diff mbox series

sunrpc: clean cache_detail immediately when flush is written frequently

Message ID 20241227083353.4125224-1-lilingfeng3@huawei.com (mailing list archive)
State Not Applicable
Delegated to: Netdev Maintainers
Headers show
Series sunrpc: clean cache_detail immediately when flush is written frequently | expand

Checks

Context Check Description
netdev/series_format warning Single patches do not need cover letters; Target tree name not specified in the subject
netdev/tree_selection success Guessed tree name to be net-next
netdev/ynl success Generated files up to date; no warnings/errors; no diff in generated;
netdev/fixes_present success Fixes tag not required for -next series
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 1 this patch: 1
netdev/build_tools success No tools touched, skip
netdev/cc_maintainers success CCed 14 of 14 maintainers
netdev/build_clang success Errors and warnings before: 2 this patch: 2
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/deprecated_api success None detected
netdev/check_selftest success No net selftest shell script
netdev/verify_fixes success No Fixes tag
netdev/build_allmodconfig_warn success Errors and warnings before: 1 this patch: 1
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 14 lines checked
netdev/build_clang_rust success No Rust files in patch. Skipping build
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0
netdev/contest success net-next-2024-12-27--09-00 (tests: 878)

Commit Message

Li Lingfeng Dec. 27, 2024, 8:33 a.m. UTC 
We will write /proc/net/rpc/xxx/flush if we want to clean cache_detail.
This updates nextcheck to the current time and calls cache_flush -->
cache_clean to clean cache_detail.
If we write this interface again within one second, it will only increase
flush_time and nextcheck without actually cleaning cache_detail.
Therefore, if we keep writing this interface repeatedly within one second,
flush_time and nextcheck will keep increasing, even far exceeding the
current time, making it impossible to clear cache_detail through the flush
interface or cache_cleaner.
If someone frequently calls the flush interface, we should immediately
clean the corresponding cache_detail instead of continuously accumulating
nextcheck.

Signed-off-by: Li Lingfeng <lilingfeng3@huawei.com>
---
 net/sunrpc/cache.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)
diff mbox series

Patch

diff --git a/net/sunrpc/cache.c b/net/sunrpc/cache.c
index 059f6ef1ad18..73668df0450b 100644
--- a/net/sunrpc/cache.c
+++ b/net/sunrpc/cache.c
@@ -1531,9 +1531,13 @@  static ssize_t write_flush(struct file *file, const char __user *buf,
 	 * or by one second if it has already reached the current time.
 	 * Newly added cache entries will always have ->last_refresh greater
 	 * that ->flush_time, so they don't get flushed prematurely.
+	 *
+	 * If someone frequently calls the flush interface, we should
+	 * immediately clean the corresponding cache_detail instead of
+	 * continuously accumulating nextcheck.
 	 */
 
-	if (cd->flush_time >= now)
+	if (cd->flush_time >= now && cd->flush_time < (now + 5))
 		now = cd->flush_time + 1;
 
 	cd->flush_time = now;