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![Dmitry Monakhov](/assets/img/avatar_default.png)
Currently if some one try to advance bvec beyond it's size we simply
dump WARN_ONCE and continue to iterate beyond bvec array boundaries.
This simply means that we endup dereferencing/corrupting random memory
region.
Sane reaction would be to propagate error back to calling context
But bvec_iter_advance's calling context is not always good for error
handling. For safity reason let truncate iterator size to zero which
will break external iteration loop which prevent us from unpredictable
memory range corruption. And even it caller ignores an error, it will
corrupt it's own bvecs, not others.
This patch does:
- Return error back to caller with hope that it will react on this
- Truncate iterator size
Code was added long time ago here 4550dd6c
, luckily no one hit it
in real life :)
Signed-off-by: Dmitry Monakhov <dmonakhov@openvz.org>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
[hch: switch to true/false returns instead of errno values]
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
352 lines
8.7 KiB
C
352 lines
8.7 KiB
C
/*
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* NVDIMM Block Window Driver
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* Copyright (c) 2014, Intel Corporation.
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms and conditions of the GNU General Public License,
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* version 2, as published by the Free Software Foundation.
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*
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* This program is distributed in the hope it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
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* more details.
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*/
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#include <linux/blkdev.h>
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#include <linux/fs.h>
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#include <linux/genhd.h>
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#include <linux/module.h>
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#include <linux/moduleparam.h>
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#include <linux/nd.h>
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#include <linux/sizes.h>
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#include "nd.h"
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static u32 nsblk_meta_size(struct nd_namespace_blk *nsblk)
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{
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return nsblk->lbasize - ((nsblk->lbasize >= 4096) ? 4096 : 512);
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}
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static u32 nsblk_internal_lbasize(struct nd_namespace_blk *nsblk)
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{
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return roundup(nsblk->lbasize, INT_LBASIZE_ALIGNMENT);
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}
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static u32 nsblk_sector_size(struct nd_namespace_blk *nsblk)
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{
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return nsblk->lbasize - nsblk_meta_size(nsblk);
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}
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static resource_size_t to_dev_offset(struct nd_namespace_blk *nsblk,
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resource_size_t ns_offset, unsigned int len)
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{
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int i;
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for (i = 0; i < nsblk->num_resources; i++) {
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if (ns_offset < resource_size(nsblk->res[i])) {
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if (ns_offset + len > resource_size(nsblk->res[i])) {
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dev_WARN_ONCE(&nsblk->common.dev, 1,
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"illegal request\n");
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return SIZE_MAX;
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}
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return nsblk->res[i]->start + ns_offset;
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}
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ns_offset -= resource_size(nsblk->res[i]);
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}
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dev_WARN_ONCE(&nsblk->common.dev, 1, "request out of range\n");
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return SIZE_MAX;
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}
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static struct nd_blk_region *to_ndbr(struct nd_namespace_blk *nsblk)
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{
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struct nd_region *nd_region;
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struct device *parent;
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parent = nsblk->common.dev.parent;
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nd_region = container_of(parent, struct nd_region, dev);
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return container_of(nd_region, struct nd_blk_region, nd_region);
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}
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#ifdef CONFIG_BLK_DEV_INTEGRITY
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static int nd_blk_rw_integrity(struct nd_namespace_blk *nsblk,
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struct bio_integrity_payload *bip, u64 lba, int rw)
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{
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struct nd_blk_region *ndbr = to_ndbr(nsblk);
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unsigned int len = nsblk_meta_size(nsblk);
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resource_size_t dev_offset, ns_offset;
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u32 internal_lbasize, sector_size;
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int err = 0;
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internal_lbasize = nsblk_internal_lbasize(nsblk);
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sector_size = nsblk_sector_size(nsblk);
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ns_offset = lba * internal_lbasize + sector_size;
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dev_offset = to_dev_offset(nsblk, ns_offset, len);
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if (dev_offset == SIZE_MAX)
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return -EIO;
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while (len) {
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unsigned int cur_len;
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struct bio_vec bv;
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void *iobuf;
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bv = bvec_iter_bvec(bip->bip_vec, bip->bip_iter);
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/*
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* The 'bv' obtained from bvec_iter_bvec has its .bv_len and
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* .bv_offset already adjusted for iter->bi_bvec_done, and we
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* can use those directly
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*/
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cur_len = min(len, bv.bv_len);
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iobuf = kmap_atomic(bv.bv_page);
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err = ndbr->do_io(ndbr, dev_offset, iobuf + bv.bv_offset,
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cur_len, rw);
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kunmap_atomic(iobuf);
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if (err)
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return err;
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len -= cur_len;
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dev_offset += cur_len;
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if (!bvec_iter_advance(bip->bip_vec, &bip->bip_iter, cur_len))
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return -EIO;
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}
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return err;
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}
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#else /* CONFIG_BLK_DEV_INTEGRITY */
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static int nd_blk_rw_integrity(struct nd_namespace_blk *nsblk,
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struct bio_integrity_payload *bip, u64 lba, int rw)
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{
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return 0;
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}
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#endif
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static int nsblk_do_bvec(struct nd_namespace_blk *nsblk,
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struct bio_integrity_payload *bip, struct page *page,
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unsigned int len, unsigned int off, int rw, sector_t sector)
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{
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struct nd_blk_region *ndbr = to_ndbr(nsblk);
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resource_size_t dev_offset, ns_offset;
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u32 internal_lbasize, sector_size;
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int err = 0;
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void *iobuf;
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u64 lba;
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internal_lbasize = nsblk_internal_lbasize(nsblk);
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sector_size = nsblk_sector_size(nsblk);
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while (len) {
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unsigned int cur_len;
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/*
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* If we don't have an integrity payload, we don't have to
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* split the bvec into sectors, as this would cause unnecessary
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* Block Window setup/move steps. the do_io routine is capable
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* of handling len <= PAGE_SIZE.
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*/
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cur_len = bip ? min(len, sector_size) : len;
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lba = div_u64(sector << SECTOR_SHIFT, sector_size);
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ns_offset = lba * internal_lbasize;
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dev_offset = to_dev_offset(nsblk, ns_offset, cur_len);
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if (dev_offset == SIZE_MAX)
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return -EIO;
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iobuf = kmap_atomic(page);
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err = ndbr->do_io(ndbr, dev_offset, iobuf + off, cur_len, rw);
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kunmap_atomic(iobuf);
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if (err)
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return err;
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if (bip) {
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err = nd_blk_rw_integrity(nsblk, bip, lba, rw);
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if (err)
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return err;
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}
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len -= cur_len;
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off += cur_len;
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sector += sector_size >> SECTOR_SHIFT;
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}
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return err;
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}
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static blk_qc_t nd_blk_make_request(struct request_queue *q, struct bio *bio)
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{
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struct bio_integrity_payload *bip;
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struct nd_namespace_blk *nsblk;
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struct bvec_iter iter;
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unsigned long start;
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struct bio_vec bvec;
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int err = 0, rw;
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bool do_acct;
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if (!bio_integrity_prep(bio))
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return BLK_QC_T_NONE;
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bip = bio_integrity(bio);
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nsblk = q->queuedata;
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rw = bio_data_dir(bio);
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do_acct = nd_iostat_start(bio, &start);
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bio_for_each_segment(bvec, bio, iter) {
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unsigned int len = bvec.bv_len;
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BUG_ON(len > PAGE_SIZE);
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err = nsblk_do_bvec(nsblk, bip, bvec.bv_page, len,
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bvec.bv_offset, rw, iter.bi_sector);
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if (err) {
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dev_dbg(&nsblk->common.dev,
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"io error in %s sector %lld, len %d,\n",
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(rw == READ) ? "READ" : "WRITE",
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(unsigned long long) iter.bi_sector, len);
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bio->bi_status = errno_to_blk_status(err);
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break;
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}
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}
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if (do_acct)
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nd_iostat_end(bio, start);
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bio_endio(bio);
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return BLK_QC_T_NONE;
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}
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static int nsblk_rw_bytes(struct nd_namespace_common *ndns,
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resource_size_t offset, void *iobuf, size_t n, int rw,
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unsigned long flags)
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{
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struct nd_namespace_blk *nsblk = to_nd_namespace_blk(&ndns->dev);
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struct nd_blk_region *ndbr = to_ndbr(nsblk);
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resource_size_t dev_offset;
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dev_offset = to_dev_offset(nsblk, offset, n);
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if (unlikely(offset + n > nsblk->size)) {
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dev_WARN_ONCE(&ndns->dev, 1, "request out of range\n");
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return -EFAULT;
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}
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if (dev_offset == SIZE_MAX)
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return -EIO;
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return ndbr->do_io(ndbr, dev_offset, iobuf, n, rw);
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}
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static const struct block_device_operations nd_blk_fops = {
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.owner = THIS_MODULE,
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.revalidate_disk = nvdimm_revalidate_disk,
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};
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static void nd_blk_release_queue(void *q)
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{
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blk_cleanup_queue(q);
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}
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static void nd_blk_release_disk(void *disk)
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{
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del_gendisk(disk);
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put_disk(disk);
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}
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static int nsblk_attach_disk(struct nd_namespace_blk *nsblk)
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{
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struct device *dev = &nsblk->common.dev;
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resource_size_t available_disk_size;
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struct request_queue *q;
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struct gendisk *disk;
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u64 internal_nlba;
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internal_nlba = div_u64(nsblk->size, nsblk_internal_lbasize(nsblk));
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available_disk_size = internal_nlba * nsblk_sector_size(nsblk);
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q = blk_alloc_queue(GFP_KERNEL);
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if (!q)
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return -ENOMEM;
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if (devm_add_action_or_reset(dev, nd_blk_release_queue, q))
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return -ENOMEM;
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blk_queue_make_request(q, nd_blk_make_request);
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blk_queue_max_hw_sectors(q, UINT_MAX);
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blk_queue_logical_block_size(q, nsblk_sector_size(nsblk));
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queue_flag_set_unlocked(QUEUE_FLAG_NONROT, q);
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q->queuedata = nsblk;
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disk = alloc_disk(0);
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if (!disk)
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return -ENOMEM;
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disk->first_minor = 0;
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disk->fops = &nd_blk_fops;
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disk->queue = q;
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disk->flags = GENHD_FL_EXT_DEVT;
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nvdimm_namespace_disk_name(&nsblk->common, disk->disk_name);
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set_capacity(disk, 0);
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device_add_disk(dev, disk);
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if (devm_add_action_or_reset(dev, nd_blk_release_disk, disk))
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return -ENOMEM;
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if (nsblk_meta_size(nsblk)) {
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int rc = nd_integrity_init(disk, nsblk_meta_size(nsblk));
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if (rc)
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return rc;
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}
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set_capacity(disk, available_disk_size >> SECTOR_SHIFT);
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revalidate_disk(disk);
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return 0;
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}
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static int nd_blk_probe(struct device *dev)
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{
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struct nd_namespace_common *ndns;
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struct nd_namespace_blk *nsblk;
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ndns = nvdimm_namespace_common_probe(dev);
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if (IS_ERR(ndns))
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return PTR_ERR(ndns);
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nsblk = to_nd_namespace_blk(&ndns->dev);
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nsblk->size = nvdimm_namespace_capacity(ndns);
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dev_set_drvdata(dev, nsblk);
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ndns->rw_bytes = nsblk_rw_bytes;
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if (is_nd_btt(dev))
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return nvdimm_namespace_attach_btt(ndns);
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else if (nd_btt_probe(dev, ndns) == 0) {
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/* we'll come back as btt-blk */
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return -ENXIO;
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} else
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return nsblk_attach_disk(nsblk);
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}
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static int nd_blk_remove(struct device *dev)
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{
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if (is_nd_btt(dev))
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nvdimm_namespace_detach_btt(to_nd_btt(dev));
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return 0;
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}
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static struct nd_device_driver nd_blk_driver = {
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.probe = nd_blk_probe,
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.remove = nd_blk_remove,
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.drv = {
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.name = "nd_blk",
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},
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.type = ND_DRIVER_NAMESPACE_BLK,
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};
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static int __init nd_blk_init(void)
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{
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return nd_driver_register(&nd_blk_driver);
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}
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static void __exit nd_blk_exit(void)
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{
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driver_unregister(&nd_blk_driver.drv);
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}
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MODULE_AUTHOR("Ross Zwisler <ross.zwisler@linux.intel.com>");
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MODULE_LICENSE("GPL v2");
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MODULE_ALIAS_ND_DEVICE(ND_DEVICE_NAMESPACE_BLK);
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module_init(nd_blk_init);
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module_exit(nd_blk_exit);
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