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/iov_iter.c') 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 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/iov_iter.c') 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 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 --- lib/iov_iter.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'lib/iov_iter.c') 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 From 70e969eb235ee6a030ff140b1852b598bf66f9c8 Mon Sep 17 00:00:00 2001 From: Takashi Iwai Date: Tue, 15 Aug 2023 21:01:12 +0200 Subject: iov_iter: Export import_ubuf() Export import_ubuf() to be used in sound subsystem for generic memory handling as Linus suggested. It's used for constructing an iov_iter of a single segment user-space copy for PCM data. Cc: Alexander Viro Link: https://lore.kernel.org/r/CAHk-=wh-mUL6mp4chAc6E_UjwpPLyCPRCJK+iB4ZMD2BqjwGHA@mail.gmail.com Link: https://lore.kernel.org/r/20230815190136.8987-2-tiwai@suse.de Signed-off-by: Takashi Iwai --- lib/iov_iter.c | 1 + 1 file changed, 1 insertion(+) (limited to 'lib/iov_iter.c') diff --git a/lib/iov_iter.c b/lib/iov_iter.c index e4dc809d1075..3743bbcbbb89 100644 --- a/lib/iov_iter.c +++ b/lib/iov_iter.c @@ -1544,6 +1544,7 @@ int import_ubuf(int rw, void __user *buf, size_t len, struct iov_iter *i) iov_iter_ubuf(i, rw, buf, len); return 0; } +EXPORT_SYMBOL_GPL(import_ubuf); /** * iov_iter_restore() - Restore a &struct iov_iter to the same state as when -- cgit From f741bd7178c95abd7aeac5a9d933ee542f9a5509 Mon Sep 17 00:00:00 2001 From: David Howells Date: Fri, 8 Sep 2023 17:03:20 +0100 Subject: iov_iter: Fix iov_iter_extract_pages() with zero-sized entries iov_iter_extract_pages() doesn't correctly handle skipping over initial zero-length entries in ITER_KVEC and ITER_BVEC-type iterators. The problem is that it accidentally reduces maxsize to 0 when it skipping and thus runs to the end of the array and returns 0. Fix this by sticking the calculated size-to-copy in a new variable rather than back in maxsize. Fixes: 7d58fe731028 ("iov_iter: Add a function to extract a page list from an iterator") Signed-off-by: David Howells Reviewed-by: Christoph Hellwig Cc: Christian Brauner Cc: Jens Axboe Cc: Al Viro Cc: David Hildenbrand Cc: John Hubbard Signed-off-by: Linus Torvalds --- lib/iov_iter.c | 30 +++++++++++++++--------------- 1 file changed, 15 insertions(+), 15 deletions(-) (limited to 'lib/iov_iter.c') diff --git a/lib/iov_iter.c b/lib/iov_iter.c index b31597b0ca20..27234a820eeb 100644 --- a/lib/iov_iter.c +++ b/lib/iov_iter.c @@ -1654,14 +1654,14 @@ static ssize_t iov_iter_extract_bvec_pages(struct iov_iter *i, size_t *offset0) { struct page **p, *page; - size_t skip = i->iov_offset, offset; + size_t skip = i->iov_offset, offset, size; int k; for (;;) { if (i->nr_segs == 0) return 0; - maxsize = min(maxsize, i->bvec->bv_len - skip); - if (maxsize) + size = min(maxsize, i->bvec->bv_len - skip); + if (size) break; i->iov_offset = 0; i->nr_segs--; @@ -1674,16 +1674,16 @@ static ssize_t iov_iter_extract_bvec_pages(struct iov_iter *i, offset = skip % PAGE_SIZE; *offset0 = offset; - maxpages = want_pages_array(pages, maxsize, offset, maxpages); + maxpages = want_pages_array(pages, size, offset, maxpages); if (!maxpages) return -ENOMEM; p = *pages; for (k = 0; k < maxpages; k++) p[k] = page + k; - maxsize = min_t(size_t, maxsize, maxpages * PAGE_SIZE - offset); - iov_iter_advance(i, maxsize); - return maxsize; + size = min_t(size_t, size, maxpages * PAGE_SIZE - offset); + iov_iter_advance(i, size); + return size; } /* @@ -1698,14 +1698,14 @@ static ssize_t iov_iter_extract_kvec_pages(struct iov_iter *i, { struct page **p, *page; const void *kaddr; - size_t skip = i->iov_offset, offset, len; + size_t skip = i->iov_offset, offset, len, size; int k; for (;;) { if (i->nr_segs == 0) return 0; - maxsize = min(maxsize, i->kvec->iov_len - skip); - if (maxsize) + size = min(maxsize, i->kvec->iov_len - skip); + if (size) break; i->iov_offset = 0; i->nr_segs--; @@ -1717,13 +1717,13 @@ static ssize_t iov_iter_extract_kvec_pages(struct iov_iter *i, offset = (unsigned long)kaddr & ~PAGE_MASK; *offset0 = offset; - maxpages = want_pages_array(pages, maxsize, offset, maxpages); + maxpages = want_pages_array(pages, size, offset, maxpages); if (!maxpages) return -ENOMEM; p = *pages; kaddr -= offset; - len = offset + maxsize; + len = offset + size; for (k = 0; k < maxpages; k++) { size_t seg = min_t(size_t, len, PAGE_SIZE); @@ -1737,9 +1737,9 @@ static ssize_t iov_iter_extract_kvec_pages(struct iov_iter *i, kaddr += PAGE_SIZE; } - maxsize = min_t(size_t, maxsize, maxpages * PAGE_SIZE - offset); - iov_iter_advance(i, maxsize); - return maxsize; + size = min_t(size_t, size, maxpages * PAGE_SIZE - offset); + iov_iter_advance(i, size); + return size; } /* -- cgit