Commit 4b5cff7e authored by Roberto Bergantinos Corpas's avatar Roberto Bergantinos Corpas Committed by Chuck Lever
Browse files

sunrpc: clean-up cache downcall 



We can simplify code around cache_downcall unifying memory
allocations using kvmalloc. This has the benefit of getting rid of
cache_slow_downcall (and queue_io_mutex), and also matches userland
allocation size and limits.

Signed-off-by: default avatarRoberto Bergantinos Corpas <rbergant@redhat.com>
Signed-off-by: default avatarChuck Lever <chuck.lever@oracle.com>
parent 4420440c

net/sunrpc/cache.c

+11 −30
Original line number Diff line number Diff line
@@ -778,7 +778,6 @@ void cache_clean_deferred(void *owner) 
 */



static DEFINE_SPINLOCK(queue_lock);

static DEFINE_MUTEX(queue_io_mutex);



struct cache_queue {

	struct list_head	list;
@@ -906,44 +905,26 @@ static ssize_t cache_do_downcall(char *kaddr, const char __user *buf, 
	return ret;

}



static ssize_t cache_slow_downcall(const char __user *buf,

				   size_t count, struct cache_detail *cd)

{

	static char write_buf[32768]; /* protected by queue_io_mutex */

	ssize_t ret = -EINVAL;



	if (count >= sizeof(write_buf))

		goto out;

	mutex_lock(&queue_io_mutex);

	ret = cache_do_downcall(write_buf, buf, count, cd);

	mutex_unlock(&queue_io_mutex);

out:

	return ret;

}



static ssize_t cache_downcall(struct address_space *mapping,

			      const char __user *buf,

			      size_t count, struct cache_detail *cd)

{

	struct page *page;

	char *kaddr;

	char *write_buf;

	ssize_t ret = -ENOMEM;



	if (count >= PAGE_SIZE)

		goto out_slow;

	if (count >= 32768) { /* 32k is max userland buffer, lets check anyway */

		ret = -EINVAL;

		goto out;

	}



	page = find_or_create_page(mapping, 0, GFP_KERNEL);

	if (!page)

		goto out_slow;

	write_buf = kvmalloc(count + 1, GFP_KERNEL);

	if (!write_buf)

		goto out;



	kaddr = kmap(page);

	ret = cache_do_downcall(kaddr, buf, count, cd);

	kunmap(page);

	unlock_page(page);

	put_page(page);

	ret = cache_do_downcall(write_buf, buf, count, cd);

	kvfree(write_buf);

out:

	return ret;

out_slow:

	return cache_slow_downcall(buf, count, cd);

}



static ssize_t cache_write(struct file *filp, const char __user *buf,