Commit 8d1d4b53 authored by Caleb Sander Mateos's avatar Caleb Sander Mateos Committed by Andrew Morton
Browse files

scatterlist: inline sg_next() 

sg_next() is a short function called frequently in I/O paths. Define it
in the header file so it can be inlined into its callers.

Link: https://lkml.kernel.org/r/20250416160615.3571958-1-csander@purestorage.com


Signed-off-by: default avatarCaleb Sander Mateos <csander@purestorage.com>
Cc: Eric Biggers <ebiggers@kernel.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent 7d9b0527

include/linux/scatterlist.h

+22 −1
Original line number Diff line number Diff line
@@ -94,6 +94,28 @@ static inline bool sg_is_last(struct scatterlist *sg) 
	return __sg_flags(sg) & SG_END;

}



/**

 * sg_next - return the next scatterlist entry in a list

 * @sg:		The current sg entry

 *

 * Description:

 *   Usually the next entry will be @sg@ + 1, but if this sg element is part

 *   of a chained scatterlist, it could jump to the start of a new

 *   scatterlist array.

 *

 **/

static inline struct scatterlist *sg_next(struct scatterlist *sg)

{

	if (sg_is_last(sg))

		return NULL;



	sg++;

	if (unlikely(sg_is_chain(sg)))

		sg = sg_chain_ptr(sg);



	return sg;

}



/**

 * sg_assign_page - Assign a given page to an SG entry

 * @sg:		    SG entry
@@ -418,7 +440,6 @@ static inline void sg_init_marker(struct scatterlist *sgl, 


int sg_nents(struct scatterlist *sg);

int sg_nents_for_len(struct scatterlist *sg, u64 len);

struct scatterlist *sg_next(struct scatterlist *);

struct scatterlist *sg_last(struct scatterlist *s, unsigned int);

void sg_init_table(struct scatterlist *, unsigned int);

void sg_init_one(struct scatterlist *, const void *, unsigned int);

lib/scatterlist.c

+0 −23
Original line number Diff line number Diff line
@@ -13,29 +13,6 @@ 
#include <linux/uio.h>

#include <linux/folio_queue.h>



/**

 * sg_next - return the next scatterlist entry in a list

 * @sg:		The current sg entry

 *

 * Description:

 *   Usually the next entry will be @sg@ + 1, but if this sg element is part

 *   of a chained scatterlist, it could jump to the start of a new

 *   scatterlist array.

 *

 **/

struct scatterlist *sg_next(struct scatterlist *sg)

{

	if (sg_is_last(sg))

		return NULL;



	sg++;

	if (unlikely(sg_is_chain(sg)))

		sg = sg_chain_ptr(sg);



	return sg;

}

EXPORT_SYMBOL(sg_next);



/**

 * sg_nents - return total count of entries in scatterlist

 * @sg:		The scatterlist