Commit 84989f83 authored by Jia Zhu's avatar Jia Zhu Committed by Zizhi Wo
Browse files

cachefiles: narrow the scope of triggering EPOLLIN events in ondemand mode 

mainline inclusion
from mainline-v6.8-rc1
commit b817e22b2e91257ace32a6768c3c003faeaa1c5c
category: feature
bugzilla: https://gitee.com/openeuler/kernel/issues/IA6I1T

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=b817e22b2e91257ace32a6768c3c003faeaa1c5c



--------------------------------

Don't trigger EPOLLIN when there are only reopening read requests in
xarray.

Suggested-by: default avatarXin Yin <yinxin.x@bytedance.com>
Signed-off-by: default avatarJia Zhu <zhujia.zj@bytedance.com>
Link: https://lore.kernel.org/r/20231120041422.75170-5-zhujia.zj@bytedance.com


Reviewed-by: default avatarJingbo Xu <jefflexu@linux.alibaba.com>
Reviewed-by: default avatarDavid Howells <dhowells@redhat.com>
Signed-off-by: default avatarChristian Brauner <brauner@kernel.org>
Signed-off-by: default avatarZizhi Wo <wozizhi@huawei.com>
parent 81dd7909

fs/cachefiles/daemon.c

+12 −2
Original line number Diff line number Diff line
@@ -355,14 +355,24 @@ static __poll_t cachefiles_daemon_poll(struct file *file, 
					   struct poll_table_struct *poll)

{

	struct cachefiles_cache *cache = file->private_data;

	XA_STATE(xas, &cache->reqs, 0);

	struct cachefiles_req *req;

	__poll_t mask;



	poll_wait(file, &cache->daemon_pollwq, poll);

	mask = 0;



	if (cachefiles_in_ondemand_mode(cache)) {

		if (!xa_empty(&cache->reqs))

		if (!xa_empty(&cache->reqs)) {

			rcu_read_lock();

			xas_for_each_marked(&xas, req, ULONG_MAX, CACHEFILES_REQ_NEW) {

				if (!cachefiles_ondemand_is_reopening_read(req)) {

					mask |= EPOLLIN;

					break;

				}

			}

			rcu_read_unlock();

		}

	} else {

		if (test_bit(CACHEFILES_STATE_CHANGED, &cache->flags))

			mask |= EPOLLIN;

fs/cachefiles/internal.h

+12 −0
Original line number Diff line number Diff line
@@ -329,6 +329,13 @@ cachefiles_ondemand_set_object_##_state(struct cachefiles_object *object) \ 
CACHEFILES_OBJECT_STATE_FUNCS(open, OPEN);

CACHEFILES_OBJECT_STATE_FUNCS(close, CLOSE);

CACHEFILES_OBJECT_STATE_FUNCS(reopening, REOPENING);



static inline bool cachefiles_ondemand_is_reopening_read(struct cachefiles_req *req)

{

	return cachefiles_ondemand_object_is_reopening(req->object) &&

			req->msg.opcode == CACHEFILES_OP_READ;

}



#else

static inline ssize_t cachefiles_ondemand_daemon_read(struct cachefiles_cache *cache,

					char __user *_buffer, size_t buflen)
@@ -359,6 +366,11 @@ static inline int cachefiles_ondemand_init_obj_info(struct cachefiles_object *ob 
static inline void cachefiles_ondemand_deinit_obj_info(struct cachefiles_object *obj)

{

}



static inline bool cachefiles_ondemand_is_reopening_read(struct cachefiles_req *req)

{

	return false;

}

#endif



/*