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-rw-r--r--drivers/scsi/scsi_lib.c16
-rw-r--r--include/linux/scatterlist.h6
-rw-r--r--lib/scatterlist.c25
3 files changed, 27 insertions, 20 deletions
diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index 8723abeb018e..bbd7a0a08692 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -564,6 +564,11 @@ static struct scatterlist *scsi_sg_alloc(unsigned int nents, gfp_t gfp_mask)
return mempool_alloc(sgp->pool, gfp_mask);
}
+static void scsi_free_sgtable(struct scsi_data_buffer *sdb)
+{
+ __sg_free_table(&sdb->table, SCSI_MAX_SG_SEGMENTS, false, scsi_sg_free);
+}
+
static int scsi_alloc_sgtable(struct scsi_data_buffer *sdb, int nents,
gfp_t gfp_mask)
{
@@ -572,19 +577,12 @@ static int scsi_alloc_sgtable(struct scsi_data_buffer *sdb, int nents,
BUG_ON(!nents);
ret = __sg_alloc_table(&sdb->table, nents, SCSI_MAX_SG_SEGMENTS,
- gfp_mask, scsi_sg_alloc);
+ NULL, gfp_mask, scsi_sg_alloc);
if (unlikely(ret))
- __sg_free_table(&sdb->table, SCSI_MAX_SG_SEGMENTS,
- scsi_sg_free);
-
+ scsi_free_sgtable(sdb);
return ret;
}
-static void scsi_free_sgtable(struct scsi_data_buffer *sdb)
-{
- __sg_free_table(&sdb->table, SCSI_MAX_SG_SEGMENTS, scsi_sg_free);
-}
-
/*
* Function: scsi_release_buffers()
*
diff --git a/include/linux/scatterlist.h b/include/linux/scatterlist.h
index a964f7285600..f4ec8bbcb372 100644
--- a/include/linux/scatterlist.h
+++ b/include/linux/scatterlist.h
@@ -229,10 +229,10 @@ void sg_init_one(struct scatterlist *, const void *, unsigned int);
typedef struct scatterlist *(sg_alloc_fn)(unsigned int, gfp_t);
typedef void (sg_free_fn)(struct scatterlist *, unsigned int);
-void __sg_free_table(struct sg_table *, unsigned int, sg_free_fn *);
+void __sg_free_table(struct sg_table *, unsigned int, bool, sg_free_fn *);
void sg_free_table(struct sg_table *);
-int __sg_alloc_table(struct sg_table *, unsigned int, unsigned int, gfp_t,
- sg_alloc_fn *);
+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,
diff --git a/lib/scatterlist.c b/lib/scatterlist.c
index 3a8e8e8fb2a5..b4415fceb7e7 100644
--- a/lib/scatterlist.c
+++ b/lib/scatterlist.c
@@ -165,6 +165,7 @@ static void sg_kfree(struct scatterlist *sg, unsigned int nents)
* __sg_free_table - Free a previously mapped sg table
* @table: The sg table header to use
* @max_ents: The maximum number of entries per single scatterlist
+ * @skip_first_chunk: don't free the (preallocated) first scatterlist chunk
* @free_fn: Free function
*
* Description:
@@ -174,7 +175,7 @@ static void sg_kfree(struct scatterlist *sg, unsigned int nents)
*
**/
void __sg_free_table(struct sg_table *table, unsigned int max_ents,
- sg_free_fn *free_fn)
+ bool skip_first_chunk, sg_free_fn *free_fn)
{
struct scatterlist *sgl, *next;
@@ -202,7 +203,10 @@ void __sg_free_table(struct sg_table *table, unsigned int max_ents,
}
table->orig_nents -= sg_size;
- free_fn(sgl, alloc_size);
+ if (!skip_first_chunk) {
+ free_fn(sgl, alloc_size);
+ skip_first_chunk = false;
+ }
sgl = next;
}
@@ -217,7 +221,7 @@ EXPORT_SYMBOL(__sg_free_table);
**/
void sg_free_table(struct sg_table *table)
{
- __sg_free_table(table, SG_MAX_SINGLE_ALLOC, sg_kfree);
+ __sg_free_table(table, SG_MAX_SINGLE_ALLOC, false, sg_kfree);
}
EXPORT_SYMBOL(sg_free_table);
@@ -241,8 +245,8 @@ EXPORT_SYMBOL(sg_free_table);
*
**/
int __sg_alloc_table(struct sg_table *table, unsigned int nents,
- unsigned int max_ents, gfp_t gfp_mask,
- sg_alloc_fn *alloc_fn)
+ unsigned int max_ents, struct scatterlist *first_chunk,
+ gfp_t gfp_mask, sg_alloc_fn *alloc_fn)
{
struct scatterlist *sg, *prv;
unsigned int left;
@@ -269,7 +273,12 @@ int __sg_alloc_table(struct sg_table *table, unsigned int nents,
left -= sg_size;
- sg = alloc_fn(alloc_size, gfp_mask);
+ if (first_chunk) {
+ sg = first_chunk;
+ first_chunk = NULL;
+ } else {
+ sg = alloc_fn(alloc_size, gfp_mask);
+ }
if (unlikely(!sg)) {
/*
* Adjust entry count to reflect that the last
@@ -324,9 +333,9 @@ int sg_alloc_table(struct sg_table *table, unsigned int nents, gfp_t gfp_mask)
int ret;
ret = __sg_alloc_table(table, nents, SG_MAX_SINGLE_ALLOC,
- gfp_mask, sg_kmalloc);
+ NULL, gfp_mask, sg_kmalloc);
if (unlikely(ret))
- __sg_free_table(table, SG_MAX_SINGLE_ALLOC, sg_kfree);
+ __sg_free_table(table, SG_MAX_SINGLE_ALLOC, false, sg_kfree);
return ret;
}