When vmballoon_vmci_init() sets a doorbell using VMCI_DOORBELL_SET, for some reason it does not consider the status and looks at the result. However, the hypervisor does not update the result - it updates the status. This might cause VMCI doorbell not to be enabled, resulting in degraded performance.

Fixes: 48e3d668b790 ("VMware balloon: Enable notification via VMCI") Cc: stable@vger.kernel.org Reviewed-by: Xavier Deguillard xdeguillard@vmware.com Signed-off-by: Nadav Amit namit@vmware.com --- drivers/misc/vmw_balloon.c | 37 +++++++++++++++++++------------------ 1 file changed, 19 insertions(+), 18 deletions(-)

diff --git a/drivers/misc/vmw_balloon.c b/drivers/misc/vmw_balloon.c index 60ab83d3d0ef..a7df4c24a28d 100644 --- a/drivers/misc/vmw_balloon.c +++ b/drivers/misc/vmw_balloon.c @@ -1036,29 +1036,30 @@ static void vmballoon_vmci_cleanup(struct vmballoon *b) */ static int vmballoon_vmci_init(struct vmballoon *b) { - int error = 0; + unsigned long error, dummy;

- if ((b->capabilities & VMW_BALLOON_SIGNALLED_WAKEUP_CMD) != 0) { - error = vmci_doorbell_create(&b->vmci_doorbell, - VMCI_FLAG_DELAYED_CB, - VMCI_PRIVILEGE_FLAG_RESTRICTED, - vmballoon_doorbell, b); - - if (error == VMCI_SUCCESS) { - VMWARE_BALLOON_CMD(VMCI_DOORBELL_SET, - b->vmci_doorbell.context, - b->vmci_doorbell.resource, error); - STATS_INC(b->stats.doorbell_set); - } - } + if ((b->capabilities & VMW_BALLOON_SIGNALLED_WAKEUP_CMD) == 0) + return 0;

- if (error != 0) { - vmballoon_vmci_cleanup(b); + error = vmci_doorbell_create(&b->vmci_doorbell, VMCI_FLAG_DELAYED_CB, + VMCI_PRIVILEGE_FLAG_RESTRICTED, + vmballoon_doorbell, b);

- return -EIO; - } + if (error != VMCI_SUCCESS) + goto fail; + + error = VMWARE_BALLOON_CMD(VMCI_DOORBELL_SET, b->vmci_doorbell.context, + b->vmci_doorbell.resource, dummy); + + STATS_INC(b->stats.doorbell_set); + + if (error != VMW_BALLOON_SUCCESS) + goto fail;

return 0; +fail: + vmballoon_vmci_cleanup(b); + return -EIO; }

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