State New
Headers
Series Userspace P2PDMA with O_DIRECT NVMe devices |

Commit Message

Logan Gunthorpe Oct. 21, 2022, 5:41 p.m. UTC 
  Add iov_iter_get_pages_flags() and iov_iter_get_pages_alloc_flags()
which take a flags argument that is passed to get_user_pages_fast().

This is so that FOLL_PCI_P2PDMA can be passed when appropriate.

Signed-off-by: Logan Gunthorpe <logang@deltatee.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
---
 include/linux/uio.h |  6 ++++++
 lib/iov_iter.c      | 32 ++++++++++++++++++++++++--------
 2 files changed, 30 insertions(+), 8 deletions(-)

Comments

Chaitanya Kulkarni Oct. 25, 2022, 1:14 a.m. UTC | #1 
On 10/21/22 10:41, Logan Gunthorpe wrote:
> Add iov_iter_get_pages_flags() and iov_iter_get_pages_alloc_flags()
> which take a flags argument that is passed to get_user_pages_fast().
> 
> This is so that FOLL_PCI_P2PDMA can be passed when appropriate.
> 
> Signed-off-by: Logan Gunthorpe <logang@deltatee.com>
> Reviewed-by: Christoph Hellwig <hch@lst.de>
> ---
>   include/linux/uio.h |  6 ++++++
>   lib/iov_iter.c      | 32 ++++++++++++++++++++++++--------
>   2 files changed, 30 insertions(+), 8 deletions(-)
> 
> diff --git a/include/linux/uio.h b/include/linux/uio.h
> index 2e3134b14ffd..9ede533ce64c 100644
> --- a/include/linux/uio.h
> +++ b/include/linux/uio.h
> @@ -247,8 +247,14 @@ void iov_iter_pipe(struct iov_iter *i, unsigned int direction, struct pipe_inode
>   void iov_iter_discard(struct iov_iter *i, unsigned int direction, size_t count);
>   void iov_iter_xarray(struct iov_iter *i, unsigned int direction, struct xarray *xarray,
>   		     loff_t start, size_t count);
> +ssize_t iov_iter_get_pages(struct iov_iter *i, struct page **pages,
> +		size_t maxsize, unsigned maxpages, size_t *start,
> +		unsigned gup_flags);
>   ssize_t iov_iter_get_pages2(struct iov_iter *i, struct page **pages,
>   			size_t maxsize, unsigned maxpages, size_t *start);
> +ssize_t iov_iter_get_pages_alloc(struct iov_iter *i,
> +		struct page ***pages, size_t maxsize, size_t *start,
> +		unsigned gup_flags);
>   ssize_t iov_iter_get_pages_alloc2(struct iov_iter *i, struct page ***pages,
>   			size_t maxsize, size_t *start);
>   int iov_iter_npages(const struct iov_iter *i, int maxpages);
> diff --git a/lib/iov_iter.c b/lib/iov_iter.c
> index c3ca28ca68a6..53efad017f3c 100644
> --- a/lib/iov_iter.c
> +++ b/lib/iov_iter.c
> @@ -1430,7 +1430,8 @@ static struct page *first_bvec_segment(const struct iov_iter *i,
>   
>   static ssize_t __iov_iter_get_pages_alloc(struct iov_iter *i,
>   		   struct page ***pages, size_t maxsize,
> -		   unsigned int maxpages, size_t *start)
> +		   unsigned int maxpages, size_t *start,
> +		   unsigned int gup_flags)
>   {
>   	unsigned int n;
>   
> @@ -1442,7 +1443,6 @@ static ssize_t __iov_iter_get_pages_alloc(struct iov_iter *i,
>   		maxsize = MAX_RW_COUNT;
>   
>   	if (likely(user_backed_iter(i))) {
> -		unsigned int gup_flags = 0;
>   		unsigned long addr;
>   		int res;
>   
> @@ -1492,33 +1492,49 @@ static ssize_t __iov_iter_get_pages_alloc(struct iov_iter *i,
>   	return -EFAULT;
>   }
>   
> -ssize_t iov_iter_get_pages2(struct iov_iter *i,
> +ssize_t iov_iter_get_pages(struct iov_iter *i,
>   		   struct page **pages, size_t maxsize, unsigned maxpages,
> -		   size_t *start)
> +		   size_t *start, unsigned gup_flags)
>   {
>   	if (!maxpages)
>   		return 0;
>   	BUG_ON(!pages);
>   
> -	return __iov_iter_get_pages_alloc(i, &pages, maxsize, maxpages, start);
> +	return __iov_iter_get_pages_alloc(i, &pages, maxsize, maxpages,
> +					  start, gup_flags);
> +}
> +EXPORT_SYMBOL_GPL(iov_iter_get_pages);
> +
> +ssize_t iov_iter_get_pages2(struct iov_iter *i, struct page **pages,
> +		size_t maxsize, unsigned maxpages, size_t *start)
> +{
> +	return iov_iter_get_pages(i, pages, maxsize, maxpages, start, 0);
>   }
>   EXPORT_SYMBOL(iov_iter_get_pages2);
>   
> -ssize_t iov_iter_get_pages_alloc2(struct iov_iter *i,
> +ssize_t iov_iter_get_pages_alloc(struct iov_iter *i,
>   		   struct page ***pages, size_t maxsize,
> -		   size_t *start)
> +		   size_t *start, unsigned gup_flags)
>   {
>   	ssize_t len;
>   
>   	*pages = NULL;
>   
> -	len = __iov_iter_get_pages_alloc(i, pages, maxsize, ~0U, start);
> +	len = __iov_iter_get_pages_alloc(i, pages, maxsize, ~0U, start,
> +					 gup_flags);
>   	if (len <= 0) {
>   		kvfree(*pages);
>   		*pages = NULL;
>   	}
>   	return len;
>   }
> +EXPORT_SYMBOL_GPL(iov_iter_get_pages_alloc);
> +
> +ssize_t iov_iter_get_pages_alloc2(struct iov_iter *i,
> +		struct page ***pages, size_t maxsize, size_t *start)
> +{
> +	return iov_iter_get_pages_alloc(i, pages, maxsize, start, 0);
> +}
>   EXPORT_SYMBOL(iov_iter_get_pages_alloc2);
Just one minor question why not make following functions
EXPORT_SYMBOL_GPL() ?

1. iov_iter_get_pages2()
2. iov_iter_get_pages_alloc2()

Reviewed-by: Chaitanya Kukkarni <kch@nvidia.com>

-ck
Logan Gunthorpe Oct. 25, 2022, 3:35 p.m. UTC | #2 
On 2022-10-24 19:14, Chaitanya Kulkarni wrote:
> On 10/21/22 10:41, Logan Gunthorpe wrote:
>> Add iov_iter_get_pages_flags() and iov_iter_get_pages_alloc_flags()
>> which take a flags argument that is passed to get_user_pages_fast().
>>
>> This is so that FOLL_PCI_P2PDMA can be passed when appropriate.
>>
>> Signed-off-by: Logan Gunthorpe <logang@deltatee.com>
>> Reviewed-by: Christoph Hellwig <hch@lst.de>
>> ---
>>   include/linux/uio.h |  6 ++++++
>>   lib/iov_iter.c      | 32 ++++++++++++++++++++++++--------
>>   2 files changed, 30 insertions(+), 8 deletions(-)
>>
>> diff --git a/include/linux/uio.h b/include/linux/uio.h
>> index 2e3134b14ffd..9ede533ce64c 100644
>> --- a/include/linux/uio.h
>> +++ b/include/linux/uio.h
>> @@ -247,8 +247,14 @@ void iov_iter_pipe(struct iov_iter *i, unsigned int direction, struct pipe_inode
>>   void iov_iter_discard(struct iov_iter *i, unsigned int direction, size_t count);
>>   void iov_iter_xarray(struct iov_iter *i, unsigned int direction, struct xarray *xarray,
>>   		     loff_t start, size_t count);
>> +ssize_t iov_iter_get_pages(struct iov_iter *i, struct page **pages,
>> +		size_t maxsize, unsigned maxpages, size_t *start,
>> +		unsigned gup_flags);
>>   ssize_t iov_iter_get_pages2(struct iov_iter *i, struct page **pages,
>>   			size_t maxsize, unsigned maxpages, size_t *start);
>> +ssize_t iov_iter_get_pages_alloc(struct iov_iter *i,
>> +		struct page ***pages, size_t maxsize, size_t *start,
>> +		unsigned gup_flags);
>>   ssize_t iov_iter_get_pages_alloc2(struct iov_iter *i, struct page ***pages,
>>   			size_t maxsize, size_t *start);
>>   int iov_iter_npages(const struct iov_iter *i, int maxpages);
>> diff --git a/lib/iov_iter.c b/lib/iov_iter.c
>> index c3ca28ca68a6..53efad017f3c 100644
>> --- a/lib/iov_iter.c
>> +++ b/lib/iov_iter.c
>> @@ -1430,7 +1430,8 @@ static struct page *first_bvec_segment(const struct iov_iter *i,
>>   
>>   static ssize_t __iov_iter_get_pages_alloc(struct iov_iter *i,
>>   		   struct page ***pages, size_t maxsize,
>> -		   unsigned int maxpages, size_t *start)
>> +		   unsigned int maxpages, size_t *start,
>> +		   unsigned int gup_flags)
>>   {
>>   	unsigned int n;
>>   
>> @@ -1442,7 +1443,6 @@ static ssize_t __iov_iter_get_pages_alloc(struct iov_iter *i,
>>   		maxsize = MAX_RW_COUNT;
>>   
>>   	if (likely(user_backed_iter(i))) {
>> -		unsigned int gup_flags = 0;
>>   		unsigned long addr;
>>   		int res;
>>   
>> @@ -1492,33 +1492,49 @@ static ssize_t __iov_iter_get_pages_alloc(struct iov_iter *i,
>>   	return -EFAULT;
>>   }
>>   
>> -ssize_t iov_iter_get_pages2(struct iov_iter *i,
>> +ssize_t iov_iter_get_pages(struct iov_iter *i,
>>   		   struct page **pages, size_t maxsize, unsigned maxpages,
>> -		   size_t *start)
>> +		   size_t *start, unsigned gup_flags)
>>   {
>>   	if (!maxpages)
>>   		return 0;
>>   	BUG_ON(!pages);
>>   
>> -	return __iov_iter_get_pages_alloc(i, &pages, maxsize, maxpages, start);
>> +	return __iov_iter_get_pages_alloc(i, &pages, maxsize, maxpages,
>> +					  start, gup_flags);
>> +}
>> +EXPORT_SYMBOL_GPL(iov_iter_get_pages);
>> +
>> +ssize_t iov_iter_get_pages2(struct iov_iter *i, struct page **pages,
>> +		size_t maxsize, unsigned maxpages, size_t *start)
>> +{
>> +	return iov_iter_get_pages(i, pages, maxsize, maxpages, start, 0);
>>   }
>>   EXPORT_SYMBOL(iov_iter_get_pages2);
>>   
>> -ssize_t iov_iter_get_pages_alloc2(struct iov_iter *i,
>> +ssize_t iov_iter_get_pages_alloc(struct iov_iter *i,
>>   		   struct page ***pages, size_t maxsize,
>> -		   size_t *start)
>> +		   size_t *start, unsigned gup_flags)
>>   {
>>   	ssize_t len;
>>   
>>   	*pages = NULL;
>>   
>> -	len = __iov_iter_get_pages_alloc(i, pages, maxsize, ~0U, start);
>> +	len = __iov_iter_get_pages_alloc(i, pages, maxsize, ~0U, start,
>> +					 gup_flags);
>>   	if (len <= 0) {
>>   		kvfree(*pages);
>>   		*pages = NULL;
>>   	}
>>   	return len;
>>   }
>> +EXPORT_SYMBOL_GPL(iov_iter_get_pages_alloc);
>> +
>> +ssize_t iov_iter_get_pages_alloc2(struct iov_iter *i,
>> +		struct page ***pages, size_t maxsize, size_t *start)
>> +{
>> +	return iov_iter_get_pages_alloc(i, pages, maxsize, start, 0);
>> +}
>>   EXPORT_SYMBOL(iov_iter_get_pages_alloc2);
> Just one minor question why not make following functions
> EXPORT_SYMBOL_GPL() ?
> 
> 1. iov_iter_get_pages2()
> 2. iov_iter_get_pages_alloc2()

They previously were not GPL, so I didn't think that should be changed
in this patch.

Thanks for the review!

Logan
Christoph Hellwig Oct. 25, 2022, 3:41 p.m. UTC | #3 
> > Just one minor question why not make following functions
> > EXPORT_SYMBOL_GPL() ?
> > 
> > 1. iov_iter_get_pages2()
> > 2. iov_iter_get_pages_alloc2()
> 
> They previously were not GPL, so I didn't think that should be changed
> in this patch.

Yes.  While they should have been _GPL from the start, rocking that
boat is a bit pointless now.  We just need to make sure to do the
right thing for the pinning variants that are going to replace them soon.
Logan Gunthorpe Oct. 27, 2022, 2:22 p.m. UTC | #4 
On 2022-10-27 01:11, Jay Fang wrote:
> On 2022/10/22 1:41, Logan Gunthorpe wrote:
>> Add iov_iter_get_pages_flags() and iov_iter_get_pages_alloc_flags()
>> which take a flags argument that is passed to get_user_pages_fast().
>>
>> This is so that FOLL_PCI_P2PDMA can be passed when appropriate.
>>
>> Signed-off-by: Logan Gunthorpe <logang@deltatee.com>
>> Reviewed-by: Christoph Hellwig <hch@lst.de>
>> ---
>>  include/linux/uio.h |  6 ++++++
>>  lib/iov_iter.c      | 32 ++++++++++++++++++++++++--------
>>  2 files changed, 30 insertions(+), 8 deletions(-)
>>
>> diff --git a/include/linux/uio.h b/include/linux/uio.h
>> index 2e3134b14ffd..9ede533ce64c 100644
>> --- a/include/linux/uio.h
>> +++ b/include/linux/uio.h
>> @@ -247,8 +247,14 @@ void iov_iter_pipe(struct iov_iter *i, unsigned int direction, struct pipe_inode
>>  void iov_iter_discard(struct iov_iter *i, unsigned int direction, size_t count);
>>  void iov_iter_xarray(struct iov_iter *i, unsigned int direction, struct xarray *xarray,
>>  		     loff_t start, size_t count);
>> +ssize_t iov_iter_get_pages(struct iov_iter *i, struct page **pages,
>> +		size_t maxsize, unsigned maxpages, size_t *start,
>> +		unsigned gup_flags);
>>  ssize_t iov_iter_get_pages2(struct iov_iter *i, struct page **pages,
>>  			size_t maxsize, unsigned maxpages, size_t *start);
>> +ssize_t iov_iter_get_pages_alloc(struct iov_iter *i,
>> +		struct page ***pages, size_t maxsize, size_t *start,
>> +		unsigned gup_flags);
>>  ssize_t iov_iter_get_pages_alloc2(struct iov_iter *i, struct page ***pages,
>>  			size_t maxsize, size_t *start);
>>  int iov_iter_npages(const struct iov_iter *i, int maxpages);
>> diff --git a/lib/iov_iter.c b/lib/iov_iter.c
>> index c3ca28ca68a6..53efad017f3c 100644
>> --- a/lib/iov_iter.c
>> +++ b/lib/iov_iter.c
>> @@ -1430,7 +1430,8 @@ static struct page *first_bvec_segment(const struct iov_iter *i,
>>  
>>  static ssize_t __iov_iter_get_pages_alloc(struct iov_iter *i,
>>  		   struct page ***pages, size_t maxsize,
>> -		   unsigned int maxpages, size_t *start)
>> +		   unsigned int maxpages, size_t *start,
>> +		   unsigned int gup_flags)
> 
> Hi,
> found some checkpatch warnings, like this:
> WARNING: Prefer 'unsigned int' to bare use of 'unsigned'
> #50: FILE: lib/iov_iter.c:1497:
> +		   size_t *start, unsigned gup_flags)

We usually stick with the choices of the nearby code instead of
the warnings of checkpatch.

Thanks,

Logan
diff mbox series

Patch

diff --git a/include/linux/uio.h b/include/linux/uio.h
index 2e3134b14ffd..9ede533ce64c 100644
--- a/include/linux/uio.h
+++ b/include/linux/uio.h
@@ -247,8 +247,14 @@  void iov_iter_pipe(struct iov_iter *i, unsigned int direction, struct pipe_inode
 void iov_iter_discard(struct iov_iter *i, unsigned int direction, size_t count);
 void iov_iter_xarray(struct iov_iter *i, unsigned int direction, struct xarray *xarray,
 		     loff_t start, size_t count);
+ssize_t iov_iter_get_pages(struct iov_iter *i, struct page **pages,
+		size_t maxsize, unsigned maxpages, size_t *start,
+		unsigned gup_flags);
 ssize_t iov_iter_get_pages2(struct iov_iter *i, struct page **pages,
 			size_t maxsize, unsigned maxpages, size_t *start);
+ssize_t iov_iter_get_pages_alloc(struct iov_iter *i,
+		struct page ***pages, size_t maxsize, size_t *start,
+		unsigned gup_flags);
 ssize_t iov_iter_get_pages_alloc2(struct iov_iter *i, struct page ***pages,
 			size_t maxsize, size_t *start);
 int iov_iter_npages(const struct iov_iter *i, int maxpages);
diff --git a/lib/iov_iter.c b/lib/iov_iter.c
index c3ca28ca68a6..53efad017f3c 100644
--- a/lib/iov_iter.c
+++ b/lib/iov_iter.c
@@ -1430,7 +1430,8 @@  static struct page *first_bvec_segment(const struct iov_iter *i,
 
 static ssize_t __iov_iter_get_pages_alloc(struct iov_iter *i,
 		   struct page ***pages, size_t maxsize,
-		   unsigned int maxpages, size_t *start)
+		   unsigned int maxpages, size_t *start,
+		   unsigned int gup_flags)
 {
 	unsigned int n;
 
@@ -1442,7 +1443,6 @@  static ssize_t __iov_iter_get_pages_alloc(struct iov_iter *i,
 		maxsize = MAX_RW_COUNT;
 
 	if (likely(user_backed_iter(i))) {
-		unsigned int gup_flags = 0;
 		unsigned long addr;
 		int res;
 
@@ -1492,33 +1492,49 @@  static ssize_t __iov_iter_get_pages_alloc(struct iov_iter *i,
 	return -EFAULT;
 }
 
-ssize_t iov_iter_get_pages2(struct iov_iter *i,
+ssize_t iov_iter_get_pages(struct iov_iter *i,
 		   struct page **pages, size_t maxsize, unsigned maxpages,
-		   size_t *start)
+		   size_t *start, unsigned gup_flags)
 {
 	if (!maxpages)
 		return 0;
 	BUG_ON(!pages);
 
-	return __iov_iter_get_pages_alloc(i, &pages, maxsize, maxpages, start);
+	return __iov_iter_get_pages_alloc(i, &pages, maxsize, maxpages,
+					  start, gup_flags);
+}
+EXPORT_SYMBOL_GPL(iov_iter_get_pages);
+
+ssize_t iov_iter_get_pages2(struct iov_iter *i, struct page **pages,
+		size_t maxsize, unsigned maxpages, size_t *start)
+{
+	return iov_iter_get_pages(i, pages, maxsize, maxpages, start, 0);
 }
 EXPORT_SYMBOL(iov_iter_get_pages2);
 
-ssize_t iov_iter_get_pages_alloc2(struct iov_iter *i,
+ssize_t iov_iter_get_pages_alloc(struct iov_iter *i,
 		   struct page ***pages, size_t maxsize,
-		   size_t *start)
+		   size_t *start, unsigned gup_flags)
 {
 	ssize_t len;
 
 	*pages = NULL;
 
-	len = __iov_iter_get_pages_alloc(i, pages, maxsize, ~0U, start);
+	len = __iov_iter_get_pages_alloc(i, pages, maxsize, ~0U, start,
+					 gup_flags);
 	if (len <= 0) {
 		kvfree(*pages);
 		*pages = NULL;
 	}
 	return len;
 }
+EXPORT_SYMBOL_GPL(iov_iter_get_pages_alloc);
+
+ssize_t iov_iter_get_pages_alloc2(struct iov_iter *i,
+		struct page ***pages, size_t maxsize, size_t *start)
+{
+	return iov_iter_get_pages_alloc(i, pages, maxsize, start, 0);
+}
 EXPORT_SYMBOL(iov_iter_get_pages_alloc2);
 
 size_t csum_and_copy_from_iter(void *addr, size_t bytes, __wsum *csum,