From 6e5a30cba5e7c03b2cd564e968f1dd667a0f7c42 Mon Sep 17 00:00:00 2001 From: FUJITA Tomonori Date: Thu, 28 Aug 2008 16:17:08 +0900 Subject: [PATCH] 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 Signed-off-by: Douglas Gilbert Cc: Mike Christie Cc: James Bottomley Signed-off-by: Jens Axboe --- drivers/scsi/sg.c | 173 ++++++++-------------------------------------- 1 file changed, 27 insertions(+), 146 deletions(-) diff --git a/drivers/scsi/sg.c b/drivers/scsi/sg.c index 487c7776cc4e..cb6de0752ee1 100644 --- a/drivers/scsi/sg.c +++ b/drivers/scsi/sg.c @@ -138,6 +138,7 @@ typedef struct sg_request { /* SG_MAX_QUEUE requests outstanding per file */ 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 @@ static int sg_start_req(Sg_request *srp, unsigned char *cmd) 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 @@ sg_finish_rem_req(Sg_request * srp) 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 @@ sg_build_sgat(Sg_scatter_hold * schp, const Sg_fd * sfp, int tablesize) 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; - - if (((unsigned long)hp->dxferp & - queue_dma_alignment(sdev->request_queue)) != 0) - return 1; + int res; + struct request *rq = srp->rq; + struct request_queue *q = sfp->parentdp->device->request_queue; - 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 @@ sg_remove_scat(Sg_scatter_hold * schp) 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 @@ sg_remove_scat(Sg_scatter_hold * schp) 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)); } -- 2.20.1