From: Ross Zwisler <ross.zwisler@linux.intel.com>
To: linux-kernel@vger.kernel.org
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>,
"H. Peter Anvin" <hpa@zytor.com>,
"J. Bruce Fields" <bfields@fieldses.org>,
"Theodore Ts'o" <tytso@mit.edu>,
Alexander Viro <viro@zeniv.linux.org.uk>,
Andreas Dilger <adilger.kernel@dilger.ca>,
Dan Williams <dan.j.williams@intel.com>,
Dave Chinner <david@fromorbit.com>,
Ingo Molnar <mingo@redhat.com>, Jan Kara <jack@suse.com>,
Jeff Layton <jlayton@poochiereds.net>,
Matthew Wilcox <willy@linux.intel.com>,
Thomas Gleixner <tglx@linutronix.de>,
linux-ext4@vger.kernel.org, linux-fsdevel@vger.kernel.org,
linux-mm@kvack.org, linux-nvdimm@ml01.01.org, x86@kernel.org,
xfs@oss.sgi.com, Andrew Morton <akpm@linux-foundation.org>,
Matthew Wilcox <matthew.r.wilcox@intel.com>
Subject: [RFC 05/11] mm: add follow_pte_pmd()
Date: Thu, 29 Oct 2015 14:12:09 -0600 [thread overview]
Message-ID: <1446149535-16200-6-git-send-email-ross.zwisler@linux.intel.com> (raw)
In-Reply-To: <1446149535-16200-1-git-send-email-ross.zwisler@linux.intel.com>
Similar to follow_pte(), follow_pte_pmd() allows either a PTE leaf or a
huge page PMD leaf to be found and returned.
Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com>
---
include/linux/mm.h | 2 ++
mm/memory.c | 41 +++++++++++++++++++++++++++++++++--------
2 files changed, 35 insertions(+), 8 deletions(-)
diff --git a/include/linux/mm.h b/include/linux/mm.h
index 80001de..393441c 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -1166,6 +1166,8 @@ int copy_page_range(struct mm_struct *dst, struct mm_struct *src,
struct vm_area_struct *vma);
void unmap_mapping_range(struct address_space *mapping,
loff_t const holebegin, loff_t const holelen, int even_cows);
+int follow_pte_pmd(struct mm_struct *mm, unsigned long address,
+ pte_t **ptepp, pmd_t **pmdpp, spinlock_t **ptlp);
int follow_pfn(struct vm_area_struct *vma, unsigned long address,
unsigned long *pfn);
int follow_phys(struct vm_area_struct *vma, unsigned long address,
diff --git a/mm/memory.c b/mm/memory.c
index deb679c..c2b8c0a 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -3512,8 +3512,8 @@ int __pmd_alloc(struct mm_struct *mm, pud_t *pud, unsigned long address)
}
#endif /* __PAGETABLE_PMD_FOLDED */
-static int __follow_pte(struct mm_struct *mm, unsigned long address,
- pte_t **ptepp, spinlock_t **ptlp)
+static int __follow_pte_pmd(struct mm_struct *mm, unsigned long address,
+ pte_t **ptepp, pmd_t **pmdpp, spinlock_t **ptlp)
{
pgd_t *pgd;
pud_t *pud;
@@ -3529,12 +3529,23 @@ static int __follow_pte(struct mm_struct *mm, unsigned long address,
goto out;
pmd = pmd_offset(pud, address);
- VM_BUG_ON(pmd_trans_huge(*pmd));
- if (pmd_none(*pmd) || unlikely(pmd_bad(*pmd)))
- goto out;
- /* We cannot handle huge page PFN maps. Luckily they don't exist. */
- if (pmd_huge(*pmd))
+ if (pmd_huge(*pmd)) {
+ if (!pmdpp)
+ goto out;
+
+ *ptlp = pmd_lock(mm, pmd);
+ if (pmd_huge(*pmd)) {
+ /* Success, we found a large PTE */
+ *pmdpp = pmd;
+ return 0;
+ }
+ /* Somebody removed the PMD entry, try it as a pte */
+ spin_unlock(*ptlp);
+ }
+
+ /* FIXME: pmd_bad() is sometimes set for DAX pmds? */
+ if (pmd_none(*pmd) || unlikely(pmd_bad(*pmd)))
goto out;
ptep = pte_offset_map_lock(mm, pmd, address, ptlp);
@@ -3557,9 +3568,23 @@ static inline int follow_pte(struct mm_struct *mm, unsigned long address,
/* (void) is needed to make gcc happy */
(void) __cond_lock(*ptlp,
- !(res = __follow_pte(mm, address, ptepp, ptlp)));
+ !(res = __follow_pte_pmd(mm, address, ptepp, NULL,
+ ptlp)));
+ return res;
+}
+
+int follow_pte_pmd(struct mm_struct *mm, unsigned long address,
+ pte_t **ptepp, pmd_t **pmdpp, spinlock_t **ptlp)
+{
+ int res;
+
+ /* (void) is needed to make gcc happy */
+ (void) __cond_lock(*ptlp,
+ !(res = __follow_pte_pmd(mm, address, ptepp, pmdpp,
+ ptlp)));
return res;
}
+EXPORT_SYMBOL(follow_pte_pmd);
/**
* follow_pfn - look up PFN at a user virtual address
--
2.1.0
next prev parent reply other threads:[~2015-10-29 20:12 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-10-29 20:12 [RFC 00/11] DAX fsynx/msync support Ross Zwisler
2015-10-29 20:12 ` [RFC 01/11] pmem: add wb_cache_pmem() to the PMEM API Ross Zwisler
2015-10-29 20:12 ` [RFC 02/11] mm: add pmd_mkclean() Ross Zwisler
2015-10-29 20:12 ` [RFC 03/11] pmem: enable REQ_FLUSH handling Ross Zwisler
2015-10-29 20:12 ` [RFC 04/11] dax: support dirty DAX entries in radix tree Ross Zwisler
2015-10-29 20:12 ` Ross Zwisler [this message]
2015-10-29 20:12 ` [RFC 06/11] mm: add pgoff_mkclean() Ross Zwisler
2015-10-29 20:12 ` [RFC 07/11] mm: add find_get_entries_tag() Ross Zwisler
2015-10-29 20:12 ` [RFC 08/11] fs: add get_block() to struct inode_operations Ross Zwisler
2015-10-29 20:12 ` [RFC 09/11] dax: add support for fsync/sync Ross Zwisler
2015-10-29 20:12 ` [RFC 10/11] xfs, ext2: call dax_pfn_mkwrite() on write fault Ross Zwisler
2015-10-29 20:12 ` [RFC 11/11] ext4: add ext4_dax_pfn_mkwrite() Ross Zwisler
2015-10-29 22:49 ` [RFC 00/11] DAX fsynx/msync support Ross Zwisler
2015-10-30 3:55 ` Dave Chinner
2015-10-30 18:39 ` Ross Zwisler
2015-11-01 23:29 ` Dave Chinner
2015-11-02 14:22 ` Jeff Moyer
2015-11-02 20:10 ` Dave Chinner
2015-11-02 21:02 ` Jeff Moyer
2015-11-04 18:34 ` Jeff Moyer
2015-11-05 8:33 ` Dave Chinner
2015-11-05 19:49 ` Jeff Moyer
2015-11-05 20:54 ` Jens Axboe
2015-10-30 18:34 ` Dan Williams
2015-10-30 19:43 ` Ross Zwisler
2015-10-30 19:51 ` Dan Williams
2015-11-01 23:36 ` Dave Chinner
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