From: Jeff Layton <jlayton@poochiereds.net>
To: Al Viro <viro@ZenIV.linux.org.uk>
Cc: bfields@fieldses.org, linux-nfs@vger.kernel.org,
linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH 2/4] fs: add a kerneldoc header to fput
Date: Mon, 14 Sep 2015 09:45:53 -0400 [thread overview]
Message-ID: <1442238355-8203-3-git-send-email-jeff.layton@primarydata.com> (raw)
In-Reply-To: <1442238355-8203-1-git-send-email-jeff.layton@primarydata.com>
...and move its EXPORT_SYMBOL just below the function.
Signed-off-by: Jeff Layton <jeff.layton@primarydata.com>
---
fs/file_table.c | 17 ++++++++++++++++-
1 file changed, 16 insertions(+), 1 deletion(-)
diff --git a/fs/file_table.c b/fs/file_table.c
index f4833af62eae..d63f4a399d39 100644
--- a/fs/file_table.c
+++ b/fs/file_table.c
@@ -260,6 +260,21 @@ void flush_delayed_fput(void)
flush_delayed_work(&delayed_fput_work);
}
+/**
+ * fput - put a struct file reference
+ * @file: file of which to put the reference
+ *
+ * This function decrements the reference count for the struct file reference,
+ * and queues it up for destruction if the count goes to zero. In the case of
+ * most tasks we queue it to the task_work infrastructure, which will be run
+ * just before the task returns back to userspace. kthreads however never
+ * return to userspace, so for those we add them to a global list and schedule
+ * a delayed workqueue job to do the work of putting them.
+ *
+ * Why not just do it synchronously? __fput can be quite stack intensive, so
+ * doing a final fput has the possibility of blowing up if we don't take steps
+ * to ensure that we have enough stack space to make it work.
+ */
void fput(struct file *file)
{
if (atomic_long_dec_and_test(&file->f_count)) {
@@ -280,6 +295,7 @@ void fput(struct file *file)
schedule_delayed_work(&delayed_fput_work, 1);
}
}
+EXPORT_SYMBOL(fput);
/*
* synchronous analog of fput(); for kernel threads that might be needed
@@ -298,7 +314,6 @@ void __fput_sync(struct file *file)
}
}
-EXPORT_SYMBOL(fput);
void put_filp(struct file *file)
{
--
2.4.3
next prev parent reply other threads:[~2015-09-14 13:49 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-09-14 13:45 [PATCH 0/4] fs: allow userland tasks to use delayed_fput infrastructure Jeff Layton
2015-09-14 13:45 ` Jeff Layton
2015-09-14 13:45 ` [PATCH 1/4] fs: have flush_delayed_fput flush the workqueue job Jeff Layton
2015-09-14 13:45 ` Jeff Layton [this message]
2015-09-14 13:45 ` [PATCH 3/4] fs: add fput_queue Jeff Layton
2015-09-14 13:45 ` Jeff Layton
2015-09-14 14:15 ` Al Viro
2015-09-14 14:19 ` Jeff Layton
2015-09-14 16:39 ` Al Viro
2015-09-14 17:30 ` Jeff Layton
2015-09-14 13:45 ` [PATCH 4/4] fs: export flush_delayed_fput Jeff Layton
2015-09-14 14:48 ` [PATCH 0/4] fs: allow userland tasks to use delayed_fput infrastructure J. Bruce Fields
2015-09-14 14:48 ` J. Bruce Fields
2015-09-14 15:21 ` Jeff Layton
2015-09-14 15:21 ` Jeff Layton
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=1442238355-8203-3-git-send-email-jeff.layton@primarydata.com \
--to=jlayton@poochiereds.net \
--cc=bfields@fieldses.org \
--cc=linux-fsdevel@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-nfs@vger.kernel.org \
--cc=viro@ZenIV.linux.org.uk \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.