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author | Linus Torvalds <torvalds@linux-foundation.org> | 2015-02-12 14:13:23 -0800 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2015-02-12 14:13:23 -0800 |
commit | 3e12cefbe143b4947171ff92dd50024c4841e291 (patch) | |
tree | f58ec23a4092576ed08843cca5f5443a32106bd1 /fs/block_dev.c | |
parent | 6bec0035286119eefc32a5b1102127e6a4032cb2 (diff) | |
parent | d427e3c82ef4fc5fbb22c0cef0b040e6767b1028 (diff) | |
download | linux-3e12cefbe143b4947171ff92dd50024c4841e291.tar.gz |
Merge branch 'for-3.20/core' of git://git.kernel.dk/linux-block
Pull core block IO changes from Jens Axboe: "This contains: - A series from Christoph that cleans up and refactors various parts of the REQ_BLOCK_PC handling. Contributions in that series from Dongsu Park and Kent Overstreet as well. - CFQ: - A bug fix for cfq for realtime IO scheduling from Jeff Moyer. - A stable patch fixing a potential crash in CFQ in OOM situations. From Konstantin Khlebnikov. - blk-mq: - Add support for tag allocation policies, from Shaohua. This is a prep patch enabling libata (and other SCSI parts) to use the blk-mq tagging, instead of rolling their own. - Various little tweaks from Keith and Mike, in preparation for DM blk-mq support. - Minor little fixes or tweaks from me. - A double free error fix from Tony Battersby. - The partition 4k issue fixes from Matthew and Boaz. - Add support for zero+unprovision for blkdev_issue_zeroout() from Martin" * 'for-3.20/core' of git://git.kernel.dk/linux-block: (27 commits) block: remove unused function blk_bio_map_sg block: handle the null_mapped flag correctly in blk_rq_map_user_iov blk-mq: fix double-free in error path block: prevent request-to-request merging with gaps if not allowed blk-mq: make blk_mq_run_queues() static dm: fix multipath regression due to initializing wrong request cfq-iosched: handle failure of cfq group allocation block: Quiesce zeroout wrapper block: rewrite and split __bio_copy_iov() block: merge __bio_map_user_iov into bio_map_user_iov block: merge __bio_map_kern into bio_map_kern block: pass iov_iter to the BLOCK_PC mapping functions block: add a helper to free bio bounce buffer pages block: use blk_rq_map_user_iov to implement blk_rq_map_user block: simplify bio_map_kern block: mark blk-mq devices as stackable block: keep established cmd_flags when cloning into a blk-mq request block: add blk-mq support to blk_insert_cloned_request() block: require blk_rq_prep_clone() be given an initialized clone request blk-mq: add tag allocation policy ...
Diffstat (limited to 'fs/block_dev.c')
-rw-r--r-- | fs/block_dev.c | 40 |
1 files changed, 40 insertions, 0 deletions
diff --git a/fs/block_dev.c b/fs/block_dev.c index a9f92794d7a0..975266be67d3 100644 --- a/fs/block_dev.c +++ b/fs/block_dev.c @@ -421,6 +421,46 @@ int bdev_write_page(struct block_device *bdev, sector_t sector, } EXPORT_SYMBOL_GPL(bdev_write_page); +/** + * bdev_direct_access() - Get the address for directly-accessibly memory + * @bdev: The device containing the memory + * @sector: The offset within the device + * @addr: Where to put the address of the memory + * @pfn: The Page Frame Number for the memory + * @size: The number of bytes requested + * + * If a block device is made up of directly addressable memory, this function + * will tell the caller the PFN and the address of the memory. The address + * may be directly dereferenced within the kernel without the need to call + * ioremap(), kmap() or similar. The PFN is suitable for inserting into + * page tables. + * + * Return: negative errno if an error occurs, otherwise the number of bytes + * accessible at this address. + */ +long bdev_direct_access(struct block_device *bdev, sector_t sector, + void **addr, unsigned long *pfn, long size) +{ + long avail; + const struct block_device_operations *ops = bdev->bd_disk->fops; + + if (size < 0) + return size; + if (!ops->direct_access) + return -EOPNOTSUPP; + if ((sector + DIV_ROUND_UP(size, 512)) > + part_nr_sects_read(bdev->bd_part)) + return -ERANGE; + sector += get_start_sect(bdev); + if (sector % (PAGE_SIZE / 512)) + return -EINVAL; + avail = ops->direct_access(bdev, sector, addr, pfn, size); + if (!avail) + return -ERANGE; + return min(avail, size); +} +EXPORT_SYMBOL_GPL(bdev_direct_access); + /* * pseudo-fs */ |