This is in prep for implementing .demand_read() callback for cachefiles.
In the following patch, .demand_read() callback is responsible for
notifying user daemon the requested file range (hole) to read. Then
.demand_read() callback will get blocked until user daemon has prepared
data and filled the hole.
This patch introduces an idr tree to manage all these pending
demand-read IO.
Signed-off-by: Jeffle Xu <jefflexu@xxxxxxxxxxxxxxxxx>
---
fs/cachefiles/daemon.c | 3 +++
fs/cachefiles/internal.h | 4 ++++
2 files changed, 7 insertions(+)
diff --git a/fs/cachefiles/daemon.c b/fs/cachefiles/daemon.c
index 892a9bdba53f..01496fa8c263 100644
--- a/fs/cachefiles/daemon.c
+++ b/fs/cachefiles/daemon.c
@@ -118,6 +118,8 @@ static int cachefiles_daemon_open(struct inode *inode, struct file *file)
INIT_LIST_HEAD(&cache->volumes);
INIT_LIST_HEAD(&cache->object_list);
spin_lock_init(&cache->object_list_lock);
+ idr_init(&cache->reqs);
+ spin_lock_init(&cache->reqs_lock);
/* set default caching limits
* - limit at 1% free space and/or free files
@@ -152,6 +154,7 @@ static int cachefiles_daemon_release(struct inode *inode, struct file *file)
cachefiles_daemon_unbind(cache);
/* clean up the control file interface */
+ idr_destroy(&cache->reqs);
cache->cachefilesd = NULL;
file->private_data = NULL;
cachefiles_open = 0;
diff --git a/fs/cachefiles/internal.h b/fs/cachefiles/internal.h
index a8e6500889d7..af8ac8107f77 100644
--- a/fs/cachefiles/internal.h
+++ b/fs/cachefiles/internal.h
@@ -15,6 +15,7 @@
#include <linux/fscache-cache.h>
#include <linux/cred.h>
#include <linux/security.h>
+#include <linux/idr.h>
#define CACHEFILES_DIO_BLOCK_SIZE 4096
@@ -102,6 +103,9 @@ struct cachefiles_cache {
char *rootdirname; /* name of cache root directory */
char *secctx; /* LSM security context */
char *tag; /* cache binding tag */
+
+ struct idr reqs;
+ spinlock_t reqs_lock;
};
#include <trace/events/cachefiles.h>
--
2.27.0
--
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