This adds a new data structure, scsi_data_buffer, including scsi data
transfer. One scsi_data_buffer structure is embedded in struct
scsi_cmnd for uni-directional transfer.
This is a preparation for bidirectional support.
Signed-off-by: FUJITA Tomonori <fujita.tomonori@xxxxxxxxxxxxx>
---
drivers/scsi/scsi_lib.c | 85 ++++++++++++++++++++++-----------------------
include/scsi/scsi_cmnd.h | 38 ++++++++++++++------
2 files changed, 69 insertions(+), 54 deletions(-)
diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index 1e0f691..3adce94 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -742,16 +742,22 @@ static inline unsigned int scsi_sgtable_index(unsigned short nents)
return index;
}
-struct scatterlist *scsi_alloc_sgtable(struct scsi_cmnd *cmd, gfp_t gfp_mask)
+int scsi_alloc_sgtable(struct scsi_data_buffer *sdb, gfp_t gfp_mask,
+ int sg_count)
{
struct scsi_host_sg_pool *sgp;
struct scatterlist *sgl, *prev, *ret;
unsigned int index;
int this, left;
- BUG_ON(!cmd->use_sg);
+ /*
+ * don't allow subsequent mempool allocs to sleep, it would
+ * violate the mempool principle.
+ */
+ gfp_mask &= ~__GFP_WAIT;
+ gfp_mask |= __GFP_HIGH;
- left = cmd->use_sg;
+ left = sg_count;
ret = prev = NULL;
do {
this = left;
@@ -785,21 +791,17 @@ struct scatterlist *scsi_alloc_sgtable(struct scsi_cmnd *cmd, gfp_t gfp_mask)
if (prev)
sg_chain(prev, SCSI_MAX_SG_SEGMENTS, sgl);
- /*
- * don't allow subsequent mempool allocs to sleep, it would
- * violate the mempool principle.
- */
- gfp_mask &= ~__GFP_WAIT;
- gfp_mask |= __GFP_HIGH;
prev = sgl;
} while (left);
/*
- * ->use_sg may get modified after dma mapping has potentially
+ * ->sg_count may get modified after dma mapping has potentially
* shrunk the number of segments, so keep a copy of it for free.
*/
- cmd->__use_sg = cmd->use_sg;
- return ret;
+ sdb->sg_count = sg_count;
+ sdb->__sg_count = sg_count;
+ sdb->sglist = ret;
+ return 0;
enomem:
if (ret) {
/*
@@ -818,26 +820,26 @@ enomem:
mempool_free(prev, sgp->pool);
}
- return NULL;
+ return -ENOMEM;
}
EXPORT_SYMBOL(scsi_alloc_sgtable);
-void scsi_free_sgtable(struct scsi_cmnd *cmd)
+void scsi_free_sgtable(struct scsi_data_buffer *sdb)
{
- struct scatterlist *sgl = cmd->request_buffer;
+ struct scatterlist *sgl = sdb->sglist;
struct scsi_host_sg_pool *sgp;
/*
* if this is the biggest size sglist, check if we have
* chained parts we need to free
*/
- if (cmd->__use_sg > SCSI_MAX_SG_SEGMENTS) {
+ if (sdb->__sg_count > SCSI_MAX_SG_SEGMENTS) {
unsigned short this, left;
struct scatterlist *next;
unsigned int index;
- left = cmd->__use_sg - (SCSI_MAX_SG_SEGMENTS - 1);
+ left = sdb->__sg_count - (SCSI_MAX_SG_SEGMENTS - 1);
next = sg_chain_ptr(&sgl[SCSI_MAX_SG_SEGMENTS - 1]);
while (left && next) {
sgl = next;
@@ -861,10 +863,10 @@ void scsi_free_sgtable(struct scsi_cmnd *cmd)
/*
* Restore original, will be freed below
*/
- sgl = cmd->request_buffer;
+ sgl = sdb->sglist;
sgp = scsi_sg_pools + SG_MEMPOOL_NR - 1;
} else
- sgp = scsi_sg_pools + scsi_sgtable_index(cmd->__use_sg);
+ sgp = scsi_sg_pools + scsi_sgtable_index(sdb->__sg_count);
mempool_free(sgl, sgp->pool);
}
@@ -890,15 +892,14 @@ EXPORT_SYMBOL(scsi_free_sgtable);
*/
static void scsi_release_buffers(struct scsi_cmnd *cmd)
{
- if (cmd->use_sg)
- scsi_free_sgtable(cmd);
+ if (cmd->sdb.sglist)
+ scsi_free_sgtable(&cmd->sdb);
/*
* Zero these out. They now point to freed memory, and it is
* dangerous to hang onto the pointers.
*/
- cmd->request_buffer = NULL;
- cmd->request_bufflen = 0;
+ cmd->sdb.sglist = NULL;
}
/*
@@ -932,7 +933,7 @@ static void scsi_release_buffers(struct scsi_cmnd *cmd)
void scsi_io_completion(struct scsi_cmnd *cmd, unsigned int good_bytes)
{
int result = cmd->result;
- int this_count = cmd->request_bufflen;
+ int this_count = scsi_bufflen(cmd);
struct request_queue *q = cmd->device->request_queue;
struct request *req = cmd->request;
int clear_errors = 1;
@@ -940,8 +941,6 @@ void scsi_io_completion(struct scsi_cmnd *cmd, unsigned int good_bytes)
int sense_valid = 0;
int sense_deferred = 0;
- scsi_release_buffers(cmd);
-
if (result) {
sense_valid = scsi_command_normalize_sense(cmd, &sshdr);
if (sense_valid)
@@ -964,9 +963,11 @@ void scsi_io_completion(struct scsi_cmnd *cmd, unsigned int good_bytes)
req->sense_len = len;
}
}
- req->data_len = cmd->resid;
+ req->data_len = scsi_get_resid(cmd);
}
+ scsi_release_buffers(cmd);
+
/*
* Next deal with any sectors which we were able to correctly
* handle.
@@ -974,7 +975,7 @@ void scsi_io_completion(struct scsi_cmnd *cmd, unsigned int good_bytes)
SCSI_LOG_HLCOMPLETE(1, printk("%ld sectors total, "
"%d bytes done.\n",
req->nr_sectors, good_bytes));
- SCSI_LOG_HLCOMPLETE(1, printk("use_sg is %d\n", cmd->use_sg));
+ SCSI_LOG_HLCOMPLETE(1, printk("use_sg is %d\n", scsi_sg_count(cmd)));
if (clear_errors)
req->errors = 0;
@@ -1105,43 +1106,44 @@ EXPORT_SYMBOL(scsi_io_completion);
*/
static int scsi_init_io(struct scsi_cmnd *cmd)
{
- struct request *req = cmd->request;
- int count;
+ struct request *req = cmd->request;
+ struct scsi_data_buffer *sdb = &cmd->sdb;
+ int count;
+ int ret;
/*
* We used to not use scatter-gather for single segment request,
* but now we do (it makes highmem I/O easier to support without
* kmapping pages)
*/
- cmd->use_sg = req->nr_phys_segments;
+ ret = scsi_alloc_sgtable(sdb, GFP_ATOMIC, req->nr_phys_segments);
/*
* If sg table allocation fails, requeue request later.
*/
- cmd->request_buffer = scsi_alloc_sgtable(cmd, GFP_ATOMIC);
- if (unlikely(!cmd->request_buffer)) {
+ if (unlikely(ret)) {
scsi_unprep_request(req);
return BLKPREP_DEFER;
}
req->buffer = NULL;
if (blk_pc_request(req))
- cmd->request_bufflen = req->data_len;
+ sdb->length = req->data_len;
else
- cmd->request_bufflen = req->nr_sectors << 9;
+ sdb->length = req->nr_sectors << 9;
/*
* Next, walk the list, and fill in the addresses and sizes of
* each segment.
*/
- count = blk_rq_map_sg(req->q, req, cmd->request_buffer);
- if (likely(count <= cmd->use_sg)) {
- cmd->use_sg = count;
+ count = blk_rq_map_sg(req->q, req, sdb->sglist);
+ if (likely(count <= sdb->sg_count)) {
+ sdb->sg_count = count;
return BLKPREP_OK;
}
printk(KERN_ERR "Incorrect number of segments after building list\n");
- printk(KERN_ERR "counted %d, received %d\n", count, cmd->use_sg);
+ printk(KERN_ERR "counted %d, received %d\n", count, scsi_sg_count(cmd));
printk(KERN_ERR "req nr_sec %lu, cur_nr_sec %u\n", req->nr_sectors,
req->current_nr_sectors);
@@ -1181,7 +1183,7 @@ static void scsi_blk_pc_done(struct scsi_cmnd *cmd)
* successfully. Since this is a REQ_BLOCK_PC command the
* caller should check the request's errors value
*/
- scsi_io_completion(cmd, cmd->request_bufflen);
+ scsi_io_completion(cmd, scsi_bufflen(cmd));
}
static int scsi_setup_blk_pc_cmnd(struct scsi_device *sdev, struct request *req)
@@ -1210,9 +1212,6 @@ static int scsi_setup_blk_pc_cmnd(struct scsi_device *sdev, struct request *req)
BUG_ON(req->data_len);
BUG_ON(req->data);
- cmd->request_bufflen = 0;
- cmd->request_buffer = NULL;
- cmd->use_sg = 0;
req->buffer = NULL;
}
diff --git a/include/scsi/scsi_cmnd.h b/include/scsi/scsi_cmnd.h
index bb6358a..3eac964 100644
--- a/include/scsi/scsi_cmnd.h
+++ b/include/scsi/scsi_cmnd.h
@@ -12,6 +12,13 @@ struct scatterlist;
struct Scsi_Host;
struct scsi_device;
+struct scsi_data_buffer {
+ unsigned length;
+ int resid;
+ short sg_count;
+ short __sg_count;
+ struct scatterlist *sglist;
+};
/* embedded in scsi_cmnd */
struct scsi_pointer {
@@ -83,10 +90,6 @@ struct scsi_cmnd {
reconnects. Probably == sector
size */
- int resid; /* Number of bytes requested to be
- transferred less actual number
- transferred (0 if not supported) */
-
struct request *request; /* The command we are
working on */
@@ -118,6 +121,8 @@ struct scsi_cmnd {
unsigned char tag; /* SCSI-II queued command tag */
unsigned long pid; /* Process ID, starts at 0. Unique per host. */
+
+ struct scsi_data_buffer sdb;
};
extern struct scsi_cmnd *scsi_get_command(struct scsi_device *, gfp_t);
@@ -133,24 +138,35 @@ 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 void scsi_free_sgtable(struct scsi_cmnd *);
+extern int scsi_alloc_sgtable(struct scsi_data_buffer *, gfp_t, int);
+extern void scsi_free_sgtable(struct scsi_data_buffer *);
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_bufflen(cmd) ((cmd)->request_bufflen)
+static inline unsigned scsi_sg_count(struct scsi_cmnd *cmd)
+{
+ return cmd->sdb.sg_count;
+}
+
+static inline struct scatterlist *scsi_sglist(struct scsi_cmnd *cmd)
+{
+ return cmd->sdb.sglist;
+}
+
+static inline unsigned scsi_bufflen(struct scsi_cmnd *cmd)
+{
+ return cmd->sdb.length;
+}
static inline void scsi_set_resid(struct scsi_cmnd *cmd, int resid)
{
- cmd->resid = resid;
+ cmd->sdb.resid = resid;
}
static inline int scsi_get_resid(struct scsi_cmnd *cmd)
{
- return cmd->resid;
+ return cmd->sdb.resid;
}
#define scsi_for_each_sg(cmd, sg, nseg, __i) \
--
1.5.2.4
-
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