SG: Convert SCSI to use scatterlist helpers for sg chaining
Also change scsi_alloc_sgtable() to just return 0/failure, since it maps to the command passed in. ->request_buffer is now no longer needed, once drivers are adapted to use scsi_sglist() it can be killed. Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
This commit is contained in:
Jens Axboe
parent
0db9299f48
commit
5ed7959ede
|
|
@ -739,138 +739,41 @@ 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)
|
||||
static void scsi_sg_free(struct scatterlist *sgl, unsigned int nents)
|
||||
{
|
||||
struct scsi_host_sg_pool *sgp;
|
||||
struct scatterlist *sgl, *prev, *ret;
|
||||
unsigned int index;
|
||||
int this, left;
|
||||
|
||||
sgp = scsi_sg_pools + scsi_sgtable_index(nents);
|
||||
mempool_free(sgl, sgp->pool);
|
||||
}
|
||||
|
||||
static struct scatterlist *scsi_sg_alloc(unsigned int nents, gfp_t gfp_mask)
|
||||
{
|
||||
struct scsi_host_sg_pool *sgp;
|
||||
|
||||
sgp = scsi_sg_pools + scsi_sgtable_index(nents);
|
||||
return mempool_alloc(sgp->pool, gfp_mask);
|
||||
}
|
||||
|
||||
int scsi_alloc_sgtable(struct scsi_cmnd *cmd, gfp_t gfp_mask)
|
||||
{
|
||||
int ret;
|
||||
|
||||
BUG_ON(!cmd->use_sg);
|
||||
|
||||
left = cmd->use_sg;
|
||||
ret = prev = NULL;
|
||||
do {
|
||||
this = left;
|
||||
if (this > SCSI_MAX_SG_SEGMENTS) {
|
||||
this = SCSI_MAX_SG_SEGMENTS - 1;
|
||||
index = SG_MEMPOOL_NR - 1;
|
||||
} else
|
||||
index = scsi_sgtable_index(this);
|
||||
ret = __sg_alloc_table(&cmd->sg_table, cmd->use_sg, gfp_mask, scsi_sg_alloc);
|
||||
if (unlikely(ret))
|
||||
__sg_free_table(&cmd->sg_table, scsi_sg_free);
|
||||
|
||||
left -= this;
|
||||
|
||||
sgp = scsi_sg_pools + index;
|
||||
|
||||
sgl = mempool_alloc(sgp->pool, gfp_mask);
|
||||
if (unlikely(!sgl))
|
||||
goto enomem;
|
||||
|
||||
sg_init_table(sgl, sgp->size);
|
||||
|
||||
/*
|
||||
* first loop through, set initial index and return value
|
||||
*/
|
||||
if (!ret)
|
||||
ret = sgl;
|
||||
|
||||
/*
|
||||
* chain previous sglist, if any. we know the previous
|
||||
* sglist must be the biggest one, or we would not have
|
||||
* ended up doing another loop.
|
||||
*/
|
||||
if (prev)
|
||||
sg_chain(prev, SCSI_MAX_SG_SEGMENTS, sgl);
|
||||
|
||||
/*
|
||||
* if we have nothing left, mark the last segment as
|
||||
* end-of-list
|
||||
*/
|
||||
if (!left)
|
||||
sg_mark_end(&sgl[this - 1]);
|
||||
|
||||
/*
|
||||
* 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
|
||||
* shrunk the number of segments, so keep a copy of it for free.
|
||||
*/
|
||||
cmd->__use_sg = cmd->use_sg;
|
||||
cmd->request_buffer = cmd->sg_table.sgl;
|
||||
return ret;
|
||||
enomem:
|
||||
if (ret) {
|
||||
/*
|
||||
* Free entries chained off ret. Since we were trying to
|
||||
* allocate another sglist, we know that all entries are of
|
||||
* the max size.
|
||||
*/
|
||||
sgp = scsi_sg_pools + SG_MEMPOOL_NR - 1;
|
||||
prev = ret;
|
||||
ret = &ret[SCSI_MAX_SG_SEGMENTS - 1];
|
||||
|
||||
while ((sgl = sg_chain_ptr(ret)) != NULL) {
|
||||
ret = &sgl[SCSI_MAX_SG_SEGMENTS - 1];
|
||||
mempool_free(sgl, sgp->pool);
|
||||
}
|
||||
|
||||
mempool_free(prev, sgp->pool);
|
||||
}
|
||||
return NULL;
|
||||
}
|
||||
|
||||
EXPORT_SYMBOL(scsi_alloc_sgtable);
|
||||
|
||||
void scsi_free_sgtable(struct scsi_cmnd *cmd)
|
||||
{
|
||||
struct scatterlist *sgl = cmd->request_buffer;
|
||||
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) {
|
||||
unsigned short this, left;
|
||||
struct scatterlist *next;
|
||||
unsigned int index;
|
||||
|
||||
left = cmd->__use_sg - (SCSI_MAX_SG_SEGMENTS - 1);
|
||||
next = sg_chain_ptr(&sgl[SCSI_MAX_SG_SEGMENTS - 1]);
|
||||
while (left && next) {
|
||||
sgl = next;
|
||||
this = left;
|
||||
if (this > SCSI_MAX_SG_SEGMENTS) {
|
||||
this = SCSI_MAX_SG_SEGMENTS - 1;
|
||||
index = SG_MEMPOOL_NR - 1;
|
||||
} else
|
||||
index = scsi_sgtable_index(this);
|
||||
|
||||
left -= this;
|
||||
|
||||
sgp = scsi_sg_pools + index;
|
||||
|
||||
if (left)
|
||||
next = sg_chain_ptr(&sgl[sgp->size - 1]);
|
||||
|
||||
mempool_free(sgl, sgp->pool);
|
||||
}
|
||||
|
||||
/*
|
||||
* Restore original, will be freed below
|
||||
*/
|
||||
sgl = cmd->request_buffer;
|
||||
sgp = scsi_sg_pools + SG_MEMPOOL_NR - 1;
|
||||
} else
|
||||
sgp = scsi_sg_pools + scsi_sgtable_index(cmd->__use_sg);
|
||||
|
||||
mempool_free(sgl, sgp->pool);
|
||||
__sg_free_table(&cmd->sg_table, scsi_sg_free);
|
||||
}
|
||||
|
||||
EXPORT_SYMBOL(scsi_free_sgtable);
|
||||
|
|
@ -1120,8 +1023,7 @@ static int scsi_init_io(struct scsi_cmnd *cmd)
|
|||
/*
|
||||
* If sg table allocation fails, requeue request later.
|
||||
*/
|
||||
cmd->request_buffer = scsi_alloc_sgtable(cmd, GFP_ATOMIC);
|
||||
if (unlikely(!cmd->request_buffer)) {
|
||||
if (unlikely(scsi_alloc_sgtable(cmd, GFP_ATOMIC))) {
|
||||
scsi_unprep_request(req);
|
||||
return BLKPREP_DEFER;
|
||||
}
|
||||
|
|
|
|||
|
|
@ -359,8 +359,7 @@ static int scsi_tgt_init_cmd(struct scsi_cmnd *cmd, gfp_t gfp_mask)
|
|||
int count;
|
||||
|
||||
cmd->use_sg = rq->nr_phys_segments;
|
||||
cmd->request_buffer = scsi_alloc_sgtable(cmd, gfp_mask);
|
||||
if (!cmd->request_buffer)
|
||||
if (scsi_alloc_sgtable(cmd, gfp_mask))
|
||||
return -ENOMEM;
|
||||
|
||||
cmd->request_bufflen = rq->data_len;
|
||||
|
|
|
|||
|
|
@ -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)
|
||||
|
|
|
|||
Loading…
Reference in New Issue