diff options
author | Ingo Molnar <mingo@kernel.org> | 2021-12-13 10:48:46 +0100 |
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committer | Ingo Molnar <mingo@kernel.org> | 2021-12-13 10:48:46 +0100 |
commit | 6773cc31a9bb5122fd5c288f73ca006ad20a6c17 (patch) | |
tree | 730ec8bcc0a5ddd5030268bb3ffd4945d34728c1 /net/nfc/nci/core.c | |
parent | futex: Fix additional regressions (diff) | |
parent | Linux 5.16-rc5 (diff) | |
download | linux-dev-6773cc31a9bb5122fd5c288f73ca006ad20a6c17.tar.xz linux-dev-6773cc31a9bb5122fd5c288f73ca006ad20a6c17.zip |
Merge tag 'v5.16-rc5' into locking/core, to pick up fixes
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'net/nfc/nci/core.c')
-rw-r--r-- | net/nfc/nci/core.c | 30 |
1 files changed, 24 insertions, 6 deletions
diff --git a/net/nfc/nci/core.c b/net/nfc/nci/core.c index 6fd873aa86be..d2537383a3e8 100644 --- a/net/nfc/nci/core.c +++ b/net/nfc/nci/core.c @@ -144,12 +144,15 @@ inline int nci_request(struct nci_dev *ndev, { int rc; - if (!test_bit(NCI_UP, &ndev->flags)) - return -ENETDOWN; - /* Serialize all requests */ mutex_lock(&ndev->req_lock); - rc = __nci_request(ndev, req, opt, timeout); + /* check the state after obtaing the lock against any races + * from nci_close_device when the device gets removed. + */ + if (test_bit(NCI_UP, &ndev->flags)) + rc = __nci_request(ndev, req, opt, timeout); + else + rc = -ENETDOWN; mutex_unlock(&ndev->req_lock); return rc; @@ -473,6 +476,11 @@ static int nci_open_device(struct nci_dev *ndev) mutex_lock(&ndev->req_lock); + if (test_bit(NCI_UNREG, &ndev->flags)) { + rc = -ENODEV; + goto done; + } + if (test_bit(NCI_UP, &ndev->flags)) { rc = -EALREADY; goto done; @@ -545,6 +553,10 @@ done: static int nci_close_device(struct nci_dev *ndev) { nci_req_cancel(ndev, ENODEV); + + /* This mutex needs to be held as a barrier for + * caller nci_unregister_device + */ mutex_lock(&ndev->req_lock); if (!test_and_clear_bit(NCI_UP, &ndev->flags)) { @@ -582,8 +594,8 @@ static int nci_close_device(struct nci_dev *ndev) del_timer_sync(&ndev->cmd_timer); - /* Clear flags */ - ndev->flags = 0; + /* Clear flags except NCI_UNREG */ + ndev->flags &= BIT(NCI_UNREG); mutex_unlock(&ndev->req_lock); @@ -1266,6 +1278,12 @@ void nci_unregister_device(struct nci_dev *ndev) { struct nci_conn_info *conn_info, *n; + /* This set_bit is not protected with specialized barrier, + * However, it is fine because the mutex_lock(&ndev->req_lock); + * in nci_close_device() will help to emit one. + */ + set_bit(NCI_UNREG, &ndev->flags); + nci_close_device(ndev); destroy_workqueue(ndev->cmd_wq); |