xiaomi-sm8450/android_kernel_xiaomi_sm8450
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

dm mpath: push path selector locking down to path selectors

Browse Source 
Proper locking of the lists used by the path selectors should be handled
within the selectors (relying on dm-mpath.c code's use of the m->lock
spinlock was reckless).

Signed-off-by: Mike Snitzer <snitzer@redhat.com>
This commit is contained in:
Mike Snitzer
2016-02-15 14:25:00 -05:00
parent 21136f89d7
commit 9659f81144
3 changed files with 59 additions and 11 deletions
Download Patch File Download Diff File Expand all files Collapse all files

23
drivers/md/dm-queue-length.c
View File

@@ -29,6 +29,7 @@
struct selector {
struct list_head valid_paths;
struct list_head failed_paths;
spinlock_t lock;
};
struct path_info {
@@ -45,6 +46,7 @@ static struct selector *alloc_selector(void)
if (s) {
INIT_LIST_HEAD(&s->valid_paths);
INIT_LIST_HEAD(&s->failed_paths);
spin_lock_init(&s->lock);
}
return s;
@@ -113,6 +115,7 @@ static int ql_add_path(struct path_selector *ps, struct dm_path *path,
struct path_info *pi;
unsigned repeat_count = QL_MIN_IO;
char dummy;
unsigned long flags;
/*
* Arguments: [<repeat_count>]
@@ -147,7 +150,9 @@ static int ql_add_path(struct path_selector *ps, struct dm_path *path,
path->pscontext = pi;
spin_lock_irqsave(&s->lock, flags);
list_add_tail(&pi->list, &s->valid_paths);
spin_unlock_irqrestore(&s->lock, flags);
return 0;
}
@@ -156,16 +161,22 @@ static void ql_fail_path(struct path_selector *ps, struct dm_path *path)
{
struct selector *s = ps->context;
struct path_info *pi = path->pscontext;
unsigned long flags;
spin_lock_irqsave(&s->lock, flags);
list_move(&pi->list, &s->failed_paths);
spin_unlock_irqrestore(&s->lock, flags);
}
static int ql_reinstate_path(struct path_selector *ps, struct dm_path *path)
{
struct selector *s = ps->context;
struct path_info *pi = path->pscontext;
unsigned long flags;
spin_lock_irqsave(&s->lock, flags);
list_move_tail(&pi->list, &s->valid_paths);
spin_unlock_irqrestore(&s->lock, flags);
return 0;
}
@@ -178,9 +189,12 @@ static struct dm_path *ql_select_path(struct path_selector *ps,
{
struct selector *s = ps->context;
struct path_info *pi = NULL, *best = NULL;
struct dm_path *ret = NULL;
unsigned long flags;
spin_lock_irqsave(&s->lock, flags);
if (list_empty(&s->valid_paths))
return NULL;
goto out;
/* Change preferred (first in list) path to evenly balance. */
list_move_tail(s->valid_paths.next, &s->valid_paths);
@@ -195,11 +209,14 @@ static struct dm_path *ql_select_path(struct path_selector *ps,
}
if (!best)
return NULL;
goto out;
*repeat_count = best->repeat_count;
return best->path;
ret = best->path;
out:
spin_unlock_irqrestore(&s->lock, flags);
return ret;
}
static int ql_start_io(struct path_selector *ps, struct dm_path *path,