From: Al Viro <viro@ZenIV.linux.org.uk>
To: linux-fsdevel@vger.kernel.org
Cc: Christoph Hellwig <hch@lst.de>
Subject: [PATCH v2 3/6] aio_read_events_ring(): make a bit more readable
Date: Mon, 28 May 2018 18:57:04 +0100 [thread overview]
Message-ID: <20180528175707.10926-3-viro@ZenIV.linux.org.uk> (raw)
In-Reply-To: <20180528175707.10926-1-viro@ZenIV.linux.org.uk>
From: Al Viro <viro@zeniv.linux.org.uk>
The logics for 'avail' is
* not past the tail of cyclic buffer
* no more than asked
* not past the end of buffer
* not past the end of a page
Unobfuscate the last part.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---
fs/aio.c | 7 +++----
1 file changed, 3 insertions(+), 4 deletions(-)
diff --git a/fs/aio.c b/fs/aio.c
index a8e4353ded2f..51843b057841 100644
--- a/fs/aio.c
+++ b/fs/aio.c
@@ -1197,14 +1197,13 @@ static long aio_read_events_ring(struct kioctx *ctx,
if (head == tail)
break;
- avail = min(avail, nr - ret);
- avail = min_t(long, avail, AIO_EVENTS_PER_PAGE -
- ((head + AIO_EVENTS_OFFSET) % AIO_EVENTS_PER_PAGE));
-
pos = head + AIO_EVENTS_OFFSET;
page = ctx->ring_pages[pos / AIO_EVENTS_PER_PAGE];
pos %= AIO_EVENTS_PER_PAGE;
+ avail = min(avail, nr - ret);
+ avail = min_t(long, avail, AIO_EVENTS_PER_PAGE - pos);
+
ev = kmap(page);
copy_ret = copy_to_user(event + ret, ev + pos,
sizeof(*ev) * avail);
--
2.11.0
next prev parent reply other threads:[~2018-05-28 17:57 UTC|newest]
Thread overview: 72+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-05-23 19:19 aio poll and a new in-kernel poll API V13 Christoph Hellwig
2018-05-23 19:19 ` [PATCH 01/33] fix io_destroy()/aio_complete() race Christoph Hellwig
2018-05-23 19:19 ` [PATCH 02/33] uapi: turn __poll_t sparse checkin on by default Christoph Hellwig
2018-05-23 19:19 ` [PATCH 03/33] fs: unexport poll_schedule_timeout Christoph Hellwig
2018-05-23 19:19 ` [PATCH 04/33] fs: cleanup do_pollfd Christoph Hellwig
2018-05-23 19:19 ` [PATCH 05/33] fs: update documentation to mention __poll_t and match the code Christoph Hellwig
2018-05-23 19:19 ` [PATCH 06/33] fs: add new vfs_poll and file_can_poll helpers Christoph Hellwig
2018-05-23 19:19 ` [PATCH 07/33] fs: introduce new ->get_poll_head and ->poll_mask methods Christoph Hellwig
2018-05-23 19:19 ` [PATCH 08/33] aio: simplify KIOCB_KEY handling Christoph Hellwig
2018-05-23 19:19 ` [PATCH 09/33] aio: simplify cancellation Christoph Hellwig
2018-05-23 19:19 ` [PATCH 10/33] aio: implement IOCB_CMD_POLL Christoph Hellwig
2018-05-23 19:20 ` [PATCH 11/33] aio: try to complete poll iocbs without context switch Christoph Hellwig
2018-05-23 19:20 ` [PATCH 12/33] net: refactor socket_poll Christoph Hellwig
2018-05-23 19:20 ` [PATCH 13/33] net: add support for ->poll_mask in proto_ops Christoph Hellwig
2018-05-23 19:20 ` [PATCH 14/33] net: remove sock_no_poll Christoph Hellwig
2018-05-23 19:20 ` [PATCH 15/33] net/tcp: convert to ->poll_mask Christoph Hellwig
2018-05-23 19:20 ` [PATCH 16/33] net/unix: " Christoph Hellwig
2018-05-23 19:20 ` [PATCH 17/33] net: convert datagram_poll users tp ->poll_mask Christoph Hellwig
2018-05-23 19:20 ` [PATCH 18/33] net/dccp: convert to ->poll_mask Christoph Hellwig
2018-05-23 19:20 ` [PATCH 19/33] net/atm: " Christoph Hellwig
2018-05-23 19:20 ` [PATCH 20/33] net/vmw_vsock: " Christoph Hellwig
2018-05-23 19:20 ` [PATCH 21/33] net/tipc: " Christoph Hellwig
2018-05-23 19:20 ` [PATCH 22/33] net/sctp: " Christoph Hellwig
2018-05-23 19:20 ` [PATCH 23/33] net/bluetooth: " Christoph Hellwig
2018-05-23 19:20 ` [PATCH 24/33] net/caif: " Christoph Hellwig
2018-05-23 19:20 ` [PATCH 25/33] net/nfc: " Christoph Hellwig
2018-05-23 19:20 ` [PATCH 26/33] net/phonet: " Christoph Hellwig
2018-05-23 19:20 ` [PATCH 27/33] net/iucv: " Christoph Hellwig
2018-05-23 19:20 ` [PATCH 28/33] net/rxrpc: " Christoph Hellwig
2018-05-23 19:20 ` [PATCH 29/33] crypto: af_alg: " Christoph Hellwig
2018-05-23 19:20 ` [PATCH 30/33] pipe: " Christoph Hellwig
2018-05-23 19:20 ` [PATCH 31/33] eventfd: switch " Christoph Hellwig
2018-05-23 19:20 ` [PATCH 32/33] timerfd: convert " Christoph Hellwig
2018-05-23 19:20 ` [PATCH 33/33] random: " Christoph Hellwig
2018-05-26 0:11 ` aio poll and a new in-kernel poll API V13 Al Viro
2018-05-26 7:09 ` Al Viro
2018-05-26 7:23 ` Christoph Hellwig
2018-05-27 22:27 ` Al Viro
2018-05-27 22:28 ` [PATCH 1/4] aio: all callers of aio_{read,write,fsync,poll} treat 0 and -EIOCBQUEUED the same way Al Viro
2018-05-27 22:28 ` [PATCH 2/4] aio_read_events_ring(): make a bit more readable Al Viro
2018-05-27 22:28 ` [PATCH 3/4] aio: shift copyin of iocb into io_submit_one() Al Viro
2018-05-28 5:16 ` Christoph Hellwig
2018-05-27 22:28 ` [PATCH 4/4] aio: fold do_io_submit() into callers Al Viro
2018-05-27 23:14 ` Al Viro
2018-05-28 5:24 ` Christoph Hellwig
2018-05-28 5:15 ` [PATCH 1/4] aio: all callers of aio_{read,write,fsync,poll} treat 0 and -EIOCBQUEUED the same way Christoph Hellwig
2018-05-28 14:04 ` Al Viro
2018-05-28 17:54 ` Al Viro
2018-05-28 17:57 ` [PATCH v2 1/6] aio: take list removal to (some) callers of aio_complete() Al Viro
2018-05-28 17:57 ` [PATCH v2 2/6] aio: all callers of aio_{read,write,fsync,poll} treat 0 and -EIOCBQUEUED the same way Al Viro
2018-05-29 6:08 ` Christoph Hellwig
2018-05-28 17:57 ` Al Viro [this message]
2018-05-28 17:57 ` [PATCH v2 4/6] aio: shift copyin of iocb into io_submit_one() Al Viro
2018-05-28 17:57 ` [PATCH v2 5/6] aio: fold do_io_submit() into callers Al Viro
2018-05-29 6:10 ` Christoph Hellwig
2018-05-28 17:57 ` [PATCH v2 6/6] aio: sanitize the limit checking in io_submit(2) Al Viro
2018-05-29 6:10 ` Christoph Hellwig
2018-05-29 6:08 ` [PATCH v2 1/6] aio: take list removal to (some) callers of aio_complete() Christoph Hellwig
2018-05-28 22:20 ` [PATCH 1/4] vmsplice: lift import_iovec() into do_vmsplice() Al Viro
2018-05-28 22:20 ` [PATCH 2/4] vmsplice(): lift importing iovec into vmsplice(2) and compat counterpart Al Viro
2018-05-28 22:20 ` [PATCH 3/4] signalfd: lift sigmask copyin and size checks to callers of do_signalfd4() Al Viro
2018-05-28 22:20 ` [PATCH 4/4] orangefs: simplify compat ioctl handling Al Viro
2018-05-31 11:11 ` kbuild test robot
2018-05-31 20:54 ` Mike Marshall
2018-05-31 21:03 ` Al Viro
2018-06-01 21:13 ` Mike Marshall
2018-06-06 22:57 ` [1/4] vmsplice: lift import_iovec() into do_vmsplice() Andrei Vagin
2018-06-07 17:56 ` Andrei Vagin
2018-06-11 20:14 ` Cyrill Gorcunov
2018-06-11 20:16 ` Al Viro
2018-06-11 20:18 ` Cyrill Gorcunov
2018-06-14 22:22 ` Andrey Vagin
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