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nbd: protect cmd->status with cmd->lock 

We already do this for the most part, except in timeout and clear_req.
For the timeout case we take the lock after we grab a ref on the config,
but that isn't really necessary because we're safe to touch the cmd at
this point, so just move the order around.

For the clear_req cause this is initiated by the user, so again is safe.

Reviewed-by: Mike Christie <mchristi@redhat.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
alistair/sunxi64-5.4-dsi
Josef Bacik 2019-10-21 15:56:27 -04:00 committed by Jens Axboe
parent 2b2ed9750f
commit de6346ecbc
1 changed files with 7 additions and 5 deletions
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12
drivers/block/nbd.c
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@ -385,17 +385,16 @@ static enum blk_eh_timer_return nbd_xmit_timeout(struct request *req,
struct nbd_device *nbd = cmd->nbd;
struct nbd_config *config;
if (!mutex_trylock(&cmd->lock))
return BLK_EH_RESET_TIMER;
if (!refcount_inc_not_zero(&nbd->config_refs)) {
cmd->status = BLK_STS_TIMEOUT;
mutex_unlock(&cmd->lock);
goto done;
}
config = nbd->config;
if (!mutex_trylock(&cmd->lock)) {
nbd_config_put(nbd);
return BLK_EH_RESET_TIMER;
}
if (config->num_connections > 1) {
dev_err_ratelimited(nbd_to_dev(nbd),
"Connection timed out, retrying (%d/%d alive)\n",
@ -792,7 +791,10 @@ static bool nbd_clear_req(struct request *req, void *data, bool reserved)
{
struct nbd_cmd *cmd = blk_mq_rq_to_pdu(req);
mutex_lock(&cmd->lock);
cmd->status = BLK_STS_IOERR;
mutex_unlock(&cmd->lock);
blk_mq_complete_request(req);
return true;
}