On Thu, Oct 13 2011 at 6:19pm -0400,
Mikulas Patocka <mpatocka@xxxxxxxxxx> wrote:
> > +static int dm_bufio_trylock(struct dm_bufio_client *c)
> > +{
> > + return dm_bufio_trylock(c);
> > +}
> > +
> > +static void dm_bufio_unlock(struct dm_bufio_client *c)
> > +{
> > + dm_bufio_unlock(c);
> > +}
>
> These two functions are recursive nonsense :) There should be
> "return mutex_trylock(&c->lock);" and "mutex_unlock(&c->lock);".
Heheh. Sorry, M-x replace-string gone wild.
Here is a fixed version.
---
drivers/md/persistent-data/dm-bufio.c | 71 ++++++++++++++++++++++-----------
1 files changed, 48 insertions(+), 23 deletions(-)
diff --git a/drivers/md/persistent-data/dm-bufio.c b/drivers/md/persistent-data/dm-bufio.c
index 6be4386..e7d1aac 100644
--- a/drivers/md/persistent-data/dm-bufio.c
+++ b/drivers/md/persistent-data/dm-bufio.c
@@ -151,6 +151,23 @@ static inline int dm_bufio_cache_index(struct dm_bufio_client *c)
#define DM_BUFIO_CACHE(c) (dm_bufio_caches[dm_bufio_cache_index(c)])
#define DM_BUFIO_CACHE_NAME(c) (dm_bufio_cache_names[dm_bufio_cache_index(c)])
+#define dm_bufio_in_request() (!!current->bio_list)
+
+static void dm_bufio_lock(struct dm_bufio_client *c)
+{
+ mutex_lock_nested(&c->lock, dm_bufio_in_request());
+}
+
+static int dm_bufio_trylock(struct dm_bufio_client *c)
+{
+ return mutex_trylock(&c->lock);
+}
+
+static void dm_bufio_unlock(struct dm_bufio_client *c)
+{
+ mutex_unlock(&c->lock);
+}
+
/*----------------------------------------------------------------*/
/* Default cache size --- available memory divided by the ratio */
@@ -595,14 +612,14 @@ static void __wait_for_free_buffer(struct dm_bufio_client *c)
add_wait_queue(&c->free_buffer_wait, &wait);
set_task_state(current, TASK_UNINTERRUPTIBLE);
- mutex_unlock(&c->lock);
+ dm_bufio_unlock(c);
io_schedule();
set_task_state(current, TASK_RUNNING);
remove_wait_queue(&c->free_buffer_wait, &wait);
- mutex_lock(&c->lock);
+ dm_bufio_lock(c);
}
/*
@@ -836,9 +853,9 @@ static void *new_read(struct dm_bufio_client *c, sector_t block, enum new_flag n
int need_submit;
struct dm_buffer *b;
- mutex_lock(&c->lock);
+ dm_bufio_lock(c);
b = __bufio_new(c, block, nf, bp, &need_submit);
- mutex_unlock(&c->lock);
+ dm_bufio_unlock(c);
if (!b || IS_ERR(b))
return b;
@@ -867,19 +884,21 @@ void *dm_bufio_get(struct dm_bufio_client *c, sector_t block,
void *dm_bufio_read(struct dm_bufio_client *c, sector_t block,
struct dm_buffer **bp)
{
+ BUG_ON(dm_bufio_in_request());
return new_read(c, block, NF_READ, bp);
}
void *dm_bufio_new(struct dm_bufio_client *c, sector_t block,
struct dm_buffer **bp)
{
+ BUG_ON(dm_bufio_in_request());
return new_read(c, block, NF_FRESH, bp);
}
void dm_bufio_release(struct dm_buffer *b)
{
struct dm_bufio_client *c = b->c;
- mutex_lock(&c->lock);
+ dm_bufio_lock(c);
BUG_ON(test_bit(B_READING, &b->state));
BUG_ON(!b->hold_count);
b->hold_count--;
@@ -898,26 +917,27 @@ void dm_bufio_release(struct dm_buffer *b)
__free_buffer_wake(b);
}
}
- mutex_unlock(&c->lock);
+ dm_bufio_unlock(c);
}
void dm_bufio_mark_buffer_dirty(struct dm_buffer *b)
{
struct dm_bufio_client *c = b->c;
- mutex_lock(&c->lock);
+ dm_bufio_lock(c);
if (!test_and_set_bit(B_DIRTY, &b->state))
__relink_lru(b, LIST_DIRTY);
- mutex_unlock(&c->lock);
+ dm_bufio_unlock(c);
}
void dm_bufio_write_dirty_buffers_async(struct dm_bufio_client *c)
{
- mutex_lock(&c->lock);
+ BUG_ON(dm_bufio_in_request());
+ dm_bufio_lock(c);
__write_dirty_buffers_async(c, 0);
- mutex_unlock(&c->lock);
+ dm_bufio_unlock(c);
}
/*
@@ -933,7 +953,7 @@ int dm_bufio_write_dirty_buffers(struct dm_bufio_client *c)
unsigned long buffers_processed = 0;
struct dm_buffer *b, *tmp;
- mutex_lock(&c->lock);
+ dm_bufio_lock(c);
__write_dirty_buffers_async(c, 0);
again:
@@ -947,10 +967,10 @@ again:
if (buffers_processed < c->n_buffers[LIST_DIRTY]) {
dropped_lock = 1;
b->hold_count++;
- mutex_unlock(&c->lock);
+ dm_bufio_unlock(c);
wait_on_bit(&b->state, B_WRITING,
do_io_schedule, TASK_UNINTERRUPTIBLE);
- mutex_lock(&c->lock);
+ dm_bufio_lock(c);
b->hold_count--;
} else
wait_on_bit(&b->state, B_WRITING,
@@ -978,7 +998,7 @@ again:
goto again;
}
wake_up(&c->free_buffer_wait);
- mutex_unlock(&c->lock);
+ dm_bufio_unlock(c);
a = xchg(&c->async_write_error, 0);
f = dm_bufio_issue_flush(c);
@@ -1003,6 +1023,7 @@ int dm_bufio_issue_flush(struct dm_bufio_client *c)
.sector = 0,
.count = 0,
};
+ BUG_ON(dm_bufio_in_request());
return dm_io(&io_req, 1, &io_reg, NULL);
}
@@ -1023,7 +1044,9 @@ void dm_bufio_release_move(struct dm_buffer *b, sector_t new_block)
struct dm_bufio_client *c = b->c;
struct dm_buffer *new;
- mutex_lock(&c->lock);
+ BUG_ON(dm_bufio_in_request());
+
+ dm_bufio_lock(c);
retry:
new = __find(c, new_block);
@@ -1054,7 +1077,7 @@ retry:
wait_on_bit(&b->state, B_WRITING,
do_io_schedule, TASK_UNINTERRUPTIBLE);
}
- mutex_unlock(&c->lock);
+ dm_bufio_unlock(c);
dm_bufio_release(b);
}
@@ -1094,10 +1117,12 @@ static void drop_buffers(struct dm_bufio_client *c)
struct dm_buffer *b;
int i;
+ BUG_ON(dm_bufio_in_request());
+
/* an optimization ... so that the buffers are not written one-by-one */
dm_bufio_write_dirty_buffers_async(c);
- mutex_lock(&c->lock);
+ dm_bufio_lock(c);
while ((b = __get_unclaimed_buffer(c)))
__free_buffer_wake(b);
@@ -1110,7 +1135,7 @@ static void drop_buffers(struct dm_bufio_client *c)
for (i = 0; i < LIST_N; i++)
BUG_ON(!list_empty(&c->lru[i]));
- mutex_unlock(&c->lock);
+ dm_bufio_unlock(c);
}
/*
@@ -1166,9 +1191,9 @@ static int shrink(struct shrinker *shrinker, struct shrink_control *sc)
unsigned long nr_to_scan = sc->nr_to_scan;
if (sc->gfp_mask & __GFP_IO) {
- mutex_lock(&c->lock);
+ dm_bufio_lock(c);
} else {
- if (!mutex_trylock(&c->lock))
+ if (!dm_bufio_trylock(c))
return !nr_to_scan ? 0 : -1;
}
@@ -1179,7 +1204,7 @@ static int shrink(struct shrinker *shrinker, struct shrink_control *sc)
if (r > INT_MAX)
r = INT_MAX;
- mutex_unlock(&c->lock);
+ dm_bufio_unlock(c);
return r;
}
@@ -1356,7 +1381,7 @@ static void cleanup_old_buffers(void)
mutex_lock(&dm_bufio_clients_lock);
list_for_each_entry(c, &dm_bufio_all_clients, client_list) {
- if (!mutex_trylock(&c->lock))
+ if (!dm_bufio_trylock(c))
continue;
while (!list_empty(&c->lru[LIST_CLEAN])) {
@@ -1367,7 +1392,7 @@ static void cleanup_old_buffers(void)
break;
}
- mutex_unlock(&c->lock);
+ dm_bufio_unlock(c);
}
mutex_unlock(&dm_bufio_clients_lock);
}
--
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