From: VMware, Inc <>
Date: Thu, 18 Nov 2010 22:16:50 +0000 (-0800)
Subject: Move kmap outside of critical section in VMCIHost_GetUserMemory
X-Git-Tag: 2010.11.17-327185~32
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=390bb8ab054fc0a6a45056bab1ca98f2f2252ba3;p=thirdparty%2Fopen-vm-tools.git

Move kmap outside of critical section in VMCIHost_GetUserMemory

While calling get_user_pages, we grab
current->mm->mmap_sem. However, we do not need to hold on to
it while doing kmap, and since kmap may sleep, it seems like a
genuinely bad idea.

Signed-off-by: Marcelo Vanzin <mvanzin@vmware.com>
---

diff --git a/open-vm-tools/modules/linux/vmci/vmciKernelIf.c b/open-vm-tools/modules/linux/vmci/vmciKernelIf.c
index 566d441b3..d753b05d9 100644
--- a/open-vm-tools/modules/linux/vmci/vmciKernelIf.c
+++ b/open-vm-tools/modules/linux/vmci/vmciKernelIf.c
@@ -1619,6 +1619,9 @@ VMCIHost_GetUserMemory(PageStoreAttachInfo *attach,      // IN/OUT
       err = VMCI_ERROR_NO_MEM;
    }
 
+out:
+   up_write(&current->mm->mmap_sem);
+
    if (err == VMCI_SUCCESS) {
       produceQ->qHeader = kmap(attach->producePages[0]);
       produceQ->kernelIf->page = &attach->producePages[1];
@@ -1626,9 +1629,6 @@ VMCIHost_GetUserMemory(PageStoreAttachInfo *attach,      // IN/OUT
       consumeQ->kernelIf->page = &attach->consumePages[1];
    }
 
-out:
-   up_write(&current->mm->mmap_sem);
-
 errorDealloc:
    if (err < VMCI_SUCCESS) {
       if (attach->producePages != NULL) {