| Message ID | 20200228163456.1587-3-vgoyal@redhat.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | dax/pmem: Provide a dax operation to zero page range | expand |
> > Add a dax operation zero_page_range, to zero a page. This will also clear any > known poison in the page being zeroed. > > As of now, zeroing of one page is allowed in a single call. There > are no callers which are trying to zero more than a page in a single call. > Once we grow the callers which zero more than a page in single call, we > can add that support. Primary reason for not doing that yet is that this > will add little complexity in dm implementation where a range might be > spanning multiple underlying targets and one will have to split the range > into multiple sub ranges and call zero_page_range() on individual targets. > > Suggested-by: Christoph Hellwig <hch@infradead.org> > Signed-off-by: Vivek Goyal <vgoyal@redhat.com> > --- > drivers/dax/super.c | 20 ++++++++++++++++++++ > drivers/nvdimm/pmem.c | 11 +++++++++++ > include/linux/dax.h | 4 ++++ > 3 files changed, 35 insertions(+) > > diff --git a/drivers/dax/super.c b/drivers/dax/super.c > index 0aa4b6bc5101..e498daf3c0d7 100644 > --- a/drivers/dax/super.c > +++ b/drivers/dax/super.c > @@ -344,6 +344,26 @@ size_t dax_copy_to_iter(struct dax_device *dax_dev, pgoff_t pgoff, void *addr, > } > EXPORT_SYMBOL_GPL(dax_copy_to_iter); > > +int dax_zero_page_range(struct dax_device *dax_dev, pgoff_t pgoff, > + size_t nr_pages) > +{ > + if (!dax_alive(dax_dev)) > + return -ENXIO; > + > + if (!dax_dev->ops->zero_page_range) > + return -EOPNOTSUPP; > + /* > + * There are no callers that want to zero more than one page as of now. > + * Once users are there, this check can be removed after the > + * device mapper code has been updated to split ranges across targets. > + */ > + if (nr_pages != 1) > + return -EIO; > + > + return dax_dev->ops->zero_page_range(dax_dev, pgoff, nr_pages); > +} > +EXPORT_SYMBOL_GPL(dax_zero_page_range); > + > #ifdef CONFIG_ARCH_HAS_PMEM_API > void arch_wb_cache_pmem(void *addr, size_t size); > void dax_flush(struct dax_device *dax_dev, void *addr, size_t size) > diff --git a/drivers/nvdimm/pmem.c b/drivers/nvdimm/pmem.c > index 075b11682192..5b774ddd0efb 100644 > --- a/drivers/nvdimm/pmem.c > +++ b/drivers/nvdimm/pmem.c > @@ -282,6 +282,16 @@ static const struct block_device_operations pmem_fops = { > .revalidate_disk = nvdimm_revalidate_disk, > }; > > +static int pmem_dax_zero_page_range(struct dax_device *dax_dev, pgoff_t pgoff, > + size_t nr_pages) > +{ > + struct pmem_device *pmem = dax_get_private(dax_dev); > + > + return blk_status_to_errno(pmem_do_write(pmem, ZERO_PAGE(0), 0, > + PFN_PHYS(pgoff) >> SECTOR_SHIFT, > + PAGE_SIZE)); > +} > + > static long pmem_dax_direct_access(struct dax_device *dax_dev, > pgoff_t pgoff, long nr_pages, void **kaddr, pfn_t *pfn) > { > @@ -313,6 +323,7 @@ static const struct dax_operations pmem_dax_ops = { > .dax_supported = generic_fsdax_supported, > .copy_from_iter = pmem_copy_from_iter, > .copy_to_iter = pmem_copy_to_iter, > + .zero_page_range = pmem_dax_zero_page_range, > }; > > static const struct attribute_group *pmem_attribute_groups[] = { > diff --git a/include/linux/dax.h b/include/linux/dax.h > index 328c2dbb4409..71735c430c05 100644 > --- a/include/linux/dax.h > +++ b/include/linux/dax.h > @@ -34,6 +34,8 @@ struct dax_operations { > /* copy_to_iter: required operation for fs-dax direct-i/o */ > size_t (*copy_to_iter)(struct dax_device *, pgoff_t, void *, size_t, > struct iov_iter *); > + /* zero_page_range: required operation. Zero page range */ > + int (*zero_page_range)(struct dax_device *, pgoff_t, size_t); > }; > > extern struct attribute_group dax_attribute_group; > @@ -199,6 +201,8 @@ size_t dax_copy_from_iter(struct dax_device *dax_dev, pgoff_t pgoff, void *addr, > size_t bytes, struct iov_iter *i); > size_t dax_copy_to_iter(struct dax_device *dax_dev, pgoff_t pgoff, void *addr, > size_t bytes, struct iov_iter *i); > +int dax_zero_page_range(struct dax_device *dax_dev, pgoff_t pgoff, > + size_t nr_pages); > void dax_flush(struct dax_device *dax_dev, void *addr, size_t size); > > ssize_t dax_iomap_rw(struct kiocb *iocb, struct iov_iter *iter, > -- > 2.20.1 Zeroing single page seems right approach for now. Reviewed-by: Pankaj Gupta <pankaj.gupta.linux@gmail.com> > _______________________________________________ > Linux-nvdimm mailing list -- linux-nvdimm@lists.01.org > To unsubscribe send an email to linux-nvdimm-leave@lists.01.org
diff --git a/drivers/dax/super.c b/drivers/dax/super.c index 0aa4b6bc5101..e498daf3c0d7 100644 --- a/drivers/dax/super.c +++ b/drivers/dax/super.c @@ -344,6 +344,26 @@ size_t dax_copy_to_iter(struct dax_device *dax_dev, pgoff_t pgoff, void *addr, } EXPORT_SYMBOL_GPL(dax_copy_to_iter); +int dax_zero_page_range(struct dax_device *dax_dev, pgoff_t pgoff, + size_t nr_pages) +{ + if (!dax_alive(dax_dev)) + return -ENXIO; + + if (!dax_dev->ops->zero_page_range) + return -EOPNOTSUPP; + /* + * There are no callers that want to zero more than one page as of now. + * Once users are there, this check can be removed after the + * device mapper code has been updated to split ranges across targets. + */ + if (nr_pages != 1) + return -EIO; + + return dax_dev->ops->zero_page_range(dax_dev, pgoff, nr_pages); +} +EXPORT_SYMBOL_GPL(dax_zero_page_range); + #ifdef CONFIG_ARCH_HAS_PMEM_API void arch_wb_cache_pmem(void *addr, size_t size); void dax_flush(struct dax_device *dax_dev, void *addr, size_t size) diff --git a/drivers/nvdimm/pmem.c b/drivers/nvdimm/pmem.c index 075b11682192..5b774ddd0efb 100644 --- a/drivers/nvdimm/pmem.c +++ b/drivers/nvdimm/pmem.c @@ -282,6 +282,16 @@ static const struct block_device_operations pmem_fops = { .revalidate_disk = nvdimm_revalidate_disk, }; +static int pmem_dax_zero_page_range(struct dax_device *dax_dev, pgoff_t pgoff, + size_t nr_pages) +{ + struct pmem_device *pmem = dax_get_private(dax_dev); + + return blk_status_to_errno(pmem_do_write(pmem, ZERO_PAGE(0), 0, + PFN_PHYS(pgoff) >> SECTOR_SHIFT, + PAGE_SIZE)); +} + static long pmem_dax_direct_access(struct dax_device *dax_dev, pgoff_t pgoff, long nr_pages, void **kaddr, pfn_t *pfn) { @@ -313,6 +323,7 @@ static const struct dax_operations pmem_dax_ops = { .dax_supported = generic_fsdax_supported, .copy_from_iter = pmem_copy_from_iter, .copy_to_iter = pmem_copy_to_iter, + .zero_page_range = pmem_dax_zero_page_range, }; static const struct attribute_group *pmem_attribute_groups[] = { diff --git a/include/linux/dax.h b/include/linux/dax.h index 328c2dbb4409..71735c430c05 100644 --- a/include/linux/dax.h +++ b/include/linux/dax.h @@ -34,6 +34,8 @@ struct dax_operations { /* copy_to_iter: required operation for fs-dax direct-i/o */ size_t (*copy_to_iter)(struct dax_device *, pgoff_t, void *, size_t, struct iov_iter *); + /* zero_page_range: required operation. Zero page range */ + int (*zero_page_range)(struct dax_device *, pgoff_t, size_t); }; extern struct attribute_group dax_attribute_group; @@ -199,6 +201,8 @@ size_t dax_copy_from_iter(struct dax_device *dax_dev, pgoff_t pgoff, void *addr, size_t bytes, struct iov_iter *i); size_t dax_copy_to_iter(struct dax_device *dax_dev, pgoff_t pgoff, void *addr, size_t bytes, struct iov_iter *i); +int dax_zero_page_range(struct dax_device *dax_dev, pgoff_t pgoff, + size_t nr_pages); void dax_flush(struct dax_device *dax_dev, void *addr, size_t size); ssize_t dax_iomap_rw(struct kiocb *iocb, struct iov_iter *iter,
Add a dax operation zero_page_range, to zero a page. This will also clear any known poison in the page being zeroed. As of now, zeroing of one page is allowed in a single call. There are no callers which are trying to zero more than a page in a single call. Once we grow the callers which zero more than a page in single call, we can add that support. Primary reason for not doing that yet is that this will add little complexity in dm implementation where a range might be spanning multiple underlying targets and one will have to split the range into multiple sub ranges and call zero_page_range() on individual targets. Suggested-by: Christoph Hellwig <hch@infradead.org> Signed-off-by: Vivek Goyal <vgoyal@redhat.com> --- drivers/dax/super.c | 20 ++++++++++++++++++++ drivers/nvdimm/pmem.c | 11 +++++++++++ include/linux/dax.h | 4 ++++ 3 files changed, 35 insertions(+)