Date: Wed, 20 Jan 2016 00:14:34 +0000 (UTC) From: John Baldwin <jhb@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r294366 - head/sys/compat/linuxkpi/common/src Message-ID: <201601200014.u0K0EY6c092965@repo.freebsd.org>
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Author: jhb Date: Wed Jan 20 00:14:34 2016 New Revision: 294366 URL: https://svnweb.freebsd.org/changeset/base/294366 Log: Initialize vm_page_prot to VM_MEMATTR_DEFAULT instead of 0. If a driver's Linux mmap callback passed vm_page_prot through unchanged, then linux_dev_mmap_single() would try to apply whatever VM_MEMATTR_xxx value 0 is to the mapping. On x86, VM_MEMATTR_DEFAULT is the PAT value for write-back (WB) which is 6, while 0 maps to the PAT value for uncacheable (UC). Thus, any mmap request that did not explicitly set page_prot was tried to map memory as UC triggering the warning in sg_pager_getpages(). Tested by: np Reported by: Krishnamraju Eraparaju @ Chelsio MFC after: 3 days Sponsored by: Chelsio Communications Modified: head/sys/compat/linuxkpi/common/src/linux_compat.c Modified: head/sys/compat/linuxkpi/common/src/linux_compat.c ============================================================================== --- head/sys/compat/linuxkpi/common/src/linux_compat.c Wed Jan 20 00:03:28 2016 (r294365) +++ head/sys/compat/linuxkpi/common/src/linux_compat.c Wed Jan 20 00:14:34 2016 (r294366) @@ -587,7 +587,7 @@ linux_dev_mmap_single(struct cdev *dev, vma.vm_end = size; vma.vm_pgoff = *offset / PAGE_SIZE; vma.vm_pfn = 0; - vma.vm_page_prot = 0; + vma.vm_page_prot = VM_MEMATTR_DEFAULT; if (filp->f_op->mmap) { error = -filp->f_op->mmap(filp, &vma); if (error == 0) {
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