From: Vivek Goyal <vgoyal@redhat.com> To: Christoph Hellwig <hch@infradead.org> Cc: linux-fsdevel@vger.kernel.org, linux-nvdimm@lists.01.org, dm-devel@redhat.com Subject: Re: [PATCH 1/5] dax, pmem: Add a dax operation zero_page_range Date: Wed, 5 Feb 2020 15:02:59 -0500 [thread overview] Message-ID: <20200205200259.GE14544@redhat.com> (raw) In-Reply-To: <20200205183050.GA26711@infradead.org> On Wed, Feb 05, 2020 at 10:30:50AM -0800, Christoph Hellwig wrote: > > + /* > > + * There are no users as of now. Once users are there, fix dm code > > + * to be able to split a long range across targets. > > + */ > > This comment confused me. I think this wants to say something like: > > /* > * There are now callers that want to zero across a page boundary as of > * now. Once there are users this check can be removed after the > * device mapper code has been updated to split ranges across targets. > */ Yes, that's what I wanted to say but I missed one line. Thanks. Will fix it. > > > +static int pmem_dax_zero_page_range(struct dax_device *dax_dev, pgoff_t pgoff, > > + unsigned int offset, size_t len) > > +{ > > + int rc = 0; > > + phys_addr_t phys_pos = pgoff * PAGE_SIZE + offset; > > Any reason not to pass a phys_addr_t in the calling convention for the > method and maybe also for dax_zero_page_range itself? I don't have any reason not to pass phys_addr_t. If that sounds better, will make changes. > > > + sector_start = ALIGN(phys_pos, 512)/512; > > + sector_end = ALIGN_DOWN(phys_pos + bytes, 512)/512; > > Missing whitespaces. Also this could use DIV_ROUND_UP and > DIV_ROUND_DOWN. Will do. > > > + if (sector_end > sector_start) > > + nr_sectors = sector_end - sector_start; > > + > > + if (nr_sectors && > > + unlikely(is_bad_pmem(&pmem->bb, sector_start, > > + nr_sectors * 512))) > > + bad_pmem = true; > > How could nr_sectors be zero? If somebody specified a range across two sectors but none of the sector is completely written. Then nr_sectors will be zero. In fact this check shoudl probably be nr_sectors > 0 as writes with-in a sector will lead to nr_sector being -1. Am I missing something. > > > + write_pmem(pmem_addr, page, 0, bytes); > > + if (unlikely(bad_pmem)) { > > + /* > > + * Pass block aligned offset and length. That seems > > + * to work as of now. Other finer grained alignment > > + * cases can be addressed later if need be. > > + */ > > + rc = pmem_clear_poison(pmem, ALIGN(pmem_off, 512), > > + nr_sectors * 512); > > + write_pmem(pmem_addr, page, 0, bytes); > > + } > > This code largerly duplicates the write side of pmem_do_bvec. I > think it might make sense to split pmem_do_bvec into a read and a write > side as a prep patch, and then reuse the write side here. Ok, I will look into it. How about just add a helper function for write side and use that function both here and in pmem_do_bvec(). > > > +int generic_dax_zero_page_range(struct dax_device *dax_dev, pgoff_t pgoff, > > + unsigned int offset, size_t len); > > This should probably go into a separare are of the header and have > comment about being a section for generic helpers for drivers. ok, will do. Thanks Vivek _______________________________________________ Linux-nvdimm mailing list -- linux-nvdimm@lists.01.org To unsubscribe send an email to linux-nvdimm-leave@lists.01.org
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From: Vivek Goyal <vgoyal@redhat.com> To: Christoph Hellwig <hch@infradead.org> Cc: linux-fsdevel@vger.kernel.org, linux-nvdimm@lists.01.org, dan.j.williams@intel.com, dm-devel@redhat.com Subject: Re: [PATCH 1/5] dax, pmem: Add a dax operation zero_page_range Date: Wed, 5 Feb 2020 15:02:59 -0500 [thread overview] Message-ID: <20200205200259.GE14544@redhat.com> (raw) In-Reply-To: <20200205183050.GA26711@infradead.org> On Wed, Feb 05, 2020 at 10:30:50AM -0800, Christoph Hellwig wrote: > > + /* > > + * There are no users as of now. Once users are there, fix dm code > > + * to be able to split a long range across targets. > > + */ > > This comment confused me. I think this wants to say something like: > > /* > * There are now callers that want to zero across a page boundary as of > * now. Once there are users this check can be removed after the > * device mapper code has been updated to split ranges across targets. > */ Yes, that's what I wanted to say but I missed one line. Thanks. Will fix it. > > > +static int pmem_dax_zero_page_range(struct dax_device *dax_dev, pgoff_t pgoff, > > + unsigned int offset, size_t len) > > +{ > > + int rc = 0; > > + phys_addr_t phys_pos = pgoff * PAGE_SIZE + offset; > > Any reason not to pass a phys_addr_t in the calling convention for the > method and maybe also for dax_zero_page_range itself? I don't have any reason not to pass phys_addr_t. If that sounds better, will make changes. > > > + sector_start = ALIGN(phys_pos, 512)/512; > > + sector_end = ALIGN_DOWN(phys_pos + bytes, 512)/512; > > Missing whitespaces. Also this could use DIV_ROUND_UP and > DIV_ROUND_DOWN. Will do. > > > + if (sector_end > sector_start) > > + nr_sectors = sector_end - sector_start; > > + > > + if (nr_sectors && > > + unlikely(is_bad_pmem(&pmem->bb, sector_start, > > + nr_sectors * 512))) > > + bad_pmem = true; > > How could nr_sectors be zero? If somebody specified a range across two sectors but none of the sector is completely written. Then nr_sectors will be zero. In fact this check shoudl probably be nr_sectors > 0 as writes with-in a sector will lead to nr_sector being -1. Am I missing something. > > > + write_pmem(pmem_addr, page, 0, bytes); > > + if (unlikely(bad_pmem)) { > > + /* > > + * Pass block aligned offset and length. That seems > > + * to work as of now. Other finer grained alignment > > + * cases can be addressed later if need be. > > + */ > > + rc = pmem_clear_poison(pmem, ALIGN(pmem_off, 512), > > + nr_sectors * 512); > > + write_pmem(pmem_addr, page, 0, bytes); > > + } > > This code largerly duplicates the write side of pmem_do_bvec. I > think it might make sense to split pmem_do_bvec into a read and a write > side as a prep patch, and then reuse the write side here. Ok, I will look into it. How about just add a helper function for write side and use that function both here and in pmem_do_bvec(). > > > +int generic_dax_zero_page_range(struct dax_device *dax_dev, pgoff_t pgoff, > > + unsigned int offset, size_t len); > > This should probably go into a separare are of the header and have > comment about being a section for generic helpers for drivers. ok, will do. Thanks Vivek
next prev parent reply other threads:[~2020-02-05 20:03 UTC|newest] Thread overview: 52+ messages / expand[flat|nested] mbox.gz Atom feed top 2020-02-03 20:00 [RFC PATCH 0/5][V2] dax,pmem: Provide a dax operation to zero range of memory Vivek Goyal 2020-02-03 20:00 ` Vivek Goyal 2020-02-03 20:00 ` [PATCH 1/5] dax, pmem: Add a dax operation zero_page_range Vivek Goyal 2020-02-03 20:00 ` Vivek Goyal 2020-02-05 18:30 ` Christoph Hellwig 2020-02-05 18:30 ` Christoph Hellwig 2020-02-05 20:02 ` Vivek Goyal [this message] 2020-02-05 20:02 ` Vivek Goyal 2020-02-06 0:40 ` Dan Williams 2020-02-06 0:40 ` Dan Williams 2020-02-06 7:41 ` Christoph Hellwig 2020-02-06 7:41 ` Christoph Hellwig 2020-02-07 16:57 ` Dan Williams 2020-02-07 16:57 ` Dan Williams 2020-02-07 17:01 ` Vivek Goyal 2020-02-07 17:01 ` Vivek Goyal 2020-02-07 17:06 ` Dan Williams 2020-02-07 17:06 ` Dan Williams 2020-02-06 14:34 ` Vivek Goyal 2020-02-06 14:34 ` Vivek Goyal 2020-02-07 16:58 ` Dan Williams 2020-02-07 16:58 ` Dan Williams 2020-02-03 20:00 ` [PATCH 2/5] s390,dax: Add dax zero_page_range operation to dcssblk driver Vivek Goyal 2020-02-03 20:00 ` Vivek Goyal 2020-02-05 18:32 ` Christoph Hellwig 2020-02-05 18:32 ` Christoph Hellwig 2020-02-05 20:04 ` Vivek Goyal 2020-02-05 20:04 ` Vivek Goyal 2020-02-03 20:00 ` [PATCH 3/5] dm,dax: Add dax zero_page_range operation Vivek Goyal 2020-02-03 20:00 ` Vivek Goyal 2020-02-05 18:33 ` Christoph Hellwig 2020-02-05 18:33 ` Christoph Hellwig 2020-02-07 16:34 ` Vivek Goyal 2020-02-07 16:34 ` Vivek Goyal 2020-02-03 20:00 ` [PATCH 4/5] dax,iomap: Start using dax native zero_page_range() Vivek Goyal 2020-02-03 20:00 ` Vivek Goyal 2020-02-05 18:33 ` Christoph Hellwig 2020-02-05 18:33 ` Christoph Hellwig 2020-02-05 20:10 ` Vivek Goyal 2020-02-05 20:10 ` Vivek Goyal 2020-02-07 15:31 ` Vivek Goyal 2020-02-07 15:31 ` Vivek Goyal 2020-02-03 20:00 ` [PATCH 5/5] dax,iomap: Add helper dax_iomap_zero() to zero a range Vivek Goyal 2020-02-03 20:00 ` Vivek Goyal 2020-02-04 5:17 ` kbuild test robot 2020-02-04 5:17 ` [PATCH 5/5] dax, iomap: " kbuild test robot 2020-02-04 5:17 ` [PATCH 5/5] dax,iomap: " kbuild test robot 2020-02-04 5:17 ` kbuild test robot 2020-02-05 18:36 ` Christoph Hellwig 2020-02-05 18:36 ` Christoph Hellwig 2020-02-05 20:15 ` Vivek Goyal 2020-02-05 20:15 ` Vivek Goyal
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