| Message ID | 20241211232754.1583023-2-kaleshsingh@google.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | mm: Introduce arch_mmap_hint() | expand |
On Wed, Dec 11, 2024 at 3:28 PM Kalesh Singh <kaleshsingh@google.com> wrote: > > Consolidate the hint searches from both directions (topdown and > bottomup) into generic_mmap_hint(). > > No functional change is introduced. > > Signed-off-by: Kalesh Singh <kaleshsingh@google.com> > --- > > Changes in v2: > - MAP_FIXED case is also handled in arch_mmap_hint() since this is just a > special case of the hint addr being "enforced", per Yang Shi. > - Consolidate error handling in arch_mmap_hint(). Reviewed-by: Yang Shi <shy828301@gmail.com> > > include/linux/sched/mm.h | 4 +++ > mm/mmap.c | 76 ++++++++++++++++++++++++---------------- > 2 files changed, 50 insertions(+), 30 deletions(-) > > diff --git a/include/linux/sched/mm.h b/include/linux/sched/mm.h > index 928a626725e6..edeec19d1708 100644 > --- a/include/linux/sched/mm.h > +++ b/include/linux/sched/mm.h > @@ -201,6 +201,10 @@ unsigned long mm_get_unmapped_area_vmflags(struct mm_struct *mm, > unsigned long flags, > vm_flags_t vm_flags); > > +unsigned long generic_mmap_hint(struct file *filp, unsigned long addr, > + unsigned long len, unsigned long pgoff, > + unsigned long flags); > + > unsigned long > generic_get_unmapped_area(struct file *filp, unsigned long addr, > unsigned long len, unsigned long pgoff, > diff --git a/mm/mmap.c b/mm/mmap.c > index df9154b15ef9..382b4eac5406 100644 > --- a/mm/mmap.c > +++ b/mm/mmap.c > @@ -620,6 +620,47 @@ unsigned long vm_unmapped_area(struct vm_unmapped_area_info *info) > return addr; > } > > +/* > + * Look up unmapped area at the requested hint addr > + * > + * NOTE: MAP_FIXED is also handled here since it's a special case of > + * enforcing the hint address. > + * > + * Returns: > + * ERR_VALUE: If the requested mapping is not valid > + * 0: If there isn't a sufficiently large hole at the hint addr. > + * addr: If sufficient VA space is available at the hint address; > + * or MAP_FIXED was specified. > + */ > +unsigned long generic_mmap_hint(struct file *filp, unsigned long addr, > + unsigned long len, unsigned long pgoff, > + unsigned long flags) > +{ > + struct mm_struct *mm = current->mm; > + struct vm_area_struct *vma, *prev; > + const unsigned long mmap_end = arch_get_mmap_end(addr, len, flags); > + > + /* requested length too big for entire address space */ > + if (len > mmap_end - mmap_min_addr) > + return -ENOMEM; > + > + if (flags & MAP_FIXED) > + return addr; > + > + if (!addr) > + return 0; > + > + addr = PAGE_ALIGN(addr); > + vma = find_vma_prev(mm, addr, &prev); > + if (mmap_end - len >= addr && addr >= mmap_min_addr && > + (!vma || addr + len <= vm_start_gap(vma)) && > + (!prev || addr >= vm_end_gap(prev))) > + return addr; > + > + /* Fallback to VA space search */ > + return 0; > +} > + > /* Get an address range which is currently unmapped. > * For shmat() with addr=0. > * > @@ -637,25 +678,13 @@ generic_get_unmapped_area(struct file *filp, unsigned long addr, > unsigned long flags, vm_flags_t vm_flags) > { > struct mm_struct *mm = current->mm; > - struct vm_area_struct *vma, *prev; > struct vm_unmapped_area_info info = {}; > const unsigned long mmap_end = arch_get_mmap_end(addr, len, flags); > > - if (len > mmap_end - mmap_min_addr) > - return -ENOMEM; > - > - if (flags & MAP_FIXED) > + addr = generic_mmap_hint(filp, addr, len, pgoff, flags); > + if (addr) > return addr; > > - if (addr) { > - addr = PAGE_ALIGN(addr); > - vma = find_vma_prev(mm, addr, &prev); > - if (mmap_end - len >= addr && addr >= mmap_min_addr && > - (!vma || addr + len <= vm_start_gap(vma)) && > - (!prev || addr >= vm_end_gap(prev))) > - return addr; > - } > - > info.length = len; > info.low_limit = mm->mmap_base; > info.high_limit = mmap_end; > @@ -685,27 +714,14 @@ generic_get_unmapped_area_topdown(struct file *filp, unsigned long addr, > unsigned long len, unsigned long pgoff, > unsigned long flags, vm_flags_t vm_flags) > { > - struct vm_area_struct *vma, *prev; > struct mm_struct *mm = current->mm; > struct vm_unmapped_area_info info = {}; > const unsigned long mmap_end = arch_get_mmap_end(addr, len, flags); > > - /* requested length too big for entire address space */ > - if (len > mmap_end - mmap_min_addr) > - return -ENOMEM; > - > - if (flags & MAP_FIXED) > - return addr; > - > /* requesting a specific address */ > - if (addr) { > - addr = PAGE_ALIGN(addr); > - vma = find_vma_prev(mm, addr, &prev); > - if (mmap_end - len >= addr && addr >= mmap_min_addr && > - (!vma || addr + len <= vm_start_gap(vma)) && > - (!prev || addr >= vm_end_gap(prev))) > - return addr; > - } > + addr = generic_mmap_hint(filp, addr, len, pgoff, flags); > + if (addr) > + return addr; > > info.flags = VM_UNMAPPED_AREA_TOPDOWN; > info.length = len; > -- > 2.47.0.338.g60cca15819-goog > >
diff --git a/include/linux/sched/mm.h b/include/linux/sched/mm.h index 928a626725e6..edeec19d1708 100644 --- a/include/linux/sched/mm.h +++ b/include/linux/sched/mm.h @@ -201,6 +201,10 @@ unsigned long mm_get_unmapped_area_vmflags(struct mm_struct *mm, unsigned long flags, vm_flags_t vm_flags); +unsigned long generic_mmap_hint(struct file *filp, unsigned long addr, + unsigned long len, unsigned long pgoff, + unsigned long flags); + unsigned long generic_get_unmapped_area(struct file *filp, unsigned long addr, unsigned long len, unsigned long pgoff, diff --git a/mm/mmap.c b/mm/mmap.c index df9154b15ef9..382b4eac5406 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -620,6 +620,47 @@ unsigned long vm_unmapped_area(struct vm_unmapped_area_info *info) return addr; } +/* + * Look up unmapped area at the requested hint addr + * + * NOTE: MAP_FIXED is also handled here since it's a special case of + * enforcing the hint address. + * + * Returns: + * ERR_VALUE: If the requested mapping is not valid + * 0: If there isn't a sufficiently large hole at the hint addr. + * addr: If sufficient VA space is available at the hint address; + * or MAP_FIXED was specified. + */ +unsigned long generic_mmap_hint(struct file *filp, unsigned long addr, + unsigned long len, unsigned long pgoff, + unsigned long flags) +{ + struct mm_struct *mm = current->mm; + struct vm_area_struct *vma, *prev; + const unsigned long mmap_end = arch_get_mmap_end(addr, len, flags); + + /* requested length too big for entire address space */ + if (len > mmap_end - mmap_min_addr) + return -ENOMEM; + + if (flags & MAP_FIXED) + return addr; + + if (!addr) + return 0; + + addr = PAGE_ALIGN(addr); + vma = find_vma_prev(mm, addr, &prev); + if (mmap_end - len >= addr && addr >= mmap_min_addr && + (!vma || addr + len <= vm_start_gap(vma)) && + (!prev || addr >= vm_end_gap(prev))) + return addr; + + /* Fallback to VA space search */ + return 0; +} + /* Get an address range which is currently unmapped. * For shmat() with addr=0. * @@ -637,25 +678,13 @@ generic_get_unmapped_area(struct file *filp, unsigned long addr, unsigned long flags, vm_flags_t vm_flags) { struct mm_struct *mm = current->mm; - struct vm_area_struct *vma, *prev; struct vm_unmapped_area_info info = {}; const unsigned long mmap_end = arch_get_mmap_end(addr, len, flags); - if (len > mmap_end - mmap_min_addr) - return -ENOMEM; - - if (flags & MAP_FIXED) + addr = generic_mmap_hint(filp, addr, len, pgoff, flags); + if (addr) return addr; - if (addr) { - addr = PAGE_ALIGN(addr); - vma = find_vma_prev(mm, addr, &prev); - if (mmap_end - len >= addr && addr >= mmap_min_addr && - (!vma || addr + len <= vm_start_gap(vma)) && - (!prev || addr >= vm_end_gap(prev))) - return addr; - } - info.length = len; info.low_limit = mm->mmap_base; info.high_limit = mmap_end; @@ -685,27 +714,14 @@ generic_get_unmapped_area_topdown(struct file *filp, unsigned long addr, unsigned long len, unsigned long pgoff, unsigned long flags, vm_flags_t vm_flags) { - struct vm_area_struct *vma, *prev; struct mm_struct *mm = current->mm; struct vm_unmapped_area_info info = {}; const unsigned long mmap_end = arch_get_mmap_end(addr, len, flags); - /* requested length too big for entire address space */ - if (len > mmap_end - mmap_min_addr) - return -ENOMEM; - - if (flags & MAP_FIXED) - return addr; - /* requesting a specific address */ - if (addr) { - addr = PAGE_ALIGN(addr); - vma = find_vma_prev(mm, addr, &prev); - if (mmap_end - len >= addr && addr >= mmap_min_addr && - (!vma || addr + len <= vm_start_gap(vma)) && - (!prev || addr >= vm_end_gap(prev))) - return addr; - } + addr = generic_mmap_hint(filp, addr, len, pgoff, flags); + if (addr) + return addr; info.flags = VM_UNMAPPED_AREA_TOPDOWN; info.length = len;
Consolidate the hint searches from both directions (topdown and bottomup) into generic_mmap_hint(). No functional change is introduced. Signed-off-by: Kalesh Singh <kaleshsingh@google.com> --- Changes in v2: - MAP_FIXED case is also handled in arch_mmap_hint() since this is just a special case of the hint addr being "enforced", per Yang Shi. - Consolidate error handling in arch_mmap_hint(). include/linux/sched/mm.h | 4 +++ mm/mmap.c | 76 ++++++++++++++++++++++++---------------- 2 files changed, 50 insertions(+), 30 deletions(-)