sg: convert the direct IO path to use the block layer
This patch converts the direct IO path (SG_FLAG_DIRECT_IO) to use the
block layer functions (blk_get_request, blk_execute_rq_nowait,
blk_rq_map_user, etc) instead of scsi_execute_async().
Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: Douglas Gilbert <dougg@torque.net>
Cc: Mike Christie <michaelc@cs.wisc.edu>
Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
diff --git a/drivers/scsi/sg.c b/drivers/scsi/sg.c
index 487c777..cb6de07 100644
--- a/drivers/scsi/sg.c
+++ b/drivers/scsi/sg.c
@@ -138,6 +138,7 @@
char sg_io_owned; /* 1 -> packet belongs to SG_IO */
volatile char done; /* 0->before bh, 1->before read, 2->read */
struct request *rq;
+ struct bio *bio;
} Sg_request;
typedef struct sg_fd { /* holds the state of a file descriptor */
@@ -1679,21 +1680,29 @@
sg_io_hdr_t *hp = &srp->header;
int dxfer_len = (int) hp->dxfer_len;
int dxfer_dir = hp->dxfer_direction;
+ unsigned long uaddr = (unsigned long)hp->dxferp;
Sg_scatter_hold *req_schp = &srp->data;
Sg_scatter_hold *rsv_schp = &sfp->reserve;
+ struct request_queue *q = sfp->parentdp->device->request_queue;
+ unsigned long alignment = queue_dma_alignment(q) | q->dma_pad_mask;
SCSI_LOG_TIMEOUT(4, printk("sg_start_req: dxfer_len=%d\n", dxfer_len));
if ((dxfer_len <= 0) || (dxfer_dir == SG_DXFER_NONE))
return __sg_start_req(srp, hp, cmd);
+#ifdef SG_ALLOW_DIO_CODE
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)) {
- res = sg_build_direct(srp, sfp, dxfer_len);
- if (res <= 0) /* -ve -> error, 0 -> done, 1 -> try indirect */
- return res;
+ (!sfp->parentdp->device->host->unchecked_isa_dma) &&
+ !(uaddr & alignment) && !(dxfer_len & alignment)) {
+ res = __sg_start_req(srp, hp, cmd);
+ if (!res)
+ res = sg_build_direct(srp, sfp, dxfer_len);
+
+ return res;
}
+#endif
if ((!sg_res_in_use(sfp)) && (dxfer_len <= rsv_schp->bufflen))
sg_link_reserve(sfp, srp, dxfer_len);
else {
@@ -1718,8 +1727,11 @@
else
sg_remove_scat(req_schp);
- if (srp->rq)
+ if (srp->rq) {
+ if (srp->bio)
+ blk_rq_unmap_user(srp->bio);
blk_put_request(srp->rq);
+ }
sg_remove_request(sfp, srp);
}
@@ -1746,151 +1758,23 @@
return tablesize; /* number of scat_gath elements allocated */
}
-#ifdef SG_ALLOW_DIO_CODE
-/* vvvvvvvv following code borrowed from st driver's direct IO vvvvvvvvv */
- /* TODO: hopefully we can use the generic block layer code */
-
-/* Pin down user pages and put them into a scatter gather list. Returns <= 0 if
- - mapping of all pages not successful
- (i.e., either completely successful or fails)
-*/
-static int
-st_map_user_pages(struct scatterlist *sgl, const unsigned int max_pages,
- unsigned long uaddr, size_t count, int rw)
-{
- unsigned long end = (uaddr + count + PAGE_SIZE - 1) >> PAGE_SHIFT;
- unsigned long start = uaddr >> PAGE_SHIFT;
- const int nr_pages = end - start;
- int res, i, j;
- struct page **pages;
-
- /* User attempted Overflow! */
- if ((uaddr + count) < uaddr)
- return -EINVAL;
-
- /* Too big */
- if (nr_pages > max_pages)
- return -ENOMEM;
-
- /* Hmm? */
- if (count == 0)
- return 0;
-
- if ((pages = kmalloc(max_pages * sizeof(*pages), GFP_ATOMIC)) == NULL)
- return -ENOMEM;
-
- /* Try to fault in all of the necessary pages */
- down_read(¤t->mm->mmap_sem);
- /* rw==READ means read from drive, write into memory area */
- res = get_user_pages(
- current,
- current->mm,
- uaddr,
- nr_pages,
- rw == READ,
- 0, /* don't force */
- pages,
- NULL);
- up_read(¤t->mm->mmap_sem);
-
- /* Errors and no page mapped should return here */
- if (res < nr_pages)
- goto out_unmap;
-
- for (i=0; i < nr_pages; i++) {
- /* FIXME: flush superflous for rw==READ,
- * probably wrong function for rw==WRITE
- */
- flush_dcache_page(pages[i]);
- /* ?? Is locking needed? I don't think so */
- /* if (!trylock_page(pages[i]))
- goto out_unlock; */
- }
-
- sg_set_page(sgl, pages[0], 0, uaddr & ~PAGE_MASK);
- if (nr_pages > 1) {
- sgl[0].length = PAGE_SIZE - sgl[0].offset;
- count -= sgl[0].length;
- for (i=1; i < nr_pages ; i++)
- sg_set_page(&sgl[i], pages[i], count < PAGE_SIZE ? count : PAGE_SIZE, 0);
- }
- else {
- sgl[0].length = count;
- }
-
- kfree(pages);
- return nr_pages;
-
- out_unmap:
- if (res > 0) {
- for (j=0; j < res; j++)
- page_cache_release(pages[j]);
- res = 0;
- }
- kfree(pages);
- return res;
-}
-
-
-/* And unmap them... */
-static int
-st_unmap_user_pages(struct scatterlist *sgl, const unsigned int nr_pages,
- int dirtied)
-{
- int i;
-
- for (i=0; i < nr_pages; i++) {
- struct page *page = sg_page(&sgl[i]);
-
- if (dirtied)
- SetPageDirty(page);
- /* unlock_page(page); */
- /* FIXME: cache flush missing for rw==READ
- * FIXME: call the correct reference counting function
- */
- page_cache_release(page);
- }
-
- return 0;
-}
-
-/* ^^^^^^^^ above code borrowed from st driver's direct IO ^^^^^^^^^ */
-#endif
-
-
/* Returns: -ve -> error, 0 -> done, 1 -> try indirect */
static int
sg_build_direct(Sg_request * srp, Sg_fd * sfp, int dxfer_len)
{
-#ifdef SG_ALLOW_DIO_CODE
sg_io_hdr_t *hp = &srp->header;
Sg_scatter_hold *schp = &srp->data;
- int sg_tablesize = sfp->parentdp->sg_tablesize;
- int mx_sc_elems, res;
- struct scsi_device *sdev = sfp->parentdp->device;
+ int res;
+ struct request *rq = srp->rq;
+ struct request_queue *q = sfp->parentdp->device->request_queue;
- if (((unsigned long)hp->dxferp &
- queue_dma_alignment(sdev->request_queue)) != 0)
- return 1;
-
- mx_sc_elems = sg_build_sgat(schp, sfp, sg_tablesize);
- if (mx_sc_elems <= 0) {
- return 1;
- }
- res = st_map_user_pages(schp->buffer, mx_sc_elems,
- (unsigned long)hp->dxferp, dxfer_len,
- (SG_DXFER_TO_DEV == hp->dxfer_direction) ? 1 : 0);
- if (res <= 0) {
- sg_remove_scat(schp);
- return 1;
- }
- schp->k_use_sg = res;
+ 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;
-#else
- return 1;
-#endif
}
static int
@@ -2069,11 +1953,7 @@
if (schp->buffer && (schp->sglist_len > 0)) {
struct scatterlist *sg = schp->buffer;
- if (schp->dio_in_use) {
-#ifdef SG_ALLOW_DIO_CODE
- st_unmap_user_pages(sg, schp->k_use_sg, TRUE);
-#endif
- } else {
+ if (!schp->dio_in_use) {
int k;
for (k = 0; (k < schp->k_use_sg) && sg_page(sg);
@@ -2083,8 +1963,9 @@
k, sg_page(sg), sg->length));
sg_page_free(sg_page(sg), sg->length);
}
+
+ kfree(schp->buffer);
}
- kfree(schp->buffer);
}
memset(schp, 0, sizeof (*schp));
}
