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authorBoaz Harrosh <bharrosh@panasas.com>2007-12-13 13:47:40 +0200
committerJames Bottomley <James.Bottomley@HansenPartnership.com>2008-01-30 13:03:40 -0600
commit30b0c37b27485a9cb897bfe3824f6f517b8c80d6 (patch)
tree22643da8e175ff7badf2413dc8c84b2e99613a6f /drivers/scsi/scsi_lib.c
parentbb52d82f45df3a2661d88befba7c79a7db8be496 (diff)
[SCSI] implement scsi_data_buffer
In preparation for bidi we abstract all IO members of scsi_cmnd, that will need to duplicate, into a substructure. - Group all IO members of scsi_cmnd into a scsi_data_buffer structure. - Adjust accessors to new members. - scsi_{alloc,free}_sgtable receive a scsi_data_buffer instead of scsi_cmnd. And work on it. - Adjust scsi_init_io() and scsi_release_buffers() for above change. - Fix other parts of scsi_lib/scsi.c to members migration. Use accessors where appropriate. - fix Documentation about scsi_cmnd in scsi_host.h - scsi_error.c * Changed needed members of struct scsi_eh_save. * Careful considerations in scsi_eh_prep/restore_cmnd. - sd.c and sr.c * sd and sr would adjust IO size to align on device's block size so code needs to change once we move to scsi_data_buff implementation. * Convert code to use scsi_for_each_sg * Use data accessors where appropriate. - tgt: convert libsrp to use scsi_data_buffer - isd200: This driver still bangs on scsi_cmnd IO members, so need changing [jejb: rebased on top of sg_table patches fixed up conflicts and used the synergy to eliminate use_sg and sg_count] Signed-off-by: Boaz Harrosh <bharrosh@panasas.com> Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp> Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
Diffstat (limited to 'drivers/scsi/scsi_lib.c')
-rw-r--r--drivers/scsi/scsi_lib.c63
1 files changed, 25 insertions, 38 deletions
diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index 69fd62183bab..d5e77e9b3a9c 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -440,7 +440,7 @@ EXPORT_SYMBOL_GPL(scsi_execute_async);
static void scsi_init_cmd_errh(struct scsi_cmnd *cmd)
{
cmd->serial_number = 0;
- cmd->resid = 0;
+ scsi_set_resid(cmd, 0);
memset(cmd->sense_buffer, 0, SCSI_SENSE_BUFFERSIZE);
if (cmd->cmd_len == 0)
cmd->cmd_len = COMMAND_SIZE(cmd->cmnd[0]);
@@ -746,25 +746,25 @@ static struct scatterlist *scsi_sg_alloc(unsigned int nents, gfp_t gfp_mask)
return mempool_alloc(sgp->pool, gfp_mask);
}
-static int scsi_alloc_sgtable(struct scsi_cmnd *cmd, gfp_t gfp_mask)
+static int scsi_alloc_sgtable(struct scsi_data_buffer *sdb, int nents,
+ gfp_t gfp_mask)
{
int ret;
- BUG_ON(!cmd->use_sg);
+ BUG_ON(!nents);
- ret = __sg_alloc_table(&cmd->sg_table, cmd->use_sg,
- SCSI_MAX_SG_SEGMENTS, gfp_mask, scsi_sg_alloc);
+ ret = __sg_alloc_table(&sdb->table, nents, SCSI_MAX_SG_SEGMENTS,
+ gfp_mask, scsi_sg_alloc);
if (unlikely(ret))
- __sg_free_table(&cmd->sg_table, SCSI_MAX_SG_SEGMENTS,
+ __sg_free_table(&sdb->table, SCSI_MAX_SG_SEGMENTS,
scsi_sg_free);
- cmd->request_buffer = cmd->sg_table.sgl;
return ret;
}
-static void scsi_free_sgtable(struct scsi_cmnd *cmd)
+static void scsi_free_sgtable(struct scsi_data_buffer *sdb)
{
- __sg_free_table(&cmd->sg_table, SCSI_MAX_SG_SEGMENTS, scsi_sg_free);
+ __sg_free_table(&sdb->table, SCSI_MAX_SG_SEGMENTS, scsi_sg_free);
}
/*
@@ -786,15 +786,10 @@ static void scsi_free_sgtable(struct scsi_cmnd *cmd)
*/
void scsi_release_buffers(struct scsi_cmnd *cmd)
{
- if (cmd->use_sg)
- scsi_free_sgtable(cmd);
+ if (cmd->sdb.table.nents)
+ 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;
+ memset(&cmd->sdb, 0, sizeof(cmd->sdb));
}
EXPORT_SYMBOL(scsi_release_buffers);
@@ -829,7 +824,7 @@ EXPORT_SYMBOL(scsi_release_buffers);
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;
@@ -837,8 +832,6 @@ 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)
@@ -861,9 +854,11 @@ 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.
@@ -871,7 +866,6 @@ 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));
if (clear_errors)
req->errors = 0;
@@ -1002,35 +996,30 @@ int scsi_init_io(struct scsi_cmnd *cmd, gfp_t gfp_mask)
{
struct request *req = cmd->request;
int count;
-
- /*
- * 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;
+ struct scsi_data_buffer *sdb = &cmd->sdb;
/*
* If sg table allocation fails, requeue request later.
*/
- if (unlikely(scsi_alloc_sgtable(cmd, gfp_mask))) {
+ if (unlikely(scsi_alloc_sgtable(sdb, req->nr_phys_segments,
+ gfp_mask))) {
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);
- BUG_ON(count > cmd->use_sg);
- cmd->use_sg = count;
+ count = blk_rq_map_sg(req->q, req, sdb->table.sgl);
+ BUG_ON(count > sdb->table.nents);
+ sdb->table.nents = count;
return BLKPREP_OK;
}
EXPORT_SYMBOL(scsi_init_io);
@@ -1086,9 +1075,7 @@ 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;
+ memset(&cmd->sdb, 0, sizeof(cmd->sdb));
req->buffer = NULL;
}