| Message ID | 1475189370-31634-9-git-send-email-ross.zwisler@linux.intel.com (mailing list archive) |
|---|---|
| State | Not Applicable |
| Headers | show |
Looks fine,
Reviewed-by: Christoph Hellwig <hch@lst.de>
On Thu 29-09-16 16:49:26, Ross Zwisler wrote: > dax_pmd_fault() is the old struct buffer_head + get_block_t based 2 MiB DAX > fault handler. This fault handler has been disabled for several kernel > releases, and support for PMDs will be reintroduced using the struct iomap > interface instead. > > Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com> Looks good. You can add: Reviewed-by: Jan Kara <jack@suse.cz> Honza > --- > fs/dax.c | 213 ---------------------------------------------------- > include/linux/dax.h | 6 +- > 2 files changed, 1 insertion(+), 218 deletions(-) > > diff --git a/fs/dax.c b/fs/dax.c > index 406feea..b5e7b13 100644 > --- a/fs/dax.c > +++ b/fs/dax.c > @@ -909,219 +909,6 @@ int dax_fault(struct vm_area_struct *vma, struct vm_fault *vmf, > } > EXPORT_SYMBOL_GPL(dax_fault); > > -#if defined(CONFIG_TRANSPARENT_HUGEPAGE) > -/* > - * The 'colour' (ie low bits) within a PMD of a page offset. This comes up > - * more often than one might expect in the below function. > - */ > -#define PG_PMD_COLOUR ((PMD_SIZE >> PAGE_SHIFT) - 1) > - > -static void __dax_dbg(struct buffer_head *bh, unsigned long address, > - const char *reason, const char *fn) > -{ > - if (bh) { > - char bname[BDEVNAME_SIZE]; > - bdevname(bh->b_bdev, bname); > - pr_debug("%s: %s addr: %lx dev %s state %lx start %lld " > - "length %zd fallback: %s\n", fn, current->comm, > - address, bname, bh->b_state, (u64)bh->b_blocknr, > - bh->b_size, reason); > - } else { > - pr_debug("%s: %s addr: %lx fallback: %s\n", fn, > - current->comm, address, reason); > - } > -} > - > -#define dax_pmd_dbg(bh, address, reason) __dax_dbg(bh, address, reason, "dax_pmd") > - > -/** > - * dax_pmd_fault - handle a PMD fault on a DAX file > - * @vma: The virtual memory area where the fault occurred > - * @vmf: The description of the fault > - * @get_block: The filesystem method used to translate file offsets to blocks > - * > - * When a page fault occurs, filesystems may call this helper in their > - * pmd_fault handler for DAX files. > - */ > -int dax_pmd_fault(struct vm_area_struct *vma, unsigned long address, > - pmd_t *pmd, unsigned int flags, get_block_t get_block) > -{ > - struct file *file = vma->vm_file; > - struct address_space *mapping = file->f_mapping; > - struct inode *inode = mapping->host; > - struct buffer_head bh; > - unsigned blkbits = inode->i_blkbits; > - unsigned long pmd_addr = address & PMD_MASK; > - bool write = flags & FAULT_FLAG_WRITE; > - struct block_device *bdev; > - pgoff_t size, pgoff; > - sector_t block; > - int result = 0; > - bool alloc = false; > - > - /* dax pmd mappings require pfn_t_devmap() */ > - if (!IS_ENABLED(CONFIG_FS_DAX_PMD)) > - return VM_FAULT_FALLBACK; > - > - /* Fall back to PTEs if we're going to COW */ > - if (write && !(vma->vm_flags & VM_SHARED)) { > - split_huge_pmd(vma, pmd, address); > - dax_pmd_dbg(NULL, address, "cow write"); > - return VM_FAULT_FALLBACK; > - } > - /* If the PMD would extend outside the VMA */ > - if (pmd_addr < vma->vm_start) { > - dax_pmd_dbg(NULL, address, "vma start unaligned"); > - return VM_FAULT_FALLBACK; > - } > - if ((pmd_addr + PMD_SIZE) > vma->vm_end) { > - dax_pmd_dbg(NULL, address, "vma end unaligned"); > - return VM_FAULT_FALLBACK; > - } > - > - pgoff = linear_page_index(vma, pmd_addr); > - size = (i_size_read(inode) + PAGE_SIZE - 1) >> PAGE_SHIFT; > - if (pgoff >= size) > - return VM_FAULT_SIGBUS; > - /* If the PMD would cover blocks out of the file */ > - if ((pgoff | PG_PMD_COLOUR) >= size) { > - dax_pmd_dbg(NULL, address, > - "offset + huge page size > file size"); > - return VM_FAULT_FALLBACK; > - } > - > - memset(&bh, 0, sizeof(bh)); > - bh.b_bdev = inode->i_sb->s_bdev; > - block = (sector_t)pgoff << (PAGE_SHIFT - blkbits); > - > - bh.b_size = PMD_SIZE; > - > - if (get_block(inode, block, &bh, 0) != 0) > - return VM_FAULT_SIGBUS; > - > - if (!buffer_mapped(&bh) && write) { > - if (get_block(inode, block, &bh, 1) != 0) > - return VM_FAULT_SIGBUS; > - alloc = true; > - WARN_ON_ONCE(buffer_unwritten(&bh) || buffer_new(&bh)); > - } > - > - bdev = bh.b_bdev; > - > - if (bh.b_size < PMD_SIZE) { > - dax_pmd_dbg(&bh, address, "allocated block too small"); > - return VM_FAULT_FALLBACK; > - } > - > - /* > - * If we allocated new storage, make sure no process has any > - * zero pages covering this hole > - */ > - if (alloc) { > - loff_t lstart = pgoff << PAGE_SHIFT; > - loff_t lend = lstart + PMD_SIZE - 1; /* inclusive */ > - > - truncate_pagecache_range(inode, lstart, lend); > - } > - > - if (!write && !buffer_mapped(&bh)) { > - spinlock_t *ptl; > - pmd_t entry; > - struct page *zero_page = get_huge_zero_page(); > - > - if (unlikely(!zero_page)) { > - dax_pmd_dbg(&bh, address, "no zero page"); > - goto fallback; > - } > - > - ptl = pmd_lock(vma->vm_mm, pmd); > - if (!pmd_none(*pmd)) { > - spin_unlock(ptl); > - dax_pmd_dbg(&bh, address, "pmd already present"); > - goto fallback; > - } > - > - dev_dbg(part_to_dev(bdev->bd_part), > - "%s: %s addr: %lx pfn: <zero> sect: %llx\n", > - __func__, current->comm, address, > - (unsigned long long) to_sector(&bh, inode)); > - > - entry = mk_pmd(zero_page, vma->vm_page_prot); > - entry = pmd_mkhuge(entry); > - set_pmd_at(vma->vm_mm, pmd_addr, pmd, entry); > - result = VM_FAULT_NOPAGE; > - spin_unlock(ptl); > - } else { > - struct blk_dax_ctl dax = { > - .sector = to_sector(&bh, inode), > - .size = PMD_SIZE, > - }; > - long length = dax_map_atomic(bdev, &dax); > - > - if (length < 0) { > - dax_pmd_dbg(&bh, address, "dax-error fallback"); > - goto fallback; > - } > - if (length < PMD_SIZE) { > - dax_pmd_dbg(&bh, address, "dax-length too small"); > - dax_unmap_atomic(bdev, &dax); > - goto fallback; > - } > - if (pfn_t_to_pfn(dax.pfn) & PG_PMD_COLOUR) { > - dax_pmd_dbg(&bh, address, "pfn unaligned"); > - dax_unmap_atomic(bdev, &dax); > - goto fallback; > - } > - > - if (!pfn_t_devmap(dax.pfn)) { > - dax_unmap_atomic(bdev, &dax); > - dax_pmd_dbg(&bh, address, "pfn not in memmap"); > - goto fallback; > - } > - dax_unmap_atomic(bdev, &dax); > - > - /* > - * For PTE faults we insert a radix tree entry for reads, and > - * leave it clean. Then on the first write we dirty the radix > - * tree entry via the dax_pfn_mkwrite() path. This sequence > - * allows the dax_pfn_mkwrite() call to be simpler and avoid a > - * call into get_block() to translate the pgoff to a sector in > - * order to be able to create a new radix tree entry. > - * > - * The PMD path doesn't have an equivalent to > - * dax_pfn_mkwrite(), though, so for a read followed by a > - * write we traverse all the way through dax_pmd_fault() > - * twice. This means we can just skip inserting a radix tree > - * entry completely on the initial read and just wait until > - * the write to insert a dirty entry. > - */ > - if (write) { > - /* > - * We should insert radix-tree entry and dirty it here. > - * For now this is broken... > - */ > - } > - > - dev_dbg(part_to_dev(bdev->bd_part), > - "%s: %s addr: %lx pfn: %lx sect: %llx\n", > - __func__, current->comm, address, > - pfn_t_to_pfn(dax.pfn), > - (unsigned long long) dax.sector); > - result |= vmf_insert_pfn_pmd(vma, address, pmd, > - dax.pfn, write); > - } > - > - out: > - return result; > - > - fallback: > - count_vm_event(THP_FAULT_FALLBACK); > - result = VM_FAULT_FALLBACK; > - goto out; > -} > -EXPORT_SYMBOL_GPL(dax_pmd_fault); > -#endif /* CONFIG_TRANSPARENT_HUGEPAGE */ > - > /** > * dax_pfn_mkwrite - handle first write to DAX page > * @vma: The virtual memory area where the fault occurred > diff --git a/include/linux/dax.h b/include/linux/dax.h > index 4065601..d9a8350 100644 > --- a/include/linux/dax.h > +++ b/include/linux/dax.h > @@ -48,16 +48,12 @@ static inline int __dax_zero_page_range(struct block_device *bdev, > } > #endif > > -#if defined(CONFIG_TRANSPARENT_HUGEPAGE) > -int dax_pmd_fault(struct vm_area_struct *, unsigned long addr, pmd_t *, > - unsigned int flags, get_block_t); > -#else > static inline int dax_pmd_fault(struct vm_area_struct *vma, unsigned long addr, > pmd_t *pmd, unsigned int flags, get_block_t gb) > { > return VM_FAULT_FALLBACK; > } > -#endif > + > int dax_pfn_mkwrite(struct vm_area_struct *, struct vm_fault *); > #define dax_mkwrite(vma, vmf, gb) dax_fault(vma, vmf, gb) > > -- > 2.7.4 > >
diff --git a/fs/dax.c b/fs/dax.c index 406feea..b5e7b13 100644 --- a/fs/dax.c +++ b/fs/dax.c @@ -909,219 +909,6 @@ int dax_fault(struct vm_area_struct *vma, struct vm_fault *vmf, } EXPORT_SYMBOL_GPL(dax_fault); -#if defined(CONFIG_TRANSPARENT_HUGEPAGE) -/* - * The 'colour' (ie low bits) within a PMD of a page offset. This comes up - * more often than one might expect in the below function. - */ -#define PG_PMD_COLOUR ((PMD_SIZE >> PAGE_SHIFT) - 1) - -static void __dax_dbg(struct buffer_head *bh, unsigned long address, - const char *reason, const char *fn) -{ - if (bh) { - char bname[BDEVNAME_SIZE]; - bdevname(bh->b_bdev, bname); - pr_debug("%s: %s addr: %lx dev %s state %lx start %lld " - "length %zd fallback: %s\n", fn, current->comm, - address, bname, bh->b_state, (u64)bh->b_blocknr, - bh->b_size, reason); - } else { - pr_debug("%s: %s addr: %lx fallback: %s\n", fn, - current->comm, address, reason); - } -} - -#define dax_pmd_dbg(bh, address, reason) __dax_dbg(bh, address, reason, "dax_pmd") - -/** - * dax_pmd_fault - handle a PMD fault on a DAX file - * @vma: The virtual memory area where the fault occurred - * @vmf: The description of the fault - * @get_block: The filesystem method used to translate file offsets to blocks - * - * When a page fault occurs, filesystems may call this helper in their - * pmd_fault handler for DAX files. - */ -int dax_pmd_fault(struct vm_area_struct *vma, unsigned long address, - pmd_t *pmd, unsigned int flags, get_block_t get_block) -{ - struct file *file = vma->vm_file; - struct address_space *mapping = file->f_mapping; - struct inode *inode = mapping->host; - struct buffer_head bh; - unsigned blkbits = inode->i_blkbits; - unsigned long pmd_addr = address & PMD_MASK; - bool write = flags & FAULT_FLAG_WRITE; - struct block_device *bdev; - pgoff_t size, pgoff; - sector_t block; - int result = 0; - bool alloc = false; - - /* dax pmd mappings require pfn_t_devmap() */ - if (!IS_ENABLED(CONFIG_FS_DAX_PMD)) - return VM_FAULT_FALLBACK; - - /* Fall back to PTEs if we're going to COW */ - if (write && !(vma->vm_flags & VM_SHARED)) { - split_huge_pmd(vma, pmd, address); - dax_pmd_dbg(NULL, address, "cow write"); - return VM_FAULT_FALLBACK; - } - /* If the PMD would extend outside the VMA */ - if (pmd_addr < vma->vm_start) { - dax_pmd_dbg(NULL, address, "vma start unaligned"); - return VM_FAULT_FALLBACK; - } - if ((pmd_addr + PMD_SIZE) > vma->vm_end) { - dax_pmd_dbg(NULL, address, "vma end unaligned"); - return VM_FAULT_FALLBACK; - } - - pgoff = linear_page_index(vma, pmd_addr); - size = (i_size_read(inode) + PAGE_SIZE - 1) >> PAGE_SHIFT; - if (pgoff >= size) - return VM_FAULT_SIGBUS; - /* If the PMD would cover blocks out of the file */ - if ((pgoff | PG_PMD_COLOUR) >= size) { - dax_pmd_dbg(NULL, address, - "offset + huge page size > file size"); - return VM_FAULT_FALLBACK; - } - - memset(&bh, 0, sizeof(bh)); - bh.b_bdev = inode->i_sb->s_bdev; - block = (sector_t)pgoff << (PAGE_SHIFT - blkbits); - - bh.b_size = PMD_SIZE; - - if (get_block(inode, block, &bh, 0) != 0) - return VM_FAULT_SIGBUS; - - if (!buffer_mapped(&bh) && write) { - if (get_block(inode, block, &bh, 1) != 0) - return VM_FAULT_SIGBUS; - alloc = true; - WARN_ON_ONCE(buffer_unwritten(&bh) || buffer_new(&bh)); - } - - bdev = bh.b_bdev; - - if (bh.b_size < PMD_SIZE) { - dax_pmd_dbg(&bh, address, "allocated block too small"); - return VM_FAULT_FALLBACK; - } - - /* - * If we allocated new storage, make sure no process has any - * zero pages covering this hole - */ - if (alloc) { - loff_t lstart = pgoff << PAGE_SHIFT; - loff_t lend = lstart + PMD_SIZE - 1; /* inclusive */ - - truncate_pagecache_range(inode, lstart, lend); - } - - if (!write && !buffer_mapped(&bh)) { - spinlock_t *ptl; - pmd_t entry; - struct page *zero_page = get_huge_zero_page(); - - if (unlikely(!zero_page)) { - dax_pmd_dbg(&bh, address, "no zero page"); - goto fallback; - } - - ptl = pmd_lock(vma->vm_mm, pmd); - if (!pmd_none(*pmd)) { - spin_unlock(ptl); - dax_pmd_dbg(&bh, address, "pmd already present"); - goto fallback; - } - - dev_dbg(part_to_dev(bdev->bd_part), - "%s: %s addr: %lx pfn: <zero> sect: %llx\n", - __func__, current->comm, address, - (unsigned long long) to_sector(&bh, inode)); - - entry = mk_pmd(zero_page, vma->vm_page_prot); - entry = pmd_mkhuge(entry); - set_pmd_at(vma->vm_mm, pmd_addr, pmd, entry); - result = VM_FAULT_NOPAGE; - spin_unlock(ptl); - } else { - struct blk_dax_ctl dax = { - .sector = to_sector(&bh, inode), - .size = PMD_SIZE, - }; - long length = dax_map_atomic(bdev, &dax); - - if (length < 0) { - dax_pmd_dbg(&bh, address, "dax-error fallback"); - goto fallback; - } - if (length < PMD_SIZE) { - dax_pmd_dbg(&bh, address, "dax-length too small"); - dax_unmap_atomic(bdev, &dax); - goto fallback; - } - if (pfn_t_to_pfn(dax.pfn) & PG_PMD_COLOUR) { - dax_pmd_dbg(&bh, address, "pfn unaligned"); - dax_unmap_atomic(bdev, &dax); - goto fallback; - } - - if (!pfn_t_devmap(dax.pfn)) { - dax_unmap_atomic(bdev, &dax); - dax_pmd_dbg(&bh, address, "pfn not in memmap"); - goto fallback; - } - dax_unmap_atomic(bdev, &dax); - - /* - * For PTE faults we insert a radix tree entry for reads, and - * leave it clean. Then on the first write we dirty the radix - * tree entry via the dax_pfn_mkwrite() path. This sequence - * allows the dax_pfn_mkwrite() call to be simpler and avoid a - * call into get_block() to translate the pgoff to a sector in - * order to be able to create a new radix tree entry. - * - * The PMD path doesn't have an equivalent to - * dax_pfn_mkwrite(), though, so for a read followed by a - * write we traverse all the way through dax_pmd_fault() - * twice. This means we can just skip inserting a radix tree - * entry completely on the initial read and just wait until - * the write to insert a dirty entry. - */ - if (write) { - /* - * We should insert radix-tree entry and dirty it here. - * For now this is broken... - */ - } - - dev_dbg(part_to_dev(bdev->bd_part), - "%s: %s addr: %lx pfn: %lx sect: %llx\n", - __func__, current->comm, address, - pfn_t_to_pfn(dax.pfn), - (unsigned long long) dax.sector); - result |= vmf_insert_pfn_pmd(vma, address, pmd, - dax.pfn, write); - } - - out: - return result; - - fallback: - count_vm_event(THP_FAULT_FALLBACK); - result = VM_FAULT_FALLBACK; - goto out; -} -EXPORT_SYMBOL_GPL(dax_pmd_fault); -#endif /* CONFIG_TRANSPARENT_HUGEPAGE */ - /** * dax_pfn_mkwrite - handle first write to DAX page * @vma: The virtual memory area where the fault occurred diff --git a/include/linux/dax.h b/include/linux/dax.h index 4065601..d9a8350 100644 --- a/include/linux/dax.h +++ b/include/linux/dax.h @@ -48,16 +48,12 @@ static inline int __dax_zero_page_range(struct block_device *bdev, } #endif -#if defined(CONFIG_TRANSPARENT_HUGEPAGE) -int dax_pmd_fault(struct vm_area_struct *, unsigned long addr, pmd_t *, - unsigned int flags, get_block_t); -#else static inline int dax_pmd_fault(struct vm_area_struct *vma, unsigned long addr, pmd_t *pmd, unsigned int flags, get_block_t gb) { return VM_FAULT_FALLBACK; } -#endif + int dax_pfn_mkwrite(struct vm_area_struct *, struct vm_fault *); #define dax_mkwrite(vma, vmf, gb) dax_fault(vma, vmf, gb)
dax_pmd_fault() is the old struct buffer_head + get_block_t based 2 MiB DAX fault handler. This fault handler has been disabled for several kernel releases, and support for PMDs will be reintroduced using the struct iomap interface instead. Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com> --- fs/dax.c | 213 ---------------------------------------------------- include/linux/dax.h | 6 +- 2 files changed, 1 insertion(+), 218 deletions(-)