>From : Alexey Dobriyan (SK hynix) <adobriyan@xxxxxxxxx>
null_blk driver supports bio and request mode. For each mode when
processing a new request initialize cmd->error to BLK_STS_OK so that in
the completion function it will indicate success by default instead of
using previously recorded error if any.
Signed-off-by: Alexey Dobriyan (SK hynix) <adobriyan@xxxxxxxxx>
Signed-off-by: Chaitanya Kulkarni <chaitanya.kulkarni@xxxxxxx>
---
Simple test log :-
1. Without Patch :-
# dd if=/dev/zero of=/dev/nullb0 bs=4k count=4096
4096+0 records in
4096+0 records out
16777216 bytes (17 MB) copied, 0.262258 s, 64.0 MB/s
# dmesg -c
1.1 Now write again to generate an error :-
# dd if=/dev/zero of=/dev/nullb0 bs=4k count=4096
4096+0 records in
4096+0 records out
16777216 bytes (17 MB) copied, 0.283751 s, 59.1 MB/s
# dmesg -c
[ 600.946406] print_req_error: 3512 callbacks suppressed
[ 600.946409] blk_update_request: I/O error, dev nullb0, sector 0 op 0x1:(WRITE) flags 0x800 phys_seg 1 prio class 0
[ 600.947701] buffer_io_error: 4086 callbacks suppressed
[ 600.947703] Buffer I/O error on dev nullb0, logical block 0, lost async page write
[ 600.949694] blk_update_request: I/O error, dev nullb0, sector 8 op 0x1:(WRITE) flags 0x4800 phys_seg 31 prio class 0
[ 600.952283] Buffer I/O error on dev nullb0, logical block 1, lost async page write
[ 600.954002] Buffer I/O error on dev nullb0, logical block 2, lost async page write
[ 600.955722] Buffer I/O error on dev nullb0, logical block 3, lost async page write
[ 600.957472] Buffer I/O error on dev nullb0, logical block 4, lost async page write
[ 600.959228] Buffer I/O error on dev nullb0, logical block 5, lost async page write
[ 600.960622] Buffer I/O error on dev nullb0, logical block 6, lost async page write
[ 600.961587] Buffer I/O error on dev nullb0, logical block 7, lost async page write
[ 600.962529] Buffer I/O error on dev nullb0, logical block 8, lost async page write
[ 600.963473] Buffer I/O error on dev nullb0, logical block 9, lost async page write
[ 600.964574] blk_update_request: I/O error, dev nullb0, sector 256 op 0x1:(WRITE) flags 0x4800 phys_seg 31 prio class 0
[ 600.966079] blk_update_request: I/O error, dev nullb0, sector 504 op 0x1:(WRITE) flags 0x4800 phys_seg 31 prio class 0
[ 600.967897] blk_update_request: I/O error, dev nullb0, sector 752 op 0x1:(WRITE) flags 0x4800 phys_seg 31 prio class 0
[ 600.969464] blk_update_request: I/O error, dev nullb0, sector 1000 op 0x1:(WRITE) flags 0x4800 phys_seg 31 prio class 0
[ 600.972423] blk_update_request: I/O error, dev nullb0, sector 1248 op 0x1:(WRITE) flags 0x4800 phys_seg 31 prio class 0
[ 600.975262] blk_update_request: I/O error, dev nullb0, sector 1496 op 0x1:(WRITE) flags 0x4800 phys_seg 31 prio class 0
[ 600.977683] blk_update_request: I/O error, dev nullb0, sector 1744 op 0x1:(WRITE) flags 0x4800 phys_seg 31 prio class 0
[ 600.979164] blk_update_request: I/O error, dev nullb0, sector 1992 op 0x1:(WRITE) flags 0x4800 phys_seg 31 prio class 0
# dd of=/dev/null if=/dev/nullb0 bs=4k count=100
100+0 records in
100+0 records out
409600 bytes (410 kB) copied, 0.00286957 s, 143 MB/s
# dmesg -c
1.2 Read from the device and expect an error :-
# dd of=/dev/null if=/dev/nullb0 bs=4k count=100
dd: error reading ‘/dev/nullb0’: Input/output error
92+0 records in
92+0 records out
376832 bytes (377 kB) copied, 0.0127975 s, 29.4 MB/s
# dmesg -c
[ 633.362252] print_req_error: 3540 callbacks suppressed
[ 633.362261] blk_update_request: I/O error, dev nullb0, sector 984 op 0x0:(READ) flags 0x80700 phys_seg 1 prio class 0
[ 633.363834] blk_update_request: I/O error, dev nullb0, sector 992 op 0x0:(READ) flags 0x84700 phys_seg 23 prio class 0
[ 633.365366] blk_update_request: I/O error, dev nullb0, sector 1240 op 0x0:(READ) flags 0x80700 phys_seg 1 prio class 0
[ 633.365449] blk_update_request: I/O error, dev nullb0, sector 736 op 0x0:(READ) flags 0x0 phys_seg 1 prio class 0
[ 633.368981] buffer_io_error: 4087 callbacks suppressed
[ 633.368983] Buffer I/O error on dev nullb0, logical block 92, async page read
2. With patch :-
# dd if=/dev/zero of=/dev/nullb0 bs=4k count=4096
4096+0 records in
4096+0 records out
16777216 bytes (17 MB) copied, 0.270187 s, 62.1 MB/s
# dmesg -c
2.1 Now write again to generate an error :-
# dd if=/dev/zero of=/dev/nullb0 bs=4k count=4096
4096+0 records in
4096+0 records out
16777216 bytes (17 MB) copied, 0.464682 s, 36.1 MB/s
# dmesg -c
[ 696.630879] blk_update_request: I/O error, dev nullb0, sector 0 op 0x1:(WRITE) flags 0x800 phys_seg 1 prio class 0
[ 696.632550] Buffer I/O error on dev nullb0, logical block 0, lost async page write
[ 696.633733] blk_update_request: I/O error, dev nullb0, sector 8 op 0x1:(WRITE) flags 0x800 phys_seg 23 prio class 0
[ 696.636239] Buffer I/O error on dev nullb0, logical block 1, lost async page write
[ 696.637996] Buffer I/O error on dev nullb0, logical block 2, lost async page write
[ 696.639718] Buffer I/O error on dev nullb0, logical block 3, lost async page write
[ 696.641455] Buffer I/O error on dev nullb0, logical block 4, lost async page write
[ 696.643151] Buffer I/O error on dev nullb0, logical block 5, lost async page write
[ 696.644821] Buffer I/O error on dev nullb0, logical block 6, lost async page write
[ 696.645827] Buffer I/O error on dev nullb0, logical block 7, lost async page write
[ 696.646828] Buffer I/O error on dev nullb0, logical block 8, lost async page write
[ 696.647843] Buffer I/O error on dev nullb0, logical block 9, lost async page write
[ 696.649017] blk_update_request: I/O error, dev nullb0, sector 192 op 0x1:(WRITE) flags 0x800 phys_seg 1 prio class 0
[ 696.650580] blk_update_request: I/O error, dev nullb0, sector 200 op 0x1:(WRITE) flags 0x800 phys_seg 1 prio class 0
[ 696.652030] blk_update_request: I/O error, dev nullb0, sector 208 op 0x1:(WRITE) flags 0x800 phys_seg 1 prio class 0
[ 696.653491] blk_update_request: I/O error, dev nullb0, sector 216 op 0x1:(WRITE) flags 0x800 phys_seg 23 prio class 0
[ 696.656347] blk_update_request: I/O error, dev nullb0, sector 400 op 0x1:(WRITE) flags 0x800 phys_seg 1 prio class 0
[ 696.658912] blk_update_request: I/O error, dev nullb0, sector 408 op 0x1:(WRITE) flags 0x800 phys_seg 1 prio class 0
[ 696.661490] blk_update_request: I/O error, dev nullb0, sector 416 op 0x1:(WRITE) flags 0x4800 phys_seg 31 prio class 0
[ 696.665040] blk_update_request: I/O error, dev nullb0, sector 664 op 0x1:(WRITE) flags 0x4800 phys_seg 31 prio class 0
2.2 Read from the device with no error :-
# dd of=/dev/null if=/dev/nullb0 bs=4k count=100
100+0 records in
100+0 records out
409600 bytes (410 kB) copied, 0.00504116 s, 81.3 MB/s
# dmesg -c
# dmesg -c
2.3 Read from the device with no error :-
# dd of=/dev/null if=/dev/nullb0 bs=4k count=100
100+0 records in
100+0 records out
409600 bytes (410 kB) copied, 0.00435289 s, 94.1 MB/s
# dmesg -c
---
drivers/block/null_blk_main.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/drivers/block/null_blk_main.c b/drivers/block/null_blk_main.c
index 16510795e377..3bf9c05f9825 100644
--- a/drivers/block/null_blk_main.c
+++ b/drivers/block/null_blk_main.c
@@ -606,6 +606,7 @@ static struct nullb_cmd *__alloc_cmd(struct nullb_queue *nq)
cmd = &nq->cmds[tag];
cmd->tag = tag;
cmd->nq = nq;
+ cmd->error = BLK_STS_OK;
if (nq->dev->irqmode == NULL_IRQ_TIMER) {
hrtimer_init(&cmd->timer, CLOCK_MONOTONIC,
HRTIMER_MODE_REL);
@@ -1385,6 +1386,7 @@ static blk_status_t null_queue_rq(struct blk_mq_hw_ctx *hctx,
cmd->timer.function = null_cmd_timer_expired;
}
cmd->rq = bd->rq;
+ cmd->error = BLK_STS_OK;
cmd->nq = nq;
blk_mq_start_request(bd->rq);
--
2.22.1
