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| author | Julian Wiedmann <jwi@linux.ibm.com> | 2021-01-07 18:24:40 +0100 |
|---|---|---|
| committer | Jakub Kicinski <kuba@kernel.org> | 2021-01-07 18:54:06 -0800 |
| commit | 0b9902c1fcc59ba75268386c0420a554f8844168 (patch) | |
| tree | 7b05edb9171eb7b35d16ab9b4fccf1c7ed9142ca /drivers/s390/net/qeth_core.h | |
| parent | d7083427489a494cfef552321666774436514ccb (diff) | |
| download | linux-0b9902c1fcc59ba75268386c0420a554f8844168.tar.gz linux-0b9902c1fcc59ba75268386c0420a554f8844168.tar.bz2 linux-0b9902c1fcc59ba75268386c0420a554f8844168.zip | |
s390/qeth: fix deadlock during recovery
When qeth_dev_layer2_store() - holding the discipline_mutex - waits
inside qeth_l*_remove_device() for a qeth_do_reset() thread to complete,
we can hit a deadlock if qeth_do_reset() concurrently calls
qeth_set_online() and thus tries to aquire the discipline_mutex.
Move the discipline_mutex locking outside of qeth_set_online() and
qeth_set_offline(), and turn the discipline into a parameter so that
callers understand the dependency.
To fix the deadlock, we can now relax the locking:
As already established, qeth_l*_remove_device() waits for
qeth_do_reset() to complete. So qeth_do_reset() itself is under no risk
of having card->discipline ripped out while it's running, and thus
doesn't need to take the discipline_mutex.
Fixes: 9dc48ccc68b9 ("qeth: serialize sysfs-triggered device configurations")
Signed-off-by: Julian Wiedmann <jwi@linux.ibm.com>
Reviewed-by: Alexandra Winter <wintera@linux.ibm.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'drivers/s390/net/qeth_core.h')
| -rw-r--r-- | drivers/s390/net/qeth_core.h | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/drivers/s390/net/qeth_core.h b/drivers/s390/net/qeth_core.h index 6f5ddc3eab8c..28f637042d44 100644 --- a/drivers/s390/net/qeth_core.h +++ b/drivers/s390/net/qeth_core.h @@ -1079,7 +1079,8 @@ struct qeth_card *qeth_get_card_by_busid(char *bus_id); void qeth_set_allowed_threads(struct qeth_card *card, unsigned long threads, int clear_start_mask); int qeth_threads_running(struct qeth_card *, unsigned long); -int qeth_set_offline(struct qeth_card *card, bool resetting); +int qeth_set_offline(struct qeth_card *card, const struct qeth_discipline *disc, + bool resetting); int qeth_send_ipa_cmd(struct qeth_card *, struct qeth_cmd_buffer *, int (*reply_cb) |