mm/damon/core: introduce damon_set_target_pid()

The logic that finds the struct pid for a given pid number and assigns it
to a damon_target is duplicated in multiple places.  Including
damon_sysfs_add_target() of mm/damon/sysfs.c and the start functions of
the two sample modules, samples/damon/wsse.c and samples/damon/prcl.c. 
Add a function that does the work, and replace the duplicated code in the
places with calls to the function.

Link: https://lore.kernel.org/20260831142611.77572-3-sj@kernel.org
Signed-off-by: Enze Li <lienze@kylinos.cn>
Signed-off-by: SJ Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: SJ Park <sj@kernel.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Hari Mishal <harimishal1@gmail.com>
Cc: Jaeyeon Lee <jaeyeon.lee.dev@gmail.com>
Cc: Li Youhong <liyouhong@kylinos.cn>
Cc: Shuah Khan <shuah@kernel.org>
Cc: "Zenghui Yu (Huawei)" <zenghui.yu@linux.dev>
Cc: zhaozhengzhuo <zhaozhengzhuo@uniontech.com>

1 files changed, 1 insertions, 0 deletions

diff --git a/include/linux/damon.h b/include/linux/damon.h
index 955b9f614e5b..7b1b6050a828 100644
--- a/include/linux/damon.h
+++ b/include/linux/damon.h
@@ -1057,6 +1057,7 @@ int damos_commit_quota_goals(struct damos_quota *dst, struct damos_quota *src);
 
 struct damon_target *damon_new_target(void);
 void damon_add_target(struct damon_ctx *ctx, struct damon_target *t);
+int damon_set_target_pid(struct damon_target *t, int pid);
 void damon_free_target(struct damon_target *t);
 void damon_destroy_target(struct damon_target *t, struct damon_ctx *ctx);
 unsigned int damon_nr_regions(struct damon_target *t);