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From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: linux-kernel@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	stable@vger.kernel.org, Jens Axboe <axboe@kernel.dk>,
	Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.11 09/31] io_uring: dont keep looping for more events if we cant flush overflow
Date: Fri, 19 Mar 2021 13:19:03 +0100	[thread overview]
Message-ID: <20210319121747.504718297@linuxfoundation.org> (raw)
In-Reply-To: <20210319121747.203523570@linuxfoundation.org>

From: Jens Axboe <axboe@kernel.dk>

[ Upstream commit ca0a26511c679a797f86589894a4523db36d833e ]

It doesn't make sense to wait for more events to come in, if we can't
even flush the overflow we already have to the ring. Return -EBUSY for
that condition, just like we do for attempts to submit with overflow
pending.

Cc: stable@vger.kernel.org # 5.11
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/io_uring.c | 15 ++++++++++++---
 1 file changed, 12 insertions(+), 3 deletions(-)

diff --git a/fs/io_uring.c b/fs/io_uring.c
index 7621978e9fc8..cab380a337e4 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -1823,18 +1823,22 @@ static bool __io_cqring_overflow_flush(struct io_ring_ctx *ctx, bool force,
 	return all_flushed;
 }
 
-static void io_cqring_overflow_flush(struct io_ring_ctx *ctx, bool force,
+static bool io_cqring_overflow_flush(struct io_ring_ctx *ctx, bool force,
 				     struct task_struct *tsk,
 				     struct files_struct *files)
 {
+	bool ret = true;
+
 	if (test_bit(0, &ctx->cq_check_overflow)) {
 		/* iopoll syncs against uring_lock, not completion_lock */
 		if (ctx->flags & IORING_SETUP_IOPOLL)
 			mutex_lock(&ctx->uring_lock);
-		__io_cqring_overflow_flush(ctx, force, tsk, files);
+		ret = __io_cqring_overflow_flush(ctx, force, tsk, files);
 		if (ctx->flags & IORING_SETUP_IOPOLL)
 			mutex_unlock(&ctx->uring_lock);
 	}
+
+	return ret;
 }
 
 static void __io_cqring_fill_event(struct io_kiocb *req, long res, long cflags)
@@ -7280,11 +7284,16 @@ static int io_cqring_wait(struct io_ring_ctx *ctx, int min_events,
 	iowq.nr_timeouts = atomic_read(&ctx->cq_timeouts);
 	trace_io_uring_cqring_wait(ctx, min_events);
 	do {
-		io_cqring_overflow_flush(ctx, false, NULL, NULL);
+		/* if we can't even flush overflow, don't wait for more */
+		if (!io_cqring_overflow_flush(ctx, false, NULL, NULL)) {
+			ret = -EBUSY;
+			break;
+		}
 		prepare_to_wait_exclusive(&ctx->wait, &iowq.wq,
 						TASK_INTERRUPTIBLE);
 		ret = io_cqring_wait_schedule(ctx, &iowq, &timeout);
 		finish_wait(&ctx->wait, &iowq.wq);
+		cond_resched();
 	} while (ret > 0);
 
 	restore_saved_sigmask_unless(ret == -EINTR);
-- 
2.30.1




  parent reply	other threads:[~2021-03-19 12:21 UTC|newest]

Thread overview: 43+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-03-19 12:18 [PATCH 5.11 00/31] 5.11.8-rc1 review Greg Kroah-Hartman
2021-03-19 12:18 ` [PATCH 5.11 01/31] io_uring: dont attempt IO reissue from the ring exit path Greg Kroah-Hartman
2021-03-19 12:18 ` [PATCH 5.11 02/31] KVM: x86/mmu: Expand on the comment in kvm_vcpu_ad_need_write_protect() Greg Kroah-Hartman
2021-03-19 12:18 ` [PATCH 5.11 03/31] KVM: x86/mmu: Set SPTE_AD_WRPROT_ONLY_MASK if and only if PML is enabled Greg Kroah-Hartman
2021-03-19 12:18 ` [PATCH 5.11 04/31] mptcp: send ack for every add_addr Greg Kroah-Hartman
2021-03-19 12:18 ` [PATCH 5.11 05/31] mptcp: pm: add lockdep assertions Greg Kroah-Hartman
2021-03-19 12:19 ` [PATCH 5.11 06/31] mptcp: dispose initial struct socket when its subflow is closed Greg Kroah-Hartman
2021-03-19 12:19 ` [PATCH 5.11 07/31] io_uring: refactor scheduling in io_cqring_wait Greg Kroah-Hartman
2021-03-19 12:19 ` [PATCH 5.11 08/31] io_uring: refactor io_cqring_wait Greg Kroah-Hartman
2021-03-19 12:19 ` Greg Kroah-Hartman [this message]
2021-03-19 12:19 ` [PATCH 5.11 10/31] io_uring: simplify do_read return parsing Greg Kroah-Hartman
2021-03-19 12:19 ` [PATCH 5.11 11/31] io_uring: clear IOCB_WAITQ for non -EIOCBQUEUED return Greg Kroah-Hartman
2021-03-19 12:19 ` [PATCH 5.11 12/31] gpiolib: Read "gpio-line-names" from a firmware node Greg Kroah-Hartman
2021-03-19 12:27   ` Marek Vasut
2021-03-19 12:36     ` Greg Kroah-Hartman
2021-03-19 12:45       ` Marek Vasut
2021-03-19 12:19 ` [PATCH 5.11 13/31] net: bonding: fix error return code of bond_neigh_init() Greg Kroah-Hartman
2021-03-19 14:12   ` Jiri Kosina
2021-03-19 14:24     ` Jiri Kosina
2021-03-19 14:29       ` Greg Kroah-Hartman
2021-03-19 14:25     ` Greg Kroah-Hartman
2021-03-19 15:14       ` Jiri Kosina
2021-03-19 12:19 ` [PATCH 5.11 14/31] regulator: pca9450: Add SD_VSEL GPIO for LDO5 Greg Kroah-Hartman
2021-03-19 12:19 ` [PATCH 5.11 15/31] regulator: pca9450: Enable system reset on WDOG_B assertion Greg Kroah-Hartman
2021-03-19 12:19 ` [PATCH 5.11 16/31] regulator: pca9450: Clear PRESET_EN bit to fix BUCK1/2/3 voltage setting Greg Kroah-Hartman
2021-03-19 12:19 ` [PATCH 5.11 17/31] gfs2: Add common helper for holding and releasing the freeze glock Greg Kroah-Hartman
2021-03-19 12:19 ` [PATCH 5.11 18/31] gfs2: move freeze glock outside the make_fs_rw and _ro functions Greg Kroah-Hartman
2021-03-19 12:19 ` [PATCH 5.11 19/31] gfs2: bypass signal_our_withdraw if no journal Greg Kroah-Hartman
2021-03-19 12:19 ` [PATCH 5.11 20/31] bpf: Prohibit alu ops for pointer types not defining ptr_limit Greg Kroah-Hartman
2021-03-19 12:19 ` [PATCH 5.11 21/31] bpf: Fix off-by-one for area size in creating mask to left Greg Kroah-Hartman
2021-03-19 12:19 ` [PATCH 5.11 22/31] bpf: Simplify alu_limit masking for pointer arithmetic Greg Kroah-Hartman
2021-03-19 12:19 ` [PATCH 5.11 23/31] bpf: Add sanity check for upper ptr_limit Greg Kroah-Hartman
2021-03-19 12:19 ` [PATCH 5.11 24/31] bpf, selftests: Fix up some test_verifier cases for unprivileged Greg Kroah-Hartman
2021-03-19 12:19 ` [PATCH 5.11 25/31] arm64: Unconditionally set virtual cpu id registers Greg Kroah-Hartman
2021-03-19 12:19 ` [PATCH 5.11 26/31] RDMA/srp: Fix support for unpopulated and unbalanced NUMA nodes Greg Kroah-Hartman
2021-03-19 12:19 ` [PATCH 5.11 27/31] fuse: fix live lock in fuse_iget() Greg Kroah-Hartman
2021-03-19 12:19 ` [PATCH 5.11 28/31] Revert "nfsd4: remove check_conflicting_opens warning" Greg Kroah-Hartman
2021-03-19 12:19 ` [PATCH 5.11 29/31] Revert "nfsd4: a clients own opens neednt prevent delegations" Greg Kroah-Hartman
2021-03-19 12:19 ` [PATCH 5.11 30/31] net: dsa: b53: Support setting learning on port Greg Kroah-Hartman
2021-03-19 12:19 ` [PATCH 5.11 31/31] crypto: x86/aes-ni-xts - use direct calls to and 4-way stride Greg Kroah-Hartman
2021-03-19 19:38 ` [PATCH 5.11 00/31] 5.11.8-rc1 review Naresh Kamboju
2021-03-20  9:52   ` Greg Kroah-Hartman
2021-03-19 21:23 ` Guenter Roeck

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