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Merge git://git.kvack.org/~bcrl/aio-next

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Pull AIO leak fixes from Ben LaHaise:
 "I've put these two patches plus Linus's change through a round of
  tests, and it passes millions of iterations of the aio numa
  migratepage test, as well as a number of repetitions of a few simple
  read and write tests.

  The first patch fixes the memory leak Kent introduced, while the
  second patch makes aio_migratepage() much more paranoid and robust"

* git://git.kvack.org/~bcrl/aio-next:
  aio/migratepages: make aio migrate pages sane
  aio: fix kioctx leak introduced by "aio: Fix a trinity splat"
This commit is contained in:
Linus Torvalds
2013-12-22 11:03:49 -08:00
parent 3dc9acb676 8e321fefb0
commit a8472b4bb1
3 changed files with 55 additions and 16 deletions
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55
fs/aio.c
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@ -244,9 +244,14 @@ static void aio_free_ring(struct kioctx *ctx)
int i;
for (i = 0; i < ctx->nr_pages; i++) {
struct page *page;
pr_debug("pid(%d) [%d] page->count=%d\n", current->pid, i,
page_count(ctx->ring_pages[i]));
put_page(ctx->ring_pages[i]);
page = ctx->ring_pages[i];
if (!page)
continue;
ctx->ring_pages[i] = NULL;
put_page(page);
}
put_aio_ring_file(ctx);
@ -280,18 +285,38 @@ static int aio_migratepage(struct address_space *mapping, struct page *new,
unsigned long flags;
int rc;
rc = 0;
/* Make sure the old page hasn't already been changed */
spin_lock(&mapping->private_lock);
ctx = mapping->private_data;
if (ctx) {
pgoff_t idx;
spin_lock_irqsave(&ctx->completion_lock, flags);
idx = old->index;
if (idx < (pgoff_t)ctx->nr_pages) {
if (ctx->ring_pages[idx] != old)
rc = -EAGAIN;
} else
rc = -EINVAL;
spin_unlock_irqrestore(&ctx->completion_lock, flags);
} else
rc = -EINVAL;
spin_unlock(&mapping->private_lock);
if (rc != 0)
return rc;
/* Writeback must be complete */
BUG_ON(PageWriteback(old));
put_page(old);
get_page(new);
rc = migrate_page_move_mapping(mapping, new, old, NULL, mode);
rc = migrate_page_move_mapping(mapping, new, old, NULL, mode, 1);
if (rc != MIGRATEPAGE_SUCCESS) {
get_page(old);
put_page(new);
return rc;
}
get_page(new);
/* We can potentially race against kioctx teardown here. Use the
* address_space's private data lock to protect the mapping's
* private_data.
@ -303,13 +328,24 @@ static int aio_migratepage(struct address_space *mapping, struct page *new,
spin_lock_irqsave(&ctx->completion_lock, flags);
migrate_page_copy(new, old);
idx = old->index;
if (idx < (pgoff_t)ctx->nr_pages)
ctx->ring_pages[idx] = new;
if (idx < (pgoff_t)ctx->nr_pages) {
/* And only do the move if things haven't changed */
if (ctx->ring_pages[idx] == old)
ctx->ring_pages[idx] = new;
else
rc = -EAGAIN;
} else
rc = -EINVAL;
spin_unlock_irqrestore(&ctx->completion_lock, flags);
} else
rc = -EBUSY;
spin_unlock(&mapping->private_lock);
if (rc == MIGRATEPAGE_SUCCESS)
put_page(old);
else
put_page(new);
return rc;
}
#endif
@ -640,7 +676,8 @@ static struct kioctx *ioctx_alloc(unsigned nr_events)
aio_nr += ctx->max_reqs;
spin_unlock(&aio_nr_lock);
percpu_ref_get(&ctx->users); /* io_setup() will drop this ref */
percpu_ref_get(&ctx->users); /* io_setup() will drop this ref */
percpu_ref_get(&ctx->reqs); /* free_ioctx_users() will drop this */
err = ioctx_add_table(ctx, mm);
if (err)