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authorLinus Torvalds <torvalds@linux-foundation.org>2008-01-29 08:51:05 +1100
committerLinus Torvalds <torvalds@linux-foundation.org>2008-01-29 08:51:05 +1100
commit68fbda7de07e56eb90dd6e58a162527411b388b1 (patch)
tree118f82bb86fdf9dd3480ccabf96a7e5d3ab8bdb9 /include
parentd4928196fe9ec07d18139ba2735876b0c8aa738f (diff)
parent7cedb1f17fb7f4374d11501f61656ae9d3ba47e9 (diff)
Merge branch 'sg' of git://git.kernel.dk/linux-2.6-block
* 'sg' of git://git.kernel.dk/linux-2.6-block: SG: work with the SCSI fixed maximum allocations. SG: Convert SCSI to use scatterlist helpers for sg chaining SG: Move functions to lib/scatterlist.c and add sg chaining allocator helpers
Diffstat (limited to 'include')
-rw-r--r--include/linux/scatterlist.h126
-rw-r--r--include/scsi/scsi_cmnd.h7
2 files changed, 29 insertions, 104 deletions
diff --git a/include/linux/scatterlist.h b/include/linux/scatterlist.h
index e3ff21dbac5..a3d567a974e 100644
--- a/include/linux/scatterlist.h
+++ b/include/linux/scatterlist.h
@@ -7,6 +7,12 @@
#include <linux/string.h>
#include <asm/io.h>
+struct sg_table {
+ struct scatterlist *sgl; /* the list */
+ unsigned int nents; /* number of mapped entries */
+ unsigned int orig_nents; /* original size of list */
+};
+
/*
* Notes on SG table design.
*
@@ -106,31 +112,6 @@ static inline void sg_set_buf(struct scatterlist *sg, const void *buf,
sg_set_page(sg, virt_to_page(buf), buflen, offset_in_page(buf));
}
-/**
- * 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)
-{
-#ifdef CONFIG_DEBUG_SG
- BUG_ON(sg->sg_magic != SG_MAGIC);
-#endif
- if (sg_is_last(sg))
- return NULL;
-
- sg++;
- if (unlikely(sg_is_chain(sg)))
- sg = sg_chain_ptr(sg);
-
- return sg;
-}
-
/*
* Loop over each sg element, following the pointer to a new list if necessary
*/
@@ -138,40 +119,6 @@ static inline struct scatterlist *sg_next(struct scatterlist *sg)
for (__i = 0, sg = (sglist); __i < (nr); __i++, sg = sg_next(sg))
/**
- * sg_last - return the last scatterlist entry in a list
- * @sgl: First entry in the scatterlist
- * @nents: Number of entries in the scatterlist
- *
- * Description:
- * Should only be used casually, it (currently) scan the entire list
- * to get the last entry.
- *
- * Note that the @sgl@ pointer passed in need not be the first one,
- * the important bit is that @nents@ denotes the number of entries that
- * exist from @sgl@.
- *
- **/
-static inline struct scatterlist *sg_last(struct scatterlist *sgl,
- unsigned int nents)
-{
-#ifndef ARCH_HAS_SG_CHAIN
- struct scatterlist *ret = &sgl[nents - 1];
-#else
- struct scatterlist *sg, *ret = NULL;
- unsigned int i;
-
- for_each_sg(sgl, sg, nents, i)
- ret = sg;
-
-#endif
-#ifdef CONFIG_DEBUG_SG
- BUG_ON(sgl[0].sg_magic != SG_MAGIC);
- BUG_ON(!sg_is_last(ret));
-#endif
- return ret;
-}
-
-/**
* sg_chain - Chain two sglists together
* @prv: First scatterlist
* @prv_nents: Number of entries in prv
@@ -223,47 +170,6 @@ static inline void sg_mark_end(struct scatterlist *sg)
}
/**
- * sg_init_table - Initialize SG table
- * @sgl: The SG table
- * @nents: Number of entries in table
- *
- * Notes:
- * If this is part of a chained sg table, sg_mark_end() should be
- * used only on the last table part.
- *
- **/
-static inline void sg_init_table(struct scatterlist *sgl, unsigned int nents)
-{
- memset(sgl, 0, sizeof(*sgl) * nents);
-#ifdef CONFIG_DEBUG_SG
- {
- unsigned int i;
- for (i = 0; i < nents; i++)
- sgl[i].sg_magic = SG_MAGIC;
- }
-#endif
- sg_mark_end(&sgl[nents - 1]);
-}
-
-/**
- * sg_init_one - Initialize a single entry sg list
- * @sg: SG entry
- * @buf: Virtual address for IO
- * @buflen: IO length
- *
- * Notes:
- * This should not be used on a single entry that is part of a larger
- * table. Use sg_init_table() for that.
- *
- **/
-static inline void sg_init_one(struct scatterlist *sg, const void *buf,
- unsigned int buflen)
-{
- sg_init_table(sg, 1);
- sg_set_buf(sg, buf, buflen);
-}
-
-/**
* sg_phys - Return physical address of an sg entry
* @sg: SG entry
*
@@ -293,4 +199,24 @@ static inline void *sg_virt(struct scatterlist *sg)
return page_address(sg_page(sg)) + sg->offset;
}
+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);
+
+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 *);
+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, gfp_t);
+
+/*
+ * Maximum number of entries that will be allocated in one piece, if
+ * a list larger than this is required then chaining will be utilized.
+ */
+#define SG_MAX_SINGLE_ALLOC (PAGE_SIZE / sizeof(struct scatterlist))
+
#endif /* _LINUX_SCATTERLIST_H */
diff --git a/include/scsi/scsi_cmnd.h b/include/scsi/scsi_cmnd.h
index abd7479ff45..a457fca66f6 100644
--- a/include/scsi/scsi_cmnd.h
+++ b/include/scsi/scsi_cmnd.h
@@ -8,7 +8,6 @@
#include <linux/scatterlist.h>
struct request;
-struct scatterlist;
struct Scsi_Host;
struct scsi_device;
@@ -68,8 +67,8 @@ struct scsi_cmnd {
void *request_buffer; /* Actual requested buffer */
/* These elements define the operation we ultimately want to perform */
+ struct sg_table sg_table;
unsigned short use_sg; /* Number of pieces of scatter-gather */
- unsigned short __use_sg;
unsigned underflow; /* Return error if less than
this amount is transferred */
@@ -128,14 +127,14 @@ extern void *scsi_kmap_atomic_sg(struct scatterlist *sg, int sg_count,
size_t *offset, size_t *len);
extern void scsi_kunmap_atomic_sg(void *virt);
-extern struct scatterlist *scsi_alloc_sgtable(struct scsi_cmnd *, gfp_t);
+extern int scsi_alloc_sgtable(struct scsi_cmnd *, gfp_t);
extern void scsi_free_sgtable(struct scsi_cmnd *);
extern int scsi_dma_map(struct scsi_cmnd *cmd);
extern void scsi_dma_unmap(struct scsi_cmnd *cmd);
#define scsi_sg_count(cmd) ((cmd)->use_sg)
-#define scsi_sglist(cmd) ((struct scatterlist *)(cmd)->request_buffer)
+#define scsi_sglist(cmd) ((cmd)->sg_table.sgl)
#define scsi_bufflen(cmd) ((cmd)->request_bufflen)
static inline void scsi_set_resid(struct scsi_cmnd *cmd, int resid)