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osdep/linux/hostdisk: Use stat() instead of udevadm for partition lookup

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The 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 grub-mkconfig to somewhere near 55% on
system without LVM (which uses libdevmapper instead sysfs_partition_path()).

Remove udevadm call as it does not help us more than calling stat() directly.

Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Signed-off-by: Petr Vorel <pvorel@suse.cz>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
This commit is contained in:
Jeff Mahoney 2021-07-15 17:35:28 +02:00 committed by Daniel Kiper
parent e94b4f2327
commit 1ea4e5ef09
1 changed files with 6 additions and 46 deletions
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52
grub-core/osdep/linux/hostdisk.c
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@ -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>
@ -98,54 +99,13 @@ grub_util_get_fd_size_os (grub_util_fd_t fd, const char *name, unsigned *log_sec
static char *
sysfs_partition_path (const char *dev, const char *entry)
{
const char *argv[7];
int fd;
pid_t pid;
FILE *udevadm;
char *buf = NULL;
size_t len = 0;
char *path = NULL;
struct stat st;
argv[0] = "udevadm";
argv[1] = "info";
argv[2] = "--query";
argv[3] = "path";
argv[4] = "--name";
argv[5] = dev;
argv[6] = NULL;
if (stat (dev, &st) == 0 && S_ISBLK (st.st_mode))
return xasprintf ("/sys/dev/block/%u:%u/%s",
major (st.st_rdev), minor (st.st_rdev), entry);
pid = grub_util_exec_pipe (argv, &fd);
if (!pid)
return NULL;
/* Parent. Read udevadm's output. */
udevadm = fdopen (fd, "r");
if (!udevadm)
{
grub_util_warn (_("Unable to open stream from %s: %s"),
"udevadm", strerror (errno));
close (fd);
goto out;
}
if (getline (&buf, &len, udevadm) > 0)
{
char *newline;
newline = strchr (buf, '\n');
if (newline)
*newline = '\0';
path = xasprintf ("/sys%s/%s", buf, entry);
}
out:
if (udevadm)
fclose (udevadm);
waitpid (pid, NULL, 0);
free (buf);
return path;
return NULL;
}
static int