linux-kernel - [PATCH v4 3/6] uio: return status with iov truncation

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Date:   Fri, 24 Jul 2020 21:19:19 +0530
From:   Kanchan Joshi <joshi.k@...sung.com>
To:     axboe@...nel.dk, viro@...iv.linux.org.uk, bcrl@...ck.org
Cc:     willy@...radead.org, hch@...radead.org, Damien.LeMoal@....com,
        asml.silence@...il.com, linux-fsdevel@...r.kernel.org,
        linux-kernel@...r.kernel.org, linux-aio@...ck.org,
        io-uring@...r.kernel.org, linux-block@...r.kernel.org,
        linux-api@...r.kernel.org, SelvaKumar S <selvakuma.s1@...sung.com>,
        Kanchan Joshi <joshi.k@...sung.com>,
        Nitesh Shetty <nj.shetty@...sung.com>,
        Javier Gonzalez <javier.gonz@...sung.com>
Subject: [PATCH v4 3/6] uio: return status with iov truncation

From: SelvaKumar S <selvakuma.s1@...sung.com>

Make iov_iter_truncate to report whether it actually truncated.
This helps callers which want to process the iov_iter in its entirety.

Signed-off-by: SelvaKumar S <selvakuma.s1@...sung.com>
Signed-off-by: Kanchan Joshi <joshi.k@...sung.com>
Signed-off-by: Nitesh Shetty <nj.shetty@...sung.com>
Signed-off-by: Javier Gonzalez <javier.gonz@...sung.com>
---
 include/linux/uio.h | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/include/linux/uio.h b/include/linux/uio.h
index 9576fd8..c681a60 100644
--- a/include/linux/uio.h
+++ b/include/linux/uio.h
@@ -241,7 +241,7 @@ static inline size_t iov_iter_count(const struct iov_iter *i)
  * greater than the amount of data in iov_iter is fine - it'll just do
  * nothing in that case.
  */
-static inline void iov_iter_truncate(struct iov_iter *i, u64 count)
+static inline bool iov_iter_truncate(struct iov_iter *i, u64 count)
 {
 	/*
 	 * count doesn't have to fit in size_t - comparison extends both
@@ -249,8 +249,11 @@ static inline void iov_iter_truncate(struct iov_iter *i, u64 count)
 	 * conversion in assignement is by definition greater than all
 	 * values of size_t, including old i->count.
 	 */
-	if (i->count > count)
+	if (i->count > count) {
 		i->count = count;
+		return true;
+	}
+	return false;
 }
 
 /*
-- 
2.7.4