From: Jens Axboe <axboe@kernel.dk>
Date: Wed, 13 Jun 2018 22:54:51 +0000 (-0600)
Subject: block: kill read-ahead if the submitting process is getting killed
X-Git-Url: https://git.kernel.dk/?a=commitdiff_plain;h=refs%2Fheads%2Freadpages-ahead-args;p=linux-2.6-block.git

block: kill read-ahead if the submitting process is getting killed

If we have tons of read-ahead coming in and the process is getting
killed, then it can take forever to kill said process since each
IO could take seconds on a loaded rotating drive.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
---

diff --git a/block/blk-core.c b/block/blk-core.c
index cf0ee764b908..839401541da3 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -35,6 +35,7 @@
 #include <linux/blk-cgroup.h>
 #include <linux/debugfs.h>
 #include <linux/bpf.h>
+#include <linux/sched/signal.h>
 
 #define CREATE_TRACE_POINTS
 #include <trace/events/block.h>
@@ -2530,6 +2531,13 @@ blk_qc_t submit_bio(struct bio *bio)
 	if (bio_has_data(bio)) {
 		unsigned int count;
 
+		if (unlikely((bio->bi_opf & REQ_RAHEAD) &&
+		    fatal_signal_pending(current))) {
+			bio->bi_status = BLK_STS_AGAIN;
+			bio_endio(bio);
+			return BLK_QC_T_NONE;
+		}
+
 		if (unlikely(bio_op(bio) == REQ_OP_WRITE_SAME))
 			count = queue_logical_block_size(bio->bi_disk->queue) >> 9;
 		else