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bh=3G3sKLO6NWg4Qi1Gepthcp6ipQZ6DSu/XMOeps2uwWE=; b=Qu2hdYVHIHXuOBeqesZPLGHdGr9o4THJ1eXdrAT1Uk8mVF8oIZbMFxVcj/DYwF20clWzsP yB4O+46BqzxVJQbitJpeMpM8TWvFo5hQyWn5hxjWWaFzNuPFyBTh7MIa1+bLGVBot9JlPN Iks5h3CYsfsEXWkq79SaAlSD4p1WwT0= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-551-CToXHsdXO_ifGZvqbzsW0w-1; Fri, 19 May 2023 20:01:12 -0400 X-MC-Unique: CToXHsdXO_ifGZvqbzsW0w-1 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.rdu2.redhat.com [10.11.54.4]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id AAB3C185A78E; Sat, 20 May 2023 00:01:11 +0000 (UTC) Received: from warthog.procyon.org.uk (unknown [10.42.28.221]) by smtp.corp.redhat.com (Postfix) with ESMTP id B202B2026D49; Sat, 20 May 2023 00:01:09 +0000 (UTC) From: David Howells To: Jens Axboe , Al Viro , Christoph Hellwig Cc: David Howells , Matthew Wilcox , Jan Kara , Jeff Layton , David Hildenbrand , Jason Gunthorpe , Logan Gunthorpe , Hillf Danton , Christian Brauner , Linus Torvalds , linux-fsdevel@vger.kernel.org, linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, Christoph Hellwig Subject: [PATCH v21 06/30] splice: Check for zero count in vfs_splice_read() Date: Sat, 20 May 2023 01:00:25 +0100 Message-Id: <20230520000049.2226926-7-dhowells@redhat.com> In-Reply-To: <20230520000049.2226926-1-dhowells@redhat.com> References: <20230520000049.2226926-1-dhowells@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.1 on 10.11.54.4 X-Rspamd-Queue-Id: 149ED18000A X-Rspam-User: X-Stat-Signature: tkdtf87dgihb7mps6cngwxj16qz3wt75 X-Rspamd-Server: rspam03 X-HE-Tag: 1684540876-181738 X-HE-Meta: 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 5KrTBB9u 9T38iOKG05WVJTn3ZXYRVUBcngdsJ+/dmRsfPPmXf9RcRzj08OlxAKuObCFjNo1bufnaI4fn4Xk42X2QVLBH/Va+41HNkIDzfbWRJ4z28ebKIK1MEOgKs+vEQ1i9N0tEjEJy7f9OhjTyAPo9UeOr7J+v3x/TmKoxxOHUKs1BhdFKMtES3KdStykMRK0m91Xk9L1sqckckgsSON78eBr0W8qk5UVnyBo8HYkAKznykzWvEwPr2p9WYin7Khwd8OXBvnb2hKU49E6ljaoiktOrUxPpwVfWm8H2I6xjqdloj87/KOTtC6FCVoxS1mcixbe9OEmtIb0IQ0O+8Kk/cStQ5nvz85qdTiKFEzJM6liU7sUkEYsfNFMirv8u2n9YHzVg01/fqP4ar66xxzY4= X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: Make vfs_splice_read() return immediately if the length is 0. Signed-off-by: David Howells cc: Christoph Hellwig cc: Jens Axboe cc: Al Viro cc: linux-block@vger.kernel.org cc: linux-fsdevel@vger.kernel.org cc: linux-mm@kvack.org Reviewed-by: Christian Brauner --- fs/splice.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/fs/splice.c b/fs/splice.c index d815a69f6589..fe3309ffeb26 100644 --- a/fs/splice.c +++ b/fs/splice.c @@ -891,6 +891,8 @@ long vfs_splice_read(struct file *in, loff_t *ppos, if (unlikely(!(in->f_mode & FMODE_READ))) return -EBADF; + if (!len) + return 0; /* Don't try to read more the pipe has space for. */ p_space = pipe->max_usage - pipe_occupancy(pipe->head, pipe->tail);