| Message ID | 20181018202318.9131-4-josef@toxicpanda.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | drop the mmap_sem when doing IO in the fault path | expand |
On Thu, Oct 18, 2018 at 04:23:14PM -0400, Josef Bacik wrote: > Johannes' patches didn't quite cover all of the IO cases that we need to > drop the mmap_sem for, this patch covers the rest of them. > > Signed-off-by: Josef Bacik <josef@toxicpanda.com> > --- > mm/filemap.c | 11 +++++++++++ > 1 file changed, 11 insertions(+) > > diff --git a/mm/filemap.c b/mm/filemap.c > index 1ed35cd99b2c..65395ee132a0 100644 > --- a/mm/filemap.c > +++ b/mm/filemap.c > @@ -2523,6 +2523,7 @@ vm_fault_t filemap_fault(struct vm_fault *vmf) > int error; > struct mm_struct *mm = vmf->vma->vm_mm; > struct file *file = vmf->vma->vm_file; > + struct file *fpin = NULL; > struct address_space *mapping = file->f_mapping; > struct file_ra_state *ra = &file->f_ra; > struct inode *inode = mapping->host; > @@ -2610,11 +2611,15 @@ vm_fault_t filemap_fault(struct vm_fault *vmf) > return ret | VM_FAULT_LOCKED; > > no_cached_page: > + fpin = maybe_unlock_mmap_for_io(vmf->vma, vmf->flags); > + > /* > * We're only likely to ever get here if MADV_RANDOM is in > * effect. > */ > error = page_cache_read(file, offset, vmf->gfp_mask); > + if (fpin) > + goto out_retry; Please put the unlock after the comment explaining the goto label so it's clear that the pin is associated only with the read operations like so: no_cached_page: /* * We're only likely to ever get here if MADV_RANDOM is in * effect. */ fpin = maybe_unlock_mmap_for_io(vmf->vma, vmf->flags); error = page_cache_read(file, offset, vmf->gfp_mask); if (fpin) goto out_retry; > > /* > * The page we want has now been added to the page cache. > @@ -2634,6 +2639,8 @@ vm_fault_t filemap_fault(struct vm_fault *vmf) > return VM_FAULT_SIGBUS; > > page_not_uptodate: > + fpin = maybe_unlock_mmap_for_io(vmf->vma, vmf->flags); > + > /* > * Umm, take care of errors if the page isn't up-to-date. > * Try to re-read it _once_. We do this synchronously, Same here. Cheers, Dave.
diff --git a/mm/filemap.c b/mm/filemap.c index 1ed35cd99b2c..65395ee132a0 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -2523,6 +2523,7 @@ vm_fault_t filemap_fault(struct vm_fault *vmf) int error; struct mm_struct *mm = vmf->vma->vm_mm; struct file *file = vmf->vma->vm_file; + struct file *fpin = NULL; struct address_space *mapping = file->f_mapping; struct file_ra_state *ra = &file->f_ra; struct inode *inode = mapping->host; @@ -2610,11 +2611,15 @@ vm_fault_t filemap_fault(struct vm_fault *vmf) return ret | VM_FAULT_LOCKED; no_cached_page: + fpin = maybe_unlock_mmap_for_io(vmf->vma, vmf->flags); + /* * We're only likely to ever get here if MADV_RANDOM is in * effect. */ error = page_cache_read(file, offset, vmf->gfp_mask); + if (fpin) + goto out_retry; /* * The page we want has now been added to the page cache. @@ -2634,6 +2639,8 @@ vm_fault_t filemap_fault(struct vm_fault *vmf) return VM_FAULT_SIGBUS; page_not_uptodate: + fpin = maybe_unlock_mmap_for_io(vmf->vma, vmf->flags); + /* * Umm, take care of errors if the page isn't up-to-date. * Try to re-read it _once_. We do this synchronously, @@ -2647,6 +2654,8 @@ vm_fault_t filemap_fault(struct vm_fault *vmf) if (!PageUptodate(page)) error = -EIO; } + if (fpin) + goto out_retry; put_page(page); if (!error || error == AOP_TRUNCATED_PAGE) @@ -2665,6 +2674,8 @@ vm_fault_t filemap_fault(struct vm_fault *vmf) } out_retry: + if (fpin) + fput(fpin); if (page) put_page(page); return ret | VM_FAULT_RETRY;
Johannes' patches didn't quite cover all of the IO cases that we need to drop the mmap_sem for, this patch covers the rest of them. Signed-off-by: Josef Bacik <josef@toxicpanda.com> --- mm/filemap.c | 11 +++++++++++ 1 file changed, 11 insertions(+)