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examine: tidy up some code. 

Michael Shigorin reports that the 'lcc' compiler isn't able
to deduce that 'st' must be initialized in

		if (c->SparcAdjust)
			st->ss->update_super(st, NULL, "sparc2.2",

just because the only times it isn't initialised, 'err' is set non-zero.

This results in a 'possibly uninitialised' warning.
While there is no bug in the code, this does suggest that maybe
the code could be made more obviously correct.

So this patch:
 1/ moves the "err" variable inside the for loop, so an error in
    one device doesn't stop the other devices from being processed
 2/ calls 'continue' early if the device cannot be opened, so that
    a level of indent can be removed, and so that it is clear that
    'st' is always initialised before being used
 3/ frees 'st' if an error occured in load_super or load_container.

Reported-by: Michael Shigorin <mike@altlinux.org>
Signed-off-by: NeilBrown <neilb@suse.com>
Signed-off-by: Jes Sorensen <Jes.Sorensen@gmail.com>
This commit is contained in:
NeilBrown 2017-03-03 10:57:00 +11:00 committed by Jes Sorensen
parent 9d67f6496c
commit 36352fc957
1 changed files with 40 additions and 37 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

77
Examine.c
View File

@ -53,7 +53,6 @@ int Examine(struct mddev_dev *devlist,
*/
int fd;
int rv = 0;
int err = 0;
struct array {
struct supertype *st;
@ -66,6 +65,8 @@ int Examine(struct mddev_dev *devlist,
for (; devlist ; devlist = devlist->next) {
struct supertype *st;
int have_container = 0;
int err = 0;
int container = 0;
fd = dev_open(devlist->devname, O_RDONLY);
if (fd < 0) {
@ -74,44 +75,46 @@ int Examine(struct mddev_dev *devlist,
devlist->devname, strerror(errno));
rv = 1;
}
continue;
}
if (forcest)
st = dup_super(forcest);
else if (must_be_container(fd)) {
/* might be a container */
st = super_by_fd(fd, NULL);
container = 1;
} else
st = guess_super(fd);
if (st) {
err = 1;
st->ignore_hw_compat = 1;
if (!container)
err = st->ss->load_super(st, fd,
(c->brief||c->scan) ? NULL
:devlist->devname);
if (err && st->ss->load_container) {
err = st->ss->load_container(st, fd,
(c->brief||c->scan) ? NULL
:devlist->devname);
if (!err)
have_container = 1;
}
st->ignore_hw_compat = 0;
} else {
if (!c->brief) {
pr_err("No md superblock detected on %s.\n", devlist->devname);
rv = 1;
}
err = 1;
}
else {
int container = 0;
if (forcest)
st = dup_super(forcest);
else if (must_be_container(fd)) {
/* might be a container */
st = super_by_fd(fd, NULL);
container = 1;
} else
st = guess_super(fd);
if (st) {
err = 1;
st->ignore_hw_compat = 1;
if (!container)
err = st->ss->load_super(st, fd,
(c->brief||c->scan) ? NULL
:devlist->devname);
if (err && st->ss->load_container) {
err = st->ss->load_container(st, fd,
(c->brief||c->scan) ? NULL
:devlist->devname);
if (!err)
have_container = 1;
}
st->ignore_hw_compat = 0;
} else {
if (!c->brief) {
pr_err("No md superblock detected on %s.\n", devlist->devname);
rv = 1;
}
err = 1;
}
close(fd);
}
if (err)
close(fd);
if (err) {
if (st)
st->ss->free_super(st);
continue;
}
if (c->SparcAdjust)
st->ss->update_super(st, NULL, "sparc2.2",
@ -121,7 +124,7 @@ int Examine(struct mddev_dev *devlist,
if (c->brief && st->ss->brief_examine_super == NULL) {
if (!c->scan)
pr_err("No brief listing for %s on %s\n",
st->ss->name, devlist->devname);
st->ss->name, devlist->devname);
} else if (c->brief) {
struct array *ap;
char *d;