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Tue, 23 Aug 2022 12:30:14 +0000 (GMT) Received: from oc-nschnelle.boeblingen.de.ibm.com (unknown [9.155.199.46]) by d06av24.portsmouth.uk.ibm.com (Postfix) with ESMTP; Tue, 23 Aug 2022 12:30:14 +0000 (GMT) Message-ID: <376889563c9da4d6f97ea8a412697e0867a0d4bd.camel@linux.ibm.com> Subject: Re: [PATCH v2 09/11] s390: mm: Convert to GENERIC_IOREMAP From: Niklas Schnelle To: Baoquan He , linux-kernel@vger.kernel.org Cc: linux-mm@kvack.org, akpm@linux-foundation.org, hch@infradead.org, agordeev@linux.ibm.com, wangkefeng.wang@huawei.com, linux-arm-kernel@lists.infradead.org, Heiko Carstens , Vasily Gorbik , Christian Borntraeger , Sven Schnelle , linux-s390@vger.kernel.org Date: Tue, 23 Aug 2022 14:30:14 +0200 In-Reply-To: <20220820003125.353570-10-bhe@redhat.com> References: <20220820003125.353570-1-bhe@redhat.com> <20220820003125.353570-10-bhe@redhat.com> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.28.5 (3.28.5-18.el8) Mime-Version: 1.0 Content-Transfer-Encoding: 7bit X-TM-AS-GCONF: 00 X-Proofpoint-GUID: bzKEo_tu4kET95yAtSRkCupSln-3hD_9 X-Proofpoint-ORIG-GUID: TEislebOP0p_FPvz37-H8NxrCsfUGppc X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.205,Aquarius:18.0.895,Hydra:6.0.517,FMLib:17.11.122.1 definitions=2022-08-23_04,2022-08-22_02,2022-06-22_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 bulkscore=0 mlxlogscore=999 suspectscore=0 impostorscore=0 malwarescore=0 priorityscore=1501 lowpriorityscore=0 clxscore=1015 adultscore=0 phishscore=0 mlxscore=0 spamscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2207270000 definitions=main-2208230048 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, 2022-08-20 at 08:31 +0800, Baoquan He wrote: > Add hooks arch_ioremap() and arch_iounmap() for s390's special > operation when ioremap() and iounmap(), then ioremap_[wc|wt]() are > converted to use ioremap_prot() from GENERIC_IOREMAP. > > Signed-off-by: Baoquan He > Cc: Heiko Carstens > Cc: Vasily Gorbik > Cc: Alexander Gordeev > Cc: Christian Borntraeger > Cc: Sven Schnelle > Cc: linux-s390@vger.kernel.org > --- > arch/s390/Kconfig | 1 + > arch/s390/include/asm/io.h | 26 +++++++++++------ > arch/s390/pci/pci.c | 60 +++++--------------------------------- > 3 files changed, 26 insertions(+), 61 deletions(-) > > diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig > index 318fce77601d..c59e1b25f59d 100644 > --- a/arch/s390/Kconfig > +++ b/arch/s390/Kconfig > @@ -135,6 +135,7 @@ config S390 > select GENERIC_SMP_IDLE_THREAD > select GENERIC_TIME_VSYSCALL > select GENERIC_VDSO_TIME_NS > + select GENERIC_IOREMAP > select HAVE_ALIGNED_STRUCT_PAGE if SLUB > select HAVE_ARCH_AUDITSYSCALL > select HAVE_ARCH_JUMP_LABEL > diff --git a/arch/s390/include/asm/io.h b/arch/s390/include/asm/io.h > index e3882b012bfa..f837e20b7bbd 100644 > --- a/arch/s390/include/asm/io.h > +++ b/arch/s390/include/asm/io.h > @@ -22,11 +22,23 @@ void unxlate_dev_mem_ptr(phys_addr_t phys, void *addr); > > #define IO_SPACE_LIMIT 0 > > -void __iomem *ioremap_prot(phys_addr_t addr, size_t size, unsigned long prot); > -void __iomem *ioremap(phys_addr_t addr, size_t size); > -void __iomem *ioremap_wc(phys_addr_t addr, size_t size); > -void __iomem *ioremap_wt(phys_addr_t addr, size_t size); > -void iounmap(volatile void __iomem *addr); > + Checkpatch nitpick, remove the empty line addition above so as not to create two consecutive empty lines. > +/* > + * I/O memory mapping functions. > + */ > +void __iomem * > +arch_ioremap(phys_addr_t *paddr, size_t size, unsigned long *prot_val); > +#define arch_ioremap arch_ioremap > + > +int arch_iounmap(void __iomem *addr); > +#define arch_iounmap arch_iounmap > + > +#define _PAGE_IOREMAP pgprot_val(PAGE_KERNEL) > + > +#define ioremap_wc(addr, size) \ > + ioremap_prot((addr), (size), pgprot_val(pgprot_writecombine(PAGE_KERNEL))) > +#define ioremap_wt(addr, size) \ > + ioremap_prot((addr), (size), pgprot_val(pgprot_writethrough(PAGE_KERNEL))) > > static inline void __iomem *ioport_map(unsigned long port, unsigned int nr) > { > @@ -51,10 +63,6 @@ static inline void ioport_unmap(void __iomem *p) > #define pci_iomap_wc pci_iomap_wc > #define pci_iomap_wc_range pci_iomap_wc_range > > -#define ioremap ioremap > -#define ioremap_wt ioremap_wt > -#define ioremap_wc ioremap_wc > - > #define memcpy_fromio(dst, src, count) zpci_memcpy_fromio(dst, src, count) > #define memcpy_toio(dst, src, count) zpci_memcpy_toio(dst, src, count) > #define memset_io(dst, val, count) zpci_memset_io(dst, val, count) > diff --git a/arch/s390/pci/pci.c b/arch/s390/pci/pci.c > index 73cdc5539384..984cad9cd5a1 100644 > --- a/arch/s390/pci/pci.c > +++ b/arch/s390/pci/pci.c > @@ -244,64 +244,20 @@ void __iowrite64_copy(void __iomem *to, const void *from, size_t count) > zpci_memcpy_toio(to, from, count); > } > > -static void __iomem *__ioremap(phys_addr_t addr, size_t size, pgprot_t prot) > +void __iomem * > +arch_ioremap(phys_addr_t *paddr, size_t size, unsigned long *prot_val) > { > - unsigned long offset, vaddr; > - struct vm_struct *area; > - phys_addr_t last_addr; > - > - last_addr = addr + size - 1; > - if (!size || last_addr < addr) > - return NULL; > - > if (!static_branch_unlikely(&have_mio)) > - return (void __iomem *) addr; > - > - offset = addr & ~PAGE_MASK; > - addr &= PAGE_MASK; > - size = PAGE_ALIGN(size + offset); > - area = get_vm_area(size, VM_IOREMAP); > - if (!area) > - return NULL; > - > - vaddr = (unsigned long) area->addr; > - if (ioremap_page_range(vaddr, vaddr + size, addr, prot)) { > - free_vm_area(area); > - return NULL; > - } > - return (void __iomem *) ((unsigned long) area->addr + offset); > -} > - > -void __iomem *ioremap_prot(phys_addr_t addr, size_t size, unsigned long prot) > -{ > - return __ioremap(addr, size, __pgprot(prot)); > + return (void __iomem *) *paddr; Another checkpatch nitpick no space after the cast. > + return NULL; > } > -EXPORT_SYMBOL(ioremap_prot); > > -void __iomem *ioremap(phys_addr_t addr, size_t size) > +int arch_iounmap(void __iomem *addr) > { > - return __ioremap(addr, size, PAGE_KERNEL); > -} > -EXPORT_SYMBOL(ioremap); > - > -void __iomem *ioremap_wc(phys_addr_t addr, size_t size) > -{ > - return __ioremap(addr, size, pgprot_writecombine(PAGE_KERNEL)); > -} > -EXPORT_SYMBOL(ioremap_wc); > - > -void __iomem *ioremap_wt(phys_addr_t addr, size_t size) > -{ > - return __ioremap(addr, size, pgprot_writethrough(PAGE_KERNEL)); > -} > -EXPORT_SYMBOL(ioremap_wt); > - > -void iounmap(volatile void __iomem *addr) > -{ > - if (static_branch_likely(&have_mio)) > - vunmap((__force void *) ((unsigned long) addr & PAGE_MASK)); > + if (!static_branch_likely(&have_mio)) > + return -EINVAL; As Christoph suggested this might be a good opportunity to add a comment for this branch. One other nitpick. The return value doesn't really matter here since anything != NULL turns iounmap() into a no-op so this looks correct but semantically I think returning -EINVAL wrongly suggests that addr was invalid. Maybe -ENXIO would be better at conveying that there is nothing to unmap. Looking at your patch 1 another idea would be to have 3 kinds of return values for arch_iounmap() too e.g.: arch_iounmap() return an __iomem pointer - IS_ERR means skip vunmap and return directly - NULL means continue to vunmap - a non-NULL, non-IS_ERR pointer has been unmapped successfully Then we would simply return addr in case of !static_branch_likely(&have_mio) and NULL otherwise. What do you think? Either way no strong opinion on my side, functionally it makes no difference. > + return 0; > } > -EXPORT_SYMBOL(iounmap); > > /* Create a virtual mapping cookie for a PCI BAR */ > static void __iomem *pci_iomap_range_fh(struct pci_dev *pdev, int bar, Apart from the above nitpicks and suggestion this looks good to me. I did also test this with and without PCI MIO support including use of PCI MIO instructions in user-space (added in rdma-core v40). So feel free to add: Tested-by: Niklas Schnelle Acked-by: Niklas Schnelle Since it looks like there will be a v3 due to other comments anyway please Cc me on that directly and I'm sure I can upgrade the Acked-by to Reviewed-by when we're closer to the final code.