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dm mirror: remove VLA usage 

On the quest to remove all VLAs from the kernel[1], this avoids VLAs
in dm-raid1.c by just using the maximum size for the stack arrays.
The nr_mirrors value was already capped at 9, so this makes it a trivial
adjustment to the array sizes.

[1] https://lkml.org/lkml/2018/3/7/621

Signed-off-by: Kees Cook <keescook@chromium.org>
Acked-by: Heinz Mauelshagen <heinzm@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
This commit is contained in:
Kees Cook 2018-04-10 21:43:15 -07:00 committed by Mike Snitzer
parent 3d97c829ed
commit 65972a6fa9
1 changed files with 6 additions and 4 deletions
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10
drivers/md/dm-raid1.c
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@ -23,6 +23,8 @@
#define MAX_RECOVERY 1 /* Maximum number of regions recovered in parallel. */
#define MAX_NR_MIRRORS (DM_KCOPYD_MAX_REGIONS + 1)
#define DM_RAID1_HANDLE_ERRORS 0x01
#define DM_RAID1_KEEP_LOG 0x02
#define errors_handled(p) ((p)->features & DM_RAID1_HANDLE_ERRORS)
@ -255,7 +257,7 @@ static int mirror_flush(struct dm_target *ti)
unsigned long error_bits;
unsigned int i;
struct dm_io_region io[ms->nr_mirrors];
struct dm_io_region io[MAX_NR_MIRRORS];
struct mirror *m;
struct dm_io_request io_req = {
.bi_op = REQ_OP_WRITE,
@ -651,7 +653,7 @@ static void write_callback(unsigned long error, void *context)
static void do_write(struct mirror_set *ms, struct bio *bio)
{
unsigned int i;
struct dm_io_region io[ms->nr_mirrors], *dest = io;
struct dm_io_region io[MAX_NR_MIRRORS], *dest = io;
struct mirror *m;
struct dm_io_request io_req = {
.bi_op = REQ_OP_WRITE,
@ -1083,7 +1085,7 @@ static int mirror_ctr(struct dm_target *ti, unsigned int argc, char **argv)
argc -= args_used;
if (!argc || sscanf(argv[0], "%u%c", &nr_mirrors, &dummy) != 1 ||
nr_mirrors < 2 || nr_mirrors > DM_KCOPYD_MAX_REGIONS + 1) {
nr_mirrors < 2 || nr_mirrors > MAX_NR_MIRRORS) {
ti->error = "Invalid number of mirrors";
dm_dirty_log_destroy(dl);
return -EINVAL;
@ -1404,7 +1406,7 @@ static void mirror_status(struct dm_target *ti, status_type_t type,
int num_feature_args = 0;
struct mirror_set *ms = (struct mirror_set *) ti->private;
struct dm_dirty_log *log = dm_rh_dirty_log(ms->rh);
char buffer[ms->nr_mirrors + 1];
char buffer[MAX_NR_MIRRORS + 1];
switch (type) {
case STATUSTYPE_INFO: