summaryrefslogtreecommitdiff
path: root/lib/scatterlist.c
diff options
context:
space:
mode:
Diffstat (limited to 'lib/scatterlist.c')
-rw-r--r--lib/scatterlist.c160
1 files changed, 95 insertions, 65 deletions
diff --git a/lib/scatterlist.c b/lib/scatterlist.c
index 27efa6178153..abb3432ed744 100644
--- a/lib/scatterlist.c
+++ b/lib/scatterlist.c
@@ -182,6 +182,7 @@ static void sg_kfree(struct scatterlist *sg, unsigned int nents)
* @nents_first_chunk: Number of entries int the (preallocated) first
* scatterlist chunk, 0 means no such preallocated first chunk
* @free_fn: Free function
+ * @num_ents: Number of entries in the table
*
* Description:
* Free an sg table previously allocated and setup with
@@ -190,7 +191,8 @@ static void sg_kfree(struct scatterlist *sg, unsigned int nents)
*
**/
void __sg_free_table(struct sg_table *table, unsigned int max_ents,
- unsigned int nents_first_chunk, sg_free_fn *free_fn)
+ unsigned int nents_first_chunk, sg_free_fn *free_fn,
+ unsigned int num_ents)
{
struct scatterlist *sgl, *next;
unsigned curr_max_ents = nents_first_chunk ?: max_ents;
@@ -199,8 +201,8 @@ void __sg_free_table(struct sg_table *table, unsigned int max_ents,
return;
sgl = table->sgl;
- while (table->orig_nents) {
- unsigned int alloc_size = table->orig_nents;
+ while (num_ents) {
+ unsigned int alloc_size = num_ents;
unsigned int sg_size;
/*
@@ -218,7 +220,7 @@ void __sg_free_table(struct sg_table *table, unsigned int max_ents,
next = NULL;
}
- table->orig_nents -= sg_size;
+ num_ents -= sg_size;
if (nents_first_chunk)
nents_first_chunk = 0;
else
@@ -232,13 +234,27 @@ void __sg_free_table(struct sg_table *table, unsigned int max_ents,
EXPORT_SYMBOL(__sg_free_table);
/**
+ * sg_free_append_table - Free a previously allocated append sg table.
+ * @table: The mapped sg append table header
+ *
+ **/
+void sg_free_append_table(struct sg_append_table *table)
+{
+ __sg_free_table(&table->sgt, SG_MAX_SINGLE_ALLOC, false, sg_kfree,
+ table->total_nents);
+}
+EXPORT_SYMBOL(sg_free_append_table);
+
+
+/**
* sg_free_table - Free a previously allocated sg table
* @table: The mapped sg table header
*
**/
void sg_free_table(struct sg_table *table)
{
- __sg_free_table(table, SG_MAX_SINGLE_ALLOC, false, sg_kfree);
+ __sg_free_table(table, SG_MAX_SINGLE_ALLOC, false, sg_kfree,
+ table->orig_nents);
}
EXPORT_SYMBOL(sg_free_table);
@@ -359,13 +375,12 @@ int sg_alloc_table(struct sg_table *table, unsigned int nents, gfp_t gfp_mask)
ret = __sg_alloc_table(table, nents, SG_MAX_SINGLE_ALLOC,
NULL, 0, gfp_mask, sg_kmalloc);
if (unlikely(ret))
- __sg_free_table(table, SG_MAX_SINGLE_ALLOC, 0, sg_kfree);
-
+ sg_free_table(table);
return ret;
}
EXPORT_SYMBOL(sg_alloc_table);
-static struct scatterlist *get_next_sg(struct sg_table *table,
+static struct scatterlist *get_next_sg(struct sg_append_table *table,
struct scatterlist *cur,
unsigned long needed_sges,
gfp_t gfp_mask)
@@ -386,54 +401,52 @@ static struct scatterlist *get_next_sg(struct sg_table *table,
return ERR_PTR(-ENOMEM);
sg_init_table(new_sg, alloc_size);
if (cur) {
+ table->total_nents += alloc_size - 1;
__sg_chain(next_sg, new_sg);
- table->orig_nents += alloc_size - 1;
} else {
- table->sgl = new_sg;
- table->orig_nents = alloc_size;
- table->nents = 0;
+ table->sgt.sgl = new_sg;
+ table->total_nents = alloc_size;
}
return new_sg;
}
/**
- * __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
+ * sg_alloc_append_table_from_pages - Allocate and initialize an append sg
+ * table from an array of pages
+ * @sgt_append: The sg append table 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)
* @max_segment: Maximum size of a scatterlist element in bytes
- * @prv: Last populated sge in sgt
* @left_pages: Left pages caller have to set after this call
* @gfp_mask: GFP allocation mask
*
* Description:
- * If @prv is NULL, allocate and initialize an sg table from a list of pages,
- * else reuse the scatterlist passed in at @prv.
- * Contiguous ranges of the pages are squashed into a single scatterlist
- * entry up to the maximum size specified in @max_segment. A user may
- * provide an offset at a start and a size of valid data in a buffer
- * specified by the page array.
+ * In the first call it allocate and initialize an sg table from a list of
+ * pages, else reuse the scatterlist from sgt_append. Contiguous ranges of
+ * the pages are squashed into a single scatterlist entry up to the maximum
+ * size specified in @max_segment. 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_append_table
*
* Returns:
- * Last SGE in sgt on success, PTR_ERR on otherwise.
- * The allocation in @sgt must be released by sg_free_table.
+ * 0 on success, negative error on failure
*
* Notes:
* If this function returns non-0 (eg failure), the caller must call
- * sg_free_table() to cleanup any leftover allocations.
+ * sg_free_append_table() to cleanup any leftover allocations.
+ *
+ * In the fist call, sgt_append must by initialized.
*/
-struct scatterlist *__sg_alloc_table_from_pages(struct sg_table *sgt,
+int sg_alloc_append_table_from_pages(struct sg_append_table *sgt_append,
struct page **pages, unsigned int n_pages, unsigned int offset,
unsigned long size, unsigned int max_segment,
- struct scatterlist *prv, unsigned int left_pages,
- gfp_t gfp_mask)
+ unsigned int left_pages, gfp_t gfp_mask)
{
unsigned int chunks, cur_page, seg_len, i, prv_len = 0;
unsigned int added_nents = 0;
- struct scatterlist *s = prv;
+ struct scatterlist *s = sgt_append->prv;
/*
* The algorithm below requires max_segment to be aligned to PAGE_SIZE
@@ -441,25 +454,26 @@ struct scatterlist *__sg_alloc_table_from_pages(struct sg_table *sgt,
*/
max_segment = ALIGN_DOWN(max_segment, PAGE_SIZE);
if (WARN_ON(max_segment < PAGE_SIZE))
- return ERR_PTR(-EINVAL);
+ return -EINVAL;
- if (IS_ENABLED(CONFIG_ARCH_NO_SG_CHAIN) && prv)
- return ERR_PTR(-EOPNOTSUPP);
+ if (IS_ENABLED(CONFIG_ARCH_NO_SG_CHAIN) && sgt_append->prv)
+ return -EOPNOTSUPP;
- if (prv) {
- unsigned long paddr = (page_to_pfn(sg_page(prv)) * PAGE_SIZE +
- prv->offset + prv->length) /
- PAGE_SIZE;
+ if (sgt_append->prv) {
+ unsigned long paddr =
+ (page_to_pfn(sg_page(sgt_append->prv)) * PAGE_SIZE +
+ sgt_append->prv->offset + sgt_append->prv->length) /
+ PAGE_SIZE;
if (WARN_ON(offset))
- return ERR_PTR(-EINVAL);
+ return -EINVAL;
/* Merge contiguous pages into the last SG */
- prv_len = prv->length;
+ prv_len = sgt_append->prv->length;
while (n_pages && page_to_pfn(pages[0]) == paddr) {
- if (prv->length + PAGE_SIZE > max_segment)
+ if (sgt_append->prv->length + PAGE_SIZE > max_segment)
break;
- prv->length += PAGE_SIZE;
+ sgt_append->prv->length += PAGE_SIZE;
paddr++;
pages++;
n_pages--;
@@ -496,15 +510,16 @@ struct scatterlist *__sg_alloc_table_from_pages(struct sg_table *sgt,
}
/* Pass how many chunks might be left */
- s = get_next_sg(sgt, s, chunks - i + left_pages, gfp_mask);
+ s = get_next_sg(sgt_append, s, chunks - i + left_pages,
+ gfp_mask);
if (IS_ERR(s)) {
/*
* Adjust entry length to be as before function was
* called.
*/
- if (prv)
- prv->length = prv_len;
- return s;
+ if (sgt_append->prv)
+ sgt_append->prv->length = prv_len;
+ return PTR_ERR(s);
}
chunk_size = ((j - cur_page) << PAGE_SHIFT) - offset;
sg_set_page(s, pages[cur_page],
@@ -514,42 +529,58 @@ struct scatterlist *__sg_alloc_table_from_pages(struct sg_table *sgt,
offset = 0;
cur_page = j;
}
- sgt->nents += added_nents;
+ sgt_append->sgt.nents += added_nents;
+ sgt_append->sgt.orig_nents = sgt_append->sgt.nents;
+ sgt_append->prv = s;
out:
if (!left_pages)
sg_mark_end(s);
- return s;
+ return 0;
}
-EXPORT_SYMBOL(__sg_alloc_table_from_pages);
+EXPORT_SYMBOL(sg_alloc_append_table_from_pages);
/**
- * sg_alloc_table_from_pages - Allocate and initialize an sg table from
- * an array of pages
+ * sg_alloc_table_from_pages_segment - Allocate and initialize an sg table from
+ * an array of pages and given maximum
+ * segment.
* @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)
+ * @max_segment: Maximum size of a scatterlist element in bytes
* @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.
+ * ranges of the pages are squashed into a single scatterlist node up to the
+ * maximum size specified in @max_segment. A user may provide an offset at a
+ * start and a size of valid data in a buffer specified by the page array.
*
- * Returns:
+ * 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)
+int sg_alloc_table_from_pages_segment(struct sg_table *sgt, struct page **pages,
+ unsigned int n_pages, unsigned int offset,
+ unsigned long size, unsigned int max_segment,
+ gfp_t gfp_mask)
{
- return PTR_ERR_OR_ZERO(__sg_alloc_table_from_pages(sgt, pages, n_pages,
- offset, size, UINT_MAX, NULL, 0, gfp_mask));
+ struct sg_append_table append = {};
+ int err;
+
+ err = sg_alloc_append_table_from_pages(&append, pages, n_pages, offset,
+ size, max_segment, 0, gfp_mask);
+ if (err) {
+ sg_free_append_table(&append);
+ return err;
+ }
+ memcpy(sgt, &append.sgt, sizeof(*sgt));
+ WARN_ON(append.total_nents != sgt->orig_nents);
+ return 0;
}
-EXPORT_SYMBOL(sg_alloc_table_from_pages);
+EXPORT_SYMBOL(sg_alloc_table_from_pages_segment);
#ifdef CONFIG_SGL_ALLOC
@@ -887,9 +918,8 @@ void sg_miter_stop(struct sg_mapping_iter *miter)
miter->__offset += miter->consumed;
miter->__remaining -= miter->consumed;
- if ((miter->__flags & SG_MITER_TO_SG) &&
- !PageSlab(miter->page))
- flush_kernel_dcache_page(miter->page);
+ if (miter->__flags & SG_MITER_TO_SG)
+ flush_dcache_page(miter->page);
if (miter->__flags & SG_MITER_ATOMIC) {
WARN_ON_ONCE(preemptible());