On Wed, 2015-03-25 at 17:04 +0100, Christoph Hellwig wrote:
> From: Ross Zwisler <ross.zwisler@xxxxxxxxxxxxxxx>
>
> PMEM is a new driver that presents a reserved range of memory as a
> block device. This is useful for developing with NV-DIMMs, and
> can be used with volatile memory as a development platform.
>
> Signed-off-by: Ross Zwisler <ross.zwisler@xxxxxxxxxxxxxxx>
> [hch: convert to use a platform_device for discovery, fix partition
> support]
Overall I really like this approach. It makes things simpler, removes
unneeded code and most importantly removes the ability for the user to have a
configuration where the PMEM / memmap reservation via the command line don't
match the parameters given to pmem.
What needed to be fixed with the partition support? I used to have real
numbers for first_minor and passed into alloc_disk(), but simplified it based
on code found in this commit in the nvme driver:
469071a37afc NVMe: Dynamically allocate partition numbers
This has worked fine for me - is there some test case in which it breaks?
> +static int pmem_probe(struct platform_device *pdev)
> +{
> + struct pmem_device *pmem;
> + struct gendisk *disk;
> + struct resource *res;
> + int idx, err;
> +
> + if (WARN_ON(pdev->num_resources > 1))
> + return -ENXIO;
> +
> + res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> + if (!res)
> + return -ENXIO;
> +
> + pmem = kzalloc(sizeof(*pmem), GFP_KERNEL);
> + if (unlikely(!pmem))
> + return -ENOMEM;
> +
> + pmem->phys_addr = res->start;
> + pmem->size = resource_size(res);
> +
> + err = pmem_mapmem(pmem);
> + if (unlikely(err))
> + goto out_free_dev;
> +
> + err = -ENOMEM;
> + pmem->pmem_queue = blk_alloc_queue(GFP_KERNEL);
> + if (unlikely(!pmem->pmem_queue))
> + goto out_unmap;
> +
> + blk_queue_make_request(pmem->pmem_queue, pmem_make_request);
> + blk_queue_max_hw_sectors(pmem->pmem_queue, 1024);
> + blk_queue_bounce_limit(pmem->pmem_queue, BLK_BOUNCE_ANY);
> +
> + disk = alloc_disk(PMEM_MINORS);
> + if (unlikely(!disk))
> + goto out_free_queue;
> +
> + idx = atomic_inc_return(&pmem_index) - 1;
> +
> + disk->major = pmem_major;
> + disk->first_minor = PMEM_MINORS * idx;
> + disk->fops = &pmem_fops;
> + disk->private_data = pmem;
> + disk->queue = pmem->pmem_queue;
> + disk->flags = GENHD_FL_EXT_DEVT;
> + sprintf(disk->disk_name, "pmem%d", idx);
> + disk->driverfs_dev = &pdev->dev;
> + set_capacity(disk, pmem->size >> SECTOR_SHIFT);
> + pmem->pmem_disk = disk;
> +
> + add_disk(disk);
> +
> + platform_set_drvdata(pdev, pmem);
> + return 0;
> +
> +out_free_queue:
> + blk_cleanup_queue(pmem->pmem_queue);
> +out_unmap:
> + pmem_unmapmem(pmem);
> +out_free_dev:
> + kfree(pmem);
> +out:
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