[PATCH v2 04/11] net/smc: smc_splice_read: always request MSG_DONTWAIT

From: Ahelenia Ziemiańska
Date: Wed Dec 20 2023 - 22:10:18 EST


Otherwise we risk sleeping with the pipe locked for indeterminate
lengths of time ‒ this meant that splice(smc -> pipe) with no data
would hold the pipe lock, and any open/read/write/close on the pipe
would enter uninterruptible sleep.

Signed-off-by: Ahelenia Ziemiańska <nabijaczleweli@xxxxxxxxxxxxxxxxxx>
---
net/smc/af_smc.c | 6 +-----
1 file changed, 1 insertion(+), 5 deletions(-)

diff --git a/net/smc/af_smc.c b/net/smc/af_smc.c
index 73eebddbbf41..a11a966d031a 100644
--- a/net/smc/af_smc.c
+++ b/net/smc/af_smc.c
@@ -3248,12 +3248,8 @@ static ssize_t smc_splice_read(struct socket *sock, loff_t *ppos,
rc = -ESPIPE;
goto out;
}
- if (flags & SPLICE_F_NONBLOCK)
- flags = MSG_DONTWAIT;
- else
- flags = 0;
SMC_STAT_INC(smc, splice_cnt);
- rc = smc_rx_recvmsg(smc, NULL, pipe, len, flags);
+ rc = smc_rx_recvmsg(smc, NULL, pipe, len, MSG_DONTWAIT);
}
out:
release_sock(sk);
--
2.39.2

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