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sg: incorporate sg_build_direct into sg_start_req 

Calling blk_rq_map_user() at a single place is better than at
different two places. It makes the code more understandable.

Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
This commit is contained in:
FUJITA Tomonori 2008-09-02 22:50:05 +09:00 committed by Jens Axboe
parent 44c7b0eaa0
commit 626710c9d6
1 changed files with 34 additions and 48 deletions
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82
drivers/scsi/sg.c
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@ -202,7 +202,6 @@ static Sg_request *sg_get_rq_mark(Sg_fd * sfp, int pack_id);
static Sg_request *sg_add_request(Sg_fd * sfp);
static int sg_remove_request(Sg_fd * sfp, Sg_request * srp);
static int sg_res_in_use(Sg_fd * sfp);
static int sg_build_direct(Sg_request * srp, Sg_fd * sfp, int dxfer_len);
static Sg_device *sg_get_dev(int dev);
#ifdef CONFIG_SCSI_PROC_FS
static int sg_last_dev(void);
@ -1628,16 +1627,17 @@ exit_sg(void)
static int sg_start_req(Sg_request *srp, unsigned char *cmd)
{
int res = 0;
int res;
struct request *rq;
Sg_fd *sfp = srp->parentfp;
sg_io_hdr_t *hp = &srp->header;
int dxfer_len = (int) hp->dxfer_len;
int dxfer_dir = hp->dxfer_direction;
unsigned int iov_count = hp->iovec_count;
Sg_scatter_hold *req_schp = &srp->data;
Sg_scatter_hold *rsv_schp = &sfp->reserve;
struct request_queue *q = sfp->parentdp->device->request_queue;
struct rq_map_data map_data;
struct rq_map_data *md, map_data;
int rw = hp->dxfer_direction == SG_DXFER_TO_DEV ? WRITE : READ;
SCSI_LOG_TIMEOUT(4, printk(KERN_INFO "sg_start_req: dxfer_len=%d\n",
@ -1660,38 +1660,43 @@ static int sg_start_req(Sg_request *srp, unsigned char *cmd)
if ((dxfer_len <= 0) || (dxfer_dir == SG_DXFER_NONE))
return 0;
if (sg_allow_dio && (hp->flags & SG_FLAG_DIRECT_IO) &&
(dxfer_dir != SG_DXFER_UNKNOWN) && (0 == hp->iovec_count) &&
(!sfp->parentdp->device->host->unchecked_isa_dma) &&
if (sg_allow_dio && hp->flags & SG_FLAG_DIRECT_IO &&
dxfer_dir != SG_DXFER_UNKNOWN && !iov_count &&
!sfp->parentdp->device->host->unchecked_isa_dma &&
blk_rq_aligned(q, hp->dxferp, dxfer_len))
return sg_build_direct(srp, sfp, dxfer_len);
if ((!sg_res_in_use(sfp)) && (dxfer_len <= rsv_schp->bufflen))
sg_link_reserve(sfp, srp, dxfer_len);
md = NULL;
else
res = sg_build_indirect(req_schp, sfp, dxfer_len);
md = &map_data;
if (!res) {
struct request *rq = srp->rq;
Sg_scatter_hold *schp = &srp->data;
int iovec_count = (int) hp->iovec_count;
if (md) {
if (!sg_res_in_use(sfp) && dxfer_len <= rsv_schp->bufflen)
sg_link_reserve(sfp, srp, dxfer_len);
else {
res = sg_build_indirect(req_schp, sfp, dxfer_len);
if (res)
return res;
}
map_data.pages = schp->pages;
map_data.page_order = schp->page_order;
map_data.nr_entries = schp->k_use_sg;
if (iovec_count)
res = blk_rq_map_user_iov(q, rq, &map_data, hp->dxferp,
iovec_count,
hp->dxfer_len, GFP_ATOMIC);
else
res = blk_rq_map_user(q, rq, &map_data, hp->dxferp,
hp->dxfer_len, GFP_ATOMIC);
if (!res)
srp->bio = rq->bio;
md->pages = req_schp->pages;
md->page_order = req_schp->page_order;
md->nr_entries = req_schp->k_use_sg;
}
if (iov_count)
res = blk_rq_map_user_iov(q, rq, md, hp->dxferp, iov_count,
hp->dxfer_len, GFP_ATOMIC);
else
res = blk_rq_map_user(q, rq, md, hp->dxferp,
hp->dxfer_len, GFP_ATOMIC);
if (!res) {
srp->bio = rq->bio;
if (!md) {
req_schp->dio_in_use = 1;
hp->info |= SG_INFO_DIRECT_IO;
}
}
return res;
}
@ -1730,25 +1735,6 @@ sg_build_sgat(Sg_scatter_hold * schp, const Sg_fd * sfp, int tablesize)
return tablesize; /* number of scat_gath elements allocated */
}
/* Returns: -ve -> error, 0 -> done, 1 -> try indirect */
static int
sg_build_direct(Sg_request * srp, Sg_fd * sfp, int dxfer_len)
{
sg_io_hdr_t *hp = &srp->header;
Sg_scatter_hold *schp = &srp->data;
int res;
struct request *rq = srp->rq;
struct request_queue *q = sfp->parentdp->device->request_queue;
res = blk_rq_map_user(q, rq, NULL, hp->dxferp, dxfer_len, GFP_ATOMIC);
if (res)
return res;
srp->bio = rq->bio;
schp->dio_in_use = 1;
hp->info |= SG_INFO_DIRECT_IO;
return 0;
}
static int
sg_build_indirect(Sg_scatter_hold * schp, Sg_fd * sfp, int buff_size)
{