tjh.dev / kernel
Linux kernel mirror (for testing) git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel os linux
1
fork

Configure Feed

Select the types of activity you want to include in your feed.

userfaultfd: mfill_atomic(): remove retry logic

Since __mfill_atomic_pte() handles the retry for both anonymous and shmem,
there is no need to retry copying the date from the userspace in the loop
in mfill_atomic().

Drop the retry logic from mfill_atomic().

[rppt@kernel.org: remove safety measure of not returning ENOENT from _copy]
Link: https://lore.kernel.org/ac5zcDUY8CFHr6Lw@kernel.org
Link: https://lore.kernel.org/20260402041156.1377214-12-rppt@kernel.org
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Andrei Vagin <avagin@google.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: David Hildenbrand (Arm) <david@kernel.org>
Cc: Harry Yoo <harry.yoo@oracle.com>
Cc: Harry Yoo (Oracle) <harry@kernel.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: James Houghton <jthoughton@google.com>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Lorenzo Stoakes (Oracle) <ljs@kernel.org>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Nikita Kalyazin <kalyazin@amazon.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Sean Christopherson <seanjc@google.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: David Carlier <devnexen@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

authored by

Mike Rapoport (Microsoft) and committed by
Andrew Morton 6ab70303 f74991b4

-27
-27
mm/userfaultfd.c
··· 29 29 struct vm_area_struct *vma; 30 30 unsigned long src_addr; 31 31 unsigned long dst_addr; 32 - struct folio *folio; 33 32 pmd_t *pmd; 34 33 }; 35 34 ··· 530 531 ops->filemap_remove(folio, state->vma); 531 532 err_folio_put: 532 533 folio_put(folio); 533 - /* Don't return -ENOENT so that our caller won't retry */ 534 - if (ret == -ENOENT) 535 - ret = -EFAULT; 536 534 return ret; 537 535 } 538 536 ··· 895 899 VM_WARN_ON_ONCE(src_start + len <= src_start); 896 900 VM_WARN_ON_ONCE(dst_start + len <= dst_start); 897 901 898 - retry: 899 902 err = mfill_get_vma(&state); 900 903 if (err) 901 904 goto out; ··· 921 926 err = mfill_atomic_pte(&state); 922 927 cond_resched(); 923 928 924 - if (unlikely(err == -ENOENT)) { 925 - void *kaddr; 926 - 927 - mfill_put_vma(&state); 928 - VM_WARN_ON_ONCE(!state.folio); 929 - 930 - kaddr = kmap_local_folio(state.folio, 0); 931 - err = copy_from_user(kaddr, 932 - (const void __user *)state.src_addr, 933 - PAGE_SIZE); 934 - kunmap_local(kaddr); 935 - if (unlikely(err)) { 936 - err = -EFAULT; 937 - goto out; 938 - } 939 - flush_dcache_folio(state.folio); 940 - goto retry; 941 - } else 942 - VM_WARN_ON_ONCE(state.folio); 943 - 944 929 if (!err) { 945 930 state.dst_addr += PAGE_SIZE; 946 931 state.src_addr += PAGE_SIZE; ··· 935 960 936 961 mfill_put_vma(&state); 937 962 out: 938 - if (state.folio) 939 - folio_put(state.folio); 940 963 VM_WARN_ON_ONCE(copied < 0); 941 964 VM_WARN_ON_ONCE(err > 0); 942 965 VM_WARN_ON_ONCE(!copied && !err);