[PATCH v3 1/5] scsi: replace "scsi_data_buffer" with "sg_table" in SG functions

From: Ming Lin
Date: Mon Apr 04 2016 - 17:48:35 EST


From: Ming Lin <ming.l@xxxxxxxxxxxxxxx>

Replace parameter "struct scsi_data_buffer" with "struct sg_table" in
SG alloc/free functions to make them generic.

Reviewed-by: Christoph Hellwig <hch@xxxxxx>
Signed-off-by: Ming Lin <ming.l@xxxxxxxxxxxxxxx>
---
drivers/scsi/scsi_lib.c | 41 +++++++++++++++++++++++------------------
1 file changed, 23 insertions(+), 18 deletions(-)

diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index 8106515..4229c18 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -583,14 +583,14 @@ 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, bool mq)
+static void scsi_free_sgtable(struct sg_table *table, bool mq)
{
- if (mq && sdb->table.orig_nents <= SCSI_MAX_SG_SEGMENTS)
+ if (mq && table->orig_nents <= SCSI_MAX_SG_SEGMENTS)
return;
- __sg_free_table(&sdb->table, SCSI_MAX_SG_SEGMENTS, mq, scsi_sg_free);
+ __sg_free_table(table, SCSI_MAX_SG_SEGMENTS, mq, scsi_sg_free);
}

-static int scsi_alloc_sgtable(struct scsi_data_buffer *sdb, int nents, bool mq)
+static int scsi_alloc_sgtable(struct sg_table *table, int nents, bool mq)
{
struct scatterlist *first_chunk = NULL;
int ret;
@@ -599,17 +599,17 @@ static int scsi_alloc_sgtable(struct scsi_data_buffer *sdb, int nents, bool mq)

if (mq) {
if (nents <= SCSI_MAX_SG_SEGMENTS) {
- sdb->table.nents = sdb->table.orig_nents = nents;
- sg_init_table(sdb->table.sgl, nents);
+ table->nents = table->orig_nents = nents;
+ sg_init_table(table->sgl, nents);
return 0;
}
- first_chunk = sdb->table.sgl;
+ first_chunk = table->sgl;
}

- ret = __sg_alloc_table(&sdb->table, nents, SCSI_MAX_SG_SEGMENTS,
+ ret = __sg_alloc_table(table, nents, SCSI_MAX_SG_SEGMENTS,
first_chunk, GFP_ATOMIC, scsi_sg_alloc);
if (unlikely(ret))
- scsi_free_sgtable(sdb, mq);
+ scsi_free_sgtable(table, mq);
return ret;
}

@@ -625,12 +625,17 @@ static void scsi_uninit_cmd(struct scsi_cmnd *cmd)

static void scsi_mq_free_sgtables(struct scsi_cmnd *cmd)
{
+ struct scsi_data_buffer *sdb;
+
if (cmd->sdb.table.nents)
- scsi_free_sgtable(&cmd->sdb, true);
- if (cmd->request->next_rq && cmd->request->next_rq->special)
- scsi_free_sgtable(cmd->request->next_rq->special, true);
+ scsi_free_sgtable(&cmd->sdb.table, true);
+ if (cmd->request->next_rq) {
+ sdb = cmd->request->next_rq->special;
+ if (sdb)
+ scsi_free_sgtable(&sdb->table, true);
+ }
if (scsi_prot_sg_count(cmd))
- scsi_free_sgtable(cmd->prot_sdb, true);
+ scsi_free_sgtable(&cmd->prot_sdb->table, true);
}

static void scsi_mq_uninit_cmd(struct scsi_cmnd *cmd)
@@ -669,19 +674,19 @@ static void scsi_mq_uninit_cmd(struct scsi_cmnd *cmd)
static void scsi_release_buffers(struct scsi_cmnd *cmd)
{
if (cmd->sdb.table.nents)
- scsi_free_sgtable(&cmd->sdb, false);
+ scsi_free_sgtable(&cmd->sdb.table, false);

memset(&cmd->sdb, 0, sizeof(cmd->sdb));

if (scsi_prot_sg_count(cmd))
- scsi_free_sgtable(cmd->prot_sdb, false);
+ scsi_free_sgtable(&cmd->prot_sdb->table, false);
}

static void scsi_release_bidi_buffers(struct scsi_cmnd *cmd)
{
struct scsi_data_buffer *bidi_sdb = cmd->request->next_rq->special;

- scsi_free_sgtable(bidi_sdb, false);
+ scsi_free_sgtable(&bidi_sdb->table, false);
kmem_cache_free(scsi_sdb_cache, bidi_sdb);
cmd->request->next_rq->special = NULL;
}
@@ -1085,7 +1090,7 @@ static int scsi_init_sgtable(struct request *req, struct scsi_data_buffer *sdb)
/*
* If sg table allocation fails, requeue request later.
*/
- if (unlikely(scsi_alloc_sgtable(sdb, req->nr_phys_segments,
+ if (unlikely(scsi_alloc_sgtable(&sdb->table, req->nr_phys_segments,
req->mq_ctx != NULL)))
return BLKPREP_DEFER;

@@ -1158,7 +1163,7 @@ int scsi_init_io(struct scsi_cmnd *cmd)

ivecs = blk_rq_count_integrity_sg(rq->q, rq->bio);

- if (scsi_alloc_sgtable(prot_sdb, ivecs, is_mq)) {
+ if (scsi_alloc_sgtable(&prot_sdb->table, ivecs, is_mq)) {
error = BLKPREP_DEFER;
goto err_exit;
}
--
1.9.1