forked from Minki/linux
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>
This commit is contained in:
FUJITA Tomonori
Jens Axboe
parent
10865dfa34
commit
6e5a30cba5
@ -138,6 +138,7 @@ typedef struct sg_request { /* SG_MAX_QUEUE requests outstanding per file */
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char sg_io_owned; /* 1 -> packet belongs to SG_IO */
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volatile char done; /* 0->before bh, 1->before read, 2->read */
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struct request *rq;
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struct bio *bio;
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} Sg_request;
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typedef struct sg_fd { /* holds the state of a file descriptor */
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@ -1679,21 +1680,29 @@ static int sg_start_req(Sg_request *srp, unsigned char *cmd)
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sg_io_hdr_t *hp = &srp->header;
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int dxfer_len = (int) hp->dxfer_len;
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int dxfer_dir = hp->dxfer_direction;
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unsigned long uaddr = (unsigned long)hp->dxferp;
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Sg_scatter_hold *req_schp = &srp->data;
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Sg_scatter_hold *rsv_schp = &sfp->reserve;
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struct request_queue *q = sfp->parentdp->device->request_queue;
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unsigned long alignment = queue_dma_alignment(q) | q->dma_pad_mask;
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SCSI_LOG_TIMEOUT(4, printk("sg_start_req: dxfer_len=%d\n", dxfer_len));
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if ((dxfer_len <= 0) || (dxfer_dir == SG_DXFER_NONE))
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return __sg_start_req(srp, hp, cmd);
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#ifdef SG_ALLOW_DIO_CODE
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if (sg_allow_dio && (hp->flags & SG_FLAG_DIRECT_IO) &&
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(dxfer_dir != SG_DXFER_UNKNOWN) && (0 == hp->iovec_count) &&
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(!sfp->parentdp->device->host->unchecked_isa_dma)) {
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res = sg_build_direct(srp, sfp, dxfer_len);
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if (res <= 0) /* -ve -> error, 0 -> done, 1 -> try indirect */
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return res;
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(!sfp->parentdp->device->host->unchecked_isa_dma) &&
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!(uaddr & alignment) && !(dxfer_len & alignment)) {
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res = __sg_start_req(srp, hp, cmd);
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if (!res)
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res = sg_build_direct(srp, sfp, dxfer_len);
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return res;
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}
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#endif
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if ((!sg_res_in_use(sfp)) && (dxfer_len <= rsv_schp->bufflen))
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sg_link_reserve(sfp, srp, dxfer_len);
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else {
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@ -1718,8 +1727,11 @@ sg_finish_rem_req(Sg_request * srp)
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else
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sg_remove_scat(req_schp);
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if (srp->rq)
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if (srp->rq) {
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if (srp->bio)
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blk_rq_unmap_user(srp->bio);
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blk_put_request(srp->rq);
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}
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sg_remove_request(sfp, srp);
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}
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@ -1746,151 +1758,23 @@ sg_build_sgat(Sg_scatter_hold * schp, const Sg_fd * sfp, int tablesize)
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return tablesize; /* number of scat_gath elements allocated */
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}
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#ifdef SG_ALLOW_DIO_CODE
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/* vvvvvvvv following code borrowed from st driver's direct IO vvvvvvvvv */
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/* TODO: hopefully we can use the generic block layer code */
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/* Pin down user pages and put them into a scatter gather list. Returns <= 0 if
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- mapping of all pages not successful
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(i.e., either completely successful or fails)
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*/
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static int
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st_map_user_pages(struct scatterlist *sgl, const unsigned int max_pages,
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unsigned long uaddr, size_t count, int rw)
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{
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unsigned long end = (uaddr + count + PAGE_SIZE - 1) >> PAGE_SHIFT;
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unsigned long start = uaddr >> PAGE_SHIFT;
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const int nr_pages = end - start;
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int res, i, j;
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struct page **pages;
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/* User attempted Overflow! */
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if ((uaddr + count) < uaddr)
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return -EINVAL;
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/* Too big */
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if (nr_pages > max_pages)
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return -ENOMEM;
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/* Hmm? */
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if (count == 0)
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return 0;
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if ((pages = kmalloc(max_pages * sizeof(*pages), GFP_ATOMIC)) == NULL)
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return -ENOMEM;
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/* Try to fault in all of the necessary pages */
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down_read(¤t->mm->mmap_sem);
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/* rw==READ means read from drive, write into memory area */
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res = get_user_pages(
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current,
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current->mm,
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uaddr,
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nr_pages,
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rw == READ,
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0, /* don't force */
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pages,
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NULL);
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up_read(¤t->mm->mmap_sem);
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/* Errors and no page mapped should return here */
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if (res < nr_pages)
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goto out_unmap;
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for (i=0; i < nr_pages; i++) {
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/* FIXME: flush superflous for rw==READ,
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* probably wrong function for rw==WRITE
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*/
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flush_dcache_page(pages[i]);
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/* ?? Is locking needed? I don't think so */
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/* if (!trylock_page(pages[i]))
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goto out_unlock; */
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}
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sg_set_page(sgl, pages[0], 0, uaddr & ~PAGE_MASK);
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if (nr_pages > 1) {
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sgl[0].length = PAGE_SIZE - sgl[0].offset;
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count -= sgl[0].length;
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for (i=1; i < nr_pages ; i++)
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sg_set_page(&sgl[i], pages[i], count < PAGE_SIZE ? count : PAGE_SIZE, 0);
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}
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else {
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sgl[0].length = count;
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}
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kfree(pages);
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return nr_pages;
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out_unmap:
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if (res > 0) {
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for (j=0; j < res; j++)
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page_cache_release(pages[j]);
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res = 0;
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}
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kfree(pages);
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return res;
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}
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/* And unmap them... */
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static int
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st_unmap_user_pages(struct scatterlist *sgl, const unsigned int nr_pages,
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int dirtied)
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{
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int i;
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for (i=0; i < nr_pages; i++) {
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struct page *page = sg_page(&sgl[i]);
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if (dirtied)
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SetPageDirty(page);
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/* unlock_page(page); */
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/* FIXME: cache flush missing for rw==READ
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* FIXME: call the correct reference counting function
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*/
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page_cache_release(page);
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}
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return 0;
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}
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/* ^^^^^^^^ above code borrowed from st driver's direct IO ^^^^^^^^^ */
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#endif
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/* Returns: -ve -> error, 0 -> done, 1 -> try indirect */
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static int
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sg_build_direct(Sg_request * srp, Sg_fd * sfp, int dxfer_len)
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{
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#ifdef SG_ALLOW_DIO_CODE
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sg_io_hdr_t *hp = &srp->header;
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Sg_scatter_hold *schp = &srp->data;
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int sg_tablesize = sfp->parentdp->sg_tablesize;
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int mx_sc_elems, res;
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struct scsi_device *sdev = sfp->parentdp->device;
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int res;
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struct request *rq = srp->rq;
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struct request_queue *q = sfp->parentdp->device->request_queue;
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if (((unsigned long)hp->dxferp &
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queue_dma_alignment(sdev->request_queue)) != 0)
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return 1;
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mx_sc_elems = sg_build_sgat(schp, sfp, sg_tablesize);
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if (mx_sc_elems <= 0) {
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return 1;
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}
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res = st_map_user_pages(schp->buffer, mx_sc_elems,
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(unsigned long)hp->dxferp, dxfer_len,
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(SG_DXFER_TO_DEV == hp->dxfer_direction) ? 1 : 0);
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if (res <= 0) {
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sg_remove_scat(schp);
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return 1;
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}
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schp->k_use_sg = res;
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res = blk_rq_map_user(q, rq, NULL, hp->dxferp, dxfer_len, GFP_ATOMIC);
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if (res)
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return res;
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srp->bio = rq->bio;
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schp->dio_in_use = 1;
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hp->info |= SG_INFO_DIRECT_IO;
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return 0;
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#else
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return 1;
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#endif
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}
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static int
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@ -2069,11 +1953,7 @@ sg_remove_scat(Sg_scatter_hold * schp)
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if (schp->buffer && (schp->sglist_len > 0)) {
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struct scatterlist *sg = schp->buffer;
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if (schp->dio_in_use) {
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#ifdef SG_ALLOW_DIO_CODE
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st_unmap_user_pages(sg, schp->k_use_sg, TRUE);
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#endif
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} else {
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if (!schp->dio_in_use) {
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int k;
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for (k = 0; (k < schp->k_use_sg) && sg_page(sg);
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@ -2083,8 +1963,9 @@ sg_remove_scat(Sg_scatter_hold * schp)
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k, sg_page(sg), sg->length));
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sg_page_free(sg_page(sg), sg->length);
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}
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kfree(schp->buffer);
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}
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kfree(schp->buffer);
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}
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memset(schp, 0, sizeof (*schp));
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}
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