From: Boaz Harrosh <openosd@gmail.com>
To: Matthew Wilcox <matthew.r.wilcox@intel.com>,
linux-fsdevel@vger.kernel.org, linux-mm@kvack.org,
linux-kernel@vger.kernel.org
Cc: willy@linux.intel.com
Subject: Re: [PATCH v8 04/22] Change direct_access calling convention
Date: Wed, 30 Jul 2014 19:12:44 +0300 [thread overview]
Message-ID: <53D9197C.2050000@gmail.com> (raw)
In-Reply-To: <53D9174C.7040906@gmail.com>
On 07/30/2014 07:03 PM, Boaz Harrosh wrote:
<>
>> +long bdev_direct_access(struct block_device *bdev, sector_t sector,
>> + void **addr, unsigned long *pfn, long size)
>> +{
>> + const struct block_device_operations *ops = bdev->bd_disk->fops;
>> + if (!ops->direct_access)
>> + return -EOPNOTSUPP;
>
> You need to check alignment on PAGE_SIZE since this API requires it, do
> to pfn defined to a page_number.
>
> (Unless you want to define another output-param like page_offset.
> but this exercise can be left to the caller)
>
> You also need to check against the partition boundary. so something like:
>
> + if (sector & (PAGE_SECTORS-1))
> + return -EINVAL;
> + if (unlikely(sector + size > part_nr_sects_read(bdev->bd_part)))
Off course I was wrong here size is in bytes not in sectors. Which points
out that maybe this API needs to be in sectors.
[Actually it needs to be in pages both size and offset, because of return of
pfn, but its your call.]
Anyway my code above needs to be fixed with
(size + 512 -1) / 512
Thanks
Boaz
> + return -ERANGE;
>
> Then perhaps you can remove that check from drivers
>
>> + return ops->direct_access(bdev, sector + get_start_sect(bdev), addr,
>> + pfn, size);
>> +}
>> +EXPORT_SYMBOL_GPL(bdev_direct_access);
<>
next prev parent reply other threads:[~2014-07-30 16:12 UTC|newest]
Thread overview: 61+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-07-22 19:47 [PATCH v8 00/22] Support ext4 on NV-DIMMs Matthew Wilcox
2014-07-22 19:47 ` [PATCH v8 01/22] Fix XIP fault vs truncate race Matthew Wilcox
2014-07-23 11:21 ` Kirill A. Shutemov
2014-07-22 19:47 ` [PATCH v8 02/22] Allow page fault handlers to perform the COW Matthew Wilcox
2014-07-23 11:23 ` Kirill A. Shutemov
2014-07-22 19:47 ` [PATCH v8 03/22] axonram: Fix bug in direct_access Matthew Wilcox
2014-07-23 11:24 ` Kirill A. Shutemov
2014-07-22 19:47 ` [PATCH v8 04/22] Change direct_access calling convention Matthew Wilcox
2014-07-30 16:03 ` Boaz Harrosh
2014-07-30 16:12 ` Boaz Harrosh [this message]
2014-07-30 20:34 ` Matthew Wilcox
2014-07-31 10:16 ` Boaz Harrosh
2014-07-30 19:45 ` Matthew Wilcox
2014-07-31 10:11 ` Boaz Harrosh
2014-07-31 14:13 ` Matthew Wilcox
2014-07-31 15:28 ` Boaz Harrosh
2014-07-31 17:19 ` Matthew Wilcox
2014-07-31 18:04 ` Boaz Harrosh
2014-07-31 20:30 ` Zwisler, Ross
2014-08-01 18:45 ` Zwisler, Ross
2014-07-22 19:47 ` [PATCH v8 05/22] Add vm_replace_mixed() Matthew Wilcox
2014-07-23 9:10 ` Jan Kara
2014-07-23 11:45 ` Kirill A. Shutemov
2014-07-23 13:52 ` Matthew Wilcox
2014-07-23 14:20 ` Kirill A. Shutemov
2014-07-23 14:27 ` Matthew Wilcox
2014-07-23 15:55 ` Kirill A. Shutemov
2014-07-24 1:36 ` Zhang, Tianfei
2014-07-25 19:44 ` Matthew Wilcox
2014-07-28 13:25 ` Kirill A. Shutemov
2014-07-29 1:55 ` Zhang, Tianfei
2014-07-22 19:47 ` [PATCH v8 06/22] Introduce IS_DAX(inode) Matthew Wilcox
2014-07-22 19:47 ` [PATCH v8 07/22] Add copy_to_iter(), copy_from_iter() and iov_iter_zero() Matthew Wilcox
2014-07-22 19:47 ` [PATCH v8 08/22] Replace XIP read and write with DAX I/O Matthew Wilcox
2014-07-22 19:47 ` [PATCH v8 09/22] Replace ext2_clear_xip_target with dax_clear_blocks Matthew Wilcox
2014-07-22 19:47 ` [PATCH v8 10/22] Replace the XIP page fault handler with the DAX page fault handler Matthew Wilcox
2014-07-23 12:10 ` Kirill A. Shutemov
2014-07-23 13:55 ` Matthew Wilcox
2014-07-23 14:10 ` [PATCH v8 00/22] Support ext4 on NV-DIMMs Howard Chu
2014-07-23 14:34 ` Matthew Wilcox
2014-07-23 15:28 ` Howard Chu
2014-07-23 20:55 ` Theodore Ts'o
2014-07-23 16:57 ` [PATCH v8 10/22] Replace the XIP page fault handler with the DAX page fault handler Boaz Harrosh
2014-07-23 19:57 ` Matthew Wilcox
2014-07-22 19:47 ` [PATCH v8 11/22] Replace xip_truncate_page with dax_truncate_page Matthew Wilcox
2014-07-22 19:48 ` [PATCH v8 12/22] Replace XIP documentation with DAX documentation Matthew Wilcox
2014-07-22 19:48 ` [PATCH v8 13/22] Remove get_xip_mem Matthew Wilcox
2014-07-22 19:48 ` [PATCH v8 14/22] ext2: Remove ext2_xip_verify_sb() Matthew Wilcox
2014-07-22 19:48 ` [PATCH v8 15/22] ext2: Remove ext2_use_xip Matthew Wilcox
2014-07-22 19:48 ` [PATCH v8 16/22] ext2: Remove xip.c and xip.h Matthew Wilcox
2014-07-22 19:48 ` [PATCH v8 17/22] Remove CONFIG_EXT2_FS_XIP and rename CONFIG_FS_XIP to CONFIG_FS_DAX Matthew Wilcox
2014-07-22 19:48 ` [PATCH v8 18/22] ext2: Remove ext2_aops_xip Matthew Wilcox
2014-07-22 19:48 ` [PATCH v8 19/22] Get rid of most mentions of XIP in ext2 Matthew Wilcox
2014-07-22 19:48 ` [PATCH v8 20/22] xip: Add xip_zero_page_range Matthew Wilcox
2014-07-22 19:48 ` [PATCH v8 21/22] ext4: Add DAX functionality Matthew Wilcox
2014-07-22 19:48 ` [PATCH v8 22/22] brd: Rename XIP to DAX Matthew Wilcox
2014-07-23 12:30 ` [PATCH v8 00/22] Support ext4 on NV-DIMMs Kirill A. Shutemov
2014-07-23 13:59 ` Matthew Wilcox
2014-07-23 15:58 ` Boaz Harrosh
2014-07-23 19:50 ` Matthew Wilcox
2014-07-24 18:51 ` Ross Zwisler
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