From f7f9a0c8736d418af8d981000ea68ea43b395da4 Mon Sep 17 00:00:00 2001 From: "Matthew Wilcox (Oracle)" Date: Sat, 15 Jul 2023 23:03:52 -0400 Subject: iov_iter: Map the page later in copy_page_from_iter_atomic() Remove a couple of calls to kunmap_atomic() in the rare error cases. Signed-off-by: Matthew Wilcox (Oracle) Reviewed-by: Christoph Hellwig Reviewed-by: Kent Overstreet Reviewed-by: Darrick J. Wong --- lib/iov_iter.c | 16 ++++++++-------- 1 file changed, 8 insertions(+), 8 deletions(-) (limited to 'lib') diff --git a/lib/iov_iter.c b/lib/iov_iter.c index e4dc809d1075..db58af778291 100644 --- a/lib/iov_iter.c +++ b/lib/iov_iter.c @@ -569,20 +569,20 @@ EXPORT_SYMBOL(iov_iter_zero); size_t copy_page_from_iter_atomic(struct page *page, unsigned offset, size_t bytes, struct iov_iter *i) { - char *kaddr = kmap_atomic(page), *p = kaddr + offset; - if (!page_copy_sane(page, offset, bytes)) { - kunmap_atomic(kaddr); + char *p; + + if (!page_copy_sane(page, offset, bytes)) return 0; - } - if (WARN_ON_ONCE(!i->data_source)) { - kunmap_atomic(kaddr); + if (WARN_ON_ONCE(!i->data_source)) return 0; - } + + p = kmap_atomic(page) + offset; iterate_and_advance(i, bytes, base, len, off, copyin(p + off, base, len), memcpy_from_iter(i, p + off, base, len) ) - kunmap_atomic(kaddr); + kunmap_atomic(p); + return bytes; } EXPORT_SYMBOL(copy_page_from_iter_atomic); -- cgit v1.2.3 From 908a1ad89466c1febf20bfe0037b84fc66f8a3f8 Mon Sep 17 00:00:00 2001 From: "Matthew Wilcox (Oracle)" Date: Tue, 6 Jun 2023 16:43:32 -0400 Subject: iov_iter: Handle compound highmem pages in copy_page_from_iter_atomic() copy_page_from_iter_atomic() already handles !highmem compound pages correctly, but if we are passed a highmem compound page, each base page needs to be mapped & unmapped individually. Signed-off-by: Matthew Wilcox (Oracle) Reviewed-by: Christoph Hellwig Reviewed-by: Kent Overstreet Reviewed-by: Darrick J. Wong Tested-by: Kent Overstreet --- lib/iov_iter.c | 33 +++++++++++++++++++++++---------- 1 file changed, 23 insertions(+), 10 deletions(-) (limited to 'lib') diff --git a/lib/iov_iter.c b/lib/iov_iter.c index db58af778291..eb3dffb24aae 100644 --- a/lib/iov_iter.c +++ b/lib/iov_iter.c @@ -566,24 +566,37 @@ size_t iov_iter_zero(size_t bytes, struct iov_iter *i) } EXPORT_SYMBOL(iov_iter_zero); -size_t copy_page_from_iter_atomic(struct page *page, unsigned offset, size_t bytes, - struct iov_iter *i) +size_t copy_page_from_iter_atomic(struct page *page, unsigned offset, + size_t bytes, struct iov_iter *i) { - char *p; + size_t n, copied = 0; if (!page_copy_sane(page, offset, bytes)) return 0; if (WARN_ON_ONCE(!i->data_source)) return 0; - p = kmap_atomic(page) + offset; - iterate_and_advance(i, bytes, base, len, off, - copyin(p + off, base, len), - memcpy_from_iter(i, p + off, base, len) - ) - kunmap_atomic(p); + do { + char *p; - return bytes; + n = bytes - copied; + if (PageHighMem(page)) { + page += offset / PAGE_SIZE; + offset %= PAGE_SIZE; + n = min_t(size_t, n, PAGE_SIZE - offset); + } + + p = kmap_atomic(page) + offset; + iterate_and_advance(i, n, base, len, off, + copyin(p + off, base, len), + memcpy_from_iter(i, p + off, base, len) + ) + kunmap_atomic(p); + copied += n; + offset += n; + } while (PageHighMem(page) && copied != bytes && n > 0); + + return copied; } EXPORT_SYMBOL(copy_page_from_iter_atomic); -- cgit v1.2.3 From 1b0306981e0f1e5a9ad3d08b9c88bfe21b68e3b9 Mon Sep 17 00:00:00 2001 From: "Matthew Wilcox (Oracle)" Date: Sun, 9 Jul 2023 18:17:33 -0400 Subject: iov_iter: Add copy_folio_from_iter_atomic() Add a folio wrapper around copy_page_from_iter_atomic(). Signed-off-by: Matthew Wilcox (Oracle) Reviewed-by: Darrick J. Wong --- include/linux/uio.h | 9 ++++++++- lib/iov_iter.c | 2 +- 2 files changed, 9 insertions(+), 2 deletions(-) (limited to 'lib') diff --git a/include/linux/uio.h b/include/linux/uio.h index ff81e5ccaef2..42bce38a8e87 100644 --- a/include/linux/uio.h +++ b/include/linux/uio.h @@ -163,7 +163,7 @@ static inline size_t iov_length(const struct iovec *iov, unsigned long nr_segs) return ret; } -size_t copy_page_from_iter_atomic(struct page *page, unsigned offset, +size_t copy_page_from_iter_atomic(struct page *page, size_t offset, size_t bytes, struct iov_iter *i); void iov_iter_advance(struct iov_iter *i, size_t bytes); void iov_iter_revert(struct iov_iter *i, size_t bytes); @@ -184,6 +184,13 @@ static inline size_t copy_folio_to_iter(struct folio *folio, size_t offset, { return copy_page_to_iter(&folio->page, offset, bytes, i); } + +static inline size_t copy_folio_from_iter_atomic(struct folio *folio, + size_t offset, size_t bytes, struct iov_iter *i) +{ + return copy_page_from_iter_atomic(&folio->page, offset, bytes, i); +} + size_t copy_page_to_iter_nofault(struct page *page, unsigned offset, size_t bytes, struct iov_iter *i); diff --git a/lib/iov_iter.c b/lib/iov_iter.c index eb3dffb24aae..424737045b97 100644 --- a/lib/iov_iter.c +++ b/lib/iov_iter.c @@ -566,7 +566,7 @@ size_t iov_iter_zero(size_t bytes, struct iov_iter *i) } EXPORT_SYMBOL(iov_iter_zero); -size_t copy_page_from_iter_atomic(struct page *page, unsigned offset, +size_t copy_page_from_iter_atomic(struct page *page, size_t offset, size_t bytes, struct iov_iter *i) { size_t n, copied = 0; -- cgit v1.2.3