From 33204663ef85d9ce79009b2246afe6a2fef8eb1b Mon Sep 17 00:00:00 2001 From: Julien Grall Date: Mon, 29 Jun 2015 17:35:24 +0100 Subject: block/xen-blkfront: Split blkif_queue_request in 2 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Currently, blkif_queue_request has 2 distinct execution path: - Send a discard request - Send a read/write request The function is also allocating grants to use for generating the request. Although, this is only used for read/write request. Rather than having a function with 2 distinct execution path, separate the function in 2. This will also remove one level of tabulation. Signed-off-by: Julien Grall Reviewed-by: Roger Pau Monné Signed-off-by: David Vrabel --- drivers/block/xen-blkfront.c | 277 ++++++++++++++++++++++++------------------- 1 file changed, 153 insertions(+), 124 deletions(-) (limited to 'drivers/block/xen-blkfront.c') diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c index 611170896b8c..bf9ccfe03f45 100644 --- a/drivers/block/xen-blkfront.c +++ b/drivers/block/xen-blkfront.c @@ -394,13 +394,35 @@ static int blkif_ioctl(struct block_device *bdev, fmode_t mode, return 0; } -/* - * Generate a Xen blkfront IO request from a blk layer request. Reads - * and writes are handled as expected. - * - * @req: a request struct - */ -static int blkif_queue_request(struct request *req) +static int blkif_queue_discard_req(struct request *req) +{ + struct blkfront_info *info = req->rq_disk->private_data; + struct blkif_request *ring_req; + unsigned long id; + + /* Fill out a communications ring structure. */ + ring_req = RING_GET_REQUEST(&info->ring, info->ring.req_prod_pvt); + id = get_id_from_freelist(info); + info->shadow[id].request = req; + + ring_req->operation = BLKIF_OP_DISCARD; + ring_req->u.discard.nr_sectors = blk_rq_sectors(req); + ring_req->u.discard.id = id; + ring_req->u.discard.sector_number = (blkif_sector_t)blk_rq_pos(req); + if ((req->cmd_flags & REQ_SECURE) && info->feature_secdiscard) + ring_req->u.discard.flag = BLKIF_DISCARD_SECURE; + else + ring_req->u.discard.flag = 0; + + info->ring.req_prod_pvt++; + + /* Keep a private copy so we can reissue requests when recovering. */ + info->shadow[id].req = *ring_req; + + return 0; +} + +static int blkif_queue_rw_req(struct request *req) { struct blkfront_info *info = req->rq_disk->private_data; struct blkif_request *ring_req; @@ -420,9 +442,6 @@ static int blkif_queue_request(struct request *req) struct scatterlist *sg; int nseg, max_grefs; - if (unlikely(info->connected != BLKIF_STATE_CONNECTED)) - return 1; - max_grefs = req->nr_phys_segments; if (max_grefs > BLKIF_MAX_SEGMENTS_PER_REQUEST) /* @@ -452,139 +471,131 @@ static int blkif_queue_request(struct request *req) id = get_id_from_freelist(info); info->shadow[id].request = req; - if (unlikely(req->cmd_flags & (REQ_DISCARD | REQ_SECURE))) { - ring_req->operation = BLKIF_OP_DISCARD; - ring_req->u.discard.nr_sectors = blk_rq_sectors(req); - ring_req->u.discard.id = id; - ring_req->u.discard.sector_number = (blkif_sector_t)blk_rq_pos(req); - if ((req->cmd_flags & REQ_SECURE) && info->feature_secdiscard) - ring_req->u.discard.flag = BLKIF_DISCARD_SECURE; - else - ring_req->u.discard.flag = 0; + BUG_ON(info->max_indirect_segments == 0 && + req->nr_phys_segments > BLKIF_MAX_SEGMENTS_PER_REQUEST); + BUG_ON(info->max_indirect_segments && + req->nr_phys_segments > info->max_indirect_segments); + nseg = blk_rq_map_sg(req->q, req, info->shadow[id].sg); + ring_req->u.rw.id = id; + if (nseg > BLKIF_MAX_SEGMENTS_PER_REQUEST) { + /* + * The indirect operation can only be a BLKIF_OP_READ or + * BLKIF_OP_WRITE + */ + BUG_ON(req->cmd_flags & (REQ_FLUSH | REQ_FUA)); + ring_req->operation = BLKIF_OP_INDIRECT; + ring_req->u.indirect.indirect_op = rq_data_dir(req) ? + BLKIF_OP_WRITE : BLKIF_OP_READ; + ring_req->u.indirect.sector_number = (blkif_sector_t)blk_rq_pos(req); + ring_req->u.indirect.handle = info->handle; + ring_req->u.indirect.nr_segments = nseg; } else { - BUG_ON(info->max_indirect_segments == 0 && - req->nr_phys_segments > BLKIF_MAX_SEGMENTS_PER_REQUEST); - BUG_ON(info->max_indirect_segments && - req->nr_phys_segments > info->max_indirect_segments); - nseg = blk_rq_map_sg(req->q, req, info->shadow[id].sg); - ring_req->u.rw.id = id; - if (nseg > BLKIF_MAX_SEGMENTS_PER_REQUEST) { + ring_req->u.rw.sector_number = (blkif_sector_t)blk_rq_pos(req); + ring_req->u.rw.handle = info->handle; + ring_req->operation = rq_data_dir(req) ? + BLKIF_OP_WRITE : BLKIF_OP_READ; + if (req->cmd_flags & (REQ_FLUSH | REQ_FUA)) { /* - * The indirect operation can only be a BLKIF_OP_READ or - * BLKIF_OP_WRITE + * Ideally we can do an unordered flush-to-disk. + * In case the backend onlysupports barriers, use that. + * A barrier request a superset of FUA, so we can + * implement it the same way. (It's also a FLUSH+FUA, + * since it is guaranteed ordered WRT previous writes.) */ - BUG_ON(req->cmd_flags & (REQ_FLUSH | REQ_FUA)); - ring_req->operation = BLKIF_OP_INDIRECT; - ring_req->u.indirect.indirect_op = rq_data_dir(req) ? - BLKIF_OP_WRITE : BLKIF_OP_READ; - ring_req->u.indirect.sector_number = (blkif_sector_t)blk_rq_pos(req); - ring_req->u.indirect.handle = info->handle; - ring_req->u.indirect.nr_segments = nseg; - } else { - ring_req->u.rw.sector_number = (blkif_sector_t)blk_rq_pos(req); - ring_req->u.rw.handle = info->handle; - ring_req->operation = rq_data_dir(req) ? - BLKIF_OP_WRITE : BLKIF_OP_READ; - if (req->cmd_flags & (REQ_FLUSH | REQ_FUA)) { - /* - * Ideally we can do an unordered flush-to-disk. In case the - * backend onlysupports barriers, use that. A barrier request - * a superset of FUA, so we can implement it the same - * way. (It's also a FLUSH+FUA, since it is - * guaranteed ordered WRT previous writes.) - */ - switch (info->feature_flush & - ((REQ_FLUSH|REQ_FUA))) { - case REQ_FLUSH|REQ_FUA: - ring_req->operation = - BLKIF_OP_WRITE_BARRIER; - break; - case REQ_FLUSH: - ring_req->operation = - BLKIF_OP_FLUSH_DISKCACHE; - break; - default: - ring_req->operation = 0; - } + switch (info->feature_flush & + ((REQ_FLUSH|REQ_FUA))) { + case REQ_FLUSH|REQ_FUA: + ring_req->operation = + BLKIF_OP_WRITE_BARRIER; + break; + case REQ_FLUSH: + ring_req->operation = + BLKIF_OP_FLUSH_DISKCACHE; + break; + default: + ring_req->operation = 0; } - ring_req->u.rw.nr_segments = nseg; } - for_each_sg(info->shadow[id].sg, sg, nseg, i) { - fsect = sg->offset >> 9; - lsect = fsect + (sg->length >> 9) - 1; + ring_req->u.rw.nr_segments = nseg; + } + for_each_sg(info->shadow[id].sg, sg, nseg, i) { + fsect = sg->offset >> 9; + lsect = fsect + (sg->length >> 9) - 1; - if ((ring_req->operation == BLKIF_OP_INDIRECT) && - (i % SEGS_PER_INDIRECT_FRAME == 0)) { - unsigned long uninitialized_var(pfn); + if ((ring_req->operation == BLKIF_OP_INDIRECT) && + (i % SEGS_PER_INDIRECT_FRAME == 0)) { + unsigned long uninitialized_var(pfn); - if (segments) - kunmap_atomic(segments); + if (segments) + kunmap_atomic(segments); - n = i / SEGS_PER_INDIRECT_FRAME; - if (!info->feature_persistent) { - struct page *indirect_page; - - /* Fetch a pre-allocated page to use for indirect grefs */ - BUG_ON(list_empty(&info->indirect_pages)); - indirect_page = list_first_entry(&info->indirect_pages, - struct page, lru); - list_del(&indirect_page->lru); - pfn = page_to_pfn(indirect_page); - } - gnt_list_entry = get_grant(&gref_head, pfn, info); - info->shadow[id].indirect_grants[n] = gnt_list_entry; - segments = kmap_atomic(pfn_to_page(gnt_list_entry->pfn)); - ring_req->u.indirect.indirect_grefs[n] = gnt_list_entry->gref; + n = i / SEGS_PER_INDIRECT_FRAME; + if (!info->feature_persistent) { + struct page *indirect_page; + + /* + * Fetch a pre-allocated page to use for + * indirect grefs + */ + BUG_ON(list_empty(&info->indirect_pages)); + indirect_page = list_first_entry(&info->indirect_pages, + struct page, lru); + list_del(&indirect_page->lru); + pfn = page_to_pfn(indirect_page); } + gnt_list_entry = get_grant(&gref_head, pfn, info); + info->shadow[id].indirect_grants[n] = gnt_list_entry; + segments = kmap_atomic(pfn_to_page(gnt_list_entry->pfn)); + ring_req->u.indirect.indirect_grefs[n] = gnt_list_entry->gref; + } - gnt_list_entry = get_grant(&gref_head, page_to_pfn(sg_page(sg)), info); - ref = gnt_list_entry->gref; + gnt_list_entry = get_grant(&gref_head, page_to_pfn(sg_page(sg)), info); + ref = gnt_list_entry->gref; - info->shadow[id].grants_used[i] = gnt_list_entry; + info->shadow[id].grants_used[i] = gnt_list_entry; - if (rq_data_dir(req) && info->feature_persistent) { - char *bvec_data; - void *shared_data; + if (rq_data_dir(req) && info->feature_persistent) { + char *bvec_data; + void *shared_data; - BUG_ON(sg->offset + sg->length > PAGE_SIZE); + BUG_ON(sg->offset + sg->length > PAGE_SIZE); - shared_data = kmap_atomic(pfn_to_page(gnt_list_entry->pfn)); - bvec_data = kmap_atomic(sg_page(sg)); + shared_data = kmap_atomic(pfn_to_page(gnt_list_entry->pfn)); + bvec_data = kmap_atomic(sg_page(sg)); - /* - * this does not wipe data stored outside the - * range sg->offset..sg->offset+sg->length. - * Therefore, blkback *could* see data from - * previous requests. This is OK as long as - * persistent grants are shared with just one - * domain. It may need refactoring if this - * changes - */ - memcpy(shared_data + sg->offset, - bvec_data + sg->offset, - sg->length); + /* + * this does not wipe data stored outside the + * range sg->offset..sg->offset+sg->length. + * Therefore, blkback *could* see data from + * previous requests. This is OK as long as + * persistent grants are shared with just one + * domain. It may need refactoring if this + * changes + */ + memcpy(shared_data + sg->offset, + bvec_data + sg->offset, + sg->length); - kunmap_atomic(bvec_data); - kunmap_atomic(shared_data); - } - if (ring_req->operation != BLKIF_OP_INDIRECT) { - ring_req->u.rw.seg[i] = - (struct blkif_request_segment) { - .gref = ref, - .first_sect = fsect, - .last_sect = lsect }; - } else { - n = i % SEGS_PER_INDIRECT_FRAME; - segments[n] = + kunmap_atomic(bvec_data); + kunmap_atomic(shared_data); + } + if (ring_req->operation != BLKIF_OP_INDIRECT) { + ring_req->u.rw.seg[i] = (struct blkif_request_segment) { - .gref = ref, - .first_sect = fsect, - .last_sect = lsect }; - } + .gref = ref, + .first_sect = fsect, + .last_sect = lsect }; + } else { + n = i % SEGS_PER_INDIRECT_FRAME; + segments[n] = + (struct blkif_request_segment) { + .gref = ref, + .first_sect = fsect, + .last_sect = lsect }; } - if (segments) - kunmap_atomic(segments); } + if (segments) + kunmap_atomic(segments); info->ring.req_prod_pvt++; @@ -597,6 +608,24 @@ static int blkif_queue_request(struct request *req) return 0; } +/* + * Generate a Xen blkfront IO request from a blk layer request. Reads + * and writes are handled as expected. + * + * @req: a request struct + */ +static int blkif_queue_request(struct request *req) +{ + struct blkfront_info *info = req->rq_disk->private_data; + + if (unlikely(info->connected != BLKIF_STATE_CONNECTED)) + return 1; + + if (unlikely(req->cmd_flags & (REQ_DISCARD | REQ_SECURE))) + return blkif_queue_discard_req(req); + else + return blkif_queue_rw_req(req); +} static inline void flush_requests(struct blkfront_info *info) { -- cgit v1.2.1 From a7a6df222351de23791bb64165f14c21ff4d1653 Mon Sep 17 00:00:00 2001 From: Julien Grall Date: Tue, 30 Jun 2015 11:58:51 +0100 Subject: block/xen-blkfront: Store a page rather a pfn in the grant structure MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit All the usage of the field pfn are done using the same idiom: pfn_to_page(grant->pfn) This will return always the same page. Store directly the page in the grant to clean up the code. Signed-off-by: Julien Grall Acked-by: Roger Pau Monné Reviewed-by: Stefano Stabellini Signed-off-by: David Vrabel --- drivers/block/xen-blkfront.c | 39 +++++++++++++++++++-------------------- 1 file changed, 19 insertions(+), 20 deletions(-) (limited to 'drivers/block/xen-blkfront.c') diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c index bf9ccfe03f45..7552ca8f8ffe 100644 --- a/drivers/block/xen-blkfront.c +++ b/drivers/block/xen-blkfront.c @@ -68,7 +68,7 @@ enum blkif_state { struct grant { grant_ref_t gref; - unsigned long pfn; + struct page *page; struct list_head node; }; @@ -221,7 +221,7 @@ static int fill_grant_buffer(struct blkfront_info *info, int num) kfree(gnt_list_entry); goto out_of_memory; } - gnt_list_entry->pfn = page_to_pfn(granted_page); + gnt_list_entry->page = granted_page; } gnt_list_entry->gref = GRANT_INVALID_REF; @@ -236,7 +236,7 @@ out_of_memory: &info->grants, node) { list_del(&gnt_list_entry->node); if (info->feature_persistent) - __free_page(pfn_to_page(gnt_list_entry->pfn)); + __free_page(gnt_list_entry->page); kfree(gnt_list_entry); i--; } @@ -245,8 +245,8 @@ out_of_memory: } static struct grant *get_grant(grant_ref_t *gref_head, - unsigned long pfn, - struct blkfront_info *info) + struct page *page, + struct blkfront_info *info) { struct grant *gnt_list_entry; unsigned long buffer_gfn; @@ -265,10 +265,10 @@ static struct grant *get_grant(grant_ref_t *gref_head, gnt_list_entry->gref = gnttab_claim_grant_reference(gref_head); BUG_ON(gnt_list_entry->gref == -ENOSPC); if (!info->feature_persistent) { - BUG_ON(!pfn); - gnt_list_entry->pfn = pfn; + BUG_ON(!page); + gnt_list_entry->page = page; } - buffer_gfn = pfn_to_gfn(gnt_list_entry->pfn); + buffer_gfn = xen_page_to_gfn(gnt_list_entry->page); gnttab_grant_foreign_access_ref(gnt_list_entry->gref, info->xbdev->otherend_id, buffer_gfn, 0); @@ -524,7 +524,7 @@ static int blkif_queue_rw_req(struct request *req) if ((ring_req->operation == BLKIF_OP_INDIRECT) && (i % SEGS_PER_INDIRECT_FRAME == 0)) { - unsigned long uninitialized_var(pfn); + struct page *uninitialized_var(page); if (segments) kunmap_atomic(segments); @@ -541,15 +541,15 @@ static int blkif_queue_rw_req(struct request *req) indirect_page = list_first_entry(&info->indirect_pages, struct page, lru); list_del(&indirect_page->lru); - pfn = page_to_pfn(indirect_page); + page = indirect_page; } - gnt_list_entry = get_grant(&gref_head, pfn, info); + gnt_list_entry = get_grant(&gref_head, page, info); info->shadow[id].indirect_grants[n] = gnt_list_entry; - segments = kmap_atomic(pfn_to_page(gnt_list_entry->pfn)); + segments = kmap_atomic(gnt_list_entry->page); ring_req->u.indirect.indirect_grefs[n] = gnt_list_entry->gref; } - gnt_list_entry = get_grant(&gref_head, page_to_pfn(sg_page(sg)), info); + gnt_list_entry = get_grant(&gref_head, sg_page(sg), info); ref = gnt_list_entry->gref; info->shadow[id].grants_used[i] = gnt_list_entry; @@ -560,7 +560,7 @@ static int blkif_queue_rw_req(struct request *req) BUG_ON(sg->offset + sg->length > PAGE_SIZE); - shared_data = kmap_atomic(pfn_to_page(gnt_list_entry->pfn)); + shared_data = kmap_atomic(gnt_list_entry->page); bvec_data = kmap_atomic(sg_page(sg)); /* @@ -1001,7 +1001,7 @@ static void blkif_free(struct blkfront_info *info, int suspend) info->persistent_gnts_c--; } if (info->feature_persistent) - __free_page(pfn_to_page(persistent_gnt->pfn)); + __free_page(persistent_gnt->page); kfree(persistent_gnt); } } @@ -1036,7 +1036,7 @@ static void blkif_free(struct blkfront_info *info, int suspend) persistent_gnt = info->shadow[i].grants_used[j]; gnttab_end_foreign_access(persistent_gnt->gref, 0, 0UL); if (info->feature_persistent) - __free_page(pfn_to_page(persistent_gnt->pfn)); + __free_page(persistent_gnt->page); kfree(persistent_gnt); } @@ -1050,7 +1050,7 @@ static void blkif_free(struct blkfront_info *info, int suspend) for (j = 0; j < INDIRECT_GREFS(segs); j++) { persistent_gnt = info->shadow[i].indirect_grants[j]; gnttab_end_foreign_access(persistent_gnt->gref, 0, 0UL); - __free_page(pfn_to_page(persistent_gnt->pfn)); + __free_page(persistent_gnt->page); kfree(persistent_gnt); } @@ -1101,8 +1101,7 @@ static void blkif_completion(struct blk_shadow *s, struct blkfront_info *info, if (bret->operation == BLKIF_OP_READ && info->feature_persistent) { for_each_sg(s->sg, sg, nseg, i) { BUG_ON(sg->offset + sg->length > PAGE_SIZE); - shared_data = kmap_atomic( - pfn_to_page(s->grants_used[i]->pfn)); + shared_data = kmap_atomic(s->grants_used[i]->page); bvec_data = kmap_atomic(sg_page(sg)); memcpy(bvec_data + sg->offset, shared_data + sg->offset, @@ -1154,7 +1153,7 @@ static void blkif_completion(struct blk_shadow *s, struct blkfront_info *info, * available pages for indirect grefs. */ if (!info->feature_persistent) { - indirect_page = pfn_to_page(s->indirect_grants[i]->pfn); + indirect_page = s->indirect_grants[i]->page; list_add(&indirect_page->lru, &info->indirect_pages); } s->indirect_grants[i]->gref = GRANT_INVALID_REF; -- cgit v1.2.1 From 4f503fbdf319e4411aa48852b8922c93a9cc0c5d Mon Sep 17 00:00:00 2001 From: Julien Grall Date: Wed, 1 Jul 2015 14:10:38 +0100 Subject: block/xen-blkfront: split get_grant in 2 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Prepare the code to support 64KB page granularity. The first implementation will use a full Linux page per indirect and persistent grant. When non-persistent grant is used, each page of a bio request may be split in multiple grant. Furthermore, the field page of the grant structure is only used to copy data from persistent grant or indirect grant. Avoid to set it for other use case as it will have no meaning given the page will be split in multiple grant. Provide 2 functions, to setup indirect grant, the other for bio page. Signed-off-by: Julien Grall Acked-by: Roger Pau Monné Signed-off-by: David Vrabel --- drivers/block/xen-blkfront.c | 88 +++++++++++++++++++++++++++++--------------- 1 file changed, 59 insertions(+), 29 deletions(-) (limited to 'drivers/block/xen-blkfront.c') diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c index 7552ca8f8ffe..f5dfc1694679 100644 --- a/drivers/block/xen-blkfront.c +++ b/drivers/block/xen-blkfront.c @@ -244,34 +244,77 @@ out_of_memory: return -ENOMEM; } -static struct grant *get_grant(grant_ref_t *gref_head, - struct page *page, - struct blkfront_info *info) +static struct grant *get_free_grant(struct blkfront_info *info) { struct grant *gnt_list_entry; - unsigned long buffer_gfn; BUG_ON(list_empty(&info->grants)); gnt_list_entry = list_first_entry(&info->grants, struct grant, - node); + node); list_del(&gnt_list_entry->node); - if (gnt_list_entry->gref != GRANT_INVALID_REF) { + if (gnt_list_entry->gref != GRANT_INVALID_REF) info->persistent_gnts_c--; + + return gnt_list_entry; +} + +static inline void grant_foreign_access(const struct grant *gnt_list_entry, + const struct blkfront_info *info) +{ + gnttab_page_grant_foreign_access_ref_one(gnt_list_entry->gref, + info->xbdev->otherend_id, + gnt_list_entry->page, + 0); +} + +static struct grant *get_grant(grant_ref_t *gref_head, + unsigned long gfn, + struct blkfront_info *info) +{ + struct grant *gnt_list_entry = get_free_grant(info); + + if (gnt_list_entry->gref != GRANT_INVALID_REF) return gnt_list_entry; + + /* Assign a gref to this page */ + gnt_list_entry->gref = gnttab_claim_grant_reference(gref_head); + BUG_ON(gnt_list_entry->gref == -ENOSPC); + if (info->feature_persistent) + grant_foreign_access(gnt_list_entry, info); + else { + /* Grant access to the GFN passed by the caller */ + gnttab_grant_foreign_access_ref(gnt_list_entry->gref, + info->xbdev->otherend_id, + gfn, 0); } + return gnt_list_entry; +} + +static struct grant *get_indirect_grant(grant_ref_t *gref_head, + struct blkfront_info *info) +{ + struct grant *gnt_list_entry = get_free_grant(info); + + if (gnt_list_entry->gref != GRANT_INVALID_REF) + return gnt_list_entry; + /* Assign a gref to this page */ gnt_list_entry->gref = gnttab_claim_grant_reference(gref_head); BUG_ON(gnt_list_entry->gref == -ENOSPC); if (!info->feature_persistent) { - BUG_ON(!page); - gnt_list_entry->page = page; + struct page *indirect_page; + + /* Fetch a pre-allocated page to use for indirect grefs */ + BUG_ON(list_empty(&info->indirect_pages)); + indirect_page = list_first_entry(&info->indirect_pages, + struct page, lru); + list_del(&indirect_page->lru); + gnt_list_entry->page = indirect_page; } - buffer_gfn = xen_page_to_gfn(gnt_list_entry->page); - gnttab_grant_foreign_access_ref(gnt_list_entry->gref, - info->xbdev->otherend_id, - buffer_gfn, 0); + grant_foreign_access(gnt_list_entry, info); + return gnt_list_entry; } @@ -524,32 +567,19 @@ static int blkif_queue_rw_req(struct request *req) if ((ring_req->operation == BLKIF_OP_INDIRECT) && (i % SEGS_PER_INDIRECT_FRAME == 0)) { - struct page *uninitialized_var(page); - if (segments) kunmap_atomic(segments); n = i / SEGS_PER_INDIRECT_FRAME; - if (!info->feature_persistent) { - struct page *indirect_page; - - /* - * Fetch a pre-allocated page to use for - * indirect grefs - */ - BUG_ON(list_empty(&info->indirect_pages)); - indirect_page = list_first_entry(&info->indirect_pages, - struct page, lru); - list_del(&indirect_page->lru); - page = indirect_page; - } - gnt_list_entry = get_grant(&gref_head, page, info); + gnt_list_entry = get_indirect_grant(&gref_head, info); info->shadow[id].indirect_grants[n] = gnt_list_entry; segments = kmap_atomic(gnt_list_entry->page); ring_req->u.indirect.indirect_grefs[n] = gnt_list_entry->gref; } - gnt_list_entry = get_grant(&gref_head, sg_page(sg), info); + gnt_list_entry = get_grant(&gref_head, + xen_page_to_gfn(sg_page(sg)), + info); ref = gnt_list_entry->gref; info->shadow[id].grants_used[i] = gnt_list_entry; -- cgit v1.2.1 From c004a6fe0c405e2aa91b2a88aa1428724e6d06f6 Mon Sep 17 00:00:00 2001 From: Julien Grall Date: Wed, 22 Jul 2015 16:44:54 +0100 Subject: block/xen-blkfront: Make it running on 64KB page granularity MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The PV block protocol is using 4KB page granularity. The goal of this patch is to allow a Linux using 64KB page granularity using block device on a non-modified Xen. The block API is using segment which should at least be the size of a Linux page. Therefore, the driver will have to break the page in chunk of 4K before giving the page to the backend. When breaking a 64KB segment in 4KB chunks, it is possible that some chunks are empty. As the PV protocol always require to have data in the chunk, we have to count the number of Xen page which will be in use and avoid sending empty chunks. Note that, a pre-defined number of grants are reserved before preparing the request. This pre-defined number is based on the number and the maximum size of the segments. If each segment contains a very small amount of data, the driver may reserve too many grants (16 grants is reserved per segment with 64KB page granularity). Furthermore, in the case of persistent grants we allocate one Linux page per grant although only the first 4KB of the page will be effectively in use. This could be improved by sharing the page with multiple grants. Signed-off-by: Julien Grall Acked-by: Roger Pau Monné Signed-off-by: David Vrabel --- drivers/block/xen-blkfront.c | 324 ++++++++++++++++++++++++++++--------------- 1 file changed, 213 insertions(+), 111 deletions(-) (limited to 'drivers/block/xen-blkfront.c') diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c index f5dfc1694679..057e05da83d1 100644 --- a/drivers/block/xen-blkfront.c +++ b/drivers/block/xen-blkfront.c @@ -78,6 +78,7 @@ struct blk_shadow { struct grant **grants_used; struct grant **indirect_grants; struct scatterlist *sg; + unsigned int num_sg; }; struct split_bio { @@ -106,8 +107,12 @@ static unsigned int xen_blkif_max_ring_order; module_param_named(max_ring_page_order, xen_blkif_max_ring_order, int, S_IRUGO); MODULE_PARM_DESC(max_ring_page_order, "Maximum order of pages to be used for the shared ring"); -#define BLK_RING_SIZE(info) __CONST_RING_SIZE(blkif, PAGE_SIZE * (info)->nr_ring_pages) -#define BLK_MAX_RING_SIZE __CONST_RING_SIZE(blkif, PAGE_SIZE * XENBUS_MAX_RING_PAGES) +#define BLK_RING_SIZE(info) \ + __CONST_RING_SIZE(blkif, XEN_PAGE_SIZE * (info)->nr_ring_pages) + +#define BLK_MAX_RING_SIZE \ + __CONST_RING_SIZE(blkif, XEN_PAGE_SIZE * XENBUS_MAX_RING_PAGES) + /* * ring-ref%i i=(-1UL) would take 11 characters + 'ring-ref' is 8, so 19 * characters are enough. Define to 20 to keep consist with backend. @@ -146,6 +151,7 @@ struct blkfront_info unsigned int discard_granularity; unsigned int discard_alignment; unsigned int feature_persistent:1; + /* Number of 4KB segments handled */ unsigned int max_indirect_segments; int is_ready; struct blk_mq_tag_set tag_set; @@ -174,10 +180,23 @@ static DEFINE_SPINLOCK(minor_lock); #define DEV_NAME "xvd" /* name in /dev */ -#define SEGS_PER_INDIRECT_FRAME \ - (PAGE_SIZE/sizeof(struct blkif_request_segment)) -#define INDIRECT_GREFS(_segs) \ - ((_segs + SEGS_PER_INDIRECT_FRAME - 1)/SEGS_PER_INDIRECT_FRAME) +/* + * Grants are always the same size as a Xen page (i.e 4KB). + * A physical segment is always the same size as a Linux page. + * Number of grants per physical segment + */ +#define GRANTS_PER_PSEG (PAGE_SIZE / XEN_PAGE_SIZE) + +#define GRANTS_PER_INDIRECT_FRAME \ + (XEN_PAGE_SIZE / sizeof(struct blkif_request_segment)) + +#define PSEGS_PER_INDIRECT_FRAME \ + (GRANTS_INDIRECT_FRAME / GRANTS_PSEGS) + +#define INDIRECT_GREFS(_grants) \ + DIV_ROUND_UP(_grants, GRANTS_PER_INDIRECT_FRAME) + +#define GREFS(_psegs) ((_psegs) * GRANTS_PER_PSEG) static int blkfront_setup_indirect(struct blkfront_info *info); static int blkfront_gather_backend_features(struct blkfront_info *info); @@ -465,14 +484,100 @@ static int blkif_queue_discard_req(struct request *req) return 0; } +struct setup_rw_req { + unsigned int grant_idx; + struct blkif_request_segment *segments; + struct blkfront_info *info; + struct blkif_request *ring_req; + grant_ref_t gref_head; + unsigned int id; + /* Only used when persistent grant is used and it's a read request */ + bool need_copy; + unsigned int bvec_off; + char *bvec_data; +}; + +static void blkif_setup_rw_req_grant(unsigned long gfn, unsigned int offset, + unsigned int len, void *data) +{ + struct setup_rw_req *setup = data; + int n, ref; + struct grant *gnt_list_entry; + unsigned int fsect, lsect; + /* Convenient aliases */ + unsigned int grant_idx = setup->grant_idx; + struct blkif_request *ring_req = setup->ring_req; + struct blkfront_info *info = setup->info; + struct blk_shadow *shadow = &info->shadow[setup->id]; + + if ((ring_req->operation == BLKIF_OP_INDIRECT) && + (grant_idx % GRANTS_PER_INDIRECT_FRAME == 0)) { + if (setup->segments) + kunmap_atomic(setup->segments); + + n = grant_idx / GRANTS_PER_INDIRECT_FRAME; + gnt_list_entry = get_indirect_grant(&setup->gref_head, info); + shadow->indirect_grants[n] = gnt_list_entry; + setup->segments = kmap_atomic(gnt_list_entry->page); + ring_req->u.indirect.indirect_grefs[n] = gnt_list_entry->gref; + } + + gnt_list_entry = get_grant(&setup->gref_head, gfn, info); + ref = gnt_list_entry->gref; + shadow->grants_used[grant_idx] = gnt_list_entry; + + if (setup->need_copy) { + void *shared_data; + + shared_data = kmap_atomic(gnt_list_entry->page); + /* + * this does not wipe data stored outside the + * range sg->offset..sg->offset+sg->length. + * Therefore, blkback *could* see data from + * previous requests. This is OK as long as + * persistent grants are shared with just one + * domain. It may need refactoring if this + * changes + */ + memcpy(shared_data + offset, + setup->bvec_data + setup->bvec_off, + len); + + kunmap_atomic(shared_data); + setup->bvec_off += len; + } + + fsect = offset >> 9; + lsect = fsect + (len >> 9) - 1; + if (ring_req->operation != BLKIF_OP_INDIRECT) { + ring_req->u.rw.seg[grant_idx] = + (struct blkif_request_segment) { + .gref = ref, + .first_sect = fsect, + .last_sect = lsect }; + } else { + setup->segments[grant_idx % GRANTS_PER_INDIRECT_FRAME] = + (struct blkif_request_segment) { + .gref = ref, + .first_sect = fsect, + .last_sect = lsect }; + } + + (setup->grant_idx)++; +} + static int blkif_queue_rw_req(struct request *req) { struct blkfront_info *info = req->rq_disk->private_data; struct blkif_request *ring_req; unsigned long id; - unsigned int fsect, lsect; - int i, ref, n; - struct blkif_request_segment *segments = NULL; + int i; + struct setup_rw_req setup = { + .grant_idx = 0, + .segments = NULL, + .info = info, + .need_copy = rq_data_dir(req) && info->feature_persistent, + }; /* * Used to store if we are able to queue the request by just using @@ -480,25 +585,23 @@ static int blkif_queue_rw_req(struct request *req) * as there are not sufficiently many free. */ bool new_persistent_gnts; - grant_ref_t gref_head; - struct grant *gnt_list_entry = NULL; struct scatterlist *sg; - int nseg, max_grefs; + int num_sg, max_grefs, num_grant; - max_grefs = req->nr_phys_segments; + max_grefs = req->nr_phys_segments * GRANTS_PER_PSEG; if (max_grefs > BLKIF_MAX_SEGMENTS_PER_REQUEST) /* * If we are using indirect segments we need to account * for the indirect grefs used in the request. */ - max_grefs += INDIRECT_GREFS(req->nr_phys_segments); + max_grefs += INDIRECT_GREFS(max_grefs); /* Check if we have enough grants to allocate a requests */ if (info->persistent_gnts_c < max_grefs) { new_persistent_gnts = 1; if (gnttab_alloc_grant_references( max_grefs - info->persistent_gnts_c, - &gref_head) < 0) { + &setup.gref_head) < 0) { gnttab_request_free_callback( &info->callback, blkif_restart_queue_callback, @@ -515,12 +618,19 @@ static int blkif_queue_rw_req(struct request *req) info->shadow[id].request = req; BUG_ON(info->max_indirect_segments == 0 && - req->nr_phys_segments > BLKIF_MAX_SEGMENTS_PER_REQUEST); + GREFS(req->nr_phys_segments) > BLKIF_MAX_SEGMENTS_PER_REQUEST); BUG_ON(info->max_indirect_segments && - req->nr_phys_segments > info->max_indirect_segments); - nseg = blk_rq_map_sg(req->q, req, info->shadow[id].sg); + GREFS(req->nr_phys_segments) > info->max_indirect_segments); + + num_sg = blk_rq_map_sg(req->q, req, info->shadow[id].sg); + num_grant = 0; + /* Calculate the number of grant used */ + for_each_sg(info->shadow[id].sg, sg, num_sg, i) + num_grant += gnttab_count_grant(sg->offset, sg->length); + ring_req->u.rw.id = id; - if (nseg > BLKIF_MAX_SEGMENTS_PER_REQUEST) { + info->shadow[id].num_sg = num_sg; + if (num_grant > BLKIF_MAX_SEGMENTS_PER_REQUEST) { /* * The indirect operation can only be a BLKIF_OP_READ or * BLKIF_OP_WRITE @@ -531,7 +641,7 @@ static int blkif_queue_rw_req(struct request *req) BLKIF_OP_WRITE : BLKIF_OP_READ; ring_req->u.indirect.sector_number = (blkif_sector_t)blk_rq_pos(req); ring_req->u.indirect.handle = info->handle; - ring_req->u.indirect.nr_segments = nseg; + ring_req->u.indirect.nr_segments = num_grant; } else { ring_req->u.rw.sector_number = (blkif_sector_t)blk_rq_pos(req); ring_req->u.rw.handle = info->handle; @@ -559,73 +669,30 @@ static int blkif_queue_rw_req(struct request *req) ring_req->operation = 0; } } - ring_req->u.rw.nr_segments = nseg; - } - for_each_sg(info->shadow[id].sg, sg, nseg, i) { - fsect = sg->offset >> 9; - lsect = fsect + (sg->length >> 9) - 1; - - if ((ring_req->operation == BLKIF_OP_INDIRECT) && - (i % SEGS_PER_INDIRECT_FRAME == 0)) { - if (segments) - kunmap_atomic(segments); - - n = i / SEGS_PER_INDIRECT_FRAME; - gnt_list_entry = get_indirect_grant(&gref_head, info); - info->shadow[id].indirect_grants[n] = gnt_list_entry; - segments = kmap_atomic(gnt_list_entry->page); - ring_req->u.indirect.indirect_grefs[n] = gnt_list_entry->gref; - } - - gnt_list_entry = get_grant(&gref_head, - xen_page_to_gfn(sg_page(sg)), - info); - ref = gnt_list_entry->gref; - - info->shadow[id].grants_used[i] = gnt_list_entry; - - if (rq_data_dir(req) && info->feature_persistent) { - char *bvec_data; - void *shared_data; + ring_req->u.rw.nr_segments = num_grant; + } - BUG_ON(sg->offset + sg->length > PAGE_SIZE); + setup.ring_req = ring_req; + setup.id = id; + for_each_sg(info->shadow[id].sg, sg, num_sg, i) { + BUG_ON(sg->offset + sg->length > PAGE_SIZE); - shared_data = kmap_atomic(gnt_list_entry->page); - bvec_data = kmap_atomic(sg_page(sg)); + if (setup.need_copy) { + setup.bvec_off = sg->offset; + setup.bvec_data = kmap_atomic(sg_page(sg)); + } - /* - * this does not wipe data stored outside the - * range sg->offset..sg->offset+sg->length. - * Therefore, blkback *could* see data from - * previous requests. This is OK as long as - * persistent grants are shared with just one - * domain. It may need refactoring if this - * changes - */ - memcpy(shared_data + sg->offset, - bvec_data + sg->offset, - sg->length); + gnttab_foreach_grant_in_range(sg_page(sg), + sg->offset, + sg->length, + blkif_setup_rw_req_grant, + &setup); - kunmap_atomic(bvec_data); - kunmap_atomic(shared_data); - } - if (ring_req->operation != BLKIF_OP_INDIRECT) { - ring_req->u.rw.seg[i] = - (struct blkif_request_segment) { - .gref = ref, - .first_sect = fsect, - .last_sect = lsect }; - } else { - n = i % SEGS_PER_INDIRECT_FRAME; - segments[n] = - (struct blkif_request_segment) { - .gref = ref, - .first_sect = fsect, - .last_sect = lsect }; - } + if (setup.need_copy) + kunmap_atomic(setup.bvec_data); } - if (segments) - kunmap_atomic(segments); + if (setup.segments) + kunmap_atomic(setup.segments); info->ring.req_prod_pvt++; @@ -633,7 +700,7 @@ static int blkif_queue_rw_req(struct request *req) info->shadow[id].req = *ring_req; if (new_persistent_gnts) - gnttab_free_grant_references(gref_head); + gnttab_free_grant_references(setup.gref_head); return 0; } @@ -750,14 +817,14 @@ static int xlvbd_init_blk_queue(struct gendisk *gd, u16 sector_size, /* Hard sector size and max sectors impersonate the equiv. hardware. */ blk_queue_logical_block_size(rq, sector_size); blk_queue_physical_block_size(rq, physical_sector_size); - blk_queue_max_hw_sectors(rq, (segments * PAGE_SIZE) / 512); + blk_queue_max_hw_sectors(rq, (segments * XEN_PAGE_SIZE) / 512); /* Each segment in a request is up to an aligned page in size. */ blk_queue_segment_boundary(rq, PAGE_SIZE - 1); blk_queue_max_segment_size(rq, PAGE_SIZE); /* Ensure a merged request will fit in a single I/O ring slot. */ - blk_queue_max_segments(rq, segments); + blk_queue_max_segments(rq, segments / GRANTS_PER_PSEG); /* Make sure buffer addresses are sector-aligned. */ blk_queue_dma_alignment(rq, 511); @@ -1116,32 +1183,65 @@ free_shadow: } +struct copy_from_grant { + const struct blk_shadow *s; + unsigned int grant_idx; + unsigned int bvec_offset; + char *bvec_data; +}; + +static void blkif_copy_from_grant(unsigned long gfn, unsigned int offset, + unsigned int len, void *data) +{ + struct copy_from_grant *info = data; + char *shared_data; + /* Convenient aliases */ + const struct blk_shadow *s = info->s; + + shared_data = kmap_atomic(s->grants_used[info->grant_idx]->page); + + memcpy(info->bvec_data + info->bvec_offset, + shared_data + offset, len); + + info->bvec_offset += len; + info->grant_idx++; + + kunmap_atomic(shared_data); +} + static void blkif_completion(struct blk_shadow *s, struct blkfront_info *info, struct blkif_response *bret) { int i = 0; struct scatterlist *sg; - char *bvec_data; - void *shared_data; - int nseg; + int num_sg, num_grant; + struct copy_from_grant data = { + .s = s, + .grant_idx = 0, + }; - nseg = s->req.operation == BLKIF_OP_INDIRECT ? + num_grant = s->req.operation == BLKIF_OP_INDIRECT ? s->req.u.indirect.nr_segments : s->req.u.rw.nr_segments; + num_sg = s->num_sg; if (bret->operation == BLKIF_OP_READ && info->feature_persistent) { - for_each_sg(s->sg, sg, nseg, i) { + for_each_sg(s->sg, sg, num_sg, i) { BUG_ON(sg->offset + sg->length > PAGE_SIZE); - shared_data = kmap_atomic(s->grants_used[i]->page); - bvec_data = kmap_atomic(sg_page(sg)); - memcpy(bvec_data + sg->offset, - shared_data + sg->offset, - sg->length); - kunmap_atomic(bvec_data); - kunmap_atomic(shared_data); + + data.bvec_offset = sg->offset; + data.bvec_data = kmap_atomic(sg_page(sg)); + + gnttab_foreach_grant_in_range(sg_page(sg), + sg->offset, + sg->length, + blkif_copy_from_grant, + &data); + + kunmap_atomic(data.bvec_data); } } /* Add the persistent grant into the list of free grants */ - for (i = 0; i < nseg; i++) { + for (i = 0; i < num_grant; i++) { if (gnttab_query_foreign_access(s->grants_used[i]->gref)) { /* * If the grant is still mapped by the backend (the @@ -1167,7 +1267,7 @@ static void blkif_completion(struct blk_shadow *s, struct blkfront_info *info, } } if (s->req.operation == BLKIF_OP_INDIRECT) { - for (i = 0; i < INDIRECT_GREFS(nseg); i++) { + for (i = 0; i < INDIRECT_GREFS(num_grant); i++) { if (gnttab_query_foreign_access(s->indirect_grants[i]->gref)) { if (!info->feature_persistent) pr_alert_ratelimited("backed has not unmapped grant: %u\n", @@ -1312,7 +1412,7 @@ static int setup_blkring(struct xenbus_device *dev, { struct blkif_sring *sring; int err, i; - unsigned long ring_size = info->nr_ring_pages * PAGE_SIZE; + unsigned long ring_size = info->nr_ring_pages * XEN_PAGE_SIZE; grant_ref_t gref[XENBUS_MAX_RING_PAGES]; for (i = 0; i < info->nr_ring_pages; i++) @@ -1641,8 +1741,8 @@ static int blkif_recover(struct blkfront_info *info) atomic_set(&split_bio->pending, pending); split_bio->bio = bio; for (i = 0; i < pending; i++) { - offset = (i * segs * PAGE_SIZE) >> 9; - size = min((unsigned int)(segs * PAGE_SIZE) >> 9, + offset = (i * segs * XEN_PAGE_SIZE) >> 9; + size = min((unsigned int)(segs * XEN_PAGE_SIZE) >> 9, (unsigned int)bio_sectors(bio) - offset); cloned_bio = bio_clone(bio, GFP_NOIO); BUG_ON(cloned_bio == NULL); @@ -1753,15 +1853,17 @@ static void blkfront_setup_discard(struct blkfront_info *info) static int blkfront_setup_indirect(struct blkfront_info *info) { - unsigned int segs; + unsigned int psegs, grants; int err, i; if (info->max_indirect_segments == 0) - segs = BLKIF_MAX_SEGMENTS_PER_REQUEST; + grants = BLKIF_MAX_SEGMENTS_PER_REQUEST; else - segs = info->max_indirect_segments; + grants = info->max_indirect_segments; + psegs = grants / GRANTS_PER_PSEG; - err = fill_grant_buffer(info, (segs + INDIRECT_GREFS(segs)) * BLK_RING_SIZE(info)); + err = fill_grant_buffer(info, + (grants + INDIRECT_GREFS(grants)) * BLK_RING_SIZE(info)); if (err) goto out_of_memory; @@ -1771,7 +1873,7 @@ static int blkfront_setup_indirect(struct blkfront_info *info) * grants, we need to allocate a set of pages that can be * used for mapping indirect grefs */ - int num = INDIRECT_GREFS(segs) * BLK_RING_SIZE(info); + int num = INDIRECT_GREFS(grants) * BLK_RING_SIZE(info); BUG_ON(!list_empty(&info->indirect_pages)); for (i = 0; i < num; i++) { @@ -1784,20 +1886,20 @@ static int blkfront_setup_indirect(struct blkfront_info *info) for (i = 0; i < BLK_RING_SIZE(info); i++) { info->shadow[i].grants_used = kzalloc( - sizeof(info->shadow[i].grants_used[0]) * segs, + sizeof(info->shadow[i].grants_used[0]) * grants, GFP_NOIO); - info->shadow[i].sg = kzalloc(sizeof(info->shadow[i].sg[0]) * segs, GFP_NOIO); + info->shadow[i].sg = kzalloc(sizeof(info->shadow[i].sg[0]) * psegs, GFP_NOIO); if (info->max_indirect_segments) info->shadow[i].indirect_grants = kzalloc( sizeof(info->shadow[i].indirect_grants[0]) * - INDIRECT_GREFS(segs), + INDIRECT_GREFS(grants), GFP_NOIO); if ((info->shadow[i].grants_used == NULL) || (info->shadow[i].sg == NULL) || (info->max_indirect_segments && (info->shadow[i].indirect_grants == NULL))) goto out_of_memory; - sg_init_table(info->shadow[i].sg, segs); + sg_init_table(info->shadow[i].sg, psegs); } -- cgit v1.2.1 From 9cce2914e2b21339dca12c91dc9f35790366cc4c Mon Sep 17 00:00:00 2001 From: Julien Grall Date: Tue, 13 Oct 2015 17:50:11 +0100 Subject: xen/xenbus: Rename *RING_PAGE* to *RING_GRANT* Linux may use a different page size than the size of grant. So make clear that the order is actually in number of grant. Signed-off-by: Julien Grall Signed-off-by: David Vrabel --- drivers/block/xen-blkfront.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) (limited to 'drivers/block/xen-blkfront.c') diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c index 057e05da83d1..833955f32430 100644 --- a/drivers/block/xen-blkfront.c +++ b/drivers/block/xen-blkfront.c @@ -111,7 +111,7 @@ MODULE_PARM_DESC(max_ring_page_order, "Maximum order of pages to be used for the __CONST_RING_SIZE(blkif, XEN_PAGE_SIZE * (info)->nr_ring_pages) #define BLK_MAX_RING_SIZE \ - __CONST_RING_SIZE(blkif, XEN_PAGE_SIZE * XENBUS_MAX_RING_PAGES) + __CONST_RING_SIZE(blkif, XEN_PAGE_SIZE * XENBUS_MAX_RING_GRANTS) /* * ring-ref%i i=(-1UL) would take 11 characters + 'ring-ref' is 8, so 19 @@ -133,7 +133,7 @@ struct blkfront_info int vdevice; blkif_vdev_t handle; enum blkif_state connected; - int ring_ref[XENBUS_MAX_RING_PAGES]; + int ring_ref[XENBUS_MAX_RING_GRANTS]; unsigned int nr_ring_pages; struct blkif_front_ring ring; unsigned int evtchn, irq; @@ -1413,7 +1413,7 @@ static int setup_blkring(struct xenbus_device *dev, struct blkif_sring *sring; int err, i; unsigned long ring_size = info->nr_ring_pages * XEN_PAGE_SIZE; - grant_ref_t gref[XENBUS_MAX_RING_PAGES]; + grant_ref_t gref[XENBUS_MAX_RING_GRANTS]; for (i = 0; i < info->nr_ring_pages; i++) info->ring_ref[i] = GRANT_INVALID_REF; @@ -2284,9 +2284,9 @@ static int __init xlblk_init(void) if (!xen_domain()) return -ENODEV; - if (xen_blkif_max_ring_order > XENBUS_MAX_RING_PAGE_ORDER) { + if (xen_blkif_max_ring_order > XENBUS_MAX_RING_GRANT_ORDER) { pr_info("Invalid max_ring_order (%d), will use default max: %d.\n", - xen_blkif_max_ring_order, XENBUS_MAX_RING_PAGE_ORDER); + xen_blkif_max_ring_order, XENBUS_MAX_RING_GRANT_ORDER); xen_blkif_max_ring_order = 0; } -- cgit v1.2.1