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Message-Id: <20091116095527.3a1265c9.randy.dunlap@oracle.com>
Date: Mon, 16 Nov 2009 09:55:27 -0800
From: Randy Dunlap <randy.dunlap@...cle.com>
To: Karel Zak <kzak@...hat.com>
Cc: LKML <linux-kernel@...r.kernel.org>,
Andrew Morton <akpm@...ux-foundation.org>,
Jens Axboe <jens.axboe@...cle.com>
Subject: Re: mmotm-1113: efi.c: __divdi3 undefined (i386)
On Mon, 16 Nov 2009 13:19:57 +0100 Karel Zak wrote:
> On Sun, Nov 15, 2009 at 10:46:31AM -0800, Randy Dunlap wrote:
> > on i386 builds:
> >
> > fs/built-in.o: In function `last_lba':
> > efi.c:(.text+0x9d9fe): undefined reference to `__divdi3'
> >
> >
> > - return (bdev->bd_inode->i_size >> 9) - 1ULL;
> > + return (bdev->bd_inode->i_size / bdev_logical_block_size(bdev)) - 1ULL;
>
> Ah.. I guess that div_u64() is more portable. Updated
> partitions-use-sector-size-for-efi-gpt.patch is below.
>
> Karel
Acked-by: Randy Dunlap <randy.dunlap@...cle.com>
Thanks.
> From fbb0c11cf349545f2499d382469749543fdc03d0 Mon Sep 17 00:00:00 2001
> From: Karel Zak <kzak@...hat.com>
> Date: Mon, 16 Nov 2009 12:19:25 +0100
> Subject: [PATCH] partitions: use sector size for EFI GPT
>
> Currently, kernel uses strictly 512-byte sectors for EFI GPT parsing.
> That's wrong.
>
> UEFI standard (version 2.3, May 2009, 5.3.1 GUID Format overview, page
> 95) defines that LBA is always based on the logical block size. It
> means bdev_logical_block_size() (aka BLKSSZGET) for Linux.
>
> This patch removes static sector size from EFI GPT parser.
>
> The problem is reproducible with the latest GNU Parted:
>
> # modprobe scsi_debug dev_size_mb=50 sector_size=4096
>
> # ./parted /dev/sdb print
> Model: Linux scsi_debug (scsi)
> Disk /dev/sdb: 52.4MB
> Sector size (logical/physical): 4096B/4096B
> Partition Table: gpt
>
> Number Start End Size File system Name Flags
> 1 24.6kB 3002kB 2978kB primary
> 2 3002kB 6001kB 2998kB primary
> 3 6001kB 9003kB 3002kB primary
>
> # blockdev --rereadpt /dev/sdb
> # dmesg | tail -1
> sdb: unknown partition table <---- !!!
>
> with this patch:
>
> # blockdev --rereadpt /dev/sdb
> # dmesg | tail -1
> sdb: sdb1 sdb2 sdb3
>
> Signed-off-by: Karel Zak <kzak@...hat.com>
> Cc: Jens Axboe <jens.axboe@...cle.com>
> ---
> fs/partitions/efi.c | 23 +++++++++++++++--------
> 1 files changed, 15 insertions(+), 8 deletions(-)
>
> diff --git a/fs/partitions/efi.c b/fs/partitions/efi.c
> index 038a602..80eeff5 100644
> --- a/fs/partitions/efi.c
> +++ b/fs/partitions/efi.c
> @@ -1,7 +1,9 @@
> /************************************************************
> * EFI GUID Partition Table handling
> - * Per Intel EFI Specification v1.02
> - * http://developer.intel.com/technology/efi/efi.htm
> + *
> + * http://www.uefi.org/specs/
> + * http://www.intel.com/technology/efi/
> + *
> * efi.[ch] by Matt Domsch <Matt_Domsch@...l.com>
> * Copyright 2000,2001,2002,2004 Dell Inc.
> *
> @@ -92,6 +94,7 @@
> *
> ************************************************************/
> #include <linux/crc32.h>
> +#include <linux/math64.h>
> #include "check.h"
> #include "efi.h"
>
> @@ -141,7 +144,8 @@ last_lba(struct block_device *bdev)
> {
> if (!bdev || !bdev->bd_inode)
> return 0;
> - return (bdev->bd_inode->i_size >> 9) - 1ULL;
> + return div_u64(bdev->bd_inode->i_size,
> + bdev_logical_block_size(bdev)) - 1ULL;
> }
>
> static inline int
> @@ -188,6 +192,7 @@ static size_t
> read_lba(struct block_device *bdev, u64 lba, u8 * buffer, size_t count)
> {
> size_t totalreadcount = 0;
> + sector_t n = lba * (bdev_logical_block_size(bdev) / 512);
>
> if (!bdev || !buffer || lba > last_lba(bdev))
> return 0;
> @@ -195,7 +200,7 @@ read_lba(struct block_device *bdev, u64 lba, u8 * buffer, size_t count)
> while (count) {
> int copied = 512;
> Sector sect;
> - unsigned char *data = read_dev_sector(bdev, lba++, §);
> + unsigned char *data = read_dev_sector(bdev, n++, §);
> if (!data)
> break;
> if (copied > count)
> @@ -601,6 +606,7 @@ efi_partition(struct parsed_partitions *state, struct block_device *bdev)
> gpt_header *gpt = NULL;
> gpt_entry *ptes = NULL;
> u32 i;
> + unsigned ssz = bdev_logical_block_size(bdev) / 512;
>
> if (!find_valid_gpt(bdev, &gpt, &ptes) || !gpt || !ptes) {
> kfree(gpt);
> @@ -611,13 +617,14 @@ efi_partition(struct parsed_partitions *state, struct block_device *bdev)
> pr_debug("GUID Partition Table is valid! Yea!\n");
>
> for (i = 0; i < le32_to_cpu(gpt->num_partition_entries) && i < state->limit-1; i++) {
> + u64 start = le64_to_cpu(ptes[i].starting_lba);
> + u64 size = le64_to_cpu(ptes[i].ending_lba) -
> + le64_to_cpu(ptes[i].starting_lba) + 1ULL;
> +
> if (!is_pte_valid(&ptes[i], last_lba(bdev)))
> continue;
>
> - put_partition(state, i+1, le64_to_cpu(ptes[i].starting_lba),
> - (le64_to_cpu(ptes[i].ending_lba) -
> - le64_to_cpu(ptes[i].starting_lba) +
> - 1ULL));
> + put_partition(state, i+1, start * ssz, size * ssz);
>
> /* If this is a RAID volume, tell md */
> if (!efi_guidcmp(ptes[i].partition_type_guid,
> --
> 1.6.5.1
>
>
---
~Randy
--
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