Messages in this thread | | | Date | Wed, 10 Feb 2021 14:41:00 +0100 | From | Christoph Hellwig <> | Subject | Re: [PATCH v3 06/11] mm, pmem: Implement ->memory_failure() in pmem driver |
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> +static int pmem_pagemap_memory_failure(struct dev_pagemap *pgmap, > + unsigned long pfn, int flags) > +{ > + struct pmem_device *pdev; > + struct gendisk *disk; > + loff_t disk_offset; > + int rc = 0; > + unsigned long size = page_size(pfn_to_page(pfn)); > + > + pdev = container_of(pgmap, struct pmem_device, pgmap); > + disk = pdev->disk;
Would be nice to initialize this at the time of declaration:
struct pmem_device *pdev = container_of(pgmap, struct pmem_device, pgmap); struct gendisk *disk = pdev->disk unsigned long size = page_size(pfn_to_page(pfn));
> + if (!disk) > + return -ENXIO; > + > + disk_offset = PFN_PHYS(pfn) - pdev->phys_addr - pdev->data_offset; > + if (disk->fops->corrupted_range) { > + rc = disk->fops->corrupted_range(disk, NULL, disk_offset, > + size, &flags); > + if (rc == -ENODEV) > + rc = -ENXIO; > + } else > + rc = -EOPNOTSUPP;
Why do we need the disk and fops check here? A pgmap registered by pmem.c should always have a disk with pmem_fops. And more importantly this has no business going through the block layer.
Instead the file system should deposit a callback when starting to use the dax_device using fs_dax_get_by_bdev / dax_get_by_host and a private data (the superblock), and we avoid all the lookup problems.
> +int mf_generic_kill_procs(unsigned long long pfn, int flags)
This function seems to be only used inside of memory-failure.c, so it could be marked static. Also I'd name it dax_generic_memory_failure or something like that to match the naming of the ->memory_failure pgmap operation.
Also maybe just splitting this out into a helper would be a nice prep patch.
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