io-wq: add io_wq_cancel_pid() to cancel based on a specific pid

Add a helper that allows the caller to cancel work based on what mm
it belongs to. This allows io_uring to cancel work from a given
task or thread when it exits.

Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/fs/io-wq.c b/fs/io-wq.c
index df78de3..182aa17 100644 (file)
--- a/fs/io-wq.c
+++ b/fs/io-wq.c
@@ -1029,6 +1029,35 @@ enum io_wq_cancel io_wq_cancel_work(struct io_wq *wq, struct io_wq_work *cwork)
        return ret;
 }
 
+static bool io_wq_pid_match(struct io_wq_work *work, void *data)
+{
+       pid_t pid = (pid_t) (unsigned long) data;
+
+       if (work)
+               return work->task_pid == pid;
+       return false;
+}
+
+enum io_wq_cancel io_wq_cancel_pid(struct io_wq *wq, pid_t pid)
+{
+       struct work_match match = {
+               .fn     = io_wq_pid_match,
+               .data   = (void *) (unsigned long) pid
+       };
+       enum io_wq_cancel ret = IO_WQ_CANCEL_NOTFOUND;
+       int node;
+
+       for_each_node(node) {
+               struct io_wqe *wqe = wq->wqes[node];
+
+               ret = io_wqe_cancel_work(wqe, &match);
+               if (ret != IO_WQ_CANCEL_NOTFOUND)
+                       break;
+       }
+
+       return ret;
+}
+
 struct io_wq_flush_data {
        struct io_wq_work work;
        struct completion done;

diff --git a/fs/io-wq.h b/fs/io-wq.h
index f152ba6..ccc7d84 100644 (file)
--- a/fs/io-wq.h
+++ b/fs/io-wq.h
@@ -76,6 +76,7 @@ struct io_wq_work {
        const struct cred *creds;
        struct fs_struct *fs;
        unsigned flags;
+       pid_t task_pid;
 };
 
 #define INIT_IO_WORK(work, _func)                      \
@@ -109,6 +110,7 @@ void io_wq_flush(struct io_wq *wq);
 
 void io_wq_cancel_all(struct io_wq *wq);
 enum io_wq_cancel io_wq_cancel_work(struct io_wq *wq, struct io_wq_work *cwork);
+enum io_wq_cancel io_wq_cancel_pid(struct io_wq *wq, pid_t pid);
 
 typedef bool (work_cancel_fn)(struct io_wq_work *, void *);