This patch makes sg dio use the block layer functions
(blk_rq_map_user, blk_execute_rq_nowait, etc). It's an updated version
of the following patch:

http://marc.theaimsgroup.com/?l=linux-scsi&m=116527334121826&w=2

This doesn't break any existing features. While it converts sg dio to
use the block layer functions, sg mmap and indirect io still use
scsi_execute_async.

This is against the Linus' tree (uses the latest block layer API)
since the scsi-misc is a bit out-of-data.

On a side note, Mike has been working on converting sg mmap and
indirectio to the block layer functions.


Signed-off-by: FUJITA Tomonori <[EMAIL PROTECTED]>
---
 drivers/scsi/sg.c |  201 ++++++++++++++++-------------------------------------
 1 files changed, 59 insertions(+), 142 deletions(-)

diff --git a/drivers/scsi/sg.c b/drivers/scsi/sg.c
index 81e3bc7..304e34b 100644
--- a/drivers/scsi/sg.c
+++ b/drivers/scsi/sg.c
@@ -136,6 +136,8 @@ typedef struct sg_request { /* SG_MAX_QU
        char orphan;            /* 1 -> drop on sight, 0 -> normal */
        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 */
@@ -690,6 +692,11 @@ sg_new_write(Sg_fd * sfp, const char __u
        return count;
 }
 
+static void sg_rq_end_io(struct request *rq, int uptodate)
+{
+       sg_cmd_done(rq->end_io_data, rq->sense, rq->errors, rq->data_len);
+}
+
 static int
 sg_common_write(Sg_fd * sfp, Sg_request * srp,
                unsigned char *cmnd, int timeout, int blocking)
@@ -742,6 +749,14 @@ sg_common_write(Sg_fd * sfp, Sg_request
        hp->duration = jiffies_to_msecs(jiffies);
 /* Now send everything of to mid-level. The next time we hear about this
    packet is when sg_cmd_done() is called (i.e. a callback). */
+       if (hp->info & SG_INFO_DIRECT_IO) {
+               memcpy(srp->rq->cmd, cmnd, hp->cmd_len);
+               srp->rq->timeout = timeout;
+               blk_execute_rq_nowait(sdp->device->request_queue, sdp->disk,
+                                         srp->rq, 1, sg_rq_end_io);
+               return 0;
+       }
+
        if (scsi_execute_async(sdp->device, cmnd, hp->cmd_len, data_dir, 
srp->data.buffer,
                                hp->dxfer_len, srp->data.k_use_sg, timeout,
                                SG_DEFAULT_RETRIES, srp, sg_cmd_done,
@@ -1651,7 +1666,10 @@ sg_finish_rem_req(Sg_request * srp)
        SCSI_LOG_TIMEOUT(4, printk("sg_finish_rem_req: res_used=%d\n", (int) 
srp->res_used));
        if (srp->res_used)
                sg_unlink_reserve(sfp, srp);
-       else
+       else if (req_schp->dio_in_use) {
+               blk_rq_unmap_user(srp->bio);
+               blk_put_request(srp->rq);
+       } else
                sg_remove_scat(req_schp);
        sg_remove_request(sfp, srp);
 }
@@ -1677,122 +1695,20 @@ sg_build_sgat(Sg_scatter_hold * schp, co
        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(&current->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(&current->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 (TestSetPageLocked(pages[i]))
-                  goto out_unlock; */
-        }
-
-       sgl[0].page = pages[0];
-       sgl[0].offset = 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++) {
-                       sgl[i].page = pages[i]; 
-                       sgl[i].length = count < PAGE_SIZE ? count : PAGE_SIZE;
-                       count -= PAGE_SIZE;
-               }
-       }
-       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)
+/* taken from the bsg tree */
+static int blk_fill_sghdr_rq(request_queue_t *q, struct request *rq,
+                            struct sg_io_hdr *hdr, int has_write_perm)
 {
-       int i;
-
-       for (i=0; i < nr_pages; i++) {
-               struct page *page = sgl[i].page;
-
-               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);
-       }
+       memset(rq->cmd, 0, BLK_MAX_CDB); /* ATAPI hates garbage after CDB */
+       /*
+        * fill in request structure
+        */
+       rq->cmd_len = hdr->cmd_len;
+       rq->cmd_type = REQ_TYPE_BLOCK_PC;
 
        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)
@@ -1800,26 +1716,34 @@ sg_build_direct(Sg_request * srp, Sg_fd
 #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, rw;
+       request_queue_t *q = sfp->parentdp->device->request_queue;
+       struct request *rq;
 
-       if (((unsigned long)hp->dxferp &
-                       queue_dma_alignment(sdev->request_queue)) != 0)
+       if (((unsigned long)hp->dxferp & queue_dma_alignment(q)))
                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;
+       rw = hp->dxfer_direction == SG_DXFER_TO_DEV ? WRITE : READ;
+
+       rq = blk_get_request(q, rw, GFP_ATOMIC);
+       if (!rq)
+               return -ENOMEM;
+
+       res = blk_fill_sghdr_rq(q, rq, hp, rw);
+       if (res) {
+               blk_put_request(rq);
+               return res;
+       }
+
+       res = blk_rq_map_user(q, rq, hp->dxferp, dxfer_len);
+       if (res) {
+               blk_put_request(rq);
+               return res;
        }
-       schp->k_use_sg = res;
+
+       srp->rq = rq;
+       srp->bio = rq->bio;
+       rq->end_io_data = srp;
        schp->dio_in_use = 1;
        hp->info |= SG_INFO_DIRECT_IO;
        return 0;
@@ -2002,23 +1926,16 @@ static void
 sg_remove_scat(Sg_scatter_hold * schp)
 {
        SCSI_LOG_TIMEOUT(4, printk("sg_remove_scat: k_use_sg=%d\n", 
schp->k_use_sg));
+
        if (schp->buffer && (schp->sglist_len > 0)) {
                struct scatterlist *sg = schp->buffer;
+               int k;
 
-               if (schp->dio_in_use) {
-#ifdef SG_ALLOW_DIO_CODE
-                       st_unmap_user_pages(sg, schp->k_use_sg, TRUE);
-#endif
-               } else {
-                       int k;
-
-                       for (k = 0; (k < schp->k_use_sg) && sg->page;
-                            ++k, ++sg) {
-                               SCSI_LOG_TIMEOUT(5, printk(
-                                   "sg_remove_scat: k=%d, pg=0x%p, len=%d\n",
-                                   k, sg->page, sg->length));
-                               sg_page_free(sg->page, sg->length);
-                       }
+               for (k = 0; (k < schp->k_use_sg) && sg->page; ++k, ++sg) {
+                       SCSI_LOG_TIMEOUT(5, printk(
+                                                "sg_remove_scat: k=%d, 
pg=0x%p, len=%d\n",
+                                                k, sg->page, sg->length));
+                       sg_page_free(sg->page, sg->length);
                }
                kfree(schp->buffer);
        }
-- 
1.4.3.2

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