| Message ID | 1543252067-30831-5-git-send-email-will.deacon@arm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Clean up huge vmap and ioremap code | expand |
On Mon, Nov 26, 2018 at 05:07:46PM +0000, Will Deacon wrote: > The current ioremap() code uses a phys_addr variable at each level of > page table, which is confusingly offset by subtracting the base virtual > address being mapped so that adding the current virtual address back on > when iterating through the page table entries gives back the corresponding > physical address. > > This is fairly confusing and results in all users of phys_addr having to > add the current virtual address back on. Instead, this patch just updates > phys_addr when iterating over the page table entries, ensuring that it's > always up-to-date and doesn't require explicit offsetting. > > Cc: Chintan Pandya <cpandya@codeaurora.org> > Cc: Toshi Kani <toshi.kani@hpe.com> > Cc: Thomas Gleixner <tglx@linutronix.de> > Cc: Michal Hocko <mhocko@suse.com> > Cc: Andrew Morton <akpm@linux-foundation.org> > Cc: Sean Christopherson <sean.j.christopherson@intel.com> > Signed-off-by: Will Deacon <will.deacon@arm.com> Tested-by: Sean Christopherson <sean.j.christopherson@intel.com> Reviewed-by: Sean Christopherson <sean.j.christopherson@intel.com>
On Mon, Nov 26, 2018 at 11:00:10AM -0800, Sean Christopherson wrote: > On Mon, Nov 26, 2018 at 05:07:46PM +0000, Will Deacon wrote: > > The current ioremap() code uses a phys_addr variable at each level of > > page table, which is confusingly offset by subtracting the base virtual > > address being mapped so that adding the current virtual address back on > > when iterating through the page table entries gives back the corresponding > > physical address. > > > > This is fairly confusing and results in all users of phys_addr having to > > add the current virtual address back on. Instead, this patch just updates > > phys_addr when iterating over the page table entries, ensuring that it's > > always up-to-date and doesn't require explicit offsetting. > > > > Cc: Chintan Pandya <cpandya@codeaurora.org> > > Cc: Toshi Kani <toshi.kani@hpe.com> > > Cc: Thomas Gleixner <tglx@linutronix.de> > > Cc: Michal Hocko <mhocko@suse.com> > > Cc: Andrew Morton <akpm@linux-foundation.org> > > Cc: Sean Christopherson <sean.j.christopherson@intel.com> > > Signed-off-by: Will Deacon <will.deacon@arm.com> > > Tested-by: Sean Christopherson <sean.j.christopherson@intel.com> > Reviewed-by: Sean Christopherson <sean.j.christopherson@intel.com> Thanks, Sean. I think Andrew can queue these now. Will
diff --git a/lib/ioremap.c b/lib/ioremap.c index 6c72764af19c..10d7c5485c39 100644 --- a/lib/ioremap.c +++ b/lib/ioremap.c @@ -101,19 +101,18 @@ static inline int ioremap_pmd_range(pud_t *pud, unsigned long addr, pmd_t *pmd; unsigned long next; - phys_addr -= addr; pmd = pmd_alloc(&init_mm, pud, addr); if (!pmd) return -ENOMEM; do { next = pmd_addr_end(addr, end); - if (ioremap_try_huge_pmd(pmd, addr, next, phys_addr + addr, prot)) + if (ioremap_try_huge_pmd(pmd, addr, next, phys_addr, prot)) continue; - if (ioremap_pte_range(pmd, addr, next, phys_addr + addr, prot)) + if (ioremap_pte_range(pmd, addr, next, phys_addr, prot)) return -ENOMEM; - } while (pmd++, addr = next, addr != end); + } while (pmd++, phys_addr += (next - addr), addr = next, addr != end); return 0; } @@ -142,19 +141,18 @@ static inline int ioremap_pud_range(p4d_t *p4d, unsigned long addr, pud_t *pud; unsigned long next; - phys_addr -= addr; pud = pud_alloc(&init_mm, p4d, addr); if (!pud) return -ENOMEM; do { next = pud_addr_end(addr, end); - if (ioremap_try_huge_pud(pud, addr, next, phys_addr + addr, prot)) + if (ioremap_try_huge_pud(pud, addr, next, phys_addr, prot)) continue; - if (ioremap_pmd_range(pud, addr, next, phys_addr + addr, prot)) + if (ioremap_pmd_range(pud, addr, next, phys_addr, prot)) return -ENOMEM; - } while (pud++, addr = next, addr != end); + } while (pud++, phys_addr += (next - addr), addr = next, addr != end); return 0; } @@ -164,7 +162,6 @@ static inline int ioremap_p4d_range(pgd_t *pgd, unsigned long addr, p4d_t *p4d; unsigned long next; - phys_addr -= addr; p4d = p4d_alloc(&init_mm, pgd, addr); if (!p4d) return -ENOMEM; @@ -173,14 +170,14 @@ static inline int ioremap_p4d_range(pgd_t *pgd, unsigned long addr, if (ioremap_p4d_enabled() && ((next - addr) == P4D_SIZE) && - IS_ALIGNED(phys_addr + addr, P4D_SIZE)) { - if (p4d_set_huge(p4d, phys_addr + addr, prot)) + IS_ALIGNED(phys_addr, P4D_SIZE)) { + if (p4d_set_huge(p4d, phys_addr, prot)) continue; } - if (ioremap_pud_range(p4d, addr, next, phys_addr + addr, prot)) + if (ioremap_pud_range(p4d, addr, next, phys_addr, prot)) return -ENOMEM; - } while (p4d++, addr = next, addr != end); + } while (p4d++, phys_addr += (next - addr), addr = next, addr != end); return 0; } @@ -196,14 +193,13 @@ int ioremap_page_range(unsigned long addr, BUG_ON(addr >= end); start = addr; - phys_addr -= addr; pgd = pgd_offset_k(addr); do { next = pgd_addr_end(addr, end); - err = ioremap_p4d_range(pgd, addr, next, phys_addr+addr, prot); + err = ioremap_p4d_range(pgd, addr, next, phys_addr, prot); if (err) break; - } while (pgd++, addr = next, addr != end); + } while (pgd++, phys_addr += (next - addr), addr = next, addr != end); flush_cache_vmap(start, end);
The current ioremap() code uses a phys_addr variable at each level of page table, which is confusingly offset by subtracting the base virtual address being mapped so that adding the current virtual address back on when iterating through the page table entries gives back the corresponding physical address. This is fairly confusing and results in all users of phys_addr having to add the current virtual address back on. Instead, this patch just updates phys_addr when iterating over the page table entries, ensuring that it's always up-to-date and doesn't require explicit offsetting. Cc: Chintan Pandya <cpandya@codeaurora.org> Cc: Toshi Kani <toshi.kani@hpe.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Michal Hocko <mhocko@suse.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Sean Christopherson <sean.j.christopherson@intel.com> Signed-off-by: Will Deacon <will.deacon@arm.com> --- lib/ioremap.c | 28 ++++++++++++---------------- 1 file changed, 12 insertions(+), 16 deletions(-)