| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Date: Fri, 21 Oct 2016 15:11:21 +0100
From: Tvrtko Ursulin <tursulin@...ulin.net>
To: Intel-gfx@...ts.freedesktop.org
Cc: linux-kernel@...r.kernel.org, linux-media@...r.kernel.org,
Chris Wilson <chris@...is-wilson.co.uk>,
Tvrtko Ursulin <tvrtko.ursulin@...el.com>,
Masahiro Yamada <yamada.masahiro@...ionext.com>
Subject: [PATCH 3/5] lib/scatterlist: Introduce and export __sg_alloc_table_from_pages
From: Tvrtko Ursulin <tvrtko.ursulin@...el.com>
Drivers like i915 benefit from being able to control the maxium
size of the sg coallesced segment while building the scatter-
gather list.
Introduce and export the __sg_alloc_table_from_pages function
which will allow it that control.
Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@...el.com>
Cc: Masahiro Yamada <yamada.masahiro@...ionext.com>
Cc: linux-kernel@...r.kernel.org
---
include/linux/scatterlist.h | 11 +++++----
lib/scatterlist.c | 55 ++++++++++++++++++++++++++++++++++-----------
2 files changed, 49 insertions(+), 17 deletions(-)
diff --git a/include/linux/scatterlist.h b/include/linux/scatterlist.h
index c981bee1a3ae..29591dbb20fd 100644
--- a/include/linux/scatterlist.h
+++ b/include/linux/scatterlist.h
@@ -261,10 +261,13 @@ void sg_free_table(struct sg_table *);
int __sg_alloc_table(struct sg_table *, unsigned int, unsigned int,
struct scatterlist *, gfp_t, sg_alloc_fn *);
int sg_alloc_table(struct sg_table *, unsigned int, gfp_t);
-int sg_alloc_table_from_pages(struct sg_table *sgt,
- struct page **pages, unsigned int n_pages,
- unsigned int offset, unsigned long size,
- gfp_t gfp_mask);
+int __sg_alloc_table_from_pages(struct sg_table *sgt, struct page **pages,
+ unsigned int n_pages, unsigned int offset,
+ unsigned long size, gfp_t gfp_mask,
+ unsigned int max_segment);
+int sg_alloc_table_from_pages(struct sg_table *sgt, struct page **pages,
+ unsigned int n_pages, unsigned int offset,
+ unsigned long size, gfp_t gfp_mask);
size_t sg_copy_buffer(struct scatterlist *sgl, unsigned int nents, void *buf,
size_t buflen, off_t skip, bool to_buffer);
diff --git a/lib/scatterlist.c b/lib/scatterlist.c
index d928fa04aee3..0378c5fd7caa 100644
--- a/lib/scatterlist.c
+++ b/lib/scatterlist.c
@@ -370,14 +370,15 @@ int sg_alloc_table(struct sg_table *table, unsigned int nents, gfp_t gfp_mask)
EXPORT_SYMBOL(sg_alloc_table);
/**
- * sg_alloc_table_from_pages - Allocate and initialize an sg table from
- * an array of pages
- * @sgt: The sg table header to use
- * @pages: Pointer to an array of page pointers
- * @n_pages: Number of pages in the pages array
- * @offset: Offset from start of the first page to the start of a buffer
- * @size: Number of valid bytes in the buffer (after offset)
- * @gfp_mask: GFP allocation mask
+ * __sg_alloc_table_from_pages - Allocate and initialize an sg table from
+ * an array of pages
+ * @sgt: The sg table header to use
+ * @pages: Pointer to an array of page pointers
+ * @n_pages: Number of pages in the pages array
+ * @offset: Offset from start of the first page to the start of a buffer
+ * @size: Number of valid bytes in the buffer (after offset)
+ * @gfp_mask: GFP allocation mask
+ * @max_segment: Maximum size of a single scatterlist node in bytes
*
* Description:
* Allocate and initialize an sg table from a list of pages. Contiguous
@@ -389,12 +390,11 @@ EXPORT_SYMBOL(sg_alloc_table);
* Returns:
* 0 on success, negative error on failure
*/
-int sg_alloc_table_from_pages(struct sg_table *sgt,
- struct page **pages, unsigned int n_pages,
- unsigned int offset, unsigned long size,
- gfp_t gfp_mask)
+int __sg_alloc_table_from_pages(struct sg_table *sgt, struct page **pages,
+ unsigned int n_pages, unsigned int offset,
+ unsigned long size, gfp_t gfp_mask,
+ unsigned int max_segment)
{
- const unsigned int max_segment = ~0;
unsigned int seg_len, chunks;
unsigned int i;
unsigned int cur_page;
@@ -444,6 +444,35 @@ int sg_alloc_table_from_pages(struct sg_table *sgt,
return 0;
}
+EXPORT_SYMBOL(__sg_alloc_table_from_pages);
+
+/**
+ * sg_alloc_table_from_pages - Allocate and initialize an sg table from
+ * an array of pages
+ * @sgt: The sg table header to use
+ * @pages: Pointer to an array of page pointers
+ * @n_pages: Number of pages in the pages array
+ * @offset: Offset from start of the first page to the start of a buffer
+ * @size: Number of valid bytes in the buffer (after offset)
+ * @gfp_mask: GFP allocation mask
+ *
+ * Description:
+ * Allocate and initialize an sg table from a list of pages. Contiguous
+ * ranges of the pages are squashed into a single scatterlist node. A user
+ * may provide an offset at a start and a size of valid data in a buffer
+ * specified by the page array. The returned sg table is released by
+ * sg_free_table.
+ *
+ * Returns:
+ * 0 on success, negative error on failure
+ */
+int sg_alloc_table_from_pages(struct sg_table *sgt, struct page **pages,
+ unsigned int n_pages, unsigned int offset,
+ unsigned long size, gfp_t gfp_mask)
+{
+ return __sg_alloc_table_from_pages(sgt, pages, n_pages, offset,
+ size, gfp_mask, ~0);
+}
EXPORT_SYMBOL(sg_alloc_table_from_pages);
void __sg_page_iter_start(struct sg_page_iter *piter,
--
2.7.4
Powered by blists - more mailing lists