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[24.9.64.241]) by smtp.gmail.com with ESMTPSA id e7sm7347246oia.9.2020.10.09.08.56.20 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 09 Oct 2020 08:56:21 -0700 (PDT) From: Shuah Khan To: arnd@arndb.de, gregkh@linuxfoundation.org, keescook@chromium.org Cc: Shuah Khan , linux-kernel@vger.kernel.org Subject: [PATCH v3 10/11] drivers/misc/vmw_vmci: convert num guest devices counter to counter_atomic32 Date: Fri, 9 Oct 2020 09:56:05 -0600 Message-Id: X-Mailer: git-send-email 2.25.1 In-Reply-To: References: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org counter_atomic* is introduced to be used when a variable is used as a simple counter and doesn't guard object lifetimes. This clearly differentiates atomic_t usages that guard object lifetimes. counter_atomic* variables wrap around to INT_MIN when it overflows and should not be used to guard resource lifetimes, device usage and open counts that control state changes, and pm states. atomic_t variable used to count number of vmci guest devices is used as just as counter and it doesn't control object lifetimes or state management. vmci_num_guest_devices is used as bool flag to determine if a guest instance exists. There is a very little chance for this counter to overflow. Convert it to use counter_atomic32. This conversion doesn't change the overflow wrap around behavior. Reviewed-by: Greg Kroah-Hartman Signed-off-by: Shuah Khan --- drivers/misc/vmw_vmci/vmci_guest.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) diff --git a/drivers/misc/vmw_vmci/vmci_guest.c b/drivers/misc/vmw_vmci/vmci_guest.c index cc8eeb361fcd..8f6aca974b5f 100644 --- a/drivers/misc/vmw_vmci/vmci_guest.c +++ b/drivers/misc/vmw_vmci/vmci_guest.c @@ -20,6 +20,7 @@ #include #include #include +#include #include "vmci_datagram.h" #include "vmci_doorbell.h" @@ -68,11 +69,11 @@ struct pci_dev *vmci_pdev; static struct vmci_guest_device *vmci_dev_g; static DEFINE_SPINLOCK(vmci_dev_spinlock); -static atomic_t vmci_num_guest_devices = ATOMIC_INIT(0); +static struct counter_atomic32 vmci_num_guest_devices = COUNTER_ATOMIC_INIT(0); bool vmci_guest_code_active(void) { - return atomic_read(&vmci_num_guest_devices) != 0; + return counter_atomic32_read(&vmci_num_guest_devices) > 0; } u32 vmci_get_vm_context_id(void) @@ -624,7 +625,7 @@ static int vmci_guest_probe_device(struct pci_dev *pdev, dev_dbg(&pdev->dev, "Registered device\n"); - atomic_inc(&vmci_num_guest_devices); + counter_atomic32_inc(&vmci_num_guest_devices); /* Enable specific interrupt bits. */ cmd = VMCI_IMR_DATAGRAM; @@ -684,7 +685,7 @@ static void vmci_guest_remove_device(struct pci_dev *pdev) dev_dbg(&pdev->dev, "Removing device\n"); - atomic_dec(&vmci_num_guest_devices); + counter_atomic32_dec(&vmci_num_guest_devices); vmci_qp_guest_endpoints_exit(); -- 2.25.1