On 7/13/21 1:48 PM, Daniel Kiper wrote:
> On Thu, Jul 08, 2021 at 05:55:58PM +0200, Petr Vorel wrote:
>> From: Jeff Mahoney <je...@suse.com>
>>
>> sysfs_partition_path calls udevadm to resolve the sysfs path for
>> a block device. That can be accomplished by stating the device node
>> and using the major/minor to follow the symlinks in /sys/dev/block/.
>>
>> This cuts the execution time of grub2-mkconfig from 10s to 2s on
>> my system.
>>
>> Signed-off-by: Jeff Mahoney <je...@suse.com>
>> [ pvorel: include grub/osdep/major.h ]
>> Signed-off-by: Petr Vorel <pvo...@suse.cz>
>> ---
>> grub-core/osdep/linux/hostdisk.c | 8 ++++++++
>> 1 file changed, 8 insertions(+)
>>
>> diff --git a/grub-core/osdep/linux/hostdisk.c
>> b/grub-core/osdep/linux/hostdisk.c
>> index da62f924e..43dc4b0ba 100644
>> --- a/grub-core/osdep/linux/hostdisk.c
>> +++ b/grub-core/osdep/linux/hostdisk.c
>> @@ -31,6 +31,7 @@
>> #include <grub/misc.h>
>> #include <grub/i18n.h>
>> #include <grub/list.h>
>> +#include <grub/osdep/major.h>
>>
>> #include <stdio.h>
>> #include <stdlib.h>
>> @@ -105,6 +106,13 @@ sysfs_partition_path (const char *dev, const char
>> *entry)
>> char *buf = NULL;
>> size_t len = 0;
>> char *path = NULL;
>> + struct stat st;
>> + int ret;
>> +
>> + ret = stat(dev, &st);
>
> Missing space between "stat" and "(".
>
>> + if (ret == 0 && S_ISBLK(st.st_mode))
>
> Same for S_ISBLK...
>
>> + return xasprintf ("/sys/dev/block/%u:%u/%s",
>> + major (st.st_rdev), minor (st.st_rdev), entry);
>>
>> argv[0] = "udevadm";
>> argv[1] = "info";
>
> Do we really need udevadm fallback mechanism? If something went wrong
> here for us I do not expect it will work for udevadm either.I suspect not. 'udevadm info --query path --name <dev>' does essentially the same thing but with many more steps and the cost starting an external program for every block device. I left it in with the assumption that it was probably there for a reason and perhaps udevadm on early udev systems did something more special than just doing stat + sysfs path building. I didn't spend any time on validating that assumption. -Jeff -- Jeff Mahoney Director, SUSE Labs Data & Performance
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