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Registered in England and Wales under Company Registration No. 3798903 Subject: [PATCH 15/29] iov_iter: Split copy_from_user_atomic() From: David Howells To: Pavel Begunkov , Matthew Wilcox , Jens Axboe , Alexander Viro Cc: dhowells@redhat.com, Linus Torvalds , linux-fsdevel@vger.kernel.org, linux-block@vger.kernel.org, linux-kernel@vger.kernel.org Date: Sat, 21 Nov 2020 14:15:19 +0000 Message-ID: <160596811958.154728.14803339635754597304.stgit@warthog.procyon.org.uk> In-Reply-To: <160596800145.154728.7192318545120181269.stgit@warthog.procyon.org.uk> References: <160596800145.154728.7192318545120181269.stgit@warthog.procyon.org.uk> User-Agent: StGit/0.23 MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 2.79 on 10.5.11.15 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Split copy_from_user_atomic() by type. Signed-off-by: David Howells --- lib/iov_iter.c | 53 ++++++++++++++++++++++++++++++++++++++++------------- 1 file changed, 40 insertions(+), 13 deletions(-) diff --git a/lib/iov_iter.c b/lib/iov_iter.c index 9a167f53ecff..a626d41fef72 100644 --- a/lib/iov_iter.c +++ b/lib/iov_iter.c @@ -1195,7 +1195,7 @@ static size_t discard_zero(size_t bytes, struct iov_iter *i) return bytes; } -static size_t xxx_copy_from_user_atomic(struct page *page, +static size_t iovec_copy_from_user_atomic(struct page *page, struct iov_iter *i, unsigned long offset, size_t bytes) { char *kaddr = kmap_atomic(page), *p = kaddr + offset; @@ -1203,21 +1203,48 @@ static size_t xxx_copy_from_user_atomic(struct page *page, kunmap_atomic(kaddr); return 0; } - if (unlikely(iov_iter_is_pipe(i) || iov_iter_is_discard(i))) { + iterate_over_iovec(i, bytes, v, + copyin((p += v.iov_len) - v.iov_len, v.iov_base, v.iov_len)); + kunmap_atomic(kaddr); + return bytes; +} + +static size_t bvec_copy_from_user_atomic(struct page *page, + struct iov_iter *i, unsigned long offset, size_t bytes) +{ + char *kaddr = kmap_atomic(page), *p = kaddr + offset; + if (unlikely(!page_copy_sane(page, offset, bytes))) { kunmap_atomic(kaddr); - WARN_ON(1); return 0; } - iterate_all_kinds(i, bytes, v, - copyin((p += v.iov_len) - v.iov_len, v.iov_base, v.iov_len), + iterate_over_bvec(i, bytes, v, memcpy_from_page((p += v.bv_len) - v.bv_len, v.bv_page, - v.bv_offset, v.bv_len), - memcpy((p += v.iov_len) - v.iov_len, v.iov_base, v.iov_len) - ) + v.bv_offset, v.bv_len)); kunmap_atomic(kaddr); return bytes; } +static size_t kvec_copy_from_user_atomic(struct page *page, + struct iov_iter *i, unsigned long offset, size_t bytes) +{ + char *kaddr = kmap_atomic(page), *p = kaddr + offset; + if (unlikely(!page_copy_sane(page, offset, bytes))) { + kunmap_atomic(kaddr); + return 0; + } + iterate_over_kvec(i, bytes, v, + memcpy((p += v.iov_len) - v.iov_len, v.iov_base, v.iov_len)); + kunmap_atomic(kaddr); + return bytes; +} + +static size_t no_copy_from_user_atomic(struct page *page, + struct iov_iter *i, unsigned long offset, size_t bytes) +{ + WARN_ON(1); + return 0; +} + static inline void pipe_truncate(struct iov_iter *i) { struct pipe_inode_info *pipe = i->pipe; @@ -2046,7 +2073,7 @@ static int xxx_for_each_range(struct iov_iter *i, size_t bytes, static const struct iov_iter_ops iovec_iter_ops = { .type = ITER_IOVEC, - .copy_from_user_atomic = xxx_copy_from_user_atomic, + .copy_from_user_atomic = iovec_copy_from_user_atomic, .advance = xxx_advance, .revert = xxx_revert, .fault_in_readable = iovec_fault_in_readable, @@ -2080,7 +2107,7 @@ static const struct iov_iter_ops iovec_iter_ops = { static const struct iov_iter_ops kvec_iter_ops = { .type = ITER_KVEC, - .copy_from_user_atomic = xxx_copy_from_user_atomic, + .copy_from_user_atomic = kvec_copy_from_user_atomic, .advance = xxx_advance, .revert = xxx_revert, .fault_in_readable = no_fault_in_readable, @@ -2114,7 +2141,7 @@ static const struct iov_iter_ops kvec_iter_ops = { static const struct iov_iter_ops bvec_iter_ops = { .type = ITER_BVEC, - .copy_from_user_atomic = xxx_copy_from_user_atomic, + .copy_from_user_atomic = bvec_copy_from_user_atomic, .advance = xxx_advance, .revert = xxx_revert, .fault_in_readable = no_fault_in_readable, @@ -2148,7 +2175,7 @@ static const struct iov_iter_ops bvec_iter_ops = { static const struct iov_iter_ops pipe_iter_ops = { .type = ITER_PIPE, - .copy_from_user_atomic = xxx_copy_from_user_atomic, + .copy_from_user_atomic = no_copy_from_user_atomic, .advance = xxx_advance, .revert = xxx_revert, .fault_in_readable = no_fault_in_readable, @@ -2182,7 +2209,7 @@ static const struct iov_iter_ops pipe_iter_ops = { static const struct iov_iter_ops discard_iter_ops = { .type = ITER_DISCARD, - .copy_from_user_atomic = xxx_copy_from_user_atomic, + .copy_from_user_atomic = no_copy_from_user_atomic, .advance = xxx_advance, .revert = xxx_revert, .fault_in_readable = no_fault_in_readable,